Preparation and Purification of Zinc Chloride

Zinc Chloride Preparation and Purification: Process and Application Analysis

Zinc chloride (ZnCl₂) is an important inorganic compound, which is widely used in zinc plating, electroplating, battery manufacturing, medicine and other fields. With the increase of industrial demand, the preparation and purification technology of zinc chloride has attracted much attention. In this paper, the preparation method, purification technology and practical application are analyzed in detail.

1. zinc chloride preparation method

1. metallic zinc oxidation method Zinc metal reacts with chlorine gas (Cl₂) at high temperatures to form zinc chloride. This is one of the most commonly used methods of preparation. The reaction formula is: [ 2Zn 2Cl₂ \rightarrow 2ZnCl₂ ] This method is simple, but requires high temperature environment and high energy consumption. The purity of chlorine and the control of reaction conditions have a direct impact on product quality.

2. chemical reaction method Zinc chloride is prepared by reacting a salt solution of zinc with hydrochloric acid or other chlorine-containing compounds. For example, zinc oxide (ZnO) reacts with hydrochloric acid: [ ZnO 2HCl \rightarrow ZnCl₂ H₂O ] This method is suitable for small-scale production in the laboratory, but the cost is high, and it is suitable for the preparation of high-purity zinc chloride.

3. waste electrolyte recovery method In the electroplating or galvanizing process, the waste electrolyte contains a large amount of zinc chloride. The recovery of zinc chloride by physical and chemical methods is environmentally friendly and can reduce costs. Common methods include evaporation concentration, crystallization separation, etc.

2. Zinc Chloride Purification Technology

1. crystallization method Crystallization is a classical method for the purification of zinc chloride. The zinc chloride-containing solution is concentrated by evaporation to supersaturation and zinc chloride crystals are formed. The crystallization process requires temperature and concentration control to obtain high purity zinc chloride. Advantages: simple process and low cost. Disadvantages: crystal purity is greatly affected by impurities in the solution.

2. recrystallization method The preliminarily purified zinc chloride is dissolved and recrystallized, and impurities are removed by multiple cycles. This method is suitable for large-scale production, but the energy consumption is high. Advantages: high purity, suitable for industrial applications. Disadvantages: complex process and long time.

3. ion exchange method Using ion exchange resin to adsorb impurity ions and remove impurities in the solution, so as to purify zinc chloride. Advantages: high purity, suitable for the production of high value-added products. Disadvantages: large equipment investment and high resin replacement cost.

3. Zinc Chloride Application and Market Prospect

Zinc chloride is widely used in industrial and civil fields:

• Galvanizing and electroplating: used for metal surface anti-corrosion treatment.
• Battery: used for zinc-manganese batteries and lithium battery electrolyte.
• Medicine and Agriculture: Used for the preparation of zinc salts or as a plant nutrient.
• Water treatment: used to precipitate heavy metal ions and purify water quality.

With the tightening of environmental protection policies and the enhancement of resource recovery awareness, the waste liquid recovery and purification technology of zinc chloride has attracted much attention. Through efficient purification technology, not only can reduce production costs, but also reduce environmental pollution, in line with the requirements of sustainable development.

4. summary and prospect

The preparation and purification technology of zinc chloride is an important research direction in the field of chemical industry. As industrial demand grows and technology advances, new methods of preparation and purification will continue to emerge. In the future, the application field of zinc chloride will be further expanded, especially in the field of new energy and environmental protection, and its demand will increase significantly. Therefore, the development of efficient, low-cost zinc chloride preparation and purification technology, has important economic and environmental significance.

Through the analysis of this article, we hope that readers will have a deeper understanding of the preparation and purification technology of zinc chloride, and provide reference for the technological progress of related industries.