CN106399692A - Concentration smelting method for resource utilization of copper-containing solid waste - Google Patents

Abstract

An enrichment and smelting method for resource utilization of copper-containing solid waste. The copper-containing solid waste is oxidized and transformed by introducing oxygen into the lime solution, and the conversion slag is mixed with other copper-containing solid waste ingredients to make the moisture, copper content and FeO content of the mixed material :SiO ₂ :CaO mass ratios were kept within the required range, and at the same time, starch was added to prepare bricks, the mixture bricks and coke were alternately added to the smelting furnace, and oxygen-enriched air was introduced for enrichment smelting, and the weight of smelting output was The phase melt control cooling system separates and produces blister copper and matte. The smelting slag is depleted and smoked in the fuming furnace to recover copper and tin respectively. The smelting slag is ground and then beneficiated to further recover copper. The core of the present invention is firstly calcium sulfate as a new type of sulfur-fixing agent, secondly using starch as a binder and a reducing agent at the same time, and thirdly realizing the harmless and resource utilization of copper-containing solid waste by controlling the copper content in the smelting slag. Finally, copper and tin in the smelting slag are recovered by matte-making depletion and fuming processes.

Description

An enrichment and smelting method for resource utilization of copper-containing solid waste

technical field

The invention relates to a metallurgical process in the field of nonferrous metallurgy, in particular to a metallurgical method for treating copper-containing solid waste by combining wet conversion and pyromelting.

Background technique

Copper is a rose-red heavy non-ferrous metal. Its excellent physical and chemical properties are widely used in various fields such as electrical, national defense, light industry, machinery manufacturing and construction. It is second only to aluminum in the consumption of non-ferrous metal materials in my country. . At present, the general use ratio of copper is as follows: 48-49% in the electrical industry, 19-20% in the communication industry, 14-16% in construction, 7-10% in transportation, and 7-9% in home appliances and others. In 2014, the output of ten non-ferrous metals in my country was 44.17 million tons, including 24.38 million tons of electrolytic aluminum, 7.96 million tons of refined copper, 4.22 million tons of lead and 5.83 million tons of zinc. Although the world's copper production is increasing, due to the global economic growth, the demand for copper has increased significantly, and the world's production and consumption are basically the same, but there is still a large gap in the supply of copper in the Chinese market.

There are only more than 20 kinds of copper minerals with industrial application value in nature, mainly including sulfide ore and oxide ore. Copper sulfide concentrate is treated by pyrometallurgical process, while copper oxide ore has poor floatability and is difficult to beneficiate and enrich, so it should be directly treated by hydrometallurgical process. At present, more than 80% of the mined copper is produced by copper sulfide concentrate through pyro-smelting process, that is, the copper concentrate is smelted through matte-making to produce copper matte, and the copper matte is sequentially processed by converter blowing and pyro-refining to produce crude copper. Copper and blister copper are electrolytically refined in a sulfuric acid system to produce cathode copper.

Although my country is the largest copper-producing country in the world, our country's copper resource reserves are extremely poor. Our country's annual self-produced copper concentrate is only 24% of my country's annual copper concentrate consumption. This data hits the nail on the head and reflects my country's excessive dependence on imports. Current status of resources. In 2010, the foreign dependence of my country's copper concentrates was 75%, and the resource problem has increasingly become a bottleneck restricting factor for development. Recycled copper has made an important contribution to my country's copper consumption demand, and also seeks a way out for my country's copper resources. In recent years, the proportion of recycled copper in the total output of refined copper in my country has generally shown a steady growth trend. In 2010, the output of refined copper in my country was 4.573 million tons, of which 1.762 million tons were recycled copper, and the output of recycled copper accounted for 38.5% of the refined copper output.

Copper-containing solid waste resources refer to solid, semi-solid, more or less waste materials containing metallic copper resources produced by human beings in production, consumption, life and other activities, which have the characteristics of pollution, resources and sociality . That is to say, in the process of social development and human life, the generation of copper-containing solid waste is inevitable. Because it contains heavy metal copper, the disposal of copper-containing solid waste is directly related to the safety of the ecological environment. At the same time, copper-containing solid waste is also It is a resource with certain value. Therefore, from two aspects of environmental protection and resources, how to deal with copper-containing solid waste is an important issue.

Copper-containing solid waste has a wide range of sources and complex components, mainly including copper sludge and environmental protection sludge produced in the purification process containing heavy metals, electroplating sludge produced in the electroplating industry, sponge copper produced in various manufacturing industries, and crushing and sorting of waste circuit boards out of the copper powder and so on. These materials generally have four characteristics:

One is that the copper-containing solid waste has a high water content, and the bound water cannot be removed by the conventional plate-and-frame filter press liquid-solid separation method, such as electroplating sludge, whose water content is as high as 60-80%. If this part of water is not removed, it cannot be processed Pyromelting treatment; second, the composition is complex. Copper-containing solid wastes such as wet-process precipitation slag and electroplating sludge often contain more heavy metals such as lead, zinc, and chromium. If this type of copper-containing solid waste is not properly treated, it will inevitably It will cause great harm to the surrounding ecological environment; the third is that the copper content in the copper-containing solid waste is quite different. Most of them are below 15% or even lower, that is, the main metal components in copper-containing materials fluctuate greatly. If such materials are directly melted into the furnace, many problems will be caused; the fourth is the problem of copper-containing solid waste and sulfur, copper-containing solid waste Medium sulfur mainly exists in the form of sulfate or sulfide. In the subsequent smelting process, not only the energy consumption is high, but also the tail gas treatment is difficult. The absorption product is gypsum slag, which is also a kind of solid waste, and its storage problem has yet to be solved.

Compared with primary copper mines, copper-containing solid waste metal resources are more abundant, of higher grade, and lower energy consumption in the treatment process. Compared with mine-produced copper, every 1 ton of recycled copper produced can save 1054Kg of standard coal, 395m ³ of water and reduce solids Waste discharge of 380t, reduction of sulfur dioxide emission of 0.14t. Copper-containing solid waste is a typical copper-containing secondary resource, similar to copper-containing secondary resources, and its treatment methods are also divided into pyroprocess and wet process.

The pyrometallurgical process is that copper-containing solid waste is reduced and smelted to produce blister copper, and then refined by reverberatory furnace fire to produce anode plates, and the anode plates are electrolytically refined to produce cathode copper. Due to the different properties of copper-containing solid waste, metallurgists have developed one-stage, two-stage and three-stage methods. The first-stage method is to fire-refine copper-containing solid waste in a reverberatory furnace, cast it into an anode plate, and then produce cathode copper through electrolytic refining. The two-stage method is to first reduce and smelt copper-containing solid waste in a blast furnace to produce blister copper, or first reduce and smelt copper-containing materials in a converter to produce blister copper, and then fire refine in a reverberatory furnace to produce anode plates, and then Copper cathodes are produced through electrolytic refining. The three-stage method is to smelt copper-containing solid waste through a blast furnace to produce black copper with more impurities. The black copper is blown in a converter to remove impurities such as lead and tin to obtain blister copper, and the blister copper is refined in a reverberatory furnace to produce anodes. plate, and finally through electrolytic refining to produce cathode copper. It can be seen that the one-stage method and the two-stage method are only suitable for the treatment of copper-containing solid waste with less impurities, while the three-stage method is suitable for the treatment of copper-containing solid waste with more impurities. The core of the pyro-smelting process is to use the pyro-smelting method to reduce copper and impurities into blister copper, and then remove impurity metals in the subsequent converter blowing or refining process. The pyroprocessing process has the advantages of short process, low cost and high recovery rate.

The hydrometallurgical process is mainly to dissolve copper-containing solid waste by wet dissolution method, the copper-containing solution is purified to remove impurities, and the purer copper-containing solution is then used to obtain cathode copper by electrowinning. Although the hydrometallurgical method has the advantages of simple process, good metal separation effect and high metal recovery rate, it has the disadvantages of poor material adaptability, high treatment cost and large output of three wastes, making this method difficult to be widely promoted.

So which process to choose to treat copper-containing solid waste needs to fully consider factors such as environmental protection, resource utilization, and treatment costs, especially not to produce secondary pollution. Therefore, developing an efficient copper-containing solid waste treatment process is still at present Problems to be solved.

Contents of the invention

In order to overcome the shortcomings of the traditional treatment methods for copper-containing solid waste, the present invention provides a combination of wet conversion and pyromelting to treat copper-containing solid waste, with high copper recovery rate, high sulfur solidification rate, low treatment cost and low environmental pollution hydro-pyrometallurgical method.

In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: the copper-containing solid waste is oxidized and transformed by introducing oxygen into the lime solution, so that all the sulfur is converted into calcium sulfate and precipitated into the conversion slag, and the conversion slag is mixed with other copper-containing solid waste ingredients to make The moisture content, copper content and FeO:SiO ₂ :CaO mass ratio of the mixed material were kept in the required range respectively, and at the same time, a certain proportion of starch was added to the mixed material to prepare bricks, and then the mixed material bricks and coke were alternately added to the In the smelting furnace, oxygen-enriched air is introduced at the same time for enrichment smelting. By controlling the copper content in the smelting slag, the tin in the material enters the smelting slag and soot, and the heavy phase melt produced by smelting is released periodically, and the cooling system is controlled. Blister copper and matte are produced separately, the smelting slag is made into matte in the fuming furnace, depleted and smoked to recover copper and tin respectively, the smelting slag is ground again and then beneficiated to further recover copper, and the smelting flue gas is dust collected and absorbed by alkali Discharge. The core of the present invention is to first use alkaline pressurized oxidation conversion to convert all the sulfur in copper-containing solid waste into calcium sulfate, so as to recover sulfur in the form of copper sulfide in the reduction smelting process; secondly, starch is used as a binder and reduction agent, which not only improves the strength of the agglomerate, but also strengthens the reduction smelting process; again, the reduction smelting process reduces and enriches copper and precious metals in the raw materials in the heavy phase melt, and the heavy phase melt adopts a controlled cooling system Selective separation produces blister copper and matte, and finally the recovery of copper and tin in the smelting slag is realized by matte-making depletion and fuming processes. These links are closely related, and they work together to achieve the purpose of resource utilization of copper-containing solid waste.

The specific process and parameters are as follows:

1 Pressurized oxidation conversion of lime

Copper-containing solid waste is oxidized and transformed by introducing oxygen into the lime solution, so that all sulfur is converted into calcium sulfate and precipitated into the conversion slag, so that water and valuables are oxidized and removed; prepare a lime solution with a molar concentration of 0.5-2.0mol/L, Add copper-containing solid waste according to the liquid-solid ratio (ratio of liquid volume to solid weight) 2-4:1, add the mixed slurry into the high-pressure reactor, and control the reaction temperature at 100-200°C and oxygen partial pressure at 0.1-1.0MPa React under the conditions for 1.0-3.0 hours. After the reaction is completed, the temperature is lowered to 60°C and the liquid and solid are separated. The conversion slag is sent to the next step for batching, and the conversion liquid is returned to use. The main chemical reactions that occur during the lime pressurized oxidation conversion process are as follows:

Ca(OH) ₂ +MeSO ₄ =Me(OH) ₂ +CaSO ₄ (1)

Ca(OH) ₂ +MeS+2O ₂ =Me(OH) ₂ +CaSO ₄ (2)

2 ingredients to make bricks

The conversion slag is mixed with other copper-containing solid waste and a certain proportion of starch is added to prepare bricks; the conversion slag is mixed with other copper-containing solid waste to keep the mass ratio of FeO:SiO ₂ :CaO in the mixed material at (1.0-1.5): 1.0: (0.4~0.6), at the same time, control the moisture and copper content of the mixed material at 15.0~25.0% and 40.0~60.0% respectively, and then add starch with a mass of 1.0~5.0% of the mixed material, and then prepare it into specifications It is a brick of length × width × height = 200 × 120 × 100mm, which can be smelted as a qualified charge after being naturally stacked for 1 to 3 days.

3 reduction smelting

Add the qualified charge and coke to the smelting furnace in proportion to reduction smelting, release the smelting products periodically, control the cooling system to separate and produce blister copper and matte; the above-mentioned qualified bricks and coke are in a weight ratio of 1:0.10~0.25 Alternately add to the smelting furnace, pass through the oxygen-enriched air with a concentration of 26.0~40.0% for smelting, and control the mass percentage of copper in the smelting slag to 2.0~4.5%, so that tin and zinc are enriched in the smelting slag and smoke respectively Among them, the smelting period is 1.5~3.0h. The heavy phase melt and smelting slag produced by smelting are released periodically and placed in cast iron ingot molds respectively. The smelting slag is sent to subsequent matte making for depletion. Rinse with sodium hydroxide solution and discharge up to the standard; the heavy phase melt contained in the cast iron ingot mold is cooled by blowing, the blowing volume is controlled at 50-100m ³ /min and the blowing time is 15-90min, when the heavy phase melts When the surface temperature of the body is 650-850°C, the heavy phase melt smelts to produce two phases of blister copper and matte, and when the surface temperature of the melt is kept at 500-650°C, they are separated while hot, the blister copper is further refined and purified, and the smelting slag is further produced. Matte smoked.

4 Depletion and fuming of matte

The smelting slag is simultaneously produced in the fuming furnace to deplete the copper and fume the volatilized tin; the liquid smelting slag contained in the cast iron ingot mold is directly added to the fuming furnace, and the mass ratio of smelting slag and pulverized coal is 1:0.25~0.40 Add pulverized coal with a particle size of over 200 mesh, and at the same time add high-sulfur, low-copper and copper-containing solid waste with a weight ratio of 1.0-5.0% of smelting slag to deplete matte making, keep the air volume at 100-300m ³ /min and blow for 90-120min, the gas The soot obtained from dust collection is the raw material for recycling tin. The fumed slag is cooled in a V-shaped slag tank. The bottom of the V-shaped slag tank is matte, and the slag on the top of the V-shaped slag tank is sold as cement raw materials.

The present invention is suitable for treating various copper-containing solid wastes, and its main composition range is (%) by weight percentage: Cu1.0～90.0, Sn1.0～15.0, Zn1.0～15.0, Pb01～15.0, Sb0.1 ~10.0 and S0.1~10.0.

Compared with the traditional treatment method of copper-containing solid waste, the present invention has the following advantages: 1. The present invention adopts a lime pressurized oxidation conversion method to oxidize and remove moisture and organic matter in copper-containing solid waste, and convert all sulfur into calcium sulfate and use it as A new type of sulfur-fixing agent is produced in the form of matte in the subsequent reduction smelting process, and the conversion rate of sulfur reaches 99.0%, which greatly reduces the concentration of sulfur in the smelting flue gas and improves the operating environment; 2. Brick making with ingredients of the present invention In the process, different grades of copper-containing solid waste are matched and the copper content in the furnace charge is controlled at 40-60%, which reduces the yield of slag in the subsequent smelting process and improves the recovery rate of copper. As a binder, the strength of bricks is increased, and the reduction smelting process is used as a reducing agent to strengthen the reduction effect; 3. In the reduction smelting process of the present invention, by controlling the copper content in the smelting slag at 2.0-4.5%, the valuable metals are reduced Enter into blister copper, matte or soot, and solidify toxic and harmful metals in smelting slag, that is, realize the two purposes of resource utilization and harmless treatment of solid waste at the same time, and the use of oxygen-enriched air greatly improves the smelting efficiency; 4. The present invention adds high-sulfur copper-containing solid waste into the fuming furnace to achieve impoverishment and fuming of matte making, so that tin sulfide volatilizes into smoke and dust, and copper sulfide enters matte, so as to achieve depletion and fuming of smelting slag and recover tin and copper respectively 5. The present invention has the advantages of stable process technical indicators, low labor intensity and low production cost.

Description of drawings

Figure 1: Schematic diagram of the process flow of the present invention.

detailed description

Example 1:

There are three types of copper-containing solid waste treated by the present invention. The first one is electroplating sludge, and its main components are (%) by weight percentage: Cu5.3, Sn1.2, Zn3.8, Pb0.50, Sb0.4 , S8.4 and H ₂ O72.5; the second is sponge copper, the main components of which are (%) by weight percentage: Cu82.4, Pb1.3, Sb1.4 and S0.3; the third is Wet process mud, its main components are (%) by weight percentage: Cu35.6, Sn3.5, Zn1.8, Pb3.2, Sb3.2 and S4.5; CaO mass percentage in industrial grade quicklime is greater than 75.0%, the mass percentage of fixed carbon in coke is greater than 75%, and the mass percentages of copper and sulfur in high-sulfur, low-copper and copper-containing solid waste are 2.0-5.0% and 5.0-8.0%, respectively.

First, prepare a lime solution with a concentration of 1.0mol/L, add the first and third types of copper-containing solid waste at a liquid-solid ratio of 3:1, add the mixed slurry into a stainless steel high-pressure reactor, and control the reaction temperature React at 150°C and oxygen partial pressure of 0.6MPa for 2.0h. After the reaction is completed, cool down to 60°C and separate the liquid from the solid; mix the conversion slag with the other two copper-containing solid wastes to make the moisture, copper content and FeO of the mixed material: The mass ratio of SiO ₂ : CaO was maintained at 16.5%, 54.0% and 1.3:1.0:0.5 respectively, and at the same time, 4.6% of the mass of the mixed material was mixed with starch, and then it was prepared into a specification of length×width×height=200×120×100mm The bricks, which are naturally stacked for 2 days, will be the qualified charge; the above-mentioned qualified bricks and coke are alternately added to the melting furnace according to the weight ratio of 1:0.10, and the oxygen-enriched air with a concentration of 28.0% is introduced for smelting, and the smelting slag is controlled. The mass percentage of copper is 2.5%, and the smelting cycle is 2.5h. The heavy phase melt and smelting slag produced by smelting are released periodically and placed in cast iron ingot molds respectively. The heavy phase melt is cooled by blowing, controlled The blowing volume is 60m ³ /min and the blowing time is 25min. When the surface temperature of the heavy phase melt is kept at 580°C, it is separated while hot, and the blister copper is further refined and purified; the liquid smelting slag contained in the cast iron ingot mold is directly hoisted into the fuming Furnace, according to the mass ratio of smelting slag and pulverized coal 1:0.30, add pulverized coal with a particle size of over 200 mesh, and at the same time add high-sulfur, low-copper and copper-containing solid waste with a weight ratio of 4.0% of smelting slag, and keep the air volume at 240m ³ /min for blowing for 100min , The soot obtained by gas dust collection is the raw material for recycling tin. The fumed slag is placed in a V-shaped slag tank for cooling. The bottom of the V-shaped slag tank is matte, and the slag at the top of the V-shaped slag tank is sold as cement raw materials.

Claims (2)

1. An enrichment and smelting method for resource utilization of copper-containing solid waste, characterized in that it comprises the following steps: (1) Lime pressure oxidation leaching Prepare a lime solution with a molar concentration of 0.5-2.0 mol/L, add copper-containing solid waste at a liquid-solid ratio of 2-4:1 based on the ratio of liquid volume L to solid weight Kg, and add the mixed slurry to the high-pressure reactor In the process, the reaction temperature is controlled at 100-200 °C and the oxygen partial pressure is 0.1-1.0 MPa to react for 1.0-3.0 hours. After the reaction is completed, the temperature is lowered to 60 °C and the liquid and solid are separated. (2) Brick making with ingredients The conversion slag is mixed with other copper-containing solid waste to keep the mass ratio of FeO:SiO ₂ :CaO in the mixed material at (1.0-1.5):1.0:(0.4-0.6), and at the same time control the moisture and copper content of the mixed material at 15.0-25.0% and 40.0-60.0%, and then add 1.0-5.0% starch of the mixed material, and then prepare it into bricks with the specification of length × width × height = 200 × 120 × 100mm, and stack them naturally for 1-20 mm. After 3 days, it will be smelted as a qualified furnace charge; (3) Reduction smelting The above-mentioned qualified bricks and coke are alternately added to the smelting furnace according to the weight ratio of 1:0.10-0.25, and the oxygen-enriched air with a concentration of 26.0-40.0% is introduced for smelting. By controlling the mass percentage of copper in the smelting slag to 2.0 ~4.5%, so that tin and zinc are enriched in the smelting slag and dust respectively. The smelting cycle is 1.5~3.0h. The heavy phase melt and smelting slag produced by smelting are released periodically and placed in the cast iron ingot mold respectively. The smelting slag is sent to the subsequent matte making for depletion, and the smelting flue gas is washed with sodium hydroxide solution after dust collection and discharged up to the standard; the heavy phase melt contained in the cast iron ingot mold is cooled by blowing, and the blowing volume is controlled at 50~ 100m ³ /min and blowing time of 15-90min, when the surface temperature of the heavy phase melt is 650-850°C, the heavy-phase melt will segregate to produce two phases of blister copper and matte, keep the melt surface temperature at 500-650 Separation while hot at ℃, the blister copper is further refined and purified, and the smelting slag is further made into matte and fumed; (4) Depletion and fuming of matte The liquid smelting slag contained in the cast iron ingot mold is directly added to the fuming furnace, and the powdered coal with a particle size of over 200 mesh is added according to the mass ratio of smelting slag and pulverized coal of 1:0.25-0.40, and at the same time, high Sulfur, low copper, and copper-containing solid waste is depleted for matte making, and the air volume is kept at 100-300m ³ /min for blowing for 90-120min. The dust obtained by gas dust collection is the raw material for tin recovery, and the fumed slag is placed in a V-shaped slag tank Medium cooling, the bottom of the V-shaped slag tank is matte, and the slag on the top of the V-shaped slag tank is sold as cement raw materials. 2. The enrichment and smelting method for resource utilization of copper-containing solid waste as claimed in claim 1, characterized in that: the range of main components of copper-containing solid waste in weight percentage is: Cu5.0-90.0, Sn1.0-15.0 , Zn1.0～15.0, Pb01～15.0, Sb0.1～10.0 and S0.1～10.0.