RU2769534C1 - One-stage nickel melting system and one-stage nickel melting method - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to a one-stage nickel melting system and a one-stage nickel melting method. The system comprises a conveyor apparatus for raw materials for transporting nickel sulphide concentrate, flux, and a first reducing agent, an apparatus for one-stage nickel melting, containing a furnace body, located consecutively wherein are a melting area of the melt bath and the reduction depletion area inside the furnace body and the settling area. The melting area of the melt bath is therein equipped with a first supply hole and a first tuyere connected with the conveyor apparatus for raw materials, and is used for melting the melt bath for nickel sulphide concentrate producing a matte with a high nickel content, containing 35 to 65 wt.% nickel, melting slag, and flue gas, the reduction depletion area is connected with the melting area of the melt bath, equipped with a second supply hole, a second tuyere, and a smoke outlet, and used to conduct the reaction of depletion of the melting slag producing depleted slag and a first metallised nickel matte, wherein the settling area is additionally located within the body of the furnace, the settling area is connected with the reduction depletion zone, located on one side of the reduction depletion area distanced from the melting area of the melt bath, is used for processing the depleted slag by settling, producing a second metallised nickel matte, and additionally has an outlet, the melting area of the melt bath is additionally equipped with a secondary air hole connected with the outlet, and an apparatus for processing flue gas, connected with the smoke outlet.EFFECT: possibility of reducing the requirements for the supply of raw materials and reduction in power consumption are provided.22 cl, 2 dwg, 4 ex

Description

The field of technology to which the present invention relates

The present disclosure relates to the technical field of metallurgy, in particular to a one-stage nickel melting system and a one-stage nickel melting method.

Background of the Invention

Commonly used pyrometallurgical processes for nickel sulfide concentrates are as follows: nickel concentrate is smelted in a smelter after material preparation and dosing, molten matte with a low nickel content is sent to a converter furnace for blowing, a blown matte with a high nickel content is used as a finished product after cooling or sent to the wet process for further processing. The smelting slag obtained by melting is subjected to depletion in an electric furnace or depletion in the zone with electrodes to obtain waste slag. The blown slag obtained by blowing is returned to the melting furnace for treatment, or returned to the melting zone with electrodes or electric settling furnace for treatment, and the electric depletion furnace can also be independently adapted for treatment. If the blown slag is depleted separately, a reducing agent and a vulcanizing agent should generally be added to obtain a plated nickel matte. However, the process has a long process chain and high energy consumption, each material is transferred to the next process mainly by ladle, the working environment is poor, and the process has certain requirements for the MgO content of the concentrate. However, the process also has the problems of high energy consumption, high capital investment, serious pollution at low altitudes, etc. Based on the existing Outokumpu flash smelting process at the Harjavalta plant in Finland in 1995, a direct Outokumpu process was developed for Nickel Sulfide Concentrate (DON) for processing nickel sulfide concentrate with high nickel content, in which nickel concentrate can be suspended melted directly into high nickel matte in one step with the following process: drying nickel sulfide concentrate to water content ≤ 0.3% , dosing with powdered flux (if the flux is coarse, it can only be fed into the furnace after fine grinding) and fly ash before entering the concentrate nozzle, and chemically reacting with oxygen-enriched air in the reaction tower to produce high nickel matte. The smelting slag and high nickel matte are precipitated, separated, and respectively discharged into a settling tank, and the high nickel matte is used as a finished product or sent to the next process for processing; the smelter slag is discharged into an electric depletion furnace. The reducing agent and the vulcanizing agent should be added to the electric lean furnace, and after the reduction-vulcanization reaction, the metallized nickel matte obtained in the electric furnace is used as a finished product or sent to the next process for processing; the slag produced in the electric furnace can be sold directly outside the process. Compared with the traditional pyrometallurgical process, the DON process has the advantages that: (1) the process is short, the nickel sulfide concentrate is directly oxidized into high nickel matte, and the purge process of low nickel matte is shortened; (2) material transportation is shortened, less metal dust and sulfur are dispersed into the environment, the working environment is good, and the recovery rate of metal and sulfur is high; (3) in the melting process, Fe is oxidized and enters the slag, and MgO in the slag can be diluted, so that the process has better adaptability to the MgO content of the raw material; (4) the melting process is carried out continuously, the influence of the converter intermittent operation on flue gas composition fluctuation is eliminated, and the subsequent flue gas treatment system has better operating conditions, less investment and low cost. However, the DON process still has some problems, which are as follows:

(1) obtaining material is difficult. Drying the nickel sulfide concentrate to reduce the water content of the material to less than 0.3%, so that the nickel sulfide concentrate can be placed in a furnace; the degree of crushing of other materials such as flux, fly ash and the like should be 1 mm or less, so that if the flux such as quartz stone and the like is a coarse material, the flux can be put into the furnace after fine crushing; large return materials from the system, such as chute stripping, coarse fly ash and the like, also need to be finely crushed before being placed in the kiln;

(2) Flash smelting requires strong oxidation smelting in the reaction tower to ensure that the nickel sulfide concentrate reacts quickly with oxygen, so that the oxygen potential of the smelting slag is high and the nickel content of the slag is high. Thus, the melting slag must be further depleted in an electric furnace;

(3) depleting melting slag in an electric furnace and adding a reducing agent and a vulcanizing agent to obtain metallized nickel matte. A reducing agent is used to reduce the nickel oxide MO in the slag, and a vulcanizing agent is used to dilute the metal and control the sulfur content of the metallized nickel matte to control the operating temperature of the melt. In addition, the vulcanizing agent is sprayed in an electric furnace by means of a spray nozzle, and the material preparation and conveying system is complicated.

In general, when using the DON process, the material must be dried before being placed in the furnace, the oxygen potential of the flash smelting is high, the nickel content of the smelter slag is high, the reduction-vulcanization must be carried out in the subsequent continuous electric slag depletion furnace, and the electric furnace has high workload and power consumption. Thus, there is a need to provide a new nickel melting process that overcomes these shortcomings.

Brief summary of the present invention

The present disclosure is mainly aimed at providing a one-stage nickel melting system and a one-stage nickel melting method, and aims to solve the problems of high requirements on raw materials fed to the furnace, high nickel content of the melting slag, high loading when the melting slag is separately processed in electric furnace, high power consumption and the like, in the DON process of the prior art.

In order to achieve the above object, according to one aspect of the present disclosure, a one-stage nickel melting system is provided, which comprises: a raw material conveyor used to transport nickel sulfide concentrate, flux, and a first reducing agent; a one-stage nickel melting apparatus, the one-stage nickel melting apparatus being a complex equipment and comprising a furnace body, the molten bath melting zone and the reduction depletion zone being arranged in series within the furnace body; the molten bath melting zone is provided with a first supply port and a first tuyere, the first supply port is connected to a raw materials conveyor device, and the molten bath melting zone is used to perform melting of the nickel sulfide concentrate molten bath to obtain a high nickel matte containing 35-65 wt. % nickel, melting slag and flue gas; the reductive depletion zone is connected to the smelting zone of the molten bath, the reductive depletion zone is provided with a second supply port, a second lance and a smoke outlet, and the reductive depletion zone is used to carry out a depletion reaction of the smelter slag to obtain a depleted slag and a first metallized nickel matte; and a flue gas treatment device which is connected to the smoke outlet.

In addition, the interior of the furnace body is also provided with a settling zone, wherein the settling zone is associated with the reduction depletion zone and is located on one side of the reducing depletion zone, which is remote from the melting zone of the melt pool, and the settling zone is used to settle the depleted slag to obtain a second metallized nickel matte; or the reduction depletion zone is provided with a depleted slag discharge port, the one-stage nickel smelting system also includes a settling furnace, the settling furnace is provided with a depleted slag inlet, the depleted slag inlet is connected to the depleted slag discharge port, and the settling furnace is used to settle the depleted slag .

In addition, the furnace body has a bottom, the bottom part under the melting zone of the molten bath is designated as the first part, the bottom part under the reduction depletion zone is designated as the second part, and the bottom part under the settling zone is designated as the third part, and the horizontal height of the bottom gradually increases in in the following order: first part, second part and third part.

In addition, the inner surface of the bottom is an inclined surface, and the inclined surface gradually slopes upward in the following order: first part, second part, and third part.

In addition, the angle of inclination of the inclined surface is 1-5°.

In addition, the device for one-stage nickel melting also contains a dividing wall located in the furnace body between the reduction depletion zone and the sedimentation zone, and the dividing wall has a communication channel at the bottom, the reduction depletion zone and the sedimentation zone are connected by a communication channel.

In addition, the device for one-stage nickel melting also includes a heating electrode passing through the furnace body into the settling zone. In addition, the furnace body has a first side wall and a second side wall opposite the first side wall, the first side wall represents the side wall of the melt pool melting zone at one end remote from the settling zone, the second side wall represents the side wall of the settling zone at one end, remote from the melting zone of the melt bath; moreover, the lower part of the first side wall is provided with a hole for unloading matte with a high Nickel content; the lower part of the second side wall is provided with an opening for unloading the slag. In addition, the settling zone also has an outlet.

In addition, a plurality of first lances are provided, and a plurality of first lances are distributed on different side walls of the melting zone of the melt pool; a plurality of second lances are provided, and a plurality of second lances are distributed on different sidewalls of the reductive depletion zone.

In addition, the furnace body is a horizontal type furnace, the molten pool melting zone and the reduction depletion zone are arranged along the length of the furnace body, and the length of the melting zone of the molten pool is 1 to 3 times that of the reduction depletion zone.

In addition, the raw materials conveyor device includes: a dosing device for dosing nickel sulfide concentrate, flux and the first reducing agent, and a conveyor located between the dosing device and the first supply opening.

In addition, the melting zone of the molten bath is further provided with a secondary air port, and the outlet port is connected to the secondary air port.

In addition, the flue gas treatment device comprises a waste heat recovery unit and a dust removal unit connected in series.

According to another aspect of the present disclosure, a one-stage method for melting nickel is also provided by using the above one-stage nickel melting system, wherein the one-stage nickel melting method includes: conveying nickel sulfide concentrate, flux, and the first reducing agent by means of a raw material conveyor device as raw materials for nickel melting ; conveying the nickel melting raw material to the melting zone of the molten bath of the one-stage nickel melting apparatus through the first feed port for the molten bath melting reaction to obtain a nickel-rich matte containing 35-65 wt. % nickel, melting slag and flue gas; ensuring that the melting slag enters the reduction depletion zone to carry out the depletion reaction and obtain the depleted slag and the first metallized nickel matte; and performing additional flue gas treatment.

In addition, the nickel content of the nickel sulfide concentrate is ≥ 6%; the melting reaction temperature of the melt bath is 1200-1400°C. In addition, the first reducing agent is one or more of anthracite, coke and char.

In addition, the mass ratio of Fe to SiO ₂ in the smelter slag is 0.8-1.3, and the nickel content in the smelter slag is 3-5 mass. %.

In addition, the first oxygen-enriched air is introduced into the interior of the molten bath by means of the first lance during the melting reaction of the molten bath, the first oxygen-enriched air having an oxygen content of 60-85%. In addition, the nickel melting feedstock further comprises recycled material from the system.

In addition, during the depletion reaction, the second reducing agent is added to the depletion reduction zone through the second supply port, and the second reducing agent is a solid particulate reducing agent; and/or a third reducing agent is introduced into the reduction depletion zone through the second lances, and the third reducing agent is a gaseous reducing agent or a powdered solid reducing agent.

In addition, the second reducing agent is one or more of anthracite, coke and char; and the third reducing agent is one or more of natural gas, carbon monoxide, and coal dust. In addition, during the depletion reaction, the second oxygen-enriched air is introduced into the depletion reaction system through the second tuyeres, and the oxygen content of the second oxygen-enriched air is 60-85%.

In addition, the one-stage nickel melting apparatus further comprises a settling zone, and the one-stage nickel melting method further comprises: ensuring that depleted slag enters the settling zone for settling processing and obtaining a second metallized nickel matte and waste; or the reduction depletion zone is provided with a depleted slag discharge port, the one-stage nickel melting system further comprises a settling furnace, the settling furnace is provided with a depleted slag inlet connected to the depleted slag discharge port, and the one-stage nickel melting method further includes: transporting the depleted slag to the settling settling furnace.

In addition, when the content of cobalt in the nickel sulfide concentrate is ≥ 0.3 wt. %, depleted slag is subjected to sedimentation treatment in a settling furnace; when the cobalt content in the nickel sulfide concentrate is < 0.3 wt. %, the settling zone is located in the device for one-stage nickel melting for settling depleted slag.

In addition, the furnace body of the one-stage nickel melting apparatus has a bottom, the bottom part under the melting zone of the molten pool is designated as the first part, the bottom part under the reduction depletion zone is designated as the second part, and the bottom part under the settling zone is designated as the third part, and the height of the bottom horizontally gradually increases in the following order: the first part, the second part and the third part; the second metallized nickel matte produced in the settling zone and the first metallized nickel matte produced in the reduction depletion zone flow by gravity into the melting zone of the molten bath and mix with the high nickel matte.

In addition, the settling zone is further provided with an outlet, and the flue gas exiting the outlet enters the molten bath melting zone as secondary air for the molten bath melting process. In addition, when the settling furnace is used for settling the depleted slag, the inlet for the depleted slag is connected to the depleted slag discharge port by a chute, and the vulcanizing agent is simultaneously added to the settling furnace during the settling process.

In addition, the metallized nickel matte produced in the settling furnace is returned to the molten bath smelting stage.

Furthermore, the flue gas post-treatment step includes: recovering the waste heat of the flue gas by means of a waste heat recovery plant to obtain a pre-treated flue gas; the pretreated flue gas is dedusted by using a dedusting plant.

The present disclosure provides a one-stage nickel melting system that includes a raw materials conveyor, a one-stage nickel melting apparatus, and a flue gas treatment apparatus; a raw materials conveyor for conveying nickel sulfide concentrate, flux and first reducing agent; device for one-stage melting of nickel is a complex equipment and contains a furnace body, and the melting zone of the melt pool and the reduction depletion zone are sequentially located inside the furnace body; the molten bath melting zone is provided with a first supply port and a first lance, the first supply port is connected to a raw materials conveyor device, and the molten bath melting zone is used for melting the nickel sulfide concentrate molten bath to produce a high nickel matte containing 35-65 wt. % nickel, melting slag and flue gas; the reductive depletion zone is connected to the smelting zone of the molten bath, the reductive depletion zone is provided with a second supply port, a second lance and a smoke outlet, and the reductive depletion zone is used to carry out a depletion reaction of the smelter slag to obtain a depleted slag and a first metallized nickel matte; and the flue gas treatment device is connected to the smoke outlet. The one-stage nickel melting system provided in the present disclosure can realize enhanced melting and slag depletion in a one-stage nickel melting apparatus, while realizing high nickel matte production by one-stage melting of nickel matte from nickel sulfide concentrate in one apparatus. Meanwhile, since the molten bath melting technology is used, the nickel content of the melting slag is low, the loading of the lean process is low, and the power consumption is low. In addition, there are no special requirements on the particle size of the raw materials and the water content of the nickel sulfide concentrate, the flux, and the first reducing agent in the molten bath melting process, and the conditions for feeding the raw materials are low.

In general, the nickel sulfide concentrate is smelted by the one-stage nickel smelting system provided by the present disclosure, which effectively solves the existing problems of difficult conditions for feeding raw materials into the furnace, high nickel content in the smelter slag, high loading when the smelter slag is separately treated in the electric furnace, high power consumption and the like, in the DON process.

Brief description of the figures

The figures that form part of this application are used to provide additional understanding of the present disclosure. Typical embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an undue limitation of the present disclosure. On the figures:

fig. 1 shows a schematic diagram of a one-stage nickel melting system according to one embodiment of the present disclosure; and

fig. 2 shows a flowchart of a one-stage nickel melting process according to one embodiment of the present disclosure.

Moreover, the above figures contain the following position numbers:

1. conveyor device for raw materials; 2. device for one-stage melting of nickel; 3. flue gas treatment device;

10. furnace body; 20. dividing wall; 30. heating electrode; 11. melting zone of the melt pool; 12. reduction depletion zone; 13. settling zone; 101. first feed hole; 102. first lance; 103. second feed hole; 104. second lance; 105. smoke outlet; 106. Discharge port for high nickel matte; 107. hole for unloading slag.

Detailed description of embodiments of the present invention

It should be noted that the examples and features in the examples herein can be combined with each other without conflict. The present disclosure will be described in more detail below with reference to the figures and together with embodiments. As described in the Background Art section, the prior art DON process has the problems of high requirements on the raw materials fed to the furnace, high nickel content of the smelting slag, high loading when the smelting slag is separately treated in an electric furnace, high energy consumption. and the like, in the DON process.

To solve the problem, the present disclosure provides a one-stage nickel melting system as shown in FIG. 1, wherein the one-stage nickel melting system comprises a raw material conveyor 1, a one-stage nickel melting apparatus 2, and a flue gas treatment apparatus 3; wherein the raw material conveyor 1 is for transporting the nickel sulfide concentrate, the flux and the first reducing agent; device 2 for one-stage melting of nickel is a complex equipment and includes a furnace body 10, and the area 11 of the smelting pool of the melt and the zone 12 reduction depletion located in series inside the body 10 of the furnace; the molten bath melting zone 11 is provided with a first supply port 101 and a first lance 102, the first supply port 101 is connected to the raw material conveyor 1, and the molten bath melting zone 11 is used to realize the melting of the nickel sulfide concentrate molten bath to produce matte with a high nickel content containing 35-65 wt. % nickel, melting slag and flue gas; the reductive depletion zone 12 is connected to the molten bath melting zone 11, the reductive depletion zone 12 is provided with a second supply port 103, a second tuyere 104, and a smoke outlet 105, and the reductive depletion zone 12 is used to carry out the depletion reaction of the smelter slag to produce depleted slag and the first metallized nickel matte; and the flue gas treatment device 3 is connected to the smoke outlet 105 .

In the present production process, the nickel sulfide concentrate, the flux and the first reducing agent enter the melting zone 11 of the molten bath of the one-stage nickel melting apparatus 2 for melting the molten bath, a series of chemical steps such as decomposition, oxidation and the like occur, and matte is formed with a high content nickel, melting slag and flue gas. There are no special requirements for the particle size of the raw materials and the water content of the nickel sulfide concentrate, flux and first reducing agent in the molten bath melting process, so that the material preparation system can be simplified, the material is directly fed into the furnace after dosing without the need for drying and fine grinding, and conditions for the supply of raw materials are low. The molten bath melting zone 11 and the reduction depletion zone 12 are located in the same furnace body and are in communication with each other, so that the molten slag obtained in the molten bath melting zone 11 can directly enter the reduction depletion zone 12 for the depletion reaction. A molten bath melting technique is used, the first reducing agent is added to the reaction process, and the oxygen potential of the smelting slag is adjusted so that the nickel content of the smelting slag is low, about 3-5 wt. %, the loading of the lean process is small, and the power consumption is low. After depletion in the reductive depletion zone 12, the oxygen potential of the slag further decreases, the nickel content in the final slag is lower, approximately 0.2-0.3%, and the degree of metal recovery is higher. In addition, since the viscosity of the smelting slag is low, it is not necessary to add a diluting vulcanizing agent to the depletion process, and the obtained first plating nickel matte can also be directly mixed with the high nickel matte obtained in the smelting process to serve as a production nickel matte. .

In general, the present disclosure effectively solves the problems of difficult conditions for supplying raw materials to the furnace, high nickel content in the smelter slag, high loading when the smelter slag is separately treated in an electric furnace, high power consumption, and the like, existing in the DON process. The materials are directly fed into the furnace after dosing, the production method is simple, the process is short, the depletion and melting of the slag are carried out in the same furnace, no vulcanizing agent is required for vulcanization, the production is stable, the operation is simple, and the environmental condition is good.

In a preferred embodiment, as shown in FIG. 1, the interior of the furnace body 10 is further provided with a settling zone 13 which is in connection with the reducing depletion zone 12 and located on the side of the reducing depleted zone 12 away from the melting zone 11 of the molten bath, wherein the settling zone 13 is used to settle the depleted slag to obtain second metallized nickel matte. Thus, the depleted slag obtained in the reduction depletion zone 12 can directly enter the settling zone 13 for settling treatment, in this case, melting, slag depletion and settling separation can be performed in one furnace, the continuity of operation is further improved with a reduced number of equipment, simplified process and reduced energy consumption.

Alternatively, in an example not shown in the figures, the reduction depletion zone 12 is provided with a depleted slag discharge port, the single-stage nickel melting system further comprises a settling furnace, wherein the settling furnace is provided with a depleted slag inlet, the depleted slag inlet is connected to the discharge port depleted slag, and the settling furnace is used to settling the depleted slag. Thus, it is equivalent to continuous melting and slag depletion operations, slag settling can be separately operated intermittently. Preferably, the lean slag inlet is connected to the lean slag discharge port via a chute through which the lean slag flows into the settling furnace. The settling furnace is preferably an electric settling furnace, the metallized nickel matte can be used separately as a product or returned to the melting zone 11 of the melt bath.

In a preferred embodiment, the furnace body 10 has a bottom, wherein the bottom part under the molten bath melting zone 11 is designated as the first part, the bottom part under the reduction depletion zone 12 is designated as the second part, and the bottom part under the settling zone 13 is designated as the third part, with the height bottom horizontally gradually increases in the following order: the first part, the second part and the third part. Thus, the first metallized nickel matte produced in the reduction depletion zone 12 and the second metallized nickel matte produced in the settling zone 13 can flow by gravity to the bottom of the molten bath melting zone 11 and mix with the high nickel matte to form production nickel. matte.

In a preferred embodiment, as shown in FIG. 1, the inner surface of the bottom is an inclined surface, and the inclined surface gradually slopes upward in the following order: first part, second part, and third part. With this arrangement, the first and second plated nickel mattes can more conveniently flow by gravity into the lower part of the melting zone 11 of the melt pool. To match the equilibrium reaction time and unloading of the nickel matte, the optimal angle of inclination of the inclined surface is 1-5°.

In a preferred embodiment, the device 2 for one-stage nickel melting also includes a dividing wall 20 located in the furnace body 10 between the reduction depletion zone 12 and the settling zone 13, wherein the dividing wall 20 has a communication channel at the bottom, the reducing depletion zone 12 and the settling zone 13 are connected by a channel connections. Thus, the reductive depletion zone 12 and the settling zone 13 can be separated by a dividing wall 20 and connected by a channel under the dividing wall 20. The presence of the dividing wall 20 provides a more uniform flow between the melt having fluidity and subjected to the depletion reaction in the reductive depletion zone 12 and the melt subjected to the settling treatment in the settling zone 13, and the dividing wall 20 can block agitation and floating materials in the reducing depletion zone 12, while further improving the effect of the settling treatment.

In a preferred embodiment, the device 2 for one-stage nickel melting further comprises a heating electrode 30 extending through the furnace body 10 into the settling zone 13 . The material in the settling zone 13 can be reheated by the heating electrode 30 to further improve the settling effect.

In a preferred embodiment, the furnace body 10 has a first side wall and a second side wall opposite the first side wall, the first side wall is the side wall of the melting zone 11 of the melt pool at one end remote from the settling zone 13, the second side wall is the side wall of the zone 13 settling at one end remote from the melting zone 11 of the melt pool; moreover, the lower part of the first side wall is provided with a hole 106 for discharging matte with a high nickel content; the lower part of the second side wall is provided with an opening 107 for discharging slag. Production nickel matte can be discharged at intervals by means of a high nickel matte discharge port, and waste slag obtained in the settling zone 13 can be discharged at intervals by means of a slag discharge port. Since the nickel content of the waste slag is ≤ 0.2%, it can be directly processed as waste slag. More preferably, the settling zone 13 also has an outlet. And the flue gas obtained from the settling treatment can be discharged through the outlet, the flue gas temperature is 700-900°C, the flue gas temperature is reduced to 300-400°C after temperature reduction and dedusting, and the flue gas is used as secondary air for reuse in the melting zone or sent to the downstream flue gas treatment device 3 together with the flue gas from the melting zone for treatment.

In order to provide a more fully oxygen-enriched environment for the molten bath melt reaction and depletion reaction process, or to more conveniently introduce gaseous reducing agent into the reductive depletion zone 12, in the preferred embodiment, a plurality of first tuyeres 102 are provided, and a plurality of first tuyeres 102 are distributed on different side walls. zone 11 melt bath melt; a plurality of second lances 104 are provided, and a plurality of second lances 104 are distributed on different side walls of the reduction depletion zone 12. In a preferred embodiment, the furnace body 10 is a horizontal type furnace, the melt bath melting zone 11 and the reduction depletion zone 12 are located along the length of the furnace body 10, and the length of the melt bath zone 11 is 1 to 3 times that of the reduction depletion zone 12. With this arrangement, the reaction time of the nickel sulfide concentrate in the molten pool smelting zone 11 and the depletion time of the smelter slag in the reducing depletion zone 12 are more suitable, so that the melting of the nickel sulfide concentrate and the depletion of the smelter slag have better continuity and stability.

The raw material conveying device 1 is used to convey raw materials for better continuity and accuracy of feeding to the melting zone 11 of the melt bath. In a preferred embodiment, the raw materials conveyor device 1 comprises: a metering device for metering the nickel sulfide concentrate, flux and the first reducing agent, and a conveyor located between the metering device and the first supply opening 101. In a particular production process, each raw material can be precisely weighed and dosed by means of a dosing device, and then continuously transported to the melting zone 11 of the melt bath by means of a conveyor. In particular, the conveyors used include, but are not limited to, belt conveyors. More preferably, movable feeders such as a movable belt conveyor or a movable permanent feeder are also located between the conveyor and the first feed opening 101. In order to facilitate the feeding, it is preferable that the first feeding hole 101 be provided in the upper part of the melting zone 11 of the melt bath, so that the top feeding can be realized and the operation is simplified.

In a preferred embodiment, the melting zone 11 of the melt bath is additionally provided with a secondary air hole and the outlet is connected to the secondary air hole. The flue gas from the settling process can then be reused as secondary air in the melting zone.

The flue gas leaving the reduction depletion zone 12 can be further processed in a flue gas treatment device 3, in a preferred embodiment, the flue gas treatment device 3 comprises a waste heat recovery unit and a dedusting unit connected in series. The flue gas leaving the reduction depletion zone 12 has a relatively high temperature, typically 1200-1350° C., and the heat of the flue gas can be recovered using a waste heat recovery unit and then further dedusted in a dedusting unit.

According to another aspect of the present disclosure, there is also provided a one-stage nickel melting method using the above one-stage nickel melting system as the nickel melting equipment, wherein, as shown in FIG. 2, the nickel smelting one-step method includes: conveying the nickel sulfide concentrate, the flux and the first reducing agent with the raw material conveying device 1 as raw materials for smelting nickel; conveying the nickel melting raw material to the melt bath melting zone 11 of the one-stage nickel melting apparatus 2 through the first feed port 101 for the melt bath reaction to obtain a high nickel matte containing 35-65 wt. % nickel, melting slag and flue gas; ensuring that smelter slag enters the reduction depletion zone 12 to carry out the depletion reaction and obtain depleted slag and a first metallized nickel matte; and performing additional flue gas treatment.

In the present production process, the nickel sulfide concentrate, the flux and the first reducing agent enter the melting zone 11 of the molten bath of the one-stage nickel melting apparatus 2 for melting the molten bath, a series of chemical steps such as decomposition, oxidation and the like occur, and matte is formed with a high content nickel, melting slag and flue gas. There are no special requirements for the particle size of the raw materials and the water content of the nickel sulfide concentrate, flux and first reducing agent in the molten bath melting process, so that the material preparation system can be simplified, the material is directly fed into the furnace after dosing without the need for drying and fine grinding, and adaptability to raw materials is better. The molten bath melting zone 11 and the reduction depletion zone 12 are located in the same furnace body and are in communication with each other, so that the molten slag obtained in the molten bath melting zone 11 can directly enter the reduction depletion zone 12 for the depletion reaction. A molten bath melting technique is used, the first reducing agent is added to the reaction process, and the oxygen potential of the smelting slag is adjusted so that the nickel content of the smelting slag is low, about 3-5 wt. %, the loading of the lean process is small, and the power consumption is low. After depletion in the reductive depletion zone 12, the oxygen potential of the slag further decreases, the nickel content in the final slag is lower, approximately 0.2-0.3%, and the degree of metal recovery is higher. In addition, since the viscosity of the smelting slag is low, no addition of a vulcanizing agent is required to dilute in the depletion process, and the obtained first metallized nickel matte can also be directly mixed with the high nickel matte obtained in the smelting process to serve as a production nickel matte. .

In general, the present disclosure effectively solves the problems of high requirements on the raw materials fed to the furnace, high nickel content in the smelter slag, high loading when the smelter slag is separately treated in an electric furnace, high power consumption, and the like, existing in the DON process. The materials are directly fed into the furnace after dosing, the production method is simple, the process is short, the depletion and melting of slag are carried out in the same furnace, no vulcanizing agent is required for vulcanization, the production is stable, the operation is simple, and the environmental condition is good.

To further improve the quality of the nickel matte, in a preferred embodiment, the nickel content of the nickel sulfide concentrate is ≥ 6%; the melting reaction temperature of the melt bath is 1200-1400°C. Thus, the nickel grade of the high nickel matte produced by the molten bath melting process is higher, and the iron content of the high nickel matte is 1-4%.

As described above, when the molten bath melting reaction mechanism is used in the present disclosure, the nickel sulfide concentrate melting process is carried out under the action of the first reducing agent, so that the oxygen potential of the melting slag can be effectively reduced and the nickel content of the melting slag can be correspondingly reduced. The specific reducing agent may be a solid reducing agent or a gaseous reducing agent, in a preferred embodiment, the first reducing agent is one or more of anthracite, coke and char. By using the above reducing agents in the melting reaction of the nickel sulfide concentrate molten bath, on the one hand, the nickel sulfide concentrate is in better contact with the reducing agents, the reaction is more complete, and, on the other hand, it can be partially used as fuel for additional heat during the reaction, so that the melting effect is further improved. In a preferred embodiment, the mass ratio of Fe to SiO ₂ in the smelter slag is 0.8-1.3 and the nickel content in the smelter slag is 3-5 wt. %. Thus, the slag has a lower viscosity, better flowability and a better depletion effect when the depletion reaction is carried out in the subsequent reductive depletion zone 12, and no additional curing agent needs to be added during the depletion process. At the same time, the nickel content in the depleted slag obtained by the depletion reaction is lower, and the grade of the first metallized nickel matte is higher. The temperature of the melting slag obtained by the molten bath melting reaction is usually 1250-1400° C., which is related to the MgO content of the slag, and the temperature of the slag rises when the MgO content of the slag is high. In a preferred embodiment, the first oxygen-enriched air is introduced into the interior of the molten bath via the first lance 102 during the molten bath melt reaction, the first oxygen-enriched air having an oxygen content of 60-85% (by volume). The specific input amount of the first oxygen-enriched air can be adjusted depending on the raw material components and product grade. In an oxygen-enriched air environment, the nickel sulfide concentrate undergoes a series of chemical reactions such as decomposition, oxidation, and the like to form nickel-rich matte, smelter slag, and flue gas. To further improve the reaction kinetics during the molten bath melting process, it is preferable that the first oxygen-enriched air is blown directly into the molten bath of the molten bath melting zone 11 by means of a side-blown submersible spray nozzle. In the reaction raw materials in the above molten bath melting, the flux may be of the type commonly used in the field, for example, quartzite flux or gold-bearing quartzite may be used, or a small amount of limestone flux may be added at the same time. Furthermore, in addition to adding the flux and the first reducing agent as reaction raw materials during the nickel sulfide concentrate molten bath melting process, it is preferable that the nickel melting raw materials also contain recycled material from the system. On the one hand, the temperature of the system in the process of melting the molten bath can be controlled by the return material from the system, so that the overheating phenomenon can be avoided, on the other hand, the nickel matte can be completely removed, the output of the nickel matte is increased, and the waste of resources is reduced. Return material from the system may be return chute sludge, fly ash, etc.

In a preferred embodiment, during the above depletion reaction, the second reducing agent is added to the reducing depletion zone 12 through the second supply port 103, and the second reducing agent is a solid particulate reducing agent; and/or introducing a third reducing agent into the reduction depletion zone 12 through the second lance 104, the third reducing agent being a gaseous reducing agent or a powdered solid reducing agent. In the depletion reaction process, the magnetic iron (magnetic iron oxide) in the smelter slag can be reduced to iron oxide by the second reducing agent and/or the third slagging reducing agent, so that the viscosity of the smelter slag can be lowered, the subsequent effect of settling separation is improved, and the nickel content and cobalt content of the depleted slag is further reduced. When the second reducing agent, a carbon-based solid reducing agent, is used, it is supplied through the second supply opening 103, the second supply opening 103 may be aligned with the smoke outlet 105, for example, at the top of the reduction depletion zone 12, so that the opening It has two functions - flue gas outlet and supply. Of course, these two holes can also be located in different places to serve their respective functions.

Compared with separately adding the second reducing agent (particulate solid reducing agent) through the second supply opening 103, more preferably the third reducing agent, which is a gaseous reducing agent or a powdered solid reducing agent, is introduced into the reduction depletion zone 12 simultaneously or separately through second lance 104. The kinetics of the depletion reaction can be further improved with a gaseous reducing agent to further improve the depletion effect. In actual operation, a side-blown submersible spray nozzle can be used to blow the third reducing agent into the molten pool of the depletion reduction zone 12 . In a preferred embodiment, the second reducing agent contains, inter alia, one or more of anthracite, coke and char; the third reducing agent contains, among other things, one or more of natural gas, carbon monoxide and coal dust.

In a preferred embodiment, during the depletion reaction, the second oxygen-enriched air is introduced into the depletion reaction system through the second tuyeres 104 and the oxygen content of the second oxygen-enriched air is 60-85% (by volume). In actual operation, the temperature of each of the melt and flue gas in the reduction depletion zone 12 is the same as in the melt bath zone 11 . The second oxygen-enriched air is preferably blown into the melt in the reduction depletion zone 12 by means of a submersible side-blown spray nozzle, which can further agitate and improve the reaction kinetics.

In a preferred embodiment, the one-stage nickel melting apparatus 2 further comprises a settling zone 13, and the one-stage nickel melting method further includes: providing depleted slag to the settling zone 13 for settling treatment and obtaining a second metallized nickel matte and waste. Thus, the depleted slag obtained in the reduction depletion zone 12 can directly enter the settling zone 13 for settling treatment, in this case, melting, slag depletion and settling separation can be performed in one furnace, the continuity of operation is further improved by a reduced number of equipment, simplified process and reduced energy consumption. In actual operation, the system in the settling zone 13 is preferably heated by the heating electrode 30, preferably with the temperature of the slag at the level of 1300-1450°C (related to the content of MgO in a particular slag). After separation by settling, the nickel content in waste slag is ≤ 0.2 wt. %, and the content of cobalt ≤ 0.15 wt. %.

Alternatively, the reduction depletion zone 12 is provided with a depleted slag discharge port, the one-stage nickel melting system further comprises a settling furnace, the settling furnace is provided with a depleted slag inlet connected to the depleted slag discharge port, and the one-stage nickel melting method further includes: conveying the depleted slag into a settling furnace for settling treatment. Thus, it is equivalent to continuous melting and slag depletion operations, slag settling can be separately operated intermittently. Preferably, the lean slag inlet is connected to the lean slag discharge port via a chute through which the lean slag flows into the settling furnace. The settling furnace is preferably an electric settling furnace, the metallized nickel matte can be separately used as a product or returned to the melting zone 11 of the molten bath.

In a preferred embodiment, when the cobalt content in the nickel sulfide concentrate is ≥ 0.3 wt. %, depleted slag is subjected to settling treatment using a settling furnace; when the cobalt content in the nickel sulfide concentrate is < 0.3 wt. %, the settling zone 13 is located in the device 2 for one-stage nickel melting for settling depleted slag. In the nickel melting process, the distribution coefficient of Ni and Co in nickel matte and slag is lower than that of plated nickel matte and slag, so that a settling zone or electric settling furnace is used, and this is due to the Co content of the raw material. If the content of Co in the raw material is high, the shape of the settling electric furnace can be adjusted, a small amount of vulcanizing agent is added to the settling electric furnace area, nickel matte with a high plating rate is formed, the proportion of Co in the plating nickel matte is increased, and the recovery rate of Co is further increased.

In a preferred embodiment, the furnace body 10 of the one-stage nickel melting apparatus 2 has a bottom, the bottom part under the molten pool melting zone 11 is designated as the first part, the bottom part under the reduction depletion zone 12 is designated as the second part, and the bottom part under the settling zone 13 is designated as the third part, and the height of the bottom horizontally gradually increases in the following order: the first part, the second part and the third part; the second metallized nickel matte produced in the settling zone and the first metallized nickel matte produced in the reduction depletion zone 12 flow by gravity into the molten bath melting zone 11 and mix with the high nickel matte.

In a preferred embodiment, the settling zone 13 is further provided with an outlet, and the flue gas exiting the outlet enters the molten bath melting zone 11 as secondary air in the molten bath melting process.

In a preferred embodiment, when the settling furnace is used for depleted slag settling, the depleted slag inlet is connected to the depleted slag discharge port through a chute, and the vulcanizing agent is simultaneously added to the settling furnace during the settling process. In a particular manufacturing process, the amount of curing agent added is preferably about 3 wt. % of the nickel sulfide concentrate, after pressing into a ball and drying, the vulcanizing agent is added to the settling furnace, the temperature is raised by heating electrodes, the resulting waste slag contains 0.2-0.3 wt. % Ni, and the resulting metallized nickel matte (containing 7-9% sulfur) can be used as a finished product or can be returned to the melting zone 11 of the melt bath. The settling furnace produces metallized nickel matte at 1300-1350°C, slag at 1400-1450°C and flue gas at 900-1000°C.

In a preferred embodiment, the flue gas post-treatment step comprises: recovering the waste heat of the flue gas by means of a waste heat recovery plant to obtain a pre-treated flue gas; the pretreated flue gas is dedusted by using a dedusting plant.

In general, the melting of the nickel sulfide concentrate is carried out by using the one-stage nickel melting system and the one-stage nickel melting method provided in the present disclosure, and the beneficial effects are as follows:

(1) the process is short, the nickel sulfide concentrate is directly oxidized into high nickel matte, the blowing process of low nickel matte is shortened, the material preparation system is simple, the material is directly fed into the furnace after dosing, without the need for drying and fine grinding;

(2) material transportation is shortened, less metal dust and sulfur are dispersed into the environment, the working environment is good;

(3) preferably, in the melting process, Fe is oxidized and enters the slag, and MgO in the slag can be diluted, so that the process has better adaptability to MgO in the raw material;

(4) the melting process is carried out continuously, the effect of the converter intermittent operation on the fluctuation of the flue gas composition is eliminated, and the subsequent flue gas treatment system has better operating conditions, less investment and low cost;

(5) the nickel sulfide concentrate is subjected to an oxidation reaction, a slag depletion reaction, and a slag separation by settling in one melting furnace (slag settling separation can also be carried out in a separate electric settling furnace). The metallized nickel matte obtained by depleting the slag is mixed with the obtained matte with a high nickel content, and there is no need for vulcanization by adding a vulcanizing agent. The depleted slag from melting can be additionally settled and separated in a settling zone (or a separate settling electric furnace) to obtain waste slag. The metallized nickel matte recovered from the settling zone is combined with high nickel matte to be used as a finished product or to be fed to the next process;

(6) in the molten bath melting process, the first reducing agent can be added to the raw materials to adjust the oxygen potential of the smelting slag, and the Ni content of the slag is lower; after additional depletion in the depletion zone, the oxygen potential of the slag further decreases, the waste slag contains little Ni and Co (Ni 0.2% - 0.3%, Co ≤ 0.15%), and the degree of recovery of metals is higher (Ni ≥ 96.5 %, Co ≥ 65%);

(7) Preferably, melting, slag depletion and slag settling are performed in the same furnace, the blowing process is eliminated, flue gas emission is reduced, and the sulfur capture rate is high (≥99%);

(8) slag melting and depletion are continuous operations, and slag settling may be a continuous operation or a batch operation depending on the scale. If continuous operation is used, production is stable, processing capacity per unit time is small, and investment in equipment is saved.

This application is described in more detail below with reference to specific examples, which should not be construed as limiting the scope of what is claimed herein.

Example 1

The equipment used is shown in Fig. 1, the melting process is shown in FIG. 2, and the specific process is as follows:

(1) nickel sulfide concentrate dosing: nickel sulfide concentrate (containing 7.72% Ni, 1.42% Cu, 0.27% Co, 40.5% Fe and 5.8% MgO), quartzite flux, reducing agent ( anthracite) and return material from the system (chute stripping, fly ash) are metered by means of a permanent feeder, the mass ratio of materials being approximately: nickel concentrate: quartz flux: first reducing agent=100:32:2.5, mixed material after dosing conveyed to the top of the melting furnace by a belt conveyor, and added to the furnace by a mobile belt conveyor;

(2) After dosing, a series of chemical steps such as decomposition, oxidation and the like take place between the mixed concentrate and oxygen-enriched air, which is blown into the molten bath in the melting zone of the melting furnace, resulting in high nickel matte, melting slag and flue gas. The resulting high nickel matte contains about 55.8% Ni, 12.74% Cu, about 3.75% Fe, and the temperature of the high nickel matte was controlled at about 1220° C. and the temperature of the slag was controlled at about 1320 °C. The Fe/SiO _{2 of} the smelter slag is about 1.2, the slag contains about 3.28% Ni and about 5.57% MgO. The temperature of the flue gas from melting (from the furnace) is approximately 1250°C, the heat of the flue gases is recovered in the waste heat boiler, and then the gas is sent to an electric dust collector to remove dust, and the dedusted flue gas is sent to the flue gas acid production system for further processing . The oxygen concentration in the primary melting air is approximately 60%;

(3) melting slag enters the depletion zone from the melting zone, a reducing agent (anthracite) is added to the depleted zone, and the amount of reducing agent added is as follows: the weight ratio of reducing agent to melting slag is approximately 2:100; while a certain amount of oxygen-enriched air is purged for stirring (oxygen concentration of approximately 60%) so that the reaction kinetics are improved. Depletion produces depleted slag and metallized nickel matte. The depletion zone is connected to the melting zone, and the resulting metallized nickel matte is lowered to the bottom of the melting furnace and mixed with the high nickel matte; the depletion zone and the settling zone with electrodes are provided with separating walls, and the depleted slag enters the settling zone with electrodes through the lower part of the separating walls for additional settling and separation of the metallized nickel matte and depleted slag. The temperature of each of the melt and flue gas in the depletion zone is the same as in the melting zone. The resulting depleted slag contains approximately 0.9% Ni;

(4) additional settling and separation of the depleted slag in the settling zone with electrodes, heating the depleted slag with the electrode, and the temperature of the slag is approximately 1350°C, the waste slag after settling and separation contains approximately 0.23% Ni and approximately 0.1% Co, and the metallized nickel matte obtained by settling flows back into the melting zone through the bottom and mixes with the high nickel matte;

(5) the temperature of the flue gas obtained in the settling zone is approximately 800°C, the temperature of the flue gas is reduced to 300-400°C after cooling and dedusting, and the flue gas is used as secondary air for reuse in the melting zone;

metallized nickel matte obtained by depletion and settling in an electric furnace contains about 67.5% Ni, about 6.18% Cu, about 3.12% Co, about 22% Fe, and is mixed with a high nickel matte obtained in the melting zone. The finished matte high nickel grade contains approximately 60.5% Ni, 10.37% Cu, 1.47% Co.

Example 2

The equipment used is shown in Fig. 1, the melting process is shown in FIG. 2, and the specific process is as follows:

(1) nickel sulfide concentrate dosing: nickel sulfide concentrate (containing 6.0% Ni, 3.2% Cu, 0.18% Co, 28.5% Fe and 8.2% MgO), quartz flux, reducing agent ( coke) and return material from the system (chute stripping, fly ash) are metered by means of a permanent feeder, the mass ratio of materials being approximately: nickel concentrate: quartz flux: first reducing agent=100:15.6:6.0, mixed material after dosing, it is transported to the top of the melting furnace by a belt conveyor and added to the furnace by a mobile belt conveyor;

(2) After dosing, a series of chemical steps such as decomposition, oxidation and the like take place between the mixed concentrate and oxygen-enriched air, which is blown into the molten bath in the melting zone of the melting furnace, resulting in high nickel matte, melting slag and flue gas. The resulting high nickel matte contains about 39.4% Ni, about 26.2% Cu, about 3.43% Fe, and the temperature of the high nickel matte was controlled at about 1280° C., and the temperature of the slag was controlled at about 1380°C. The Fe/SiO2 of the smelter slag is about 1.2, the slag contains about 3.08% Ni. The temperature of the flue gas from melting (from the furnace) is approximately 1320°C, the heat of the flue gases is recovered in the waste heat boiler, and then the gas is sent to the electric deduster to remove dust, and the dedusted flue gas is sent to the flue gas acid production system for further processing . The oxygen concentration in the primary melting air is approximately 65%;

(3) melting slag enters the depletion zone from the melting zone, a reducing agent (coke) is added to the depleted zone, and the amount of reducing agent added is: the ratio of reducing agent to melting slag is approximately 2:100; while a certain amount of oxygen-enriched air is purged for stirring (oxygen concentration of approximately 60%) so that the reaction kinetics are improved. Depletion produces depleted slag and metallized nickel matte. The depletion zone is connected to the melting zone, and the resulting metallized nickel matte is lowered to the bottom of the melting furnace and mixed with the high nickel matte; the depletion zone and the settling zone with electrodes are provided with separating walls, and the depleted slag enters the settling zone with electrodes through the lower part of the separating walls for additional settling and separation of the metallized nickel matte and depleted slag. The temperature of each of the melt and flue gas in the depletion zone is the same as in the melting zone. The resulting depleted slag contains approximately 0.8% Ni;

(4) additional settling and separation of the depleted slag in the settling zone with electrodes, heating the depleted slag with the electrode, and the temperature of the slag is approximately 1420 ° C, the waste slag after settling and separation contains approximately 0.2% Ni and approximately 0.08% Co, and the metallized nickel matte obtained by settling flows back into the melting zone through the bottom and mixes with the high nickel matte;

(5) The temperature of the flue gas produced in the settling zone is approximately 800°C, the temperature of the flue gas is reduced to 300-400°C after cooling and dedusting, and the flue gas is used as secondary air to be reused in the melting zone or sent to the subsequent a flue gas treatment system together with flue gas from the melting zone for treatment; metallized nickel matte obtained by depletion and settling in an electric furnace contains about 60.15% Ni, about 15.53% Cu, about 2.39% Co, about 17.2% Fe, and is mixed with high nickel matte obtained in the melting zone. The finished matte high nickel grade contains about 46.8% Ni, about 23.2% Cu, about 0.98% Co.

Example 3

The equipment used is shown in Fig. 1, the melting process is shown in FIG. 2, and the specific process is as follows:

(1) dosing of nickel sulfide concentrate. Nickel sulfide concentrate (containing 19.53% Ni, 1.11% Cu, 0.65% Co, 36.73% Fe and 1.42% MgO), quartz flux, reducing agent (char) and return material from the system ( chute stripping, fly ash) are dosed by means of a permanent feeder, the mass ratio of materials being approximately: nickel concentrate: quartz flux: first reducing agent=100:27.1:1.5, the mixed material after dosing is transported to the top of the melting furnace on a belt conveyor and added to the oven by means of a movable belt conveyor;

(2) After dosing, a series of chemical steps such as decomposition, oxidation and the like take place between the mixed concentrate and oxygen-enriched air, which is blown into the molten bath in the melting zone of the melting furnace, resulting in high nickel matte, melting slag and flue gas. The resulting high nickel matte contains about 65.26% Ni, about 3.3% Cu, about 4.8% Fe, and the temperature of the high nickel matte was controlled at about 1200°C, and the temperature of the slag was controlled at about 1300°C. Fe/SiO ₂ melting slag is about 1.2, the slag contains about 4.4% Ni. The temperature of the flue gas from melting (from the furnace) is approximately 1220°C, the heat of the flue gases is recovered in the waste heat boiler, and then the gas is sent to an electric deduster to remove dust, and the dedusted flue gas is sent to the flue gas acid production system for further processing . The oxygen concentration in the primary melting air is approximately 65%;

(3) melting slag enters the depletion zone from the melting zone, a reducing agent (coke) is added to the depleted zone, and the amount of reducing agent added is: the mass ratio of reducing agent to melting slag is approximately 2:100; while a certain amount of oxygen-enriched air is purged for stirring (oxygen concentration of approximately 60%) so that the reaction kinetics are improved. Depletion produces depleted slag and metallized nickel matte. The plated nickel matte contains about 65.9% Ni, about 3.84% Cu, about 3.66% Co, about 20.61% Fe, and the depletion zone is associated with the melt zone. The resulting metallized nickel matte is lowered to the bottom of the melting furnace and mixed with the high nickel matte;

(4) the slag discharge port is located in the lean zone, the lean slag flows into the settling electric furnace through the chute, and the curing agent is added from the upper electric furnace supply port, the proportion of the curing agent is: the vulcanizing agent/lean slag is approximately 3 % (vulcanizing agent pressed into balls and dried to a moisture content of < 6%). Metallized nickel matte and dump slag were obtained using a settling electric furnace;

(5) An electric settling furnace is used to heat depleted slag with an electrode, the temperature of the plated nickel matte is about 1320°C, and the temperature of the slag is about 1420°C. After settling and separation, the metallized nickel matte contains about 45% Ni, about 4.1% Cu, about 6% Co, about 8.1% S, the slag contains about 0.28% Ni, about 0.15% Co. And the metallized nickel matte obtained by settling can be sent to the next processing process as a product, and can also be returned to the melting furnace; (6) The temperature of the flue gas from the settling electric furnace is approximately 900-1000°C, the temperature of the flue gas is reduced to 300-400°C after cooling and dedusting, and the flue gas is used as secondary air to be reused in the melting zone or sent to the subsequent flue gas treatment system together with flue gas from the melting zone for treatment.

Example 4

The equipment used is shown in Fig. 1, the melting process is shown in FIG. 2, and the specific process is as follows:

(1) dosing of nickel sulfide concentrate. Nickel sulfide concentrate (containing 6.0% Ni, 3.2% Cu, 0.18% Co, 28.5% Fe and 8.2% MgO), quartzite flux, reducing agent (anthracite) and return material from the system ( chute stripping, fly ash) are dosed using a permanent feeder, the mass ratio of materials being approximately: nickel concentrate quartz flux first reducing agent = 100:15.6:6.0, the mixed material after dosing is transported to the top of the melting furnace along a conveyor, and added to the oven by means of a movable belt conveyor;

(2) After dosing, a series of chemical steps such as decomposition, oxidation and the like take place between the mixed concentrate and oxygen-enriched air, which is blown into the molten bath in the melting zone of the melting furnace, resulting in high nickel matte, melting slag and flue gas. The resulting high nickel matte contains about 39.4% Ni, about 26.2% Cu, about 3.43% Fe, and the temperature of the high nickel matte was controlled at about 1280° C., and the temperature of the slag was controlled at about 1380°C. The Fe/SiO _{2 of} the smelter slag is about 1.2, the slag contains about 3.08% Ni. The temperature of the flue gas from melting (from the furnace) is approximately 1320°C, the heat of the flue gases is recovered in the waste heat boiler, and then the gas is sent to the electric deduster to remove dust, and the dedusted flue gas is sent to the flue gas acid production system for further processing . The oxygen concentration in the primary melting air is approximately 65%;

(3) the melting slag enters the lean zone from the melting zone, the coal dust reducing agent is introduced into the lean zone by a spray nozzle, and the amount of reducing agent added is: the mass ratio of the reducing agent to the melting slag is approximately 1.2:100, and for coal dust use compressed air or nitrogen as a carrier gas to obtain some stirring effect for the molten bath to improve the reaction kinetics. Depletion produces depleted slag and metallized nickel matte. The depletion zone is connected to the melting zone, and the resulting metallized nickel matte is lowered to the bottom of the melting furnace and mixed with the high nickel matte; the depletion zone and the settling zone with electrodes are provided with separating walls, and the depleted slag enters the settling zone with electrodes through the lower part of the separating walls for additional settling and separation of the metallized nickel matte and depleted slag. The temperature of each of the melt and flue gas in the depletion zone is the same as in the melting zone. The resulting depleted slag contains approximately 0.8% Ni;

(4) further settling and separation of the depleted slag in the settling zone with electrodes, heating the depleted slag with the electrode, the temperature of the slag is approximately 1420°C, the waste slag after settling and separation contains approximately 0.2% Ni and approximately 0.08% Co, and the metallized nickel matte obtained by settling flows back into the melting zone through the bottom and mixes with the high nickel matte;

(5) The temperature of the flue gas produced in the settling zone is approximately 800°C, the temperature of the flue gas is reduced to 300-400°C after cooling and dedusting, and the flue gas is used as secondary air to be reused in the melting zone or sent to the subsequent a flue gas treatment system together with flue gas from the melting zone for treatment; metallized nickel matte obtained by depletion and settling in an electric furnace contains about 60.15% Ni, about 15.53% Cu, about 2.39% Co, about 17.2% Fe, and is mixed with high nickel matte obtained in the melting zone. The finished matte high nickel grade contains about 46.8% Ni, about 23.2% Cu, about 0.98% Co.

The foregoing is only preferred embodiments of the present disclosure and is not intended to limit the present disclosure. As will be understood by those skilled in the art, the present disclosure is subject to various modifications and changes. Any modification, equivalent replacement, improvement, etc., made to the spirit and principle of this disclosure shall be included within the protection scope of this disclosure.

Claims (40)

1. A single stage nickel melting system comprising: a raw material conveyor for conveying the nickel sulfide concentrate, the flux and the first reducing agent; a device for one-stage nickel melting, which is a complex equipment and includes a furnace body, and the melting zone of the melt pool and the reduction depletion zone are sequentially located inside the furnace body; the melting zone of the molten bath is provided with a first supply port and a first lance, the first supply port is connected to a raw material conveyor, and the melting zone of the molten bath is used to perform melting of the nickel sulfide concentrate molten bath to obtain a high nickel matte containing 35 -65 wt. % nickel, melting slag and flue gas; the reduction depletion zone is connected to the melting zone of the molten bath, the reduction depletion zone is provided with a second supply port, a second lance and a smoke outlet, and the reduction depletion zone is used to carry out a depletion reaction of the smelter slag to obtain a depleted slag and a first metallized nickel matte; the settling zone is further located inside the furnace body, the settling zone is connected with the reducing depletion zone and located on one side of the reducing depleted zone remote from the molten pool melting zone, and the settling zone is used to carry out sedimentation processing of the depleted slag to obtain a second metallized nickel matte; the settling zone additionally has an outlet; the melting zone of the melt bath is further provided with a secondary air hole, and the outlet is connected to the secondary air hole; a flue gas treatment device connected to the smoke outlet. 2. One-stage nickel melting system according to claim 1, in which the furnace body has a bottom, the bottom part under the molten pool melting zone is designated as the first part, the bottom part under the reduction depletion zone is designated as the second part, and the bottom part under the settling zone is designated as the third part, and the horizontal height of the bottom gradually increases in the following order: the first part, the second part and the third part. 3. The one-stage nickel melting system according to claim 2, wherein the inner surface of the bottom is an inclined surface, and the inclined surface gradually slopes upward in the following order: first part, second part, and third part. 4. One-stage nickel melting system according to claim 3, in which the inclined surface is inclined at an angle of 1-5°. 5. One-stage nickel melting system according to any one of paragraphs. 1-4, in which the device for one-stage melting of nickel further comprises a dividing wall located in the furnace body between the reduction depletion zone and the settling zone, and the dividing wall has a communication channel at the bottom, the reducing depletion zone and the settling zone are connected by a communication channel. 6. The single-stage nickel melting system of claim 5, wherein the single-stage nickel melting apparatus further comprises a heating electrode that extends through the furnace body into the settling zone. 7. One-stage nickel melting system according to any one of paragraphs. 1-4, in which the furnace body has a first side wall and a second side wall opposite the first side wall, the first side wall is the side wall of the melting zone of the melt pool at one end remote from the settling zone, the second side wall is the side wall of the zone settling at one end remote from the melting zone of the melt pool; and the lower part of the first side wall is provided with an outlet for discharging high nickel matte; the lower part of the second side wall is provided with an opening for unloading the slag. 8. One-stage nickel melting system according to any one of paragraphs. 1-4, in which a plurality of first lances are provided and a plurality of first lances are distributed on different side walls of the melting zone of the melt pool; a plurality of second lances are provided, and a plurality of second lances are distributed on different sidewalls of the reductive depletion zone. 9. One-stage nickel melting system according to any one of paragraphs. 1-4, in which the furnace body is a horizontal type furnace, the molten pool melting zone and the reduction depletion zone are arranged along the length of the furnace body, and the length of the melting zone of the molten pool is 1 to 3 times that of the reduction depletion zone. 10. One-stage nickel melting system according to any one of paragraphs. 1-4, in which the conveyor device for raw materials contains: a dosing device for dosing the nickel sulfide concentrate, the flux and the first reducing agent; and a conveyor that is located between the dosing device and the first feed opening. 11. One-stage nickel melting system according to any one of paragraphs. 1-4, in which the flue gas treatment device comprises a waste heat recovery unit and a dust removal unit connected in series. 12. One-stage nickel melting method using a one-stage nickel melting system according to any one of paragraphs. 1-11, and the one-stage nickel melting method includes: conveying the nickel sulfide concentrate, the flux and the first reducing agent by means of the raw material conveying device as nickel smelting raw materials; conveying the nickel smelting raw material to the melting zone of the molten bath of the single-stage nickel smelting apparatus through the first feed port for the melting reaction of the molten bath, while obtaining a nickel-rich matte containing 35-65 wt. % nickel, melting slag and flue gas; ensuring that the melting slag enters the reduction depletion zone to carry out the depletion reaction and obtain the depleted slag and the first metallized nickel matte; device for one-stage nickel melting further comprises a settling zone, one-stage method of nickel melting additionally provides for: ensuring the supply of depleted slag to the settling zone for settling processing and obtaining a second metallized nickel matte and waste; the settling zone is further provided with an outlet, and the flue gas exiting the outlet is supplied to the molten bath melting zone as secondary air during the molten bath melting process; and additional flue gas treatment. 13. The one-stage nickel melting process according to claim 12, wherein the nickel content of the nickel sulfide concentrate is ≥ 6%; the melting reaction temperature of the melt bath is 1200-1400°C. 14. The one-step nickel melting process according to claim 12 or 13, wherein the first reducing agent is one or more of anthracite, coke, and char. 15. The one-stage nickel melting method according to claim 14, wherein the mass ratio of Fe to SiO ₂ in the melting slag is 0.8-1.3, and the nickel content in the melting slag is 3-5 wt. %. 16. The one-stage nickel melting process according to claim 12, wherein the first oxygen-enriched air is introduced into the interior of the molten bath by means of the first tuyere during the molten bath melting reaction, the first oxygen-enriched air having an oxygen content of 60-85%. 17. The single stage nickel smelting process of claim 12, wherein the nickel smelting feedstock further comprises return material from the system. 18. The one-step nickel melting method according to claim 12, wherein during the depletion reaction, the second reducing agent is added to the depletion reduction zone through the second feed port, and the second reducing agent is a particulate solid reducing agent; and/or a third reducing agent is introduced into the reduction depletion zone through the second lances, and the third reducing agent is a gaseous reducing agent or a powdered solid reducing agent. 19. The one-stage nickel melting process according to claim 18, wherein the second reducing agent is one or more of anthracite, coke, and char; and the third reducing agent is one or more of natural gas, carbon monoxide, and coal dust. 20. The one-stage nickel melting process according to claim 18, wherein during the depletion reaction, the second oxygen-enriched air is introduced into the depletion reaction system through the second tuyeres, and the oxygen content of the second oxygen-enriched air is 60-85%. 21. The one-stage nickel melting method according to claim 12, wherein the body of the apparatus for one-stage nickel melting has a bottom, the bottom part under the melting zone of the molten bath is designated as the first part, the bottom part under the reduction depletion zone is designated as the second part, and the bottom part under the zone settling is designated as the third part, and the horizontal height of the bottom gradually increases in the following order: the first part, the second part and the third part; the second metallized nickel matte produced in the settling zone and the first metallized nickel matte produced in the reductive depletion zone flow by gravity into the melting zone of the molten bath and mix with the high nickel matte. 22. One-stage method of melting Nickel according to any one of paragraphs. 12-20, in which the flue gas post-treatment step includes: reusing the heat of the exhaust flue gas by means of a waste heat recovery plant to obtain a pre-treated flue gas; and carrying out dedusting treatment for pre-treated flue gas using a dedusting unit.

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