New technology for preparing electrolytic manganese metal solution and recycling iron by reducing pyrolusite with iron scraps

Abstract

The invention discloses a new technology for preparing manganese sulfate solution which is used for electrolyzing manganese metal and recycling iron through the atmospheric pressure leaching of pyrolusite and iron scraps. The technology comprises the following steps: adding pyrolusite in a certain concentration of sulphuric acid solution, mixing evenly; adding iron scraps used as the reductant in a reaction tank, performing mechanical agitation for 1h-3h under different reaction temperatures to obtain reaction leachate; according to the changes of the reaction time and the pH value, adding heavy calcium carbonate and ammonia water in turn to adjust the pH value of the solution to 6.3-6.7; then adding sodium N,N-dimethyl dithiocarbaminate (SDD) to remove impurities such as heavy metal ions and purify; filtering, adding additive to obtain manganese sulfate solution used for electrolyzing manganese; and recycling iron from filter residue through alkali leaching and acid leaching to produce polyferric sulfate. The invention has the advantage that iron scraps are used as the reductant which have wide sources and rich raw materials and can be leached out under the atmospheric pressure; and iron scraps can be recycled to produce the water purification agent and have great economic benefit.

Description

technical field [0001] The invention relates to a new process for using scrap iron filings as a reducing agent to leaching manganese sulfate solution from pyrolusite at atmospheric pressure for electrolysis of metal manganese, and simultaneously develops a new process for recovering iron and producing polymerized ferric sulfate, which belongs to hydrometallurgy field. Background technique [0002] Scrap iron scraps are produced in the process of machining or machinery manufacturing. After degreasing, scrap iron scraps can be used as chemical raw materials or produce chemical products, turning waste into treasure and reducing waste of resources. my country produces a large amount of scrap iron every year, many of which are discarded due to improper use or direct disposal as a by-product. Recycling has become particularly important. It can not only increase the added value of the economy, but also is the development trend of comprehensive utilization of waste, which is in l...

AI Technical Summary

Problems solved by technology

[0005] 2. One-step method of two mines: crush and mix a certain proportion of pyrolusite and pyrite evenly, and then leaching with sulfuric acid can reduce the manganese dioxide in pyrolusite to manganese sulfate, which saves the high-temperature roasting process compared with the reduction roasting method , Simplify the equipment and its process flow, the price of pyrite is low, the source is wide, and the cost is reduced, but the manganese leaching rate of the two-mine one-step method is low, there are many filter residues, it is difficult to purify and remove impurities, and it is difficult to obtain qualified electrolytic manganese solution

[0006] 3. Sulfur dioxide leaching method: It is a mature process to directly pass sulfur dioxide into a slurry tank equipped with pyrolusite for reduction, but the by-product manganese dithionate is produced during the leaching reaction process, which affects the quality of the product. So far Not yet widely used in industry

[0007] A kind of pyrolusite leaching process such as Chinese patent application 200610122400.5 adopts sugarcane molasses alcohol waste liquid as a reducing agent, stirs and reacts at a temperature of 50-98°C for 0.5-4h to obtain a reacted leachate, but sugarcane molasses alcohol is easy to produce organic matter in the reaction , new impurities are introduced into the solution, and the organic matter is not easy to be purified and removed

Another example is a method for producing manganese sulfate from manganese oxide ore in Chinese patent application 200710151596.5, using ferrous sulfate or sulfur as a reducing agent, and reacting at a certain temperature and pressure, although this process is relatively mature and the manganese leaching rate is high, but High cost, large amount of slag, difficult to filter and remove impurities