Production process of electrolytic manganese metal mainly can be divided in two stages: (1) prepare electrolytic solution. Manganese ore powder react with the inorganic acid, heating to prepare manganese salt solution.
Added the ammonium salt as buffer to the solution at the same time, remove iron with the method of adding addition to oxidize, add cleaning agent to remove heavy metals, and then separation and filtration, Add electrolytic additives as an electrolytic solution in the solution. At present, industrial production widely use sulfuric acid dip manganese to prepare electrolytic solution, use manganese chloride salt solution electrolysis method to prepare manganese metal has not formed the production scale. (2) The electrolytic procedure. Inject ammonium-containing sulfate manganese water-soluble electrolyte to spacer mold electrolyzer, and turn on the DC power to produce electricity out effect, and to precipitate manganese in anode plate, precipitated oxygen in the cathode plate; periodically replace the cathode plate, passivating, washing, drying, stripping and other processing to the product of the electro-deposited, obtain manganese metal products. Use manganese sulfate as raw materials prepared manganese metal, the required raw materials are mainly manganese ore powder, sulfuric acid, ammonium sulfate, oxidizing agent, reducing agent, additives, etc..
The main component of the pyrolusite is MnO2, prior to leaching should restore calcination into MnO in a reverberatory furnace or boiling furnace, particle size of manganese powder is less than 0.125mm, the particle size of anthracite powder is less than 1mm, pulverized coal ratio is 0.16-0.18 of the manganese powder, calcination temperature is 850-900. According to metal powder supplier, manganese powder leaching includes two basic processes: adsorption of the chemical reaction process and the diffusion process of sulfuric acid and the reaction product. The rate of diffusion plays an extremely important role on leaching reaction. The main factors affecting the diffusion speed have the temperature, stirring intensity, slag particle size, concentration of sulfuric acid and so on.
The stirring speed in the actual production is generally 40-70r/min, the sulfuric acid concentration is generally in the range of 100-150g / L. the sulfuric leaching manganese procedure: Add 1/5 volume of the anolyte or recycled scrap manganese slag in the acid leach tank, starting the stirrer, add the calculated manganese powder, inject measured sulfuric acid slowly. Then open steam valve to accelerate the reaction, after the vigorous reaction, add the anolyte to 4/5 volume, continue to rise temperature to 90°C. When the pH is 2-3, inspecting the Fe2 + concentration, consider adding MnO2 to make the Fe2 + oxidized to Fe3 +, the reaction was continued for 1.5-2 hours, test whether Fe2 + are fully oxidized. The solid-liquid separation is an important part of the process of the system liquid, appropriate separation can reduce waste, to ensure the quality of the solution. China's current industrial production are widely used rubber frame filter, the device structure is simple, easy to operate, good separation, but with high labor intensity.
According to the production characteristics of electrolytic manganese metal, in order to improve the technical and economic indicators should focus on the following two indicators of manganese recovery and current efficiency. Improving manganese recovery ways: (1) increase the rate of leaching, converted the manganese in the slag into manganese sulfate as far as possible; (2) do a good job in solid-liquid separation, reduce the time of the separation loss of manganese sulfate; (3) Reduce the anode precipitated manganese dioxide; (4) strengthen the electrolysis operation management, reduce the loss of manganese sulfate caused by Mn(OH)2 precipitation generated; (5) reduce each process’s run, drip, drain of the entire production process.
Improve current efficiency measures: (1) should not use non-failed electrolyte to electrolyze; (2) strictly control electrolysis conditions, make various process parameters always remain within the limits prescribed; (3) regular checks the conductive situation of the anode and cathode plate, ensure the anode and cathode plate are always in good conductive state; (4) timely clean the anode plate of the manganese dioxide deposits and cleaning electrolyzer; (5) prevent the electrolyzer earth leakage, prevent a short circuit, reduce leakage losses.
Source:http://www.mhcmp.com
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