Manufacturing method of zinc sulfate
I. Introduction
Zinc sulfate is an important chemical, widely used in agriculture, medicine, food, metallurgy and other fields. In the field of raw materials for chemical production, the manufacturing method of zinc sulfate has attracted much attention. In this paper, the manufacturing method of zinc sulfate will be discussed in detail, aiming to improve the production efficiency and quality of zinc sulfate.
Second, the nature and use of zinc sulfate
Zinc sulfate is a colorless or white crystalline powder with strong hygroscopicity. It is soluble in water and insoluble in ethanol and ether. Zinc sulfate is often used as trace element fertilizer in agriculture, which can promote the growth and development of crops; used as zinc tonic and medicine for skin diseases in medicine; used as nutritional supplements and preservatives in food; used as an additive for galvanizing and other metal surface treatment in metallurgy.
Three, the manufacturing method of zinc sulfate
1. Wet production
Wet production is the main production method of zinc sulfate, and its process includes zinc ore roasting, leaching, purification, neutralization, crystallization, centrifugal separation, drying and other steps. The specific steps are as follows:
(1) Zinc ore roasting: zinc ore is mixed with coal powder and then roasted in a rotary kiln to produce zinc roasted sand.
(2) Leaching: Zinc roasting sand is mixed with water and sulfuric acid and then leached to produce a mixed solution of zinc sulfate and iron sulfate.
(3) Purification: Reducing agents such as iron filings or pyrite are added to the mixed solution to reduce the iron ions therein to iron hydroxide precipitate, which is then removed by filtration.
(4) Neutralization: add neutralizer such as milk of lime or sodium hydroxide to the purified solution, adjust the pH to 4.0-4.5, so that the zinc ions in the solution precipitate out in the form of zinc sulfate.
(5) Crystallization: The precipitated zinc sulfate crystals are separated by centrifugation to obtain zinc sulfate crystals.
(6) Drying: Dry the zinc sulfate crystals to get the finished zinc sulfate.
Wet production process is mature, easy to operate, low production cost, but produces more waste residue, need to be properly disposed of.
2. Pyro-production
Pyro-production of zinc sulfate mainly uses zinc dross or hot-dip galvanizing dross as raw material, and produces zinc sulfate through acid leaching, purification, crystallization and other steps. Specific steps are as follows:
(1) Acid leaching: zinc dross or hot-dip galvanizing dross is mixed with dilute sulfuric acid for acid leaching to produce a mixed solution of zinc sulfate and iron sulfate.
(2) purification: add oxidizing agent (such as hydrogen peroxide) to the mixed solution to oxidize the iron ions therein to iron hydroxide precipitate, and then filter to remove.
(3) Crystallization: the purified solution is evaporated and concentrated to precipitate zinc sulfate crystals.
(4) Centrifugal separation and drying: the precipitated zinc sulfate crystals are centrifugally separated and dried to obtain the finished zinc sulfate.
The production process of thermal method is simple, but the source of raw materials is limited and the production cost is high.
Four, zinc sulfate production precautions
1. Strictly control the production process parameters to ensure stable product quality.
2. Strengthen equipment maintenance and repair, improve equipment operation rate and production efficiency.
3. Strengthen the environmental protection management of waste water, waste gas, waste residue, etc., to ensure that the production process meets the requirements of environmental protection.
4. Pay attention to safety production management and prevent the occurrence of production accidents.
V. Conclusion
The manufacturing methods of zinc sulfate are mainly two kinds of wet production and thermal production, among which the wet production process is mature, easy to operate, and low production cost, which is the main production method. In the production process, the production process parameters should be strictly controlled, equipment maintenance and repair should be strengthened, environmental protection and governance work should be enhanced, and production safety management should be emphasized in order to improve the production efficiency and quality of zinc sulfate.
