CN102094119A - Method for preparing electrolytic manganese metal with low-grade pyrolusite wet leaching - Google Patents

Abstract

The invention discloses a method for preparing electrolytic metal manganese by wet leaching of low-grade pyrolusite. The method is to crush and screen the low-grade pyrolusite, then use electrolytic manganese anode liquid to adjust slurry, add sulfuric acid to control acidity, and reduce iron powder Or waste iron filings are used as a reducing agent to reduce the high oxidation state manganese which is insoluble in water to the low oxidation state manganese which is easy to dissolve in water through redox reaction. Control certain acidity, reaction temperature and time, stir and leach, and then carry out sedimentation and filtration. The filtrate is purified and separated to obtain a pure manganese sulfate solution, and the manganese sulfate solution is electrolyzed to prepare an electrolytic manganese product. Among them, the leaching rate of manganese is greater than 98%, the recovery rate of manganese is greater than 90%, and the purity of electrolytic metal manganese is greater than 99.8%. The method of the invention has wide sources of reducing agent raw materials, low price, short reaction time, mild leaching process conditions, high manganese leaching rate, simple purification process, and does not change the existing process route for preparing electrolytic manganese metal from manganese carbonate ore.

Description

A method for preparing electrolytic metal manganese by wet leaching of low-grade pyrolusite

technical field

The invention relates to a method for preparing electrolytic metal manganese by wet leaching of low-grade pyrolusite as raw material.

Background technique

my country's manganese resources are abundant but not rich. The ascertained resource reserves are 640 million tons. The ore types are mainly manganese carbonate ore, followed by manganese oxide ore and iron-manganese ore. Most of them are poor manganese ore, and rich manganese ore only accounts for 6-8 %. The technology of producing electrolytic manganese with carbonate ore as raw material is mature, ranks the international leading level, and is widely adopted by domestic enterprises. With years of mining, my country's rich manganese ore resources have declined sharply. At present, the shortage of manganese ore resources is restricting the production and sustainable development of manganese products in my country. In some areas where the production of electrolytic manganese metal products is concentrated in my country, the grade of manganese carbonate used has been reduced from 18-20% manganese to only 10-15%. On the other hand, because the smelting of low-grade pyrolusite is difficult, the recovery rate is low, and the cost of the reduction process is too high, it is difficult to economically recover the valuable metals in the ore regardless of the existing pyrolysis process or wet process. , the economic benefit is restricted by the grade of manganese in the ore, resulting in a large amount of pyrolusite containing 20-25% manganese not being utilized. Therefore, in the field of electrolytic manganese production, the utilization of low-grade pyrolusite is still a blank. How to use low-grade pyrolusite to produce electrolytic metal manganese, especially solve the bottleneck technical problem of its reduction process, and improve the comprehensive utilization of resources. It is a subject to be solved urgently, and it is also the goal pursued by electrolytic manganese metal enterprises. This is of great strategic significance to alleviate the current shortage of manganese ore resources in my country and ensure the sustainable development of the electrolytic manganese industry.

Contents of the invention

The purpose of the present invention is to provide a method for preparing electrolytic metal manganese by using low-grade pyrolusite as raw material and adopting a wet reduction leaching process.

In the present invention, after the low-grade pyrolusite is crushed and screened, the electrolytic manganese anode liquid is used to adjust the slurry, sulfuric acid is added to control the acidity, and the reduced iron powder or scrap iron chips are used as the reducing agent, and the high Oxidized manganese is reduced to a lower oxidized manganese which is readily soluble in water. Control certain acidity, reaction temperature and time, stir and leach, and then carry out sedimentation and filtration. The filtrate is purified and separated to obtain a pure manganese sulfate solution, and the manganese sulfate solution is electrolyzed to prepare an electrolytic manganese product.

Implementation steps of the present invention are as follows:

Crush the low-grade pyrolusite to 50-300 mesh, prepare the pulp with 10% sulfuric acid or electrolytic manganese anolyte that is 2-10 times the quality of pyrolusite, and add reduced iron powder that is 0.1-0.5 times the quality of pyrolusite to the pulp Or waste iron scraps are used as a reducing agent, continuously stirred and reacted at a temperature of 50-95°C for 0.5-4 hours to obtain a reaction leaching solution, and the pH of the reaction leaching solution is adjusted to 2.0-3.0 with an acidity regulator. The acidity regulator is ammonia water, and the pH value is adjusted with ammonia water When the concentration of ammonium sulfate produced by neutralization exceeds the allowable concentration of electrolytic manganese process by 120-140g/L, use manganese carbonate ore or manganese carbonate instead of ammonia water to adjust the pH value; then add H ₂ O ₂ to oxidize Fe ²⁺ to Fe ³⁺ , stir and purify for 1-2 hours, remove iron and other heavy metal ions, filter to obtain leachate, use SDD to remove impurities in the filtrate, adjust pH to 5.0-6.7 with ammonia water, and then perform electrolysis to produce electrolytic manganese metal according to conventional methods. The leaching rate of manganese is greater than 98%, the purity of electrolytic metal manganese is greater than 99.8%, and the recovery rate of manganese is greater than 90%.

The invention adopts an all-wet process, reduces energy consumption, reduces environmental pollution, improves resource utilization, and realizes clean production. The reducing agent has wide sources of raw materials, low price, short reaction time, mild leaching process conditions, high manganese leaching rate, simple purification process, and does not change the existing process route for preparing electrolytic manganese metal from manganese carbonate ore. The raw material source of manganese ore, thereby alleviating the tight supply of manganese carbonate ore, has the dual benefits of environmental protection and economy.

Detailed ways:

Embodiment one:

The pyrolusite with a manganese content of 28.86% is crushed to 100 mesh (composition is as shown in Table 1), the pulp is prepared with 4 times of 10% dilute sulfuric acid solution of pyrolusite, and the waste iron scraps ( iron content 90%), stirred and reacted at 90°C for 2 hours to obtain a reaction leaching solution; the leaching solution was neutralized with manganese carbonate or ammonia water as an acidity regulator to a pH of 2.0-3.0, and an appropriate amount of H ₂ O ₂ was added to oxidize Fe ²⁺ to Fe ³⁺ , stirred and purified for 1 hour, and filtered to obtain leachate. SDD is used to further remove heavy metal ion impurities in the leachate after iron removal is qualified, the pH is adjusted to 6.7 with ammonia water, the concentration of ammonium sulfate is adjusted, and electrolysis is performed according to the conventional electrolytic manganese process. The leaching rate of manganese is 98.5%, the purity of electrolytic metal manganese is 99.85%, and the recovery rate of manganese is 95%.

Table 1 composition list of pyrolusite

Embodiment two:

The pyrolusite with a manganese content of 28.86% was crushed to 120 meshes (the composition is shown in Table 1), and the pulp was prepared with an electrolytic manganese anolyte 5 times that of the pyrolusite. Add reduced iron powder (containing 85% iron) of 0.3 times the mass of pyrolusite to the pulp, stir and react at 95° C. for 2 hours to obtain a reaction leaching solution. The leaching solution is neutralized with manganese carbonate as an acidity regulator until the pH is 2.0-3.0, an appropriate amount of H ₂ O ₂ is added to oxidize Fe ²⁺ to Fe ³⁺ , stirred and purified for 1 hour, and the leaching solution is obtained by filtration. SDD is used to further remove heavy metal ion impurities in the leachate after iron removal is qualified, the pH is adjusted to 6.5 with ammonia water, the concentration of ammonium sulfate is adjusted, and electrolysis is performed according to the conventional electrolytic manganese process. The leaching rate of manganese is 98.8%, the purity of electrolytic metal manganese is 99.86%, and the recovery rate of manganese is 95.3%.

Embodiment three:

The pyrolusite with a manganese content of 28.86% was crushed to 80 meshes (the composition is shown in Table 1), and the pulp was prepared with an electrolytic manganese anolyte 4.5 times that of the pyrolusite. Add scrap iron chips (90% iron content) 0.25 times the mass of pyrolusite to the pulp, stir and react at 90° C. for 2 hours to obtain a reaction leaching solution. The leaching solution was neutralized with ammonia water as an acidity regulator until the pH was 2.0-3.0, an appropriate amount of H ₂ O ₂ was added to oxidize Fe ²⁺ to Fe ³⁺ , stirred and purified for 1 hour, and the leaching solution was obtained by filtration. SDD is used to further remove heavy metal ion impurities in the leachate after iron removal is qualified, the pH is adjusted to 6.6 with ammonia water, and electrolysis is performed according to a conventional method. The leaching rate of manganese is 98.8%, the purity of electrolytic metal manganese is 99.88%, and the recovery rate of manganese is 95.5%.

Claims (3)

1. a low-grade pyrolusite wet method leaches the method for preparing electrolytic metal Mn, it is characterized in that low-grade pyrolusite is pulverized the 50-300 order, with the 2-10 of pyrolusite quality 10% sulfuric acid or electrolytic manganese anolyte modulation ore pulp doubly, the 0.1-0.5 that adds the pyrolusite quality in the ore pulp doubly reduced iron powder or waste iron filing as reductive agent, under 50-95 ℃ of temperature, constantly obtained reacting leach liquor in stirring reaction 0.5-4 hour, it is 2.0-3.0 that the reaction leach liquor is adjusted agent adjusting pH with acidity, adds H ₂O ₂With Fe ²⁺Be oxidized to Fe ³⁺, stir and purify 1-2 hour, remove heavy metal ion such as de-iron, to filter and obtain leach liquor, filtrate is used the SDD deep impurity-removing, transfers pH to 5.0-6.7 with ammoniacal liquor, carries out the electrolysis production electrolytic metal Mn more according to a conventional method.

2. a kind of low-grade pyrolusite wet method according to claim 1 leaches the method for preparing electrolytic metal Mn, it is characterized in that described low-grade pyrolusite is a manganese content greater than 15% pyrolusite.

3. a kind of low-grade pyrolusite wet method according to claim 1 leaches the method for preparing electrolytic metal Mn, it is characterized in that it is ammoniacal liquor or manganese carbonate ore or manganous carbonate that described acidity is adjusted agent.