Comprehensive utilization method of acidic and alkaline waste etching solution

Abstract

The invention provides a comprehensive treatment method of acidic and alkaline waste etching solution of circuit boards, belonging to the technology in the field of environmental protection. The method is characterized by neutralizing and precipitating the acidic waste etching solution and the alkaline waste etching solution under the condition that the pH value is 5-6.5, pulping and then mixing the precipitates and quicklime, dehydrating and then roasting the mixtures at 400-600 DEG C, dissolving calcium chloride in the roasted product by water, separating and removing the residual lime by gravity separating to obtain the copper oxide products with purity being over 98%, or taking the generated copper oxide as the raw material to produce other products. The calcium chloride and ammonia generated in the process are also subjected to concentration, crystallization, ammonia evaporation and absorption to obtain the calcium chloride and ammonia products. The comprehensive treatment methodhas the advantages of total recycle, zero discharge, large treatment capacity, low treatment cost, high product quality, diverse product categories and the like, can not only eliminate environmental pollution radically but also create higher economic benefits.

Description

technical field [0001] The invention relates to a comprehensive treatment technology for acidic and alkaline circuit board etching waste liquid, which can be used for resource treatment of circuit board etching waste liquid and belongs to the technical field of environmental protection. Background technique [0002] The etching waste liquid produced by the printed circuit board industry is a kind of industrial waste liquid with high pollution, and it is also a waste liquid with high copper content. If it is not treated as a resource, it will inevitably cause environmental pollution and waste of resources. At present, most domestic manufacturers engaged in the recycling of circuit board etching waste liquid adopt the process of precipitating and separating copper ions from the liquid phase by adjusting the appropriate pH method. Although this process has the advantages of low processing cost and large processing capacity, etc. , but this method of solid-liquid phase precipita...

AI Technical Summary

Problems solved by technology

[0002] The etching waste liquid produced by the printed circuit board industry is a kind of industrial waste liquid with high pollution, and at the same time, it is a waste liquid with high copper content. If it is not treated as a resource, it will inevitably cause environmental pollution and waste of resources.

At present, most domestic manufacturers engaged in the recycling of circuit board etching waste liquid adopt the process of precipitating and separating copper ions from the liquid phase by adjusting the appropriate pH method. Although this process has the advantages of low processing cost and large processing capacity, etc. , but this method of solid-liquid phase precipitation separation is because the solid phase precipitation produced by it absorbs a large amount of other components in the liquid phase, so in order to obtain qualified products, the solid phase precipitation must be rinsed with a large amount of water, and a large amount of water produced by rinsing Due to the low concentration of the components contained in the waste liquid, the recovery cost is very high, so it is directly discharged into the environment, causing greater secondary pollution

In the existing patents and documents, although there is a report on adding alkali to heat and distill ammonia to process circuit board etching waste liquid to recover copper and ammonia water, this method is only suitable for processing alkaline etching waste liquid, and it still belongs to solid-liquid phase precipitation separation. However, the generated copper hydroxide precipitation still needs to be rinsed, and the rinse waste water still needs to be discharged, so secondary pollution cannot be avoided. Moreover, due to the high processing cost and small processing capacity of this method, industrialization has not been realized.

It is also reported that the method of solvent extraction is used to process and recover the waste etching liquid. Although this method realizes full recovery and zero discharge, it still has the defects of high cost and small processing capacity, and the recovery of copper is not complete, so it is only suitable for circuit board manufacturers. Recycling waste liquid, so it has not been industrialized in manufacturers that centrally process circuit board etching waste liquid

And the applicant's authorized patent CN100441745C discloses a comprehensive treatment method for circuit board etching waste liquid. The chlorine content of copper is relatively high. Although it can meet the requirements for the production of feed-grade copper sulfate, it cannot meet the requirements for industrial copper oxide products, so the application range of the product is limited to a certain extent.