WO2020107670A1 - Method for concentrating iron by comprehensively utilizing steelmaking dust - Google Patents

Abstract

A method for concentrating iron by comprehensively utilizing steelmaking dust: steelmaking dust is mixed with a reducing agent, an additive and water, is pressed into balls which are dried and then baked in vacuum, and a volatile substance and solid residue are collected. The volatile substance is elemental zinc in the gas phase, which is fed into a condensation collector and then condensed into a solid; the solid residue is broken and ball-milled, then pickled to remove impurities in a residual iron phase to obtain iron concentrate. Processing parameters are controlled, while the recovery rates of iron and zinc are increased.

Description

Method for enriching iron by comprehensively utilizing steel-making dust Technical field

The invention relates to the technical field of secondary utilization of resources, in particular to a method for comprehensive utilization of steelmaking dust to enrich iron.

Background technique

With the high operation of iron and steel smelting output and the increasing attention paid by the state and iron and steel enterprises to environmental protection, the comprehensive utilization of iron and steel plant dust has become a research hotspot, which is also a worldwide problem. Steelmaking dust is extremely difficult to recycle because it contains a large amount of CaO. Converter dust usually contains about 50% Fe and 14% CaO; stainless steel dust usually contains 15% CaO, 30% Fe, 8-15% Cr, and 1-8% Ni. Iron and steel dust is rich in harmful elements such as Zn, K, Na, etc. If it is directly recycled to the steel production process without treatment, it will bring bad influences such as blast furnace nodulation, spontaneous combustion of bag ash, and upturned damage of the tuyere, which will seriously harm the iron and steel smelting The process runs smoothly.

Due to the high temperature heat flow in the ignition zone and the carbon monoxide gas generated during the oxygen blowing process in the converter steelmaking process, part of the iron will be taken away to generate a large amount of dust, and about 10% of the steel metallurgical dust will be produced for each ton of steel produced (that is, steelmaking dust, its main The composition is FeO and Fe ₂ O ₃ ), which is one of the main pollution sources of steel plants. Iron loss caused by dust has become the main reason for the low metal yield in the steelmaking process. Calculated based on the domestic annual output of 600 million tons of converter steel, excluding the loss of other elements, only the metal iron loss caused by dust emissions reaches more than 3 million tons per year, while causing greater pollution to the environment. The development of the iron and steel industry is gradually increasing due to constraints such as resources and environment, and structural contradictions are still prominent, mainly reflected in the increased constraints on energy, environment and raw materials, the low efficiency of secondary energy recovery and utilization, and the need to improve the management of energy conservation and emission reduction in enterprises. Mature energy conservation Emission reduction technology needs further system optimization.

In order to reduce costs and conserve resources, as well as environmental protection, the world has a tendency to use scrap iron instead of iron ore to produce steel. Therefore, the production of steel-making dust from designated wastes has also increased, and it has also brought about social problems of environmental pollution. Accordingly, from the national economic perspective, resources are required to reduce waste and fully recycle and reuse. Therefore, the present invention is very useful in terms of effective resource utilization and environmental protection. The sources of zinc in steel-making dust are mainly galvanized scrap steel and iron and zinc symbiotic ores that are used in large amounts in the steel-making process. The zinc in iron ore and scrap steel volatilizes and oxidizes in the furnace, and almost all of them enter the dust. Steelmaking dust contains iron, which is recycled to improve resource utilization.

At present, there are some public literatures on the treatment of steelmaking dust to recover iron, for example: patent application CN201010237178.X, which discloses a process for recovering zinc and iron from waste galvanized steelmaking dust, using waste galvanized steel Steelmaking dust is used as the raw material. The raw material is crushed and sieved to obtain the leaching material. The zinc oxide in the leaching material is leached at room temperature and weak acid, and zinc ferrite is leached at high temperature and strong acid. The leaching rate of zinc in the entire leaching process is higher than 95%; The leaching solution uses iron phosphate precipitation process to precipitate iron, and the iron precipitation rate reaches 99%; the purified zinc-rich solution is extracted and electrodeposited to obtain electrowinning zinc; and the iron phosphate obtained by the iron phosphate precipitation process can be further hydrolyzed to form Fe(OH) ₃ and HPO ₄ ^2- , the Fe(OH) ₃ produced by the reaction can be used as a raw material for iron and steel plants, and HPO ₄ ^2- can realize the recycling of iron precipitation agent phosphoric acid. The invention can not only recover the metal zinc and metal iron in the steelmaking dust of the waste galvanized steel sheet, but also realize the recycling of the iron precipitation agent phosphoric acid. However, the patent application uses a wet process, which is complicated and difficult to control. If it is used on a large scale, it will generate a lot of chemical waste, resulting in environmental pollution and lower economic benefits.

Therefore, in order to recycle the secondary resources, it is of great theoretical and practical significance to develop a process for comprehensive utilization of metallic iron from steel-making dust.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for comprehensively utilizing steelmaking dust to enrich iron. The invention mixes steel-making dust with reducing agent, additives and water for vacuum roasting, combines with vacuum degree to control temperature reasonably and control pickling process parameters reasonably, and finally makes the iron content in the residual material be further increased, ensuring metal The high iron recovery rate improves the recovery rate of elemental zinc, and obtains iron concentrates with an iron content of up to 66.16%. The recovery rate of zinc is up to 98.19%. The whole treatment process is a whole process. The process is simple, the operation is simple, and the reaction temperature is relatively low. Low, reduces the cost of comprehensive utilization of steelmaking dust, and effectively solves the problems of high cost, heavy pollution, high energy consumption, and large output of three wastes in the treatment of zinc-containing steelmaking dust in the prior art.

In order to achieve the above-mentioned objectives, the present invention adopts the following technical solutions:

A method for comprehensively enriching iron with steel-making dust includes the following steps: mixing steel-making dust with reducing agent, additives, and water, and pressing under a pressure of 11 to 19 MPa, in a mold with a diameter of 20.01 to 30 mm Pellets, the pellets are first sent to a drying oven for drying treatment, and then put into a vacuum carbon tube furnace for vacuum roasting, collecting volatiles evaporated during the vacuum roasting process and solid residues remaining in the vacuum carbon tube furnace. After the residue is crushed and ball milled, it is put into dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally enriched to obtain high-grade iron concentrate;

The volatile matter is gaseous elemental zinc, and the volatile matter is sent to a condensation collector and condensed into a solid to obtain a high-purity zinc ingot;

The conditions of the vacuum roasting are as follows: the reaction temperature is controlled at 850 to 950°C under a vacuum of 10 to 100 Pa, and the temperature is treated at a constant temperature for 80 to 100 min;

The dilute acid is a dilute hydrochloric acid solution, and the concentration of the hydrochloric acid solution is 0.01 mol/L; the specific conditions of the pickling treatment are: in a dilute hydrochloric acid solution with PH=1 to 3, the temperature is controlled to 46 to 53° C. The pickling time is 56 to 63 minutes.

Further, in the drying process, the pellets are dried to a moisture content of zero.

Further, the temperature of the drying process is ≥120°C, and the time is 1 to 3 hours.

Further, before being compressed into pellets, the steel-making dust and the reducing agent are mixed uniformly, sent to a grinder to grind to a powder with a mesh size of 80-120 mesh, and then additives and water are added to mix uniformly.

Further, the steel-making dust, reducing agent, additive and water are mixed according to the following proportion by weight: 100 parts of steel-making dust, 6-8 parts of reducing agent, 0-2 parts of additive, and 0.4-0.7 parts of water.

Further, the additive is diboron trioxide.

Further, the reducing agent is coke powder.

The document "Basic Research on the Application of Blast Furnace Dust Recycling", Beijing University of Science and Technology, Xu Gang, 2015-01-04, discloses the fire treatment, wet treatment and combined treatment of fire and wet treatment for blast furnace dust. However, the process is complicated, the control is more difficult, and secondary pollutants will be generated, causing environmental pollution, resulting in lower economic benefits; the fire method requires specific equipment and more harsh conditions, which increases the processing cost and obtains The content of iron and zinc is relatively low, of which zinc is zinc oxide, and elemental zinc cannot be obtained directly; the wet process steps are cumbersome, and the iron recovery rate is not high, and elemental zinc cannot be obtained at the same time; the combined process of fire and wet process is more complicated The required process conditions are higher, which increases the production cost. It cannot obtain elemental zinc while obtaining iron. In addition, in the literature "Basic Research on the Application of Blast Furnace Dust Recycling" (Xu Gang), the reducing agent used is industrial pure H ₂ , the reduction temperature is controlled at 910℃, and the reduction time is 2h. The final volatiles are mainly ZnS and ZnO. This application uses coke as a reducing agent. The raw material is cheap and easy to operate. Compared with hydrogen, the risk factor is greatly reduced. By controlling the vacuum degree to 10 to 100 Pa, the zinc can be almost completely volatilized and finally condensed directly. The collection device obtains high-purity zinc ingots. Moreover, in this application, the steelmaking dust with a particle size of 80 to 120 mesh is uniformly mixed, so that the steelmaking dust can fully contact with the reducing agent and additives, so that the reaction can be fully carried out during the reduction roasting process, because the reaction mainly occurs on the surface of the particles The kinetic conditions are good; the constant temperature treatment for 80 to 100 minutes ensures that the reduction process is fully carried out, so that the zinc can basically be completely volatilized, and then the zinc ingot is collected by condensation. In the end, this application combined with the wet treatment process, by reasonably controlling the PH value and pickling time, the impurities that are difficult to remove in the pyrotechnic process such as calcium, magnesium and aluminum in the residual materials and a small amount of unreduced zinc will be dissolved. Thereby, the iron in the residual material is enriched.

The working principle of this application: The method of this application uses coke powder as a reducing agent, reduces the zinc in the steel-making dust pellets to a single substance through the reduction roasting method and discharges it in a gaseous form. The iron and other valuable metals in the steel-making dust pellets and Other components remain in the vacuum furnace, so that the zinc is detached. The zinc steam is obtained through the condensation collection device to obtain high-purity zinc ingots. Excess tail gas is discharged through the activated carbon adsorption treatment to avoid secondary pollution in the recovery process. Residual materials containing valuable metals such as iron are crushed, ball milled, and then put into a hydrochloric acid solution for pickling treatment. At this time, impurities such as calcium, magnesium, aluminum, and a small amount of unreduced zinc in the residual materials will be dissolved, making The iron content in the residual material is further increased, and because the acid washing step is added, excess unvolatile zinc can be dissolved into the solution, thereby improving the recovery rate of zinc. This method first mixes steel-making dust, reducing agent, additives, and water to make pellets under a pressure of 11 to 19 MPa, in order to increase the binding force of the block, so that the zinc oxide powder in the steel-making dust can be combined with The coke powder and diboron trioxide are in full contact, so that the zinc oxide in the block is most likely to be reduced to zinc elemental. In addition, the method sets the reduction roasting conditions to control the reaction temperature to 850-950°C under a vacuum of 10-100 Pa, and constant temperature treatment for 80-100 min; if the vacuum is higher than 100Pa, the temperature is lower than 850°C, and the processing time is lower 80min, the zinc oxide cannot be fully reduced and the zinc element cannot escape from the block completely; if the vacuum is lower than 10Pa, the temperature is higher than 950℃, and the processing time is higher than 100min, the zinc oxide cannot be fully reduced to zinc element, Will cause waste of resources. Through the method of comprehensively utilizing converter steelmaking dust to recover zinc and enrich iron in the present invention, the final zinc recovery rate is as high as 98.19%, and the iron content in the iron-containing material reaches more than 66.16%, which can be directly reused as iron concentrate to make Resources are fully recovered and utilized.

Since the present invention adopts the above technical solutions, it has the following beneficial effects:

(1) In order to solve the above-mentioned defects, the present invention mixes steel-making dust with reducing agents, additives, and water, presses them into pellets, and sends them to a vacuum carbon tube furnace for reduction roasting treatment, and the residues are pickled, and Reasonable control of the pickling process parameters, debugging the pH of the hydrochloric acid solution is 2, the temperature is 50 ℃, the processing time is 60min, and finally the iron content in the residual material is further increased, and the iron concentrate with an iron content of 66.16% is obtained. The whole process is a whole process, the reaction temperature is lower, which reduces the cost of comprehensive utilization of steelmaking dust, and can also reduce energy consumption and the discharge of three wastes.

(2) While obtaining iron-containing residues in vacuum roasting, this application can fully evaporate zinc from steel-making dust and collect volatilized gaseous elemental zinc, while increasing the iron content of iron concentrate Can improve the recovery rate of zinc, and make the impurities such as calcium, magnesium, aluminum and a small amount of unreduced zinc in the residual material be dissolved during the pickling process, which further improves the recovery of zinc. The recovery rate of zinc is as high as 98.19%. Make resources fully recovered and utilized.

(3) The reasonable control of the vacuum degree of the present invention makes the gas pressure in the vacuum carbon tube furnace low, ensures that the iron element and other substances in the dust can not be volatilized, so that the iron exists in the solid state in the vacuum carbon tube furnace, and The zinc can be fully volatilized, ensuring the recovery rate of iron and the purity of zinc; the reaction conditions can promote the gasification, evaporation of metal zinc, the decomposition and reduction of metal compounds, and the degassing of molten metal, which ensures a high recovery rate of metal iron At the same time, the recovery rate of elemental zinc is improved, and the given process conditions can accelerate the speed of the reaction and reduce the temperature of the reaction, so that the metallurgical operation can be performed at a low temperature, and the energy consumption of enriched iron is reduced. For example, when the system pressure is 100Pa, the starting reaction temperature of MgO being reduced by carbothermal to metal magnesium vapor is 1476K (that is, 1203℃); under normal pressure, the starting temperature of MgO being reduced by carbothermal to metal magnesium vapor is 2154K ( That is 1881 ℃).

(4) In this application, the temperature is reasonably controlled in conjunction with the vacuum degree, so that the iron is well enriched, which is helpful for cleaning other impurities in the solid of the strip during the later pickling process, and improving the iron enrichment rate; while the zinc is in the reduction roasting process Fully volatilized in the process, which further improves the recovery rate of iron and elemental zinc, at the same time avoids too low temperature to make the zinc in the steelmaking dust difficult to volatilize, and also avoids the volatilization of magnesium or manganese caused by higher temperatures, reducing the reduction roasting Energy consumption in the process.

(5) This application promotes the reduction of zinc in steel-making dust while ensuring the iron enrichment rate by controlling the addition of additives and process parameters, and realizes the recycling of steel-making dust, obtaining high-quality zinc ingots , Reduces the energy consumption during vacuum control in the process of steelmaking dust treatment, and the process is simple, the operation is simple, vacuum reduction can effectively evaporate zinc in steelmaking dust, achieve the purpose of condensing and collecting elemental zinc, and effectively solve the existing The technology has the problems of high cost, heavy pollution, high energy consumption and large output of three wastes in the treatment of zinc-containing steelmaking dust.

detailed description

The specific embodiments of the present invention will be described in further detail below, but the present invention is not limited to these embodiments. Any improvement or substitution in the basic spirit of this embodiment still falls within the scope of the claims of the present invention.

The embodiments of the present application use steel-making dust produced in the production process of a factory in Guizhou and analyze the chemical composition, and the mass fraction of the composition is shown in Table 1 below:

Table 1 Chemical composition and content of steelmaking dust

ingredient TFe SiO ₂ MgO Al ₂ O ₃ MnO Zn Cu As Content (wt%) 58.98 1.10 2.10 0.07 0.590 6.35 0.03 0.057

The main raw materials and dosage of Examples 1 to 5 of this application are shown in Table 2 below:

Table 2 Examples 1 to 5 main raw materials and dosage

A Steelmaking dust/kg Coke powder/kg Boron trioxide/kg Example 1 100 6 0 Example 2 100 8 0 Example 3 100 8 2 Example 4 100 7 1 Example 5 100 7 1.5

Example 1

A method for comprehensively enriching iron with steelmaking dust includes the following steps:

(1) After mixing steel-making dust with reducing agent and water, it is pressed into pellets; the reducing agent is coke powder; the steel-making dust, reducing agent, additives and water are mixed in the following proportions by weight: 100 parts of steel dust, 6 parts of reducing agent, and 0.4 parts of water; the pressing into pellets is to mix steelmaking dust, reducing agent, and water first, and then send it into a mold with a diameter of 20.01 mm to form a ball; the pressing The pressure of forming pellets is 11MPa; before pressing into pellets, the steel-making dust and reducing agent are mixed uniformly, then sent to a grinder to grind to a powder with a mesh size of 80 mesh, and then water is added to mix evenly;

(2) The pellets of step (1) are sent to a vacuum carbon tube furnace for vacuum roasting to obtain volatiles and residues, and the residues are solids remaining in the vacuum carbon tube furnace; conditions for the vacuum roasting For: control the reaction temperature to 850°C under a vacuum of 10Pa, and treat it at a constant temperature for 100 minutes; before sending the pellets to a vacuum carbon tube furnace for vacuum roasting, first send the formed pellets to a drying oven for drying The moisture content is 0; the drying temperature is ≥120℃ and the time is 1h;

(3) The volatile substance in step (2), that is, gaseous elemental zinc, is sent to a condensation collector and condensed into a solid, and the solid is collected to obtain a high-purity zinc ingot;

(4) The residue in step (2) is crushed and ball milled and put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally a high-grade iron concentrate is obtained; the dilute acid is dilute Hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.01 mol/L; the conditions of the pickling treatment are: in dilute hydrochloric acid solution with PH=1, the control temperature is 46° C., and the pickling time is 56 min.

The chemical composition and content of the steel-making dust are shown in Table 1, and the amounts of the steel-making dust, reducing agent, additives and water are shown in Table 2.

Example 2

A method for comprehensively enriching iron with steelmaking dust includes the following steps:

(1) After mixing steel-making dust with reducing agent and water, it is pressed into pellets; the reducing agent is coke powder; the steel-making dust, reducing agent, additives and water are mixed in the following proportions by weight: 100 parts of steel dust, 8 parts of reducing agent, and 0.7 parts of water; the pressing into pellets is to mix steelmaking dust, reducing agent, and water first, and then send it into a mold with a diameter of 30 mm to form a ball; The pressure of the pellets is 19MPa; before pressing into pellets, the steelmaking dust and the reducing agent are mixed evenly, sent to the grinder to grind to a powder with a mesh size of 120 mesh, and then added with water to mix evenly;

(2) The pellets of step (1) are sent to a vacuum carbon tube furnace for vacuum roasting to obtain volatiles and residues, and the residues are solids remaining in the vacuum carbon tube furnace; conditions for the vacuum roasting For: control the reaction temperature to 950°C under a vacuum of 100Pa, and treat it at a constant temperature for 80 minutes; before sending the pellets to a vacuum carbon tube furnace for vacuum roasting, first send the formed pellets to a drying oven for drying treatment The moisture content is 0; the drying temperature is ≥120℃ and the time is 3h;

(3) The volatile substance in step (2), that is, gaseous elemental zinc, is sent to a condensation collector and condensed into a solid, and the solid is collected to obtain a high-purity zinc ingot;

(4) The residue in step (2) is crushed and ball milled and put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally a high-grade iron concentrate is obtained; the dilute acid is dilute Hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.01 mol/L; the conditions of the pickling treatment are: in dilute hydrochloric acid solution with PH=3, the control temperature is 53° C., and the pickling time is 63 min.

The chemical composition and content of the steel-making dust are shown in Table 1, and the amounts of the steel-making dust, reducing agent, additives and water are shown in Table 2.

Example 3

A method for comprehensively enriching iron with steelmaking dust includes the following steps:

(1) After mixing steel-making dust with reducing agents, additives, and water, and pressing into pellets; the additive is boron trioxide; the reducing agent is coke powder; the steel-making dust, reducing agent, additives Mix with water according to the following proportions: 100 parts of steelmaking dust, 8 parts of reducing agent, 2 parts of additive, and 0.5 parts of water; the pressing into pellets is to mix steelmaking dust, reducing agent, additives, and water uniformly After that, it is sent into a mold with a diameter of 21.06 mm to form a ball; the pressure of the pressed pellets is 12 MPa; before being pressed into pellets, the steelmaking dust and reducing agent are mixed evenly and sent to the grinding machine to grind into the mesh Powder with a particle size of 90 mesh, then add additives and water to mix evenly;

(2) The pellets of step (1) are sent to a vacuum carbon tube furnace for vacuum roasting to obtain volatiles and residues, and the residues are solids remaining in the vacuum carbon tube furnace; conditions for the vacuum roasting For: control the reaction temperature to 890°C under a vacuum of 20Pa, and treat it at a constant temperature for 89 minutes; before sending the pellets into a vacuum carbon tube furnace for vacuum roasting, first send the shaped pellets to a drying oven for drying The moisture content is 0; the drying temperature is ≥120℃ and the time is 1.5h;

(3) The volatile substance in step (2), that is, gaseous elemental zinc, is sent to a condensation collector and condensed into a solid, and the solid is collected to obtain a high-purity zinc ingot;

(4) The residue in step (2) is crushed and ball milled and put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally a high-grade iron concentrate is obtained; the dilute acid is dilute Hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.01 mol/L; the conditions of the pickling treatment are: in dilute hydrochloric acid solution with PH=1.5, the control temperature is 47° C., and the pickling time is 57 min.

The chemical composition and content of the steel-making dust are shown in Table 1, and the amounts of the steel-making dust, reducing agent, additives and water are shown in Table 2.

Example 4

A method for comprehensively enriching iron with steelmaking dust includes the following steps:

(1) After mixing steel-making dust with reducing agents, additives, and water, and pressing into pellets; the additive is boron trioxide; the reducing agent is coke powder; the steel-making dust, reducing agent, additives Mix with water in the following proportions by weight: 100 parts of steelmaking dust, 7 parts of reducing agent, 1 part of additive, and 0.6 parts of water; the compression into pellets is to mix steelmaking dust, reducing agent, additives, and water uniformly After that, it is fed into a mold with a diameter of 29.03mm to form balls; the pressure of the pressed pellets is 18MPa; before being pressed into pellets, the steelmaking dust and reducing agent are mixed evenly and sent to the grinding machine for grinding Powder with a particle size of 110 mesh, then add additives and water to mix evenly;

(2) The pellets of step (1) are sent to a vacuum carbon tube furnace for vacuum roasting to obtain volatiles and residues, and the residues are solids remaining in the vacuum carbon tube furnace; conditions for the vacuum roasting For: control the reaction temperature to 930 ℃ under a vacuum of 90Pa, and treat it at a constant temperature for 85 minutes; before sending the pellets into a vacuum carbon tube furnace for vacuum roasting, first send the formed pellets to a drying oven for drying treatment The moisture content is 0; the drying temperature is ≥120℃ and the time is 2.5h;

(3) The volatile substance in step (2), that is, gaseous elemental zinc, is sent to a condensation collector and condensed into a solid, and the solid is collected to obtain a high-purity zinc ingot;

(4) The residue in step (2) is crushed and ball milled and put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally a high-grade iron concentrate is obtained; the dilute acid is dilute Hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.01 mol/L; the conditions of the pickling treatment are: in dilute hydrochloric acid solution with PH=2.5, the control temperature is 52° C., and the pickling time is 62 min.

The chemical composition and content of the steel-making dust are shown in Table 1, and the amounts of the steel-making dust, reducing agent, additives and water are shown in Table 2.

Example 5

A method for comprehensively enriching iron with steelmaking dust includes the following steps:

(1) After mixing steel-making dust with reducing agents, additives, and water, and pressing into pellets; the additive is boron trioxide; the reducing agent is coke powder; the steel-making dust, reducing agent, additives Mix with water in the following proportions: 100 parts of steelmaking dust, 7 parts of reducing agent, 1.5 parts of additives, and 0.5 parts of water; the press into pellets is to mix steelmaking dust, reducing agent, additives, and water uniformly After that, it is fed into a mold with a diameter of 25.07mm to form balls; the pressure of the pressed pellets is 15MPa; before being pressed into pellets, the steelmaking dust and reducing agent are mixed evenly and sent to the grinding machine for grinding Powder with a particle size of 100 mesh, then add additives and water to mix evenly;

(2) The pellets of step (1) are sent to a vacuum carbon tube furnace for vacuum roasting to obtain volatiles and residues, and the residues are solids remaining in the vacuum carbon tube furnace; conditions for the vacuum roasting For: control the reaction temperature to 900 ℃ under a vacuum of 50Pa, and treat it at a constant temperature for 90 minutes; before sending the pellets to a vacuum carbon tube furnace for vacuum roasting, first send the formed pellets to a drying oven for drying treatment The moisture content is 0; the drying temperature is ≥120℃ and the time is 2h;

(3) The volatile substance in step (2), that is, gaseous elemental zinc, is sent to a condensation collector and condensed into a solid, and the solid is collected to obtain a high-purity zinc ingot;

(4) The residue in step (2) is crushed and ball milled and put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally a high-grade iron concentrate is obtained; the dilute acid is dilute Hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.01 mol/L; the conditions of the pickling treatment are: in dilute hydrochloric acid solution with PH=2, the control temperature is 50° C., and the pickling time is 60 min.

The chemical composition and content of the steel-making dust are shown in Table 1, and the amounts of the steel-making dust, reducing agent, additives and water are shown in Table 2.

Comparative Example 1

The difference from Examples 1 to 5 is that the conditions of the acid washing treatment are: in dilute hydrochloric acid solution with PH=4, the temperature is controlled at 56° C., the acid washing time is 68 min, and other conditions remain unchanged.

Comparative Example 2

The difference from Examples 1 to 5 is that the temperature is controlled to 800°C during vacuum baking, and other conditions remain unchanged.

Comparative Example 3

The difference from Examples 1 to 5 is that the pressure is controlled to 1 atm during roasting, and other conditions remain unchanged

Comparative Example 4

Follow the examples in patent application CN201010237178.X.

The examples 1 to 5 of the present application and the comparative examples 1 to 3 were respectively subjected to the steel making dust recovery and utilization zinc test, and the zinc recovery rate, iron content in the iron-containing material and the total cost used after processing 100 kg of steel making dust by different methods were recorded. The results are shown in Table 3 below.

Table 3 Experimental results of different methods for processing 100kg steel-making dust

Group Zinc recovery Iron content in ferrous materials Total cost Example 1 94.02% 64.40% 132 yuan Example 2 95.81% 60.38% 137 yuan Example 3 98.19% 66.16% 183 yuan Example 4 96.97% 62.88% 158 yuan Example 5 97.97% 65.67% 169 yuan Comparative Example 1 93.04% 61.78% 130 yuan Comparative Example 2 91.16% 60.47% 141 yuan Comparative Example 3 49.65% 59.47% 156 yuan Comparative Example 4 95.00% 62.56% 473 yuan

In summary, this application mixes steelmaking dust with reducing agents, additives, and water for vacuum roasting, combined with the vacuum degree to control the temperature reasonably, control the pickling process parameters reasonably, and finally make the iron content in the residual materials further Improve the recovery rate of elemental zinc while ensuring a high recovery rate of metallic iron, obtain iron concentrates with an iron content of up to 66.16%, and a recovery rate of zinc up to 98.19%; as a whole process in the entire process, the process is simple and the operation Convenient, low reaction temperature, reduces the cost of comprehensive utilization of steel-making dust, and effectively solves the high cost, heavy pollution, high energy consumption and large output of three wastes existing in the treatment of zinc-containing steel-making dust in the existing technology. The problem.

It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present invention is defined by the appended claims rather than the above description, and is therefore intended to fall within the claims All the changes within the meaning and scope of the equivalent waist are included within the protection scope of the present invention.

Claims (7)

A method for comprehensively utilizing steel-making dust to enrich iron, which is characterized by comprising the following steps: mixing steel-making dust with reducing agent, additive and water, under a pressure of 11-19 MPa and a diameter of 20.01-30 mm Pressed into pellets in the mold, the pellets are first sent to a drying oven for drying and then put into a vacuum carbon tube furnace for vacuum roasting, collecting volatiles evaporated during the vacuum roasting process and solid residues remaining in the vacuum carbon tube furnace After the residue is crushed and ball milled, it is put into a dilute acid solution for pickling treatment to remove impurities in the residual iron phase, and finally enriched to obtain high-grade iron concentrate; The volatile matter is gaseous elemental zinc, and the volatile matter is sent to a condensation collector and condensed into a solid to obtain a high-purity zinc ingot; The conditions of the vacuum roasting are as follows: the reaction temperature is controlled at 850 to 950°C under a vacuum of 10 to 100 Pa, and the temperature is treated at a constant temperature for 80 to 100 min; The dilute acid is a dilute hydrochloric acid solution, and the concentration of the hydrochloric acid solution is 0.01 mol/L; the specific conditions of the pickling treatment are: in a dilute hydrochloric acid solution with PH=1 to 3, the temperature is controlled to 46 to 53° C. The pickling time is 56 to 63 minutes. The method for comprehensively utilizing steelmaking dust to enrich iron according to claim 1, wherein the drying process is to dry the pellets to a moisture content of zero. The method for comprehensively utilizing steelmaking dust to enrich iron according to claim 1, wherein the temperature of the drying process is ≥120°C and the time is 1 to 3 hours. A method for comprehensively utilizing steel-making dust to enrich iron according to claim 1, characterized in that: before pressing into pellets, the steel-making dust and reducing agent are mixed uniformly and sent to a grinder for grinding to a mesh size For 80 ~ 120 mesh powder, then add additives and water to mix evenly. The method for comprehensively utilizing steelmaking dust to enrich iron according to claim 1, wherein the steelmaking dust, reducing agent, additives and water are mixed according to the following proportion by weight: 100 parts of steelmaking dust , 6-8 parts of reducing agent, 0-2 parts of additives, 0.4-0.7 parts of water. The method for comprehensively utilizing steelmaking dust to enrich iron according to claim 1, wherein the additive is boron trioxide. The method for comprehensively utilizing steelmaking dust to enrich iron according to claim 1, wherein the reducing agent is coke powder.