Study On Resourceful Green Regeneration Process And Equipment Of Ferric Chloride Waste Etching Solution

The resourceful green regeneration process of waste ferric chloride etchant containing copper mainly includes crystallization of CuCl₂,separation of crystal and oxidation of Fe2+.However,the current process and equipment have some disadvantages,like open type in the crystal separation process and large flow in the evaporation process,which cause environmental heat pollution and powder pollution,resulting in wide size dispersion of crystal and much contaminant on crystal surface and many other problems.According to the shortage of the existing process and equipment,researches of this paper are as follows:?1?The original process is optimized by embedding cyclone classification and concentration system.Seeds are returned to improve the monodispersity of grains.Mother liquor is heated in closed cycle system to prevent the environmental pollution and increase the quality of recycled products.?2?Based on the theory of crystallization kinetics,crystal nucleation and growth rate equat'ions are analyzed.Through the crystallization experiment,the influence of evaporation temperature,stirring rate,vacuum degree and residence time on crystal growth is studied,providing the operation basis for treatment process.?3?According to the new process,the existing equipment is modified.By means of FLUENT software numerical simulation and field commissioning,the equipment' s structure and operating parameters are optimized,which is used to extract coarse crystals and return seeds to subsystem.?4?By the field commission of the new process equipment,it is confirmed that the optimum inlet pressure is 0.25MPa and optimum feed concentration is 10%.The industrial operation results show that CuCl₂ crystal more than 65pm rises to 92.6%,its purity increases from 95%to 98%,and the workload of the centrifuge is reduced by about 96%.