CN-121972492-A - Method for efficiently removing electrolytic manganese slag sulfate by electric field enhanced ammonia process

Abstract

The invention provides a method for efficiently removing electrolytic manganese slag sulfate by an electric field enhanced ammonia method. The method comprises the steps of placing ammonium bicarbonate and ammonia water in an electrolytic tank, adding water for dissolution, then adding electrolytic manganese slag, introducing current, stirring and reacting at the water bath temperature of 25-50 ℃ to obtain a mixed system A, and carrying out solid-liquid separation on the mixed system A to obtain leaching slag and leaching liquid, wherein the leaching slag is the electrolytic manganese slag with sulfate removed. The method is characterized in that after an electric field is added, the migration efficiency of metal ions in electrolytic manganese slag can be enhanced, the electrochemical oxidation reaction is induced, the sulfate removal rate is accelerated, and the reaction activation energy is reduced. Compared with the existing technology for removing sulfate in electrolytic manganese slag, the method not only can remove sulfur and solidified heavy metal in electrolytic manganese slag efficiently, but also can realize separation and recycling of valuable components in the leaching solution. The method has the advantages of simple process, easy operation and low energy consumption, and has very important significance for realizing wet desulfurization and resource utilization of the electrolytic manganese slag.

Inventors

• LIU RENLONG
• LIANG NA
• HE WEILONG
• Teng Xurong
• YE RUI
• FENG KAI
• NIU XIAODONG
• Jian Chengzong

Assignees

• 重庆大学

Dates

Publication Date

20260505

Application Date

20260204

Claims (10)

1. 1. The method for preparing the desulphurized electrolytic manganese slag by efficiently removing the sulfate of the electrolytic manganese slag by using the electric field enhanced ammonia method is characterized by comprising the following steps of: 1) Placing ammonium bicarbonate and ammonia water in an electrolytic tank, adding water for dissolution, then adding electrolytic manganese slag, introducing current, and stirring for reaction at the water bath temperature of 25-50 ℃ to obtain a mixed system A; 2) Carrying out solid-liquid separation on the mixed system A in the step 1) to obtain leaching residues and leaching liquid, wherein the leaching residues are desulfurized electrolytic manganese residues; the desulfurization electrolytic manganese slag has a desulfurization rate of 85% or more.
2. 2. The method according to claim 1, wherein the mass ratio of the electrolytic manganese slag, the ammonium bicarbonate and the ammonia water in the step 1) is 5:2:0.18.
3. 3. The method of claim 1, wherein the liquid-to-solid ratio of water to electrolytic manganese slag in step 1) is 5 l:1 kg.
4. 4. The method of claim 1, wherein the current density in the cell after passing the current in step 1) is 30 mA/cm 2 .
5. 5. The method of claim 1, wherein the water bath temperature in step 1) is 50 ℃.
6. 6. The method of claim 1, wherein the stirring reaction in step 1) is performed under conditions of 200 r/min with stirring 60: 60 min.
7. 7. The desulphurized electrolytic manganese slag prepared by the method of any one of claims 1 to 6, which is characterized in that the desulphurized electrolytic manganese slag has a desulphurized rate of more than or equal to 85% as defined in claim 1.
8. 8. A process for preparing fertilizer grade ammonium sulfate, comprising the steps of evaporating and crystallizing the leachate of claim 1 and cooling to obtain ammonium sulfate.
9. 9. The method of claim 8, wherein the evaporative crystallization temperature is 105 ℃ and/or the cooling temperature is room temperature.
10. 10. A fertilizer grade ammonium sulfate prepared by the method of claim 8 or 9.

Description

Method for efficiently removing electrolytic manganese slag sulfate by electric field enhanced ammonia process Technical Field The invention relates to the field of solid waste recycling technology and separation and purification, in particular to a method for efficiently removing electrolytic manganese slag sulfate by an electric field enhanced ammonia method. Background The metal manganese is produced by electrolytic process with manganese carbonate ore or reduced manganese oxide ore as material and through sulfuric acid leaching, purifying, impurity eliminating and other steps. Electrolytic manganese slag is an acidic solid waste generated in the production process of manganese metal. And (3) generating 8-12 tons of electrolytic manganese slag approximately at the beginning of each 1 ton of metal manganese. China is the largest electrolytic manganese producing country, consuming country and export country. The total stock of electrolytic manganese slag in China is about 1.7 hundred million tons and increases up at a speed of 1000 ten thousand tons/year. In China, electrolytic manganese slag is mainly piled up in an open-air slag warehouse, but the mode not only occupies a large amount of land, but also can cause environmental pollution. Research shows that harmful substances in electrolytic manganese slag, such as manganese, ammonia nitrogen, heavy metal and the like, are easy to migrate in the long-term stacking process, have great pollution hidden trouble to soil and groundwater around a slag warehouse, and the sustainable development of the manganese industry is severely limited by the electrolytic manganese slag stored in a large quantity. In many researches on innocent treatment and resource utilization of electrolytic manganese slag, the electrolytic manganese slag is used for preparing important components of building materials such as cement, bricks, geopolymers, ceramsite and the like. However, the use of electrolytic manganese slag in this field is significantly limited by its high sulfate content. Specifically, the existence of sulfate can not only obviously prolong the setting time of cement and reduce the volume stability and early strength of the cement SO as to weaken the mechanical properties of later stages, but also release a large amount of SO 2 gas when the sulfate is pyrolyzed to prepare sintered products such as glass ceramics, ceramic particles and the like, SO that bubbles are generated in the products, and the quality of the products is influenced. At present, the electrolytic manganese slag desulfurization and heavy metal solidification technology mainly comprises calcination, water washing and bioleaching. Although the removal of sulfate and the fixation of heavy metals can be realized by calcination, a large amount of sulfate begins to decompose at about 900 ℃, and the calcination energy consumption is high. The water washing can only remove part of soluble sulfate, and the water consumption in the water washing process is large, and the safety of the recycled product is low. Bioleaching is the current novel technology, but the operation of separating bacteria is difficult, the leaching time is long, and the leaching efficiency is unstable. In view of the limitations of the existing method, it is particularly urgent to explore a novel technology capable of realizing sulfate removal and heavy metal solidification in electrolytic manganese slag and valuable component separation and recycling. The invention adopts an electric field coupling ammonium bicarbonate system, is favorable for efficiently and rapidly removing sulfate from electrolytic manganese slag, and can oxidize and fix manganese and iron in the electrolytic manganese slag and mineralize and fix other metals such as calcium and magnesium. The desulfurized leaching residue can be used as a resource. The whole process system realizes green low-carbon circulation. The method has the advantages of low energy consumption, simple operation, easy obtainment of equipment and the like, and can realize the removal of sulfur in electrolytic manganese slag and the separation and recycling of valuable components in the leaching liquid. Disclosure of Invention The invention aims to provide a method for efficiently removing sulfate from electrolytic manganese slag by an electric field enhanced ammonia method, which removes sulfate from electrolytic manganese slag by controlling conditions such as current density, ammonium salt concentration, reaction temperature, leaching time, stirring rate and the like. The leaching solution is separated and recycled through processes such as evaporation crystallization, cooling filtration and the like, and the leaching slag can be recycled. The method can ensure that sulfur is leached out efficiently and simultaneously solidify heavy metals such as manganese and the like, and realize the removal of sulfur in electrolytic manganese slag and the separation and recycling of valuable components in l