CN1345981A

CN1345981A - Process for enriching germanium and silver in zinc smelting process of heat acid leaching-ferro-alum method

Info

Publication number: CN1345981A
Application number: CN00126604A
Authority: CN
Inventors: 刘中清; 唐谟堂; 何静; 郭兰平; 杨声海; 郭山川; 彭长宏; 张显中; 姚维义; 范其明; 段恒建
Original assignee: HUIDONG LEAD-ZINC MINE SICHUAN PROV; Central South University
Current assignee: HUIDONG LEAD-ZINC MINE SICHUAN PROV; Central South University
Priority date: 2000-09-25
Filing date: 2000-09-25
Publication date: 2002-04-24

Abstract

The method for concentrating germanium and silver from zinc calcined ore is characterized by adopting improved traditional thermal pickling-iron vitriol method and zinc-smelting process, changing iron precipitation reagent and utilizing circulation leaching-partial opening method to concentrate germanium and silver. Said invention has no need of increasing equipment investment, can directly concentrate germanium and silver, the direct recovery rate of germanium is greater than or equal to 88%, its total recovery rate is greater than or equal to 90%, and the direct recovery rate of silver is greater than or equal to 90%, the concentrated slag germanium is greater than or equal to 300g.t (-1) and silver is greater than or equal to 1500 g.t(-1). The iron vitriol slag produced by said invented method contains rich fertilizer elements of potassium and zinc, can be used for preparing composite fertilizer.

Description

Method for enriching germanium and silver in hot acid leaching-jarosite method zinc smelting process

The invention relates to a method for comprehensively recovering germanium and silver in zinc sulfide concentrate, which is characterized in that when zinc calcine rich in germanium and silver is treated by the traditional hot acid leaching-jarosite method zinc smelting process, corresponding measures are taken to enrich the germanium and the silver in high-acid leaching slag under the condition that the original flow is basically not changed.

The rare metal element has special properties and has very important application in modern science and technology and advanced technology, and the rare metal germanium is sparsely distributed in the earth crust, has no separate mineral, often exists in the crystal lattices of other minerals in a similar way and has extremely low content. Such metals are thus mainly recovered synthetically from residues of the metallurgical and chemical industries. The rare and precious metals in the existing hot acid leaching-iron vitriol method process flow are dispersed in various zinc smelting residues by a wet method, which is extremely unfavorable for further comprehensive recovery. At present, the recovery of germanium in the hot acid leaching-zinc smelting process by an iron vitriol method is unprecedented at home and abroad.

For the enrichment of rare metals such as germanium, the acidic leaching residue of zinc hydrometallurgy is mainly treated by a Wilz method, gallium, indium and germanium are enriched in zinc oxide smoke dust, and then the processes of two-stage acid leaching, zinc powder replacement, two-stage acid leaching of the enrichment residue and gallium, indium and germanium extraction are adopted, but the germanium back-extraction rate is low, and an extracting agent is used for treating SiO₂The method is sensitive and easy to produce emulsification, has low direct germanium recovery rate and the like, and greatly limits the improvement of the total germanium recovery rate by adopting a Wilz method, wherein the volatilization rate of germanium is less than 80%. For the germanium-rich zinc oxide ore, germanium and zinc are directly volatilized and enriched by adopting a Wilz method, and wet treatment is also adopted, namely zinc is precipitated by using zinc ammonium double salt, and finally germanium is precipitated from a zinc precipitation solution by using tannin. And for hot acid leaching-When treating zinc ore containing germanium by a process of removing iron and zinc by a soda-iron alum method and a wet zinc smelting process, germanium is recovered from the solution after alum precipitation by a neutralization precipitation method, one third of the solution after alum precipitation is opened for germanium precipitation, only 75% of germanium enters the germanium precipitation slag, the problem of germanium dispersion caused by the fact that the germanium enters the high-acid leaching slag and the jarosite slag is not solved, and the high-acid leaching slag and the germanium precipitation slag must be treated respectively for recovering silver and germanium, so the treatment capacity is large.

The invention aims to provide a method for enriching germanium and silver when treating zinc calcine containing germanium and silver by using hot acid leaching-jarosite method.

The invention comprises the processes of neutral leaching of raw materials, low acid leaching, high acid leaching of low acid leaching underflow, alum precipitation of low acid leaching supernatant, displacement of alum precipitation liquid, germanium precipitation and the like, wherein the technological parameters of each process are respectively as follows:

(1) returning part of the low-acid leaching solution, strictly controlling the Ge/Fe in the medium leaching agent to be less than or equal to 1/25(wet.) and the end point pH value of the medium leaching solution to be 5.0-5.4 so as to reduce the loss of germanium in the medium leaching solution, and the temperature is 70 ℃ toThe immersion time is 0.5-4H at 90 ℃, the liquid-solid ratio is 4-12: 1, and the immersion agent contains Zn 50-100 g/L and H₂SO₄70～150g/L。

(2) Changing the traditional sodium alum precipitated iron into potassium alum precipitated iron, wherein the pH value of the precipitated iron is 1.0-1.5, and K₂SO₄Adding the raw materials in a concentrated solution form at 90-98 ℃ for 1-5 h, wherein the theoretical amount of the raw materials is 0.95-1.5 times of the theoretical amount of the raw materials, and taking zinc calcine or zinc oxide containing no germanium as a neutralizer to reduce the loss of germanium and silver in alum slag as much as possible;

(3) and circulating enrichment is carried out, and the vanadium precipitation liquid at the open circuit part enables the germanium to enter high-acid leaching slag and replacement slag. The displacement germanium precipitation conditions are as follows: the amount of zinc powder is 5-15 g/L, the temperature is 50-90 ℃, and the time is 0.5-2.0 h.

The invention uses 10g/LH for the alum dregs obtained after alum precipitation₂SO₄Washing for three times, and then washing for more than three times, wherein the amount of the washing agent is 5-15% of that of the stock solution respectively.

The germanium-silver-containing high leaching residue is treated to obtain rare metals such as germanium, silver and the like.

The material adopted by the invention is a mixture of zinc calcine containing germanium and silver and smoke dust.

The enriched germanium and silver of the invention comprises the following components (%): zn 5-10; pb 6-9; fe 6-9; ge is more than or equal to 0.03; ag is more than or equal to 0.15; SiO 2₂20～25；S3～5。

The invention has the advantages that the continuity and the integrity of the original flow are not changed, the loss of germanium in the medium leaching solution and the alum slag is respectively less than or equal to 5 percent and 10 percent, more than 89 percent of germanium is enriched in the high leaching slag, the total direct yield of the germanium is improved by more than 40 percent compared with the traditional flow, the germanium content of the high acid leaching slag is more than or equal to 300g.t^-1Silver content is more than or equal to 1500g.t^-1This is very advantageous for further comprehensive recovery.

The silver and the germanium can be treated in a centralized way, the recovery rate is high, the open circuit proportion of the solution after the vanadium precipitation is small (less than or equal to 6 percent), the total material amount of the further recovery silver and germanium treatment is less than 13 percent of the total material added, and the reduction is 30 percent compared with the conventional process; the proportion of germanium entering potassium iron vitriol slag is very low, while silver hardly enters iron vitriol slag. The potassium iron vitriol slag is rich in fertilizer elements such as potassium, zinc and the like, is expected to be further comprehensively utilized and used as a raw material for producing compound fertilizer, turns harm into benefit and reduces environmental pollution.

The technological process and the reaction principle of the invention are as follows:

neutral leaching process

When the intermediate leaching is started, the acidity is higher, a small part of germanate is decomposed and enters the solution, and free GeO₂GeO hardly remains in the leaching residue; meanwhile, with the continuous addition of the calcine, the pH value is increased, and the germanium entering the solution is precipitated again to separate out GeO₂At a pH of 5 to 5.2, with xFe₂O₃.YH₂O.zFe³⁺Or xFe (OH)₃.YH₂O.zFe³⁺The ferric hydroxide colloid in the form of the magnetic suspension can adsorb HGeO without selection^-、GeO₃ ^-And the complex anion of germanium is formed into high polymer and coprecipitated. As long as m (ge) in the medium-immersion agent is controlled: m (Fe) is not more than 1/25(mol), and the primary immersion is carried out when the pH value is 5.2-5.4

93.8% -98.8% of germanium entering the solution is precipitated. The main reaction is as follows:

………①

……………②

………………③

……………………④

…………………………………⑤

…………………………⑥

second, the process of precipitating alum and removing iron-no precipitation of germanium in precipitating iron

The acidity of the low acid leaching supernatant was about 16g.l^-1And adding potassium sulfate at 90-95 ℃ to precipitate iron into jarosite slag through jarosite which is easy to filter, and adding germanium-free calcine to adjust the pH value to be 1.0-1.5 in the iron precipitation process. The pH value of the potassium iron alum is low (less than or equal to 1.5), and the generation speed is high, so that little germanium enters the alum slag.

However, when Nateur or Ambrotite is used, the pH is more than or equal to 1.5, and Fe (OH) is formed in the solution₂ ⁺.4H₂O，Fe(OH)²⁺.5H₂O，Fe(OH)₃.3H₂O，Fe(OH)₄.2H₂O, etc., germanic acid colloid dissolved in the solution, and Fe (OH) by physical adsorption₃Colloidal coprecipitation results in the dispersion of germanium into the jarosite slag. The reaction is as follows:

………⑦

…………………………………⑧

in the formula: a represents Na⁺Or NH₄ ⁺

Most of iron can be removed under the condition that the pH value is less than 1.5 by adopting the potassium iron alum to precipitate iron, and iron hydroxide is not easy to form, so that the proportion of germanium entering alum slag is less than 10 percent, and the proportion is lower when a germanium-free neutralizing agent is adopted; meanwhile, because the potassium iron alum is more stable than the silver iron alum, the silver iron alum generated by the silver dissolved in the solution before alum precipitation can be prevented from entering the iron alum slag to cause the dispersion of the silver.

And thirdly, cyclic leaching, namely partial open circuit germanium precipitation inevitably leads to cyclic enrichment of germanium and other impurity elements in the process through the two measures, and the proportion of germanium entering the alum slag is increased when the germanium reaches a certain degree, so that the open circuit is required in time, and the germanium in the open circuit iron removing liquid is recovered by adopting a zinc powder replacement method. The replacement liquid for precipitating germanium and the solution for removing iron from precipitating vanadium are combined and returned to neutral leaching.

Description of the drawings:

FIG. 1 shows the principle process flow of the method.

Example 1 raw material main components (%): zn65.22; pb1.01; ga 0.00232; in0.00019,ge0.0082; fe2.382; s2.346; ag0.023.

The method adopts an improved hot acid leaching-iron alum method flow (figure 1), and mainly comprises ① neutral leaching process with the end point pH of 5.2-5.4 and Ge/Fe not more than 1/25 (wet), ② alum deposition process with the end point pH of 1.0-1.5 and K₂SO₄Used as iron removing agent for precipitating alum, using zinc roasted sand containing germanium as neutralizing agent, ③ when the solution germanium reaches 400mg^-1Opening a 10% (volume) solution after alum precipitation, and precipitating germanium by adopting a zinc powder displacement method; the other conditions are the same as the traditional hot acid leaching-iron vitriol method. The results of ten cycles of the cycling test at 100 g/time scale were as follows:

the total loss of germanium into neutral leaching liquid is 2.11 percent, the total loss of germanium into potassium iron alum slag is 9.55 percent, and the loss of germanium in the roasted sand used as a neutralizer for precipitating alum is 9.5 percent, which means that when the roasted sand without germanium is used as the neutralizer, the loss of germanium in the alum slag can be greatly reduced; the total recovery rate of germanium is 88.34 percent, the direct recovery rate is more than or equal to 85 percent, and the average content of germanium in the high-acid leaching residue is more than or equal to 0.039 percent; the average content of silver is more than or equal to 0.15 percent, and the total recovery rate of silver entering the high-acid leaching residue is close to 100 percent.

Example 2. the raw materials are the same as example 1, the flow and process conditions are basically the same as example 1, but zinc calcine (components (%): Zn60.14, Fel1.02, Ge0.00056) with extremely low germanium content is used as a neutralizer, and germanium is not precipitated from the solution after vanadium precipitation; ten cycles of the test were carried out on a 10 Kg/time scale, with satisfactory results: the germanium losses in the medium leaching solution and the alum slag are respectively 4.62 percent and 5.46 percent, the total recovery rate of germanium is 89.92 percent, the average germanium content of the high-acid leaching slag is 0.0326 percent, the silver recovery rate is nearly 100 percent, the total recovery rate and the direct recovery rate of zinc are respectively 96.8 percent and 92.52 percent, and the average high-acid leaching slag rate is 12.97 percent.

Claims

1. A method for enriching germanium and silver in a hot acid leaching-jarosite method zinc smelting process comprises neutral leaching of raw materials, low acid leaching, high acid leaching of low acid leaching underflow and alum precipitation of low acid leaching supernatant, and is characterized in that:

a>returning part of low acid leaching solution, maintaining the Ge/Fe ratio in the intermediate leaching agent to be less than or equal to 1/25, simultaneously ensuring the pH value of the intermediate leaching end point to be 5.0-5.4, the temperature to be 70-90 ℃, the intermediate leaching time to be 0.5-4H, the liquid-solid ratio to be 4-12: 1, and the leaching agent to contain Zn 50-100 g/L and H₂SO₄70～150g/L；

b>Adopting potassium iron alum to precipitate iron, wherein the condition of precipitating the alum is as follows: k₂SO₄Adding the raw materials in a concentrated solution form at 90-98 ℃ for 1-5 h and with the pH value of 1.0-1.5, wherein the theoretical amount is 0.95-1.5 times that of the theoretical amount, and the neutralizing agent is slowly added by using zinc calcine containing no germanium (-100 meshes) or zinc hypoxide as a neutralizing agent;

c, replacing the solution after the vitriol precipitation of the open circuit part for germanium precipitation, wherein the germanium precipitation conditions are as follows: the amount of zinc powder is 5-15 g/L, the temperature is 50-90 ℃, and the time is 0.5-2.0 h.

2. The method of claim 1, wherein: the alum residue obtained after alum precipitation is used by 10g/LH₂SO₄Washing for three times, and then washing for more than three times, wherein the amount of the washing agent is 5-15% of that of the stock solution respectively.