Process for treating copper anode slime by using side-blown converter

Abstract

The invention provides a process for treating copper anode slime by using a side-blown converter, belongs to the technical field of metallurgy, and solves the problem that the loss of precious metal is relatively large in a method for treating the anode slime by pyrometallurgy, the process comprises the following steps: mixing the copper anode slime and 98% concentrated sulfuric acid according to the mass ratio of 1: 3-1: 5 for slurrying, after slurrying is conducted for 2-3 h, the mixture is placed in a roasting furnace at the temperature of 600-800 DEG C for selenium removal, then copper in roasting slag is leached out through dilute sulphuric acid, and copper removal slag is subjected to microwave drying and brick pressing to form a raw material for side-blown smelting; blowing tailings generated in the blowing period of the Kaldo furnace need to be added before side blowing smelting to build a molten pool, then quartz stone, limestone and sodium carbonate are added to be smelted and slagging at high temperature, then gold and silver are enriched, produced gold and silver alloy can be directly blown and cast into a silver electrolysis anode plate through the Kaldo furnace, and then gold and silver are produced through silver electrolysis-gold refining. According to the method, the anode mud treatment capacity is obviously improved, the gold and silver development speed is increased, the precious metal yield is high, the environmental protection pressure is small, and the method is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy, and particularly relates to a process for treating copper anode slime by using a side-blown furnace. Background Art

[0002] Copper anode slime is an insoluble solid produced at the anode during the electrolytic refining of blister copper (metals with higher potentials in blister copper, such as precious metals, cannot be dissolved to form metal ions and enter the electrolyte during electrolysis, thus forming a metal solid state). Copper anode slime is an important raw material for extracting rare precious metals and is an effective way and an inevitable choice to make up for the gradual depletion of primary mineral resources.

[0003] As a solid by-product insoluble in the electrolyte produced during copper electrolytic refining, the yield of copper anode slime is about 0.2 - 1.0% of the mass of the blister copper anode plate. Its composition is mainly determined by the chemical composition of blister copper and the electrolysis technical conditions, and usually contains precious metals, copper, lead, selenium, tellurium, bismuth, antimony, nickel, sulfur, tin and a large amount of moisture. For example, the anode slime produced during the smelting process of copper sulfide concentrate contains more copper, selenium, silver, lead, tellurium, antimony, bismuth, arsenic and gangue minerals, while less platinum group metals; the anode slime produced during the smelting process of copper-nickel sulfide ore has high contents of copper, nickel, sulfur and tin, contains a small amount of platinum group metals, and less gold, silver and lead; the anode slime produced during the electrolysis of miscellaneous copper has higher lead and selenium contents. The particle size of copper anode slime is about 100 - 200 mesh, the color is grayish black or light gray, and the phase composition is relatively complex. 70% of the copper exists in the metallic form, and the rest exists in the form of copper compounds; silver mainly exists in the form of simple substances and compounds; most of the gold exists in the free state; the platinum group metals mainly exist in the form of metals or alloys.

[0004] The composition of anode slime is complex, with a high content of base metals and a low content of precious metals. Its treatment process is relatively complex and the process flow is also long. Generally, the main treatment process is the most popular with pyrometallurgy. Because of its large treatment capacity and short treatment process, it is beneficial to improve the realization speed of gold and silver. However, when the Kaldo furnace smelting + blowing is used for long-term treatment in pyrometallurgy, the loss of precious metals is also the key point restricting the benefit growth. Therefore, it is urgent to further develop a new side-blown furnace bath smelting technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a process for treating copper anode slime by using a side-blown furnace to solve the problem of large loss of precious metals in the method of treating anode slime by pyrometallurgy.

[0006] The technical solution of the present invention is: a process for treating copper anode slime by using a side-blown furnace, comprising the following steps: Step 1: Mix copper anode slime and concentrated sulfuric acid according to a acid mixing ratio of 1:3 - 1:5 for slurry pretreatment. After complete slurry formation, dilute the slurry material and perform solid-liquid separation to obtain the anode slime filter residue; Step 2: Place the anode slime filter residue in a roasting furnace at 600 - 800 °C for constant-temperature roasting. After roasting, cool the anode slime residue to 50 - 80 °C for selenium removal; Step 3: Place the selenium-removed anode slime residue in a sulfuric acid solution at 80 - 120 °C, stir while oxidizing under oxygen-rich conditions, and then perform solid-liquid separation to extract copper sulfate pentahydrate crystals, and further extract tellurium to obtain a pressure copper removal material; Step 4: Dry the pressure copper removal material to obtain a dry residue, limit the final moisture content of the dry residue to 6 - 8%, then press the dry residue into a brick-shaped material, and mix the brick-shaped material with a slag former, a reducing agent, and a clarifying agent for side-blown smelting to obtain a gold-silver alloy; Step 5: Place the gold-silver alloy in a Kaldo furnace at 1100 - 1300 °C, keep 15 - 25 t of the gold-silver alloy input per furnace charge to obtain a high-grade gold-silver alloy, add limestone, coke, quartzite, and sodium carbonate for blowing for 3 - 5 h, and then cast it into a silver electrolysis anode plate, and obtain pure gold and pure silver products through silver electrolysis - gold refining.

[0007] As a further improvement of the present invention, in Step 1, the pulping time is 3 - 5 h; the dilution time is 1 - 2 h.

[0008] As a further improvement of the present invention, in Step 2, the roasting time is 2 - 3 h; the roasting furnace is one of a resistance heating roasting furnace, an axial rotation roasting furnace, a reciprocating roasting furnace, a fluidized bed roasting furnace, a microwave-assisted roasting furnace, an air current roasting furnace, a high-temperature solid-phase roasting furnace, a rotary furnace, and a fixed bed furnace.

[0009] As a further improvement of the present invention, in Step 3, the stirring rate is constantly 20 Hz and the time is 3 - 5 h.

[0010] As a further improvement of the present invention, in Step 4, the side-blown smelting is carried out in a side-blown melting pool. Before feeding, use the tailings of blowing to build the melting pool. The tailings of blowing are smelting slag or blowing slag. When the depth of the melting pool reaches 100 - 200 mm, evenly feed the brick-shaped material, the slag former, the reducing agent, and the clarifying agent, and keep the addition amounts of the slag former at 15 - 25%, the reducing agent at 5 - 10%, and the clarifying agent at 5 - 10%. The furnace temperature before feeding the brick-shaped material is 1100 - 1300 °C, and the feeding speed is 2 - 5 t / h.

[0011] As a further improvement of the present invention, the slag former is one of calcium oxide, magnesium oxide, quartz, calcium silicate, and alumina, or any combination of any two or more of them; the reducing agent is one of coke, graphite, and pulverized coal, or any combination of any two or more of them; the clarifying agent is one of sodium carbonate and potassium carbonate, or a combination of the two.

[0012] The beneficial effects of the present invention are as follows: Through the pulping pretreatment of copper anode slime with concentrated sulfuric acid, the leaching rate of valuable metals can be increased, impurities can be removed, the structure and properties of the anode slime can be changed, and refractory compounds can be decomposed, thereby improving the subsequent treatment efficiency of copper anode slime; by reasonably controlling the roasting temperature, the recovery rate and purity of selenium can be effectively increased, environmental pollution can be reduced, and economic benefits can be improved; placing the selenium-removed anode slime residue in sulfuric acid solution for copper removal can increase the recovery rate of precious metals, reduce impurity interference, optimize the operation environment, and reduce production costs. The processes of material stirring, oxidation, and leaching are uniform, which can further make the copper removal effect uniform and complete. After pretreatment, selenium is removed from copper anode slime by sulfuric acid roasting through pulping with concentrated sulfuric acid, and then the anode slime in dilute sulfuric acid is subjected to pressure oxygen enrichment treatment for copper removal and tellurium precipitation. This can not only quickly recover valuable metals but also significantly reduce the impurity content of the anode slime, which has a direct advantage in improving the grade of the gold-silver alloy.

[0013] Controlling the moisture content of the pressure copper-removing material by drying can improve the subsequent treatment efficiency, reduce energy consumption and costs, prevent equipment corrosion, improve the working environment, and facilitate storage and transportation.

[0014] After the pretreatment of the anode slime, it is made into a briquette material, mixed with a reducing agent, a slag-forming agent, and a clarifying agent, and continuously fed into a side-blown furnace for bath smelting to produce a gold-silver alloy, which can increase the treatment volume and rate of the anode slime. At the same time, it can further increase the realization speed and output of gold and silver.

[0015] Through the pyrometallurgical process of side-blown furnace smelting + Kaldo furnace blowing, not only are precious metals enriched, but also impurity elements can be effectively removed, changing the technical problem of low metal recovery rate when the Kaldo furnace treats anode slime, and then achieving the goal of high recovery rate of precious metals in the pyrometallurgical treatment of copper anode slime.

[0016] Through the process of the present invention, the contents of selenium, tellurium, and copper in copper anode slime are significantly reduced, precious metals are further enriched, the grades of Au and Ag in the material are increased, and there is no heavy metal pollution. The process of the present invention has a wide application field and a high recovery rate of precious metals, and is suitable for industrial production. Description of the Drawings

[0017] Figure 1 It is a process flow chart of the present invention. Detailed Embodiments

[0018] In order to make the purpose, technical solutions, and advantages of the present invention clearer at a glance, the following describes the present invention in detail in combination with the drawings and embodiments. The embodiments here are only used to explain the present invention and do not restrict or limit the present invention.

[0019] In other words, the present invention covers any substitutions, modifications, equivalent methods, and solutions that are defined by the claims and fall within the essence and scope of the present invention. Further, examples are provided to make it easier for other researchers to understand.

[0020] Example 1: Step 1: Mix copper anode slime with concentrated sulfuric acid at a acid preparation ratio of 1:3 for slurry pretreatment. The slurry process is maintained in a tank for 3 h. After complete slurry formation, pour the slurry material into another tank filled with water for dilution. After 1 h of dilution, perform solid-liquid separation to obtain anode slime filter residue. Step 2: Place the anode slime filter residue in a roasting furnace at 600 °C for constant-temperature roasting for 2 h. The roasting furnace is a resistance heating roasting furnace. After roasting, cool the anode slime residue to 50 °C for selenium removal. Step 3: During high-pressure oxygen leaching for copper removal, place the selenium-removed anode slime residue in an 80 °C sulfuric acid solution. Under the condition of rich oxygen with a tank pressure maintained at 1.0 Mpa, oxidize while stirring. The stirring rate is kept constant at 20 Hz, and the high-pressure oxygen leaching time is 3 h. Then, use a filter press for solid-liquid separation. The separated liquid is used for the displacement reaction to extract copper sulfate pentahydrate crystals, and further extract tellurium to obtain the pressurized copper-removed material. Step 4: During side-blown bath smelting, place the pressurized copper-removed material in a microwave dryer for drying to obtain dried slag. Limit the final moisture content of the dried slag to 6%. Then, press the dried slag into briquettes to form briquette materials with a certain strength. Mix the briquette materials with a slag-forming agent, a reducing agent, and a clarifying agent for side-blown smelting to obtain a gold-silver alloy. The side-blown smelting is carried out in a side-blown bath. Before feeding, use the blown tailings to form a molten bath. The blown tailings are smelting slag or blown slag. When the molten bath depth reaches 100 mm, evenly feed the briquette materials, slag-forming agent, reducing agent, and clarifying agent. Maintain the addition amounts of the slag-forming agent at 15%, the reducing agent at 5%, and the clarifying agent at 5%. The furnace temperature before feeding the briquette materials is 1100 °C, and the feeding speed is 2 t / h. The slag-forming agent is calcium oxide; the reducing agent is a combination of coke and graphite; the clarifying agent is sodium carbonate. Step 5: During Kroll furnace blowing, place the gold-silver alloy in a Kroll furnace at 1100 °C. Keep 15 t of the gold-silver alloy input per furnace charge to obtain a high-grade gold-silver alloy. Add limestone, coke, quartzite, and sodium carbonate for blowing for 3 h, then cast into silver electrolysis anode plates, and obtain pure gold and pure silver products through silver electrolysis - gold refining.

[0021] Under the process conditions of Example 1, 88 t of anode slime dried material can be processed per day. The gold and silver grades in the produced gold-silver alloy are Ag 20 - 22% and Au 10000 - 13000 g / t respectively, and the gold and silver recovery rates can reach Ag 96.4% and Au 95.3%.

[0022] Example 2: Step 1: Mix copper anode slime with concentrated sulfuric acid at an acid preparation ratio of 1:4 for slurry pretreatment. The slurry process is maintained in a tank for 4 h. After complete slurry formation, pour the slurried material into another tank filled with water for dilution. After 1.5 h of dilution, perform solid-liquid separation to obtain the anode slime filter residue. Step 2: Place the anode slime filter residue in a roasting furnace at 700 °C for isothermal roasting for 2.5 h. The roasting furnace is an axially rotating roasting furnace. After roasting, cool the anode slime residue to 65 °C for selenium removal. During high-pressure oxygen leaching for copper removal, place the selenium-removed anode slime residue in a sulfuric acid solution at 100 °C. Under the condition of rich oxygen with a tank pressure maintained at 1.5 Mpa, oxidize and stir simultaneously. The stirring rate is constantly 20 Hz, and the high-pressure oxygen leaching time is 4 h. Then, use a filter press for solid-liquid separation. The separated liquid is used to extract copper sulfate pentahydrate crystals by vacuum evaporation method, and further extract tellurium to obtain the pressure-leached copper-removed material. Step 4: During side-blowing bath smelting, place the pressure-leached copper-removed material in a microwave dryer for drying to obtain the dried residue, with the final moisture content of the dried residue limited to 7%. Then, press the dried residue into briquettes to form the briquette material of blocky material with certain strength. Mix the briquette material with slag formers, reducers, and clarifiers for side-blowing smelting to obtain the gold-silver alloy. The side-blowing smelting is carried out in a side-blowing bath. Before feeding, use the tailings from blowing to form the bath. The tailings from blowing are smelting slag or blowing slag. When the bath depth reaches 150 mm, evenly feed the briquette material, slag formers, reducers, and clarifiers, and maintain the addition amounts of the slag former at 20%, the reducer at 10%, and the clarifier at 10%. The furnace temperature before feeding the briquette material is 1200 °C, and the feeding speed is 3 t / h. The slag former is a combination of calcium oxide, magnesium oxide, and quartz; the reducer is a combination of coke, graphite, and pulverized coal; the clarifier is a combination of sodium carbonate and potassium carbonate. Step 5: During Kaldo furnace blowing, place the gold-silver alloy in a Kaldo furnace at 1200 °C, with 20 t of the gold-silver alloy added per furnace charge to obtain a high-grade gold-silver alloy. Add limestone, coke, quartzite, and sodium carbonate for blowing for 4 h, and then cast it into the anode plate for silver electrolysis. Obtain pure gold and pure silver products through silver electrolysis - gold refining.

[0023] Under the process conditions of Example 2, 84 t of anode slime dried material can be processed per day. The gold and silver grades in the produced gold-silver alloy are Ag 22.3 - 25.4% and Au 15000 - 18000 g / t respectively, and the gold and silver recovery rates can reach Ag 97.6% and Au 98.1%.

[0024] Example 3 Step 1: Mix copper anode slime with concentrated sulfuric acid at a acid preparation ratio of 1:5 for pulping pretreatment. The pulping process is maintained for 5 h in a tank. After complete pulping, pour the pulped material into another tank filled with water for dilution. After 2 h of dilution, perform solid-liquid separation to obtain anode slime filter residue; Step 2: Place the anode slime filter residue in a roasting furnace at 800 °C for isothermal roasting for 3 h. The roasting furnace is a fixed-bed furnace. After roasting, cool the anode slime residue to 80 °C for selenium removal; During high-pressure oxygen leaching for copper removal, place the selenium-removed anode slime residue in a sulfuric acid solution at 120 °C. Under the condition of rich oxygen with the tank pressure maintained at 2.1 Mpa, oxidize and stir simultaneously. The stirring rate is kept constant at 20 Hz, and the high-pressure oxygen leaching time is 5 h. Then, perform solid-liquid separation using a filter press. The separated liquid is used to extract copper sulfate pentahydrate crystals through a displacement reaction, and further extract tellurium to obtain the pressurized copper-removed material; Step 4: During side-blowing bath smelting, place the pressurized copper-removed material in a microwave dryer for drying to obtain dried residue. Limit the final moisture content of the dried residue to 8%. Then, press the dried residue into briquettes to form briquette material with a certain strength. Mix the briquette material with slag formers, reducing agents, and clarifying agents for side-blowing smelting to obtain gold-silver alloy; Side-blowing smelting is carried out in a side-blowing bath. Before feeding, use the tailings of blowing to form a bath. The tailings of blowing are smelting slag or blowing slag. When the bath depth reaches 200 mm, uniformly feed the briquette material, slag formers, reducing agents, and clarifying agents. Keep the addition amounts of the slag former at 25%, the reducing agent at 10%, and the clarifying agent at 10%. The furnace temperature before feeding the briquette material is 1300 °C, and the feeding speed is 5 t / h; The slag former is a combination of magnesium oxide, calcium silicate, and alumina; the reducing agent is a combination of graphite and pulverized coal; the clarifying agent is potassium carbonate; Step 5: During Kaldo furnace blowing, place the gold-silver alloy in a Kaldo furnace at 1300 °C. Keep 25 t of gold-silver alloy input per furnace to obtain high-grade gold-silver alloy. Add limestone, coke, quartzite, and sodium carbonate for blowing for 5 h, then cast into silver electrolysis anode plates, and obtain pure gold and pure silver products through silver electrolysis - gold refining.

[0025] Under the process conditions of Example 3, 96 t of anode slime dried material can be processed per day. The gold and silver grades in the produced gold-silver alloy are Ag 25 - 27.3% and Au 18000 - 20000 g / t respectively, and the gold and silver recovery rates can reach Ag 98.6% and Au 98.3%.

[0026] This production process first mixes copper anode slime with concentrated sulfuric acid for pretreatment; then the pretreated anode slime is roasted at high temperature in a roasting furnace, so that selenium and sulfur in the slag are oxidized and volatilized, and precious metals are concentrated in the insoluble slag; then the selenium-removed slag is mixed with dilute sulfuric acid and leached in a high-temperature, high-pressure and highly oxidizing atmosphere to achieve the separation of precious and base metals, and a pressure copper-removed slag with low copper content is obtained; the pressure copper-removed slag is dried, and then flux, reducing agent and clarifying agent are added for bath smelting. After the slag and matte are separated, a gold-silver alloy can be obtained; the gold-silver alloy can be obtained by adding reagents and blowing at high temperature in a Kaldo furnace, and then pure gold and pure silver can be obtained through silver electrolysis-gold refining.

[0027] Through the optimization of key steps such as pretreatment with concentrated sulfuric acid, selenium removal by high-temperature roasting, copper removal method, and pyrometallurgical process, this production process shows significant advantages of high gold and silver grades and high recovery rates for the gold-silver alloy produced from anode slime treatment, achieving the dual-high goals of gold and silver grades and gold and silver recovery rates in the gold-silver alloy, and having good application prospects and promotion value.

Claims

1. A process for treating copper anode slime using a side-blown converter, characterized in that: It includes the following steps: Step 1: Mix copper anode slime with concentrated sulfuric acid at an acid mixing ratio of 1:3 - 1:5 for slurry pretreatment. After complete slurry formation, dilute the slurry material and perform solid-liquid separation to obtain anode slime filter residue; Step 2: Place the anode slime filter residue in a roasting furnace at 600 - 800 °C for constant-temperature roasting. After roasting, cool the anode slime residue to 50 - 80 °C for selenium removal; Step 3: Place the selenium-removed anode slime residue in a sulfuric acid solution at 80 - 120 °C, oxidize and stir it under oxygen-rich conditions, then perform solid-liquid separation to extract copper sulfate pentahydrate crystals, and further extract tellurium to obtain pressure-leached copper-free material; Step 4: Dry the pressure-leached copper-free material to obtain dry residue, limit the final moisture content of the dry residue to 6 - 8%, then press the dry residue into block-shaped material for briquetting. Mix the briquetting material with slag former, reducing agent, and clarifying agent and perform side-blown smelting to obtain gold-silver alloy; Step 5: Place the gold-silver alloy in a Kaldo furnace at 1100 - 1300 °C, keep 15 - 25 t of gold-silver alloy input per furnace charge to obtain high-grade gold-silver alloy, add limestone, coke, quartzite, and sodium carbonate for blowing for 3 - 5 h, then cast it into silver electrolysis anode plates, and obtain pure gold and pure silver products through silver electrolysis - gold refining.

2. The process for treating copper anode slime using a side-blown converter according to claim 1, characterized in that: In Step 1, the slurry formation time is 3 - 5 h; the dilution time is 1 - 2 h.

3. The process for treating copper anode slime by using a side-blown converter according to claim 1, characterized in that: In Step 2, the roasting time is 2 - 3 h; the roasting furnace is one of a resistance heating roasting furnace, axial rotation roasting furnace, reciprocating roasting furnace, fluidized bed roasting furnace, microwave-assisted roasting furnace, gas flow roasting furnace, high-temperature solid-phase roasting furnace, rotary furnace, fixed-bed furnace.

4. The process for treating copper anode slime using a side-blown converter according to claim 1, characterized in that: In Step 3, the stirring rate is constantly 20 Hz and the time is 3 - 5 h.

5. A process for treating copper anode slime using a side-blown converter according to claim 1, characterized in that: In Step 4, the side-blown smelting is carried out in a side-blown melting bath. Before feeding, use the tailings of blowing to build the melting bath. The tailings of blowing are smelting slag or blowing slag. When the depth of the melting bath reaches 100 - 200 mm, evenly feed the briquetting material, slag former, reducing agent, and clarifying agent, and maintain the addition amounts of the slag former at 15 - 25%, the reducing agent at 5 - 10%, and the clarifying agent at 5 - 10%. The furnace temperature before feeding the briquetting material is 1100 - 1300 °C, and the feeding speed is 2 - 5 t / h.

6. A process for treating copper anode slime using a side-blown converter according to claim 5, characterized in that: The slag former is one of calcium oxide, magnesium oxide, quartz, calcium silicate, alumina, or any combination of any two or more of them; the reducing agent is one of coke, graphite, pulverized coal, or any combination of any two or more of them; the clarifying agent is one of sodium carbonate, potassium carbonate, or a combination of the two.

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