CN101200777A - Method and equipment for continuous smelting of lead sulfide concentrate - Google Patents

Abstract

A method and equipment for continuous smelting of lead sulfide concentrate. The invention relates to a pyrometallurgy process of lead sulfide concentrate and equipment used to realize the process. In this device, a partition wall is set above the liquid slag layer in the molten pool of the furnace body, which is divided into three areas: the oxidation zone, the reduction zone and the fuming zone, each of which has its own smoke zone. The gas outlets are equipped with spray guns, the smelting material inlet is set at the top of the oxidation zone, the siphon discharge port is set at the crude lead layer at the bottom of the furnace body, and the slag discharge port is set at the liquid slag layer in the fuming zone. The smelting materials are continuously added into the furnace from the top of the oxidation zone, and the liquid metal lead is continuously discharged out of the furnace through the siphon discharge port. The _SO2 obtained in the oxidation zone is used to prepare sulfuric acid, and the high zinc and other valuable metal fumes obtained in the fuming zone are reused. . The process route of the invention is short, the heat of slag is fully utilized, the energy-saving effect is obvious, the investment in metallurgical furnace equipment is small, the operation cost is low, the fluctuation of _SO2 concentration is small, the reducing agent is cheap and has wide resources.

Description

Method and equipment for continuous smelting of lead sulfide concentrate

technical field

The invention relates to non-ferrous metal metallurgical technology, in particular to the pyrometallurgy of lead sulfide concentrate and the special equipment used to realize the process.

Background technique

Lead smelting methods can be summarized into two categories: traditional lead smelting method and direct lead smelting method. The traditional lead smelting method is the sintering machine-blast furnace smelting method; the direct lead smelting method is to cancel the sintering process of the lead sulfide concentrate, and the raw concentrate is directly smelted in the furnace. For many years, the traditional method has been the main production method of lead. However, with the continuous improvement of human awareness and requirements for environmental protection and energy conservation, the shortcomings of the traditional lead smelting method have become increasingly prominent. Many lead smelters in the world have gradually adopted direct lead smelting methods to replace traditional methods. lead smelting method. The direct lead smelting method can be classified into one-stage furnace method and two-stage furnace method. One-stage furnace method, such as Gifset method, Ausmelt method, QSL method, Kaldor method, Vanyukov method, etc., is to complete two processes of oxidation smelting and reduction smelting of crude lead smelting in one furnace. The two-stage furnace method, such as the Aisa method and the Shuikoushan method, is to complete two processes of crude lead production, oxidation smelting and reduction smelting, in two furnaces.

At present, most lead smelting enterprises in China still use the traditional sintering machine-blast furnace smelting method to produce crude lead, and some of them are starting to adopt advanced technology for transformation; a small number of production enterprises have adopted the Aisa method, Shuikoushan method and QSL method method to produce crude lead.

The traditional lead smelting method has disadvantages that are difficult for people to continue to accept: the amount of flue gas produced by sintering machines and blast furnaces is large, and the concentration of SO ₂ in the flue gas is low, which is difficult to treat economically, so that it will cause serious pollution to the environment; during the sintering process A large amount of oxidation reaction heat has not been fully utilized, and a large amount of expensive metallurgical coke will be consumed in blast furnace smelting after the sintered block is cooled, resulting in high energy consumption; long process flow, many equipments; high material turnover; Blast furnace smelting operations will produce lead-containing dust, lead-containing steam and SO ₂ flue gas, resulting in serious low-altitude pollution, poor operating environment, poor labor and industrial hygiene conditions, and great harm to the health of employees. At present, my country has banned the use of sintering machines as processing equipment for lead sulfide concentrates in new factories, and requires technical transformation of the original traditional lead smelting method within a time limit.

Shuikoushan (SKS) method and Isa method lead smelting are typical two-stage lead smelting methods, and the crude lead smelting process is completed by the combined process of Isa furnace (or SKS furnace)-blast furnace-fuming furnace. The two-stage lead smelting method is used as an oxidation smelting furnace for lead sulfide concentrate. In the smelting section, it can produce 30-70% of the total lead into the furnace as crude lead. The amount of flue gas is small, the concentration of SO ₂ is high, and the flue gas is easy to control. , more than 90% of the sulfur can be recycled, and the environmental pollution and labor industrial hygiene conditions are greatly improved compared with the traditional method. However, the slag (lead-rich slag) produced by the smelting furnace is released regularly, and needs to be cooled and crushed to a certain particle size, and then reduced to smelt in the blast furnace, and expensive metallurgical coke is added. There is insufficient utilization of reaction heat and high energy consumption. Problem: due to the low _SO2 content in the flue gas produced in the smelting section of the blast furnace, the _SO2 in the flue gas from the reduction section cannot be used to produce sulfuric acid and must be treated before it can be discharged; the slag produced by the blast furnace is sent to the fuming furnace for fuming. Recovery of valuable metals such as zinc. Fuming furnace flue gas also contains low concentration SO ₂ , which must be treated before it can be discharged.

Ausmelt method, Kaldor furnace method, QSL method and Vanyukov method lead smelting are two processes of oxidation smelting and reduction smelting completed in the same metallurgical furnace. However, the slag produced by these metallurgical furnaces needs to be sent to the fuming furnace for fuming to further recover valuable metals such as zinc. The slag needs to be cooled and then heated, melted and fumed in another furnace to produce zinc-containing fume. The potential of the slag is limited. The flue gas SO ₂ concentration in the oxidation section and the reduction section fluctuates greatly, and the acid system is difficult to operate stably. Fuming furnace flue gas contains low concentration and unstable SO ₂ , which must be treated before it can be discharged. In other words, the entire metallurgical process needs to be completed in at least two metallurgical furnaces. Moreover, low-concentration SO ₂ is often not fully utilized, and the tail gas must be treated after spending a lot of money before it can be discharged.

The Gifset method basically realizes the completion of three smelting processes of lead sulfide concentrate in the same furnace, but the material preparation of this method is complicated and needs to be ground and dried; the reduction requires expensive metallurgical coke; and a high-power electric furnace is required as a The heat supply for reduction and fuming requires high energy consumption; the equipment is complicated and the investment is high.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for continuous smelting of lead sulfide concentrate and corresponding special equipment. The process route is short, the heat of slag is fully utilized, the energy saving effect is obvious, the investment in metallurgical furnace equipment is small, and the operation cost is low. The fluctuation of _SO2 concentration is small, and the reducing agent is cheap and widely available.

The scheme of the special equipment adopted to solve the technical problem of the present invention is: a partition wall is provided in the upper space of the liquid slag layer in the molten pool of the furnace body, and it is divided into three disconnected oxidation zones, reduction zones and fuming zones. Each area has its own flue gas outlet on the top and is equipped with a spray gun respectively. The smelting material inlet is set on the top of the oxidation zone. zone liquid slag layer. There is a slope at the fuming area at the bottom of the furnace to concentrate the crude lead layer in the oxidation zone and reduction zone. Set in the lower part of the liquid slag layer.

The technological scheme of the present invention is: divide the upper space in the liquid slag layer of a metallurgical furnace into three areas, which are not connected to each other, the oxidation zone, the reduction zone and the fuming zone, and the smelting materials are added from the top of the oxidation zone, and the Oxygen and compressed air are sprayed into the liquid slag layer in the oxidation zone to smelt the sulfide ore. The flue gas containing _SO2 is discharged from the flue gas outlet of the oxidation zone and processed; it flows from the lower part of the partition wall between the oxidation zone and the reduction zone to the reduction zone. The liquid slag in the reduction zone is mixed with the reducing agent added to the zone. At the same time, the fuel coal powder and compressed air are sprayed into the liquid slag layer in the reduction zone through the spray gun. The liquid metal lead produced by reducing and smelting is continuously discharged out of the furnace through the siphon discharge port; the liquid slag flowing from the lower part of the partition wall between the reduction zone and the fuming zone to the fuming zone is sprayed into the reducing and fuel coal powder and compressed air by the spray gun, The valuable metals such as zinc are volatilized into the flue gas, the valuable metals are recovered and the tail gas is treated, and the lean slag is continuously discharged out of the furnace from the slag discharge port. Anthracite is used as reducing agent, and anthracite pulverized coal is supplemented as part of the fuel injected through the spray gun in the reduction section and fuming section; SO ₂ obtained from the flue gas outlet of the oxidation zone is used to prepare sulfuric acid.

The beneficial effects of the utility model are:

(1) Only one metallurgical furnace can complete the three metallurgical processes of oxidation smelting, reduction smelting and slag fuming of lead sulfide concentrate, and smelt high-quality crude lead and relatively pure zinc-containing and other valuable metal fumes in one step .

(2) The heat of slag is fully utilized, the energy saving effect is obvious, the investment in metallurgical furnace equipment is small, and the operating cost is low.

(3) Since each area above the liquid slag layer is completely separated, with this process method, the concentration of SO ₂ fluctuates little, and the concentration is stable between 8 and 15%. The acid system can operate continuously and stably, and the SO ₂ concentration The utilization rate is greater than 95%, and the flue gas obtained from the reduction zone and the smoke zone contains very low SO ₂ concentration, and it can be discharged after simple treatment. The environmental protection conditions are good, and the final exhaust gas can be discharged up to the standard.

(4) With this process, the preparation of raw materials is simple, the reducing agent only needs ordinary anthracite, and part of the fuel that needs to be supplemented in the reduction section and the fuming section is also ordinary anthracite pulverized coal, which is low in value and easy to obtain.

Description of drawings

Fig. 1 is the structural representation of special-purpose smelting furnace of the present invention.

The labels in the figure represent in order: flue gas outlet 1 in the oxidation zone, spray gun 2, smelting material inlet 3, smelting material 4, oxidation zone 5, liquid slag layer 6, crude lead layer 7, partition wall 8, reduction zone 9, siphon discharge Exit 10, partition wall 11, furnace wall 12 outside the furnace, slag outlet 13, fuming area 14, fuming area flue gas outlet 15, spray gun 16, reducing area flue gas outlet 17, spray gun 18, reducing agent 19, reducing agent Add port 20.

Detailed ways

Example

Referring to Fig. 1, in the liquid slag layer 6 of the molten pool of this lead sulfide concentrate continuous smelting furnace, partition walls 8 and 11 are arranged above the smelting space, and the part and the upper space of the liquid slag layer 6 are separated into mutually disconnected oxidation zones. Area 5, reduction area 9, and fuming area 14 are three areas, and the top of each area has its own flue gas outlet, that is, flue gas outlet 1 in the oxidation area, flue gas outlet 15 in the fuming area, flue gas outlet 17 in the reduction area, Each is equipped with spray guns 2, 16 and 18, the smelting material inlet 3 is set at the top of the oxidation zone 5, a siphon discharge port 10 is provided at the crude lead layer 7 at the bottom of the furnace body, and the slag discharge port 13 is provided at the fuming zone 14 6 places of the liquid slag layer. The fuming zone 14 at the bottom of the furnace body of the present invention is provided with a slope, so that the crude lead layer 7 formed during smelting is concentrated in the oxidation zone 5 and the reduction zone 9, and the siphon outlet 10 is located at the bottom of the crude lead layer 7, which is convenient for continuous discharge; the slag outlet 13 is arranged on the upper part of the liquid slag layer 6 in the fuming zone 14, and the completely treated slag is discharged out of the furnace; Continuous processing is more complete.

During continuous smelting, smelting materials 4 such as lead sulfide concentrate are added to the liquid slag layer 6 where the oxidation zone 5 is located from the smelting material inlet 3; In the layer, the oxidation and smelting of sulfide ore is realized; the flue gas containing SO ₂ is discharged from the flue gas outlet 1 of the oxidation zone, and is sent to acid production after being treated by waste heat boiler and dust collection. The liquid slag after oxidation smelting and desulfurization flows from the lower part of the partition wall 8 between the oxidation smelting zone and the reduction smelting zone to the reduction zone 9 and mixes with the reducing agent 19 added from the reducing agent inlet 20; The smelting spray gun 18 is added to the slag layer of the molten pool in the reduction smelting zone, where the lead oxide in the slag is reduced to metallic lead (coarse lead); the flue gas generated by the reduction passes through the furnace space of the reduction zone 9, and passes through the flue gas outlet 17 of the reduction zone The liquid crude lead layer 7 produced by oxidation smelting and reduction smelting is continuously discharged out of the furnace through the crude lead siphon discharge port 10. The liquid slag layer 6 after reduction and smelting flows from the lower part of the partition wall 11 between the reduction smelting area and the fuming volatilization area to the fuming area 14; In the slag layer of the melting pool in the volatilization zone, the valuable metals such as zinc in the slag are volatilized into the flue gas; the volatilized flue gas passes through the furnace space of the fuming volatilization zone, and is discharged out of the furnace through the flue gas outlet 15 of the fuming zone. Valuable metals such as zinc are recovered and tail gas is treated; lean slag after fuming and volatilization is continuously overflowed from the slag discharge port 13 and released outside the furnace.

Claims (4)

1. An equipment for continuous smelting of lead sulfide concentrate, characterized in that: a partition wall is provided in the space above the liquid slag layer in the molten pool of the furnace body, which is divided into mutually disconnected oxidation zone, reduction zone and fuming zone Each area has its own flue gas outlet on the top and is equipped with spray guns respectively. The smelting material inlet is set on the top of the oxidation zone. At the liquid slag layer in the fuming zone. 2. The equipment for continuous smelting of lead sulfide concentrate according to claim 1, characterized in that: the fuming zone at the bottom of the furnace body is provided with a slope, the thick lead layer is concentrated in the oxidation zone and the reduction zone, and the siphon outlet It is arranged at the bottom of the rough lead layer, the slag outlet is arranged at the upper part of the liquid slag layer, and the lower edge of the partition wall is arranged at the lower part of the liquid slag layer. 3. A method for continuous smelting of lead sulfide concentrate, characterized in that: the above space in the liquid slag layer of a metallurgical furnace is divided into three areas, which are not connected to each other, the oxidation zone, the reduction zone and the fuming zone, and the smelted materials are from Oxygen and compressed air are sprayed into the liquid slag layer in the oxidation zone through the spray gun at the same time to carry out oxidation and smelting of sulfide ore, and the flue gas containing _SO2 is discharged and treated from the flue gas outlet of the oxidation zone; from the oxidation zone and The lower part of the partition wall of the reduction area flows into the liquid slag in the reduction area, and mixes with the reducing agent added to the area, and at the same time, the fuel coal powder and compressed air are sprayed into the liquid slag layer in the reduction area through the spray gun, and the flue gas generated by reduction passes through the reduction area The flue gas outlet is discharged and processed, and the liquid metal lead produced by oxidation smelting and reduction smelting is continuously discharged out of the furnace through the siphon discharge port; the liquid slag flowing from the lower part of the partition wall between the reduction zone and the fuming zone to the fuming zone is sprayed into it by the spray gun Reduction and fuel coal powder and compressed air, so that the valuable metals such as zinc volatilize into the flue gas, and the valuable metals are recovered and the tail gas is treated. The lean slag is continuously released from the slag outlet. 4. The method for continuous smelting of lead sulfide concentrate according to claim 3, characterized in that: the reductant is anthracite, and the part of the fuel injected into the reduction section and the fuming section is anthracite pulverized coal through spray guns; the flue gas in the oxidation zone The SO ₂ obtained from the export is utilized to prepare sulfuric acid.

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