CN108085486B - A method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method - Google Patents

Abstract

The invention discloses a method for extracting manganese from low-grade pyrolusite by a combined grinding-pressurization method, comprising the steps of: (1) grinding the dried pyrolusite step by step to form pyrolusite powder; (2) grinding lignite Treat with 0.5 mol L ^‑1 sulfuric acid solution and then dry, and form lignite powder after step-by-step grinding; (3) mix the above pyrolusite powder with lignite powder, and fully grind to form pyrolusite/lignite composite; (4) The above-mentioned pyrolusite ^/ lignite composite was kept in a nitrogen atmosphere at 200 ^OC to 550 OC for a period of time, and cooled to room temperature to obtain a pretreatment composite; (5) the above pretreatment composite was mixed with 1 mol L ^‑ The mixture of sulfuric acid solution of ¹ is transferred into a high-pressure reactor, and kept at 180 ^OC ~300 ^OC for a certain period of time, the obtained filtrate is the pyrolusite extract, and the obtained filter residue can be used as fuel after drying. The invention has low raw material cost, simple reaction process and high manganese leaching rate, and is suitable for the industrial pyrolusite extraction process.

Description

A method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method

technical field

The invention relates to a technique for leaching manganese from low-grade pyrolusite by using lignite as a reducing agent through a combined grinding-pressurization method, which belongs to the field of hydrometallurgy.

Background technique

Manganese products play a very important role in people's daily life and in industrial and agricultural production. At present, manganese products are mainly used in the field of alloys, while manganese dioxide is mainly used in the primary battery and secondary battery industries, and its application is very extensive. The most common mineral of manganese is pyrolusite, the main component of which is manganese dioxide, and manganese also exists in the form of other minerals, such as rhodochrosite (MnCO3), rhodonite (MnSiO3), black manganese ore (MnOOH), pyrromanganite (MnS) etc. my country's manganese ore resources are mainly distributed in Guangxi, Hunan, Yunnan, Guizhou and other places. The quality and grade of the ore are relatively poor compared with foreign countries. How to develop and utilize my country's manganese ore resources to serve the national economy is an important issue.

Low-grade pyrolusite (Mn%<40%) is more abundant in the southwest of my country, but how to extract the manganese, especially how to solve the key technical problem of reduction process, is still an important link in the development and utilization of pyrolusite. Manganese ions in pyrolusite mainly exist in the form of manganese dioxide. The reducing agent reduces high-priced manganese dioxide to low-priced manganese (ІІ), and then converts it into soluble manganese salt in an acidic environment to reduce and leaching manganese from the ore.

At present, the main methods for extracting manganese from pyrolusite are:

(1) High-temperature roasting reduction method: This is a traditional method for preparing manganese sulfate products. At a reduction roasting temperature of 700-900°C, manganese dioxide in pyrolusite is finally reduced to divalent manganese oxide, which is then extracted in an acidic solution. Manganese out. The reducing agent in the reduction process usually adopts reducing substances such as coal powder, carbon monoxide, hydrogen, and methane. In the reduction process of this method, reverberatory furnace, reduction furnace, rotary kiln and other equipment should be used, and cooling water should be sprayed after high-temperature roasting to cool the rotary kiln rapidly, otherwise, the produced manganese oxide will be oxidized to manganese trioxide in the air . The generated manganese oxide is an alkaline oxide, which is easy to react with dilute sulfuric acid. In addition, the main disadvantage of this method is that it consumes a lot of energy and causes great pollution, which is not conducive to the development of pyrolusite.

(2) Sulfur dioxide reduction method: Although the sulfur dioxide reduction pyrolusite process is relatively mature, there is the formation of dithionate, which affects the quality of the product. So far, it has not been applied on a large scale in industry, and it is only used in environmental protection. Desulfurization.

(3) Two-mine one-step method: This is a reduction leaching reaction that has been studied more. This reaction can not only reduce and leach manganese dioxide in pyrolusite, but also convert iron disulfide in pyrite into iron sulfate. The two-mine one-step method can be completed in one step in the reaction tank, the process flow is simple, and the pyrite resources are abundant, which can meet the needs of pyrolusite reduction and improve the operating environment for workers to a certain extent. However, the leaching rate of manganese is low, and the impurity removal and purification cannot meet the requirements of electrolytic manganese parameters, and cannot be realized in electrolytic manganese and manganese dioxide processes. In addition, this method will also produce a large amount of waste residue, and the follow-up treatment is troublesome.

(4) Organic matter reduction method: Use organic matter such as glucose, sucrose, lactose, crop products or by-products as a reducing agent, which can react with manganese dioxide in pyrolusite in an acidic environment to reduce high-valent manganese to Mn ²⁺ . This method has moderate reaction temperature and low investment cost, and is a feasible route. However, when organic matter is used as a reducing agent, the leaching reaction is not thorough enough, and a small amount of small molecules will be produced and dissolved in the leaching solution, which is difficult to purify. Especially in the electrolysis industry, a small amount of organic matter may cause electrolysis to fail to proceed normally.

(5) Hydrogen peroxide reduction method: When hydrogen peroxide is used as the reducing agent, more hydrogen peroxide is consumed, and the price of the latter is higher, which obviously increases the cost of the whole process.

(6) Biological reduction method: When microorganisms are used as reducing agents, manganese in pyrolusite can also be leached with high efficiency. However, after the leaching is completed, how to deal with the microorganisms, how to purify the leachate and finally obtain pure manganese products have not yet been resolved.

(7) Ferrous ion or iron filings leaching method: use the reducibility of ferrous ion in acidic solution to reduce pyrolusite to soluble manganese ion at a faster speed, which is the basic principle of ferrous ion reduction method. In the acid pyrolusite solution, adding sponge iron directly can quickly reduce the tetravalent manganese in the pyrolusite to divalent manganese, which is more effective than using ferrous sulfate. These two methods are basically the same in essence, but in their follow-up treatment process, a large amount of ferric hydroxide needs to be separated and removed, and there are many problems such as complicated process, large amount of impurities, and difficult handling.

Lignite, also known as firewood coal, is the mineral coal with the lowest degree of coalification. A brown-black, dull, low-rank coal between peat and bituminous coal. It has strong chemical reactivity and strong reducibility. However, lignite is not an excellent fuel coal due to its low degree of coalification. However, precisely because of its low degree of coalification, which contains a large amount of oxidizable organic compounds, it is feasible to use it as a reducing agent to reduce pyrolusite to extract manganese, and it also has important practical significance in the comprehensive utilization of lignite. significance.

The invention uses lignite as a reducing agent to reduce high-valent manganese in pyrolusite to soluble divalent manganese in an acidic solution by increasing the reaction temperature and pressure, thereby realizing the low-cost and high-efficiency manganese extraction process. Since this is a solid-solid-liquid reaction, the present invention firstly grinds lignite and pyrolusite particles into powder particles; then these two solid particles are mixed together and then fully ground, because they are nano Particle-level particles, under such high-speed grinding, the two kinds of particles can fully contact, which is very beneficial to their subsequent reaction. Then they are ultrasonically dispersed in sulfuric acid solution; finally, they are fully reacted in a hydrothermal reactor to reduce and extract the manganese in the pyrolusite, and the filter residue can be used as fuel after being dried. The invention has low raw material cost, simple reaction process, greatly shortened reaction time, high manganese leaching rate, and is suitable for the industrial pyrolusite extraction process.

Contents of the invention

The purpose of the present invention is to provide a method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method.

Embodiments of the present invention are: a method for extracting manganese from low-grade pyrolusite with a grinding-pressurization combined method, comprising the following steps:

(1) First dry the ^pyrolusite solid in the air at 80 ℃, then pre-grind the dried pyrolusite into particles, and then continue to grind the pre-ground pyrolusite particles into pyrolusite powder;

(2) Mix lignite with 0.5 mol L ^-1 sulfuric acid solution, heat in a water bath at 50 ^OC and fully stir, filter, wash with water, dry the obtained ^lignite in air at 80 OC, and then pre-grind the dried lignite into particles, and then continue to grind this pre-ground lignite particles into lignite powder;

(3) The above-mentioned pyrolusite powder with a particle size of about 500 nm is mixed with lignite powder with a particle size of about 300 nm, and fully ground to form a pyrolusite/lignite composite; the pyrolusite with a particle size of about 500 nm The mass ratio of powder to lignite powder with a particle size of about 300 nm is 1: 1 ~ 5;

(4) Heat the above pyrolusite/lignite composite in a nitrogen atmosphere at a rate of 4 ^OC min ^-1 to 200 ^OC ~ 550 ^OC , keep it at this temperature for a period of time, and then cool it naturally to room temperature, obtain a pretreatment complex;

(5) Mix the above pretreatment compound with 1 mol L ^-1 sulfuric acid solution, then transfer the mixture into a high-pressure reactor and heat it to 180 ^OC ~ 300 ^OC for a certain period of time, then cool to room temperature, filter , the resulting filtrate is the pyrolusite extract, and then the manganese is extracted from the pyrolusite extract; the mass-volume ratio of the quality of the pretreatment compound to the sulfuric acid solution of 1 mol L ^-1 is 15 ~ 50 g: 100mL.

Preferably, in step (1), pre-grind the dried pyrolusite into particles with a particle size of about 1 mm, and then continue to grind the pre-ground pyrolusite particles into pyrolusite powder with a particle size of about 500 nm .

Preferably, in step (2), the dried lignite is pre-ground into particles of about 1 mm, and the pre-ground lignite particles are further ground into lignite powder with a particle size of about 300 nm.

As a preference, in step (4), the heating temperature is 350 ^° C to 450 ^° C, and the optimum temperature is 400 ^° C.

As a preference, in step (5), the heating temperature is 250 ^° C.

The present invention fully grinds pyrolusite and lignite to form small particles with a large surface area, thereby ensuring that the two solid substances of pyrolusite and lignite have a sufficient contact area during the reaction; by mixing the fully ground pyrolusite and lignite , and further ground to make the particles of the two fully contact; further heating this mixed solid at a certain temperature, because the pyrolusite is in full contact with the lignite, so that the high-valent manganese in the pyrolusite can be partially reduced to low-priced manganese Finally, the high-valent manganese in the pyrolusite is completely leached out through high-temperature and high-pressure leaching reactions, and the resulting filter residue is mainly unreacted or less-reacted lignite, which can be used as fuel after drying. The invention has low raw material cost, simple reaction process and high manganese leaching rate, and is suitable for the industrial pyrolusite extraction process.

Embodiment of the invention

Example 1:

(1) First dry the pyrolusite solid in an air drying oven at 80 ^OC for 24 hours; then place the dried pyrolusite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; Then transfer the pre-ground pyrolusite particles into a high-speed ball mill, and continue to grind it into pyrolusite powder with a particle size of about 500 nm.

(2) Mix lignite with 0.5 mol L ^-1 sulfuric acid solution, heat and stir in a 50 ^OC water bath for 3 hours; then filter, wash twice with water, and dry the obtained lignite in an air drying oven at 80 ^OC for 24 hours; Then put the dried lignite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; then transfer the pre-ground lignite particles into a high-speed ball mill, and continue grinding it into particles It is lignite powder with a thickness of about 300 nm.

(3) Mix the above-mentioned pyrolusite powder with a particle size of about 500 nm and lignite powder with a particle size of about 300 nm in a high-speed ball mill at a mass ratio of 1:1, and fully grind for 0.5 to 1.5 hours to form pyrolusite / lignite complex.

(4) Transfer the above pyrolusite ^/ lignite compound into a tube furnace, heat it to 200 OC at a rate of 4 ^OC min ^-1 in a nitrogen atmosphere, and keep it at this temperature for 2 hours, then cool naturally to room temperature to obtain the pretreatment complex;

(5) Mix the above-mentioned pretreatment compound with 1 mol L ^-1 sulfuric acid solution at a ratio of 15:100mL, then transfer the mixture into an autoclave, heat to 180 ^OC and keep it for 4 hours; then Cool to room temperature, filter, wash the filter residue with water until neutral, and the obtained filter residue can be used as fuel after drying; the obtained filtrate is the pyrolusite extract, and the content of soluble Mn ²⁺ is analyzed by conventional atomic absorption spectrometry After analysis, the extraction efficiency of manganese in pyrolusite was 93%.

Example 2:

(1) First dry the pyrolusite solid in an air drying oven at 80 ^OC for 24 hours; then place the dried pyrolusite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; Then transfer the pre-ground pyrolusite particles into a high-speed ball mill, and continue to grind it into pyrolusite powder with a particle size of about 500 nm.

(2) Mix lignite with 0.5 mol L ^-1 sulfuric acid solution, heat and stir in a 50 ^OC water bath for 3 hours; then filter, wash twice with water, and dry the obtained lignite in an air drying oven at 80 ^OC for 24 hours; Then put the dried lignite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; then transfer the pre-ground lignite particles into a high-speed ball mill, and continue grinding it into particles It is lignite powder with a thickness of about 300 nm.

(3) Mix the above-mentioned pyrolusite powder with a particle size of about 500 nm and lignite powder with a particle size of about 300 nm in a high-speed ball mill at a mass ratio of 1:2, and fully grind for 1 hour to form pyrolusite/lignite Complex.

(4) Transfer the above-mentioned pyrolusite ^/ lignite compound into a tube furnace, heat it to 300 OC at a rate of 4 ^OC min ^-1 in a nitrogen atmosphere, and keep it at this temperature for 2 hours, then cool naturally to room temperature to obtain the pretreatment complex;

(5) Mix the above pretreatment compound with 1 mol L ^-1 sulfuric acid solution at a ratio of 30:100mL, then transfer the mixture into an autoclave, heat to 240 ^OC and keep it for 2 hours; then Cool to room temperature, filter, wash the filter residue with water until neutral, and the obtained filter residue can be used as fuel after drying; the obtained filtrate is the pyrolusite extract, and the content of soluble Mn ²⁺ is analyzed by conventional atomic absorption spectrometry After analysis, the extraction efficiency of manganese in pyrolusite was 96%.

Example 3:

(1) First dry the pyrolusite solid in an air drying oven at 80 ^OC for 24 hours; then place the dried pyrolusite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; Then transfer the pre-ground pyrolusite particles into a high-speed ball mill, and continue to grind it into pyrolusite powder with a particle size of about 500 nm.

(2) Mix lignite with 0.5 mol L ^-1 sulfuric acid solution, heat and stir in a 50 ^OC water bath for 3 hours; then filter, wash twice with water, and dry the obtained lignite in an air drying oven at 80 ^OC for 24 hours; Then put the dried lignite in an ordinary ball mill for pre-grinding, and grind it into particles with a particle size of about 1 mm; then transfer the pre-ground lignite particles into a high-speed ball mill, and continue grinding it into particles It is lignite powder with a thickness of about 300 nm.

(3) Mix the above-mentioned pyrolusite powder with a particle size of about 500 nm and lignite powder with a particle size of about 300 nm in a high-speed ball mill at a mass ratio of 1:5, and fully grind for 1.5 hours to form pyrolusite/lignite Complex.

(4) Transfer the above pyrolusite ^/ lignite composite into a tube furnace, heat it to 450 OC at a rate of 4 ^OC min ^-1 in a nitrogen atmosphere, and keep it at this temperature for 2 hours, then cool naturally to room temperature to obtain the pretreatment complex;

(5) Mix the above pretreatment compound with 1 mol L ^-1 sulfuric acid solution at a ratio of 50:100mL, then transfer the mixture into a high-pressure reactor, heat to 300 ^OC and keep it for 1 hour; then Cool to room temperature, filter, wash the filter residue with water until neutral, and the obtained filter residue can be used as fuel after drying; the obtained filtrate is the pyrolusite extract, and the content of soluble Mn ²⁺ is analyzed by conventional atomic absorption spectrometry Carry out analysis, obtain the extraction efficiency of manganese in pyrolusite to be 97%.

Claims (4)

1. a method for extracting manganese from low-grade pyrolusite with grinding-pressurization combined method, is characterized in that comprising the following steps: (1) First dry the pyrolusite solid in the air at 80°C, then pre-grind the dried pyrolusite into particles, and then continue to grind the pre-ground pyrolusite particles into a pyrolusite powder with a particle size of 500 nm; (2) Mix lignite with 0.5 mol L ^-1 sulfuric acid solution, heat in a water bath at 50°C and fully stir, filter, wash with water, dry the obtained lignite in air at 80°C, and then pre-grind the dried lignite into Particles, and this pre-ground lignite particles continue to be ground into a particle size of 300 nm lignite powder; (3) Mix the above-mentioned pyrolusite powder with a particle size of 500 nm and lignite powder with a particle size of 300 nm, and fully grind them to form a pyrolusite/lignite composite; The mass ratio of lignite powder with a diameter of 300 nm is 1: 1 ~ 5; (4) Heat the above-mentioned pyrolusite/lignite composite in a nitrogen atmosphere at a rate of 4°C·min ^-1 to 200°C~550°C, keep it at this temperature for a period of time, and then cool it naturally to room temperature to obtain the desired processing complexes; (5) Mix the above pretreatment compound with 1 mol L ^-1 sulfuric acid solution, then transfer the mixture into a high-pressure reactor and heat it to 180°C~300°C for a certain period of time, then cool to room temperature, filter, The obtained filtrate is the pyrolusite extract, and then manganese is extracted from the pyrolusite extract; the ratio of the mass of the pretreatment compound to the mass volume of the 1 mol·L ^-1 sulfuric acid solution is 15 to 50 g : 100mL. 2. The method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method according to claim 1, characterized in that the heating temperature in step (4) is 350°C~450°C. 3. The method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method according to claim 2, characterized in that, the heating temperature is 400°C. 4. The method for extracting manganese from low-grade pyrolusite by grinding-pressurizing combined method according to claim 1, characterized in that the heating temperature in step (5) is 250°C.