Low-energy-consumption treatment process of wastewater from nonferrous metallurgy process

　　In the smelting industry, a large amount of wastewater will be produced in the smelting process, and the heavy metal residues in the smelting wastewater and the acid liquid in the smelting process will enter the wastewater with the washing liquid. How to treat the wastewater from non-ferrous metallurgical process with low energy consumption?
　　Kang Jinghui Xiaobian today introduces the low-energy treatment process of non-ferrous metallurgical process wastewater.
　　I. Sources of Wastewater from Nonferrous Metallurgical Process
　　The wastewater discharged from each link of nonferrous metal smelting process, its quality and hazards are analyzed. The main sources of nonferrous metallurgical wastewater are equipment cooling water and slag washing water, wastewater discharged from flue gas purification system and wastewater leaked or discharged from hydrometallurgical process.
　　In the process of nonferrous metal smelting, washing liquid, slag washing water, purified flue gas and workshop water are the main sources of wastewater, and various washing liquids will be used in the process of nonferrous metal smelting.
　　Including the washing liquid of various acids in each procedure, the waste acid generated, the washing water for particle removal, the waste liquid in sulfuric acid process, and the waste liquid in the hydrolysis process, etc., all have great relevance to the elimination of water pollution in the workshop.
　　All kinds of wastewater discharged in this process have the characteristics of low pH value and high heavy metal content in their physical and chemical properties, such as slag washing water in pyrometallurgical process. In the pyrometallurgical process of nonferrous metals, it is necessary to quench the molten residue, which is usually carried out with water, and the corresponding wastewater also has the characteristics of many residue particles, high heavy metal content and high water temperature.
　　Second, non-ferrous metallurgical wastewater treatment process
　　In the treatment of non-ferrous metallurgical wastewater, the liquid-solid separation can be realized only after the wastewater is evaporated, concentrated and crystallized, so that the high-concentration inorganic salt can become a solid open circuit, and the water quality of distilled water can meet the relevant requirements of reuse and discharge after evaporation and concentration. Therefore, the final treatment method of high concentration hydrometallurgical wastewater is evaporation concentration.
　　Ordinary evaporation and concentration equipment has the characteristics of high energy consumption in practical application, lacks certain economy, and the heat transfer surface is easy to scale, which will greatly reduce the evaporation efficiency after a period of use.
　　Therefore, after research and comparison, it is found that only a small amount of steam can be used to preheat wastewater by waste heat from industrial boilers and use multi-effect evaporator for evaporation concentration and flash crystallization, with low energy consumption.
　　In view of this, the multi-effect evaporator has the characteristics of energy saving and environmental protection, and can bring greater social and economic benefits to non-ferrous metallurgical enterprises with small water volume for high-concentration wastewater treatment or concentrated water treatment in reverse osmosis devices.