Process method for recycling bismuth from bismuth slag
阅读说明：本技术 一种铋渣中回收铋的工艺方法 (Process method for recycling bismuth from bismuth slag ) 是由 巫文嵩 程辉 于 2019-11-18 设计创作，主要内容包括：本发明属于铋的精炼领域,尤其涉及一种铋渣中回收铋的工艺方法,本发明通过将分银炉后期渣(铋渣)经过破碎后,进入球磨机磨成粉状,然后投入配好含有硫酸、工业盐和水溶液的浸出糟中进行反应,温度为80-90℃,经过一段时间的反应后,铋和铜进入溶液中,通过板框压滤机使浸出液液固分离。再通过中和水解铋以渣的形式得以沉淀,溶液中的铜用铁粉进行置换,最终产出海绵铜,铋渣经过火法还原炉熔炼产出粗铋,粗铋经过精炼除杂后得到最终产品精铋；本发明工艺方法操作简便,对铋的回收率高,能耗低,解决了目前分银炉后期渣处理方法回收元素单一,流程过长、金属回收率低的难点。(The invention belongs to the field of bismuth refining, and particularly relates to a process method for recovering bismuth from bismuth slag, which comprises the steps of crushing later-stage slag (bismuth slag) of a silver separating furnace, grinding the crushed slag into powder in a ball mill, adding the powder into a leaching tank which contains sulfuric acid, industrial salt and aqueous solution for reaction at the temperature of 80-90 ℃, reacting for a period of time, adding bismuth and copper into the solution, and separating the liquid and the solid of the leaching solution through a plate-and-frame filter press. Then, bismuth is precipitated in the form of slag through neutralization and hydrolysis, copper in the solution is replaced by iron powder to finally produce sponge copper, bismuth slag is smelted by a pyrogenic reduction furnace to produce crude bismuth, and the crude bismuth is refined and purified to obtain a final product refined bismuth; the process method is simple and convenient to operate, high in bismuth recovery rate and low in energy consumption, and solves the problems that the existing slag treatment method for the later stage of the silver separating furnace is single in recovery element, overlong in flow and low in metal recovery rate.)
1. A process method for recovering bismuth from bismuth slag is characterized by comprising the following steps:
A. crushing and grinding bismuth slag to obtain bismuth slag powder for later use;
B. mixing water, sulfuric acid and industrial salt to obtain leaching solution;
C. heating the leaching solution obtained in the step B to 70 ℃, adding the bismuth slag powder obtained by the treatment in the step A for leaching reaction, and filtering the leaching solution when all leaching slag is grey white to obtain a first filtrate;
D. adding soda into the first filtrate obtained in the step C to enable the pH value to reach 1.5, adding water to control the pH value to be 2.3 to perform hydrolysis precipitation reaction, performing liquid-solid separation after reacting for 1h to respectively obtain a second filtrate and bismuth precipitation slag, adding scrap iron into the second filtrate to perform displacement precipitation, performing liquid-solid separation to obtain sponge copper, adding coal powder and soda into the bismuth precipitation slag to perform reduction smelting to obtain crude bismuth;
E. d, heating the crude bismuth obtained in the step D to 650 ℃ for complete melting, fishing out the melting slag, stirring the bismuth liquid, cooling to 500 ℃, carrying out first liquation for copper removal and solidification for 10min, fishing out the copper dross slag, then continuously stirring, cooling to 320-350 ℃, carrying out second liquation for copper removal and solidification for 10min, and fishing out the copper dross slag;
F. heating the bismuth liquid after copper removal in the step E to 750 ℃ of 680-fold, blowing compressed air, turning over until white smoke is thin and lead oxide slag appears on the surface of the bismuth liquid, then adding a metal coating agent to dry the slag, fishing out arsenic and antimony slag, cooling the bismuth liquid after arsenic and antimony slag removal to 520 ℃ of 500-fold, adding caustic soda in batches, blowing compressed air simultaneously, wherein the hoof removal time is 6-10h, and when the caustic soda is added and stirred by the compressed air, the bismuth liquid after hoof and tin removal is obtained;
G. and F, cooling the bismuth liquid obtained in the step F to 400 ℃ for 350 plus materials, introducing chlorine into the bismuth liquid, stopping introducing chlorine when fishing out slag, heating to 550 ℃ for 500 plus materials, scooping out the slag, cooling to 400 ℃ for 350 plus materials after scooping out the slag each time, continuing introducing chlorine to obtain the bismuth liquid after removing lead and zinc, continuing heating the bismuth liquid to 720 ℃ for 680 plus materials, adding caustic soda and sodium nitrate, blowing compressed air, stirring, fishing out the chlorine slag, adding caustic soda to melt and cover the liquid level of the bismuth, cooling to 400 ℃ for 300 plus materials to carry out ingot casting, and finally obtaining refined bismuth.
2. The process method for recycling bismuth from bismuth slag according to claim 1, wherein in the step A, the mesh number of the bismuth slag powder is 120 meshes.
3. The process method for recovering bismuth from bismuth slag according to claim 1, wherein in the step B, the mass concentration of sulfuric acid in the aqueous solution formed by water and sulfuric acid is 16-19%, and the mass ratio of industrial salt to the aqueous solution of sulfuric acid is 1: 10.
4. The process method for recycling bismuth from bismuth slag according to claim 1, wherein in the step C, the mass ratio of the leachate to bismuth slag powder is 5:1, the leaching reaction time is 2 hours, the reaction temperature is controlled to be 80-90 ℃, and the pH value is controlled to be 0.5-1.
5. The process method for recycling bismuth from bismuth slag according to claim 1, wherein in the step D, the mass ratio of the scrap iron to the second filtrate is 1:20, and the mass ratio of the bismuth slag, the coal powder and the soda ash is 100: (5-7): (9-10), controlling the reduction smelting temperature to be 1100 ℃, and controlling the reaction time to be 8-10 h.
6. The process method for recycling bismuth from bismuth slag according to claim 1, wherein in the step F, the mass ratio of the bismuth liquid to the metal coating agent is 30:1, the metal coating agent is soda ash, chaff or sawdust, and the addition amount of the caustic soda is 1.5-2% of the mass of the bismuth liquid.
7. The process method for recycling bismuth from bismuth slag according to claim 1, wherein in the step G, the addition amount of caustic soda is 5-10% of the mass of the bismuth liquid, and the addition amount of sodium nitrate is 0.1-0.2% of the mass of the bismuth liquid.
Technical Field
The invention belongs to the field of bismuth refining, and particularly relates to a process method for recovering bismuth from bismuth slag.
Background
With the continuous development of nonferrous smelting, easily-treated minerals and raw materials are increasingly depleted, and various complex materials of difficultly-treated minerals and valuable metals, such as waste materials generated in the smelting process, production byproduct materials and the like, gradually become secondary resources for recycling valuable metal elements. The later-stage slag of the silver separating furnace is the later-stage slag with complex components obtained after the lead anode slime is smelted and blown for silver separation, and the later-stage slag becomes a valuable raw material for comprehensive recovery due to the fact that the later-stage slag contains metals such as bismuth, lead, silver, antimony and the like.
Most domestic smelting plants stack the later-stage slag for further treatment or sell the later-stage slag as a base product, the traditional treatment at present comprises two methods, namely a fire method and a wet method, and the traditional treatment comprises two methods, namely reverberatory furnace smelting and converter smelting, and the later-stage slag is prone to recovery and extraction of single elements or precious metals such as gold and silver, so that other valuable metal elements cannot be completely recovered, and resource waste and environmental pollution are caused. The later-stage slag has complex properties, the later-stage slag treatment methods with different components are different, and the later-stage slag containing more rare and noble metals is subjected to leaching, gold separation and silver emphatic enrichment to recover the noble metals; lead, copper and the like are mainly recovered from the later-stage slag with high heavy metal content, and the traditional treatment method can only selectively recover metals, but can not recover more valuable metals in the same process, so that repeated smelting is easily caused.
Disclosure of Invention
The invention provides a process method for recovering bismuth from bismuth slag to solve the technical problems.
The technical scheme for solving the technical problems is as follows: a process method for recovering bismuth from bismuth slag comprises the following steps:
A. crushing and grinding bismuth slag to obtain bismuth slag powder for later use;
B. mixing water, sulfuric acid and industrial salt to obtain leaching solution;
C. heating the leaching solution obtained in the step B to 70 ℃, adding the bismuth slag powder obtained by the treatment in the step A for leaching reaction, and filtering the leaching solution when all leaching slag is grey white to obtain a first filtrate;
D. adding soda into the first filtrate obtained in the step C to enable the pH value to reach 1.5, adding water to control the pH value to be 2.3 to perform hydrolysis precipitation reaction, performing liquid-solid separation after reacting for 1h to respectively obtain a second filtrate and bismuth precipitation slag, adding scrap iron into the second filtrate to perform displacement precipitation, performing liquid-solid separation to obtain sponge copper, adding coal powder and soda into the bismuth precipitation slag to perform reduction smelting to obtain crude bismuth;
E. d, heating the crude bismuth obtained in the step D to 650 ℃ for complete melting, fishing out the melting slag, stirring the bismuth liquid, cooling to 500 ℃, carrying out first liquation for copper removal and solidification for 10min, fishing out the copper dross slag, then continuously stirring, cooling to 320-350 ℃, carrying out second liquation for copper removal and solidification for 10min, and fishing out the copper dross slag;
F. heating the bismuth liquid after copper removal in the step E to 750 ℃ of 680-fold, blowing compressed air, turning over until white smoke is thin and lead oxide slag appears on the surface of the bismuth liquid, then adding a metal coating agent to dry the slag, fishing out arsenic and antimony slag, cooling the bismuth liquid after arsenic and antimony slag removal to 520 ℃ of 500-fold, adding caustic soda in batches, blowing compressed air simultaneously, wherein the hoof removal time is 6-10h, and when the caustic soda is added and stirred by the compressed air, the bismuth liquid after hoof and tin removal is obtained;
G. and F, cooling the bismuth liquid obtained in the step F to 400 ℃ for 350 plus materials, introducing chlorine into the bismuth liquid, stopping introducing chlorine when fishing out slag, heating to 550 ℃ for 500 plus materials, scooping out the slag, cooling to 400 ℃ for 350 plus materials after scooping out the slag each time, continuing introducing chlorine to obtain the bismuth liquid after removing lead and zinc, continuing heating the bismuth liquid to 720 ℃ for 680 plus materials, adding caustic soda and sodium nitrate, blowing compressed air, stirring, fishing out the chlorine slag, adding caustic soda to melt and cover the liquid level of the bismuth, cooling to 400 ℃ for 300 plus materials to carry out ingot casting, and finally obtaining refined bismuth.
The invention has the beneficial effects that: the process method is simple and convenient to operate, high in bismuth recovery rate and low in energy consumption, and solves the problems that the existing slag treatment method for the later stage of the silver separating furnace is single in recovery element, overlong in flow and low in metal recovery rate.
On the basis of the technical scheme, the invention can be further improved as follows.
In a further preferred embodiment of the present invention, in the step a, the mesh number of the bismuth slag powder is 120 meshes.
Further preferably, in the step B, the mass concentration of the sulfuric acid in the water and sulfuric acid forming aqueous solution is 16-19%, and the mass ratio of the industrial salt to the sulfuric acid aqueous solution is 1: 10.
As a further preferable mode of the invention, in the step C, the mass ratio of the leaching solution to the bismuth slag powder is 5:1, the leaching reaction time is 2 hours, the reaction temperature is controlled to be 80-90 ℃, and the pH value is controlled to be 0.5-1.
As a further preferable mode of the invention, in the step D, the mass ratio of the iron filings to the second filtrate is 1:20, and the mass ratio of the bismuth precipitation slag, the coal powder and the soda ash is 100: (5-7): (9-10), controlling the reduction smelting temperature to be 1100 ℃, and controlling the reaction time to be 8-10 h.
In the present invention, it is further preferable that in the step F, the mass ratio of the bismuth liquid to the metal coating agent is 30:1, the metal coating agent is soda ash, chaff or sawdust, and the amount of the added caustic soda is 1.5 to 2% of the mass of the bismuth liquid.
In the invention, in a further preferable mode, in the step G, the adding amount of the caustic soda is 5-10% of the weight of the bismuth liquid, and the adding amount of the sodium nitrate is 0.1-0.2% of the weight of the bismuth liquid.
Basic principle of the invention
After ball milling, the crushed slag (bismuth slag) at the later stage of the converter is mixed and leached with sulfuric acid and industrial salt (NaCl) at the temperature of 85-90 ℃, lead and silver are left in the slag, and bismuth and copper enter a solution in the states of bismuth sulfate and copper sulfate; by utilizing the characteristic that bismuth hydrolysis is stronger than copper, firstly hydrolyzing, neutralizing and precipitating bismuth, precipitating with bismuth oxychloride, then replacing precipitated copper, neutralizing and hydrolyzing to produce precipitated bismuth slag, and reducing, smelting and refining the precipitated bismuth slag in a smelting furnace to produce refined bismuth.
The main chemical reaction
H2SO4+BiO＝BiSO4+H2O
H2SO4+CuO＝CuSO4+H2O
BiSO4+6H++Cl-→BiOCl+3H2O
2CuSO4+Fe+4H+＝2Cu(OH)2+FeSO4
BiOCl+CO＝Bi+CO2+Cl2
Brief description of the procedure
Crushing later-stage slag (bismuth slag) of the silver separating furnace, grinding the crushed slag into powder in a ball mill, adding the powder into a leaching tank which contains sulfuric acid, industrial salt and aqueous solution for reaction at the temperature of 80-90 ℃, reacting for a period of time, adding bismuth and copper into the solution, and separating the liquid and the solid of the leaching solution through a plate-and-frame filter press. And then neutralizing and hydrolyzing bismuth to precipitate in the form of slag, replacing copper in the solution with iron powder to finally produce sponge copper, smelting bismuth slag in a pyrogenic reduction furnace to produce crude bismuth, and refining and removing impurities from the crude bismuth to obtain a final product refined bismuth.
Detailed Description
The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.