Study On Comprehensive Recovery And Utilization Technology Of Alkaline Etching Waste Liquid Containing Copper

Alkaline copper-containing etching waste liquid is the waste produced in the etching process of printed circuit board.Its main components are Cu（NH₃）₄Cl₂,chlorine and ammonia nitrogen.If it is discharged directly without proper disposal,it will not only waste precious resources,but also cause great harm to the environment.The harmless treatment of the waste liquid has been widely concerned by people.This paper studies the alkaline copper etching liquid waste as raw material for making alkali type copper carbonate,the activity of copper oxide,sodium chloride process,explores the sodium chloride etching liquid waste recycling processing glass thinning fluorine sodium silicate process,test to determine the most suitable process conditions of the preparation of various products,and the activity of copper oxide production process equipment selection and economic benefit estimation,environmental assessment;The products were analyzed and characterized by chemical analysis,XRD,TG and SEM.The main results were as follows:（1）The optimum conditions for preparing basic copper carbonate from alkaline copper containing etching waste liquor were determined as follows:stirring speed250rpm,n（Na₂CO₃）:n(Cu²⁺)=1.5:1,m（copper）:m（assistant A）=1.1:1,deamination temperature 85℃.The results of chemical analysis show that the copper content of the product is more than 55.80%,the sulfate content is less than 0.04%,and the chlorine content is less than 300ppm,and the main indicators meet the requirements ofⅠproducts in the standard of industrial basic copper carbonate.The XRD and SEM results showed that the main phase of the product was basic copper carbonate with irregular ginger block morphology and particle size ranging from 10μm to 90μm.（2）The optimum conditions for the preparing active copper oxide from basic copper carbonate were determined as follows:reaction temperature 90℃,liquid-solid ratio 3:1,stirring speed 200rpm,m（assistant B）:m（basic copper carbonate）=2.5:1,calcination at 550℃for 1h.The results of chemical analysis showed that the purity of the product reached 99.19%,the content of chlorine was less than 15ppm,the dissolution rate was less than 20s,and the main indexes met the requirements of the standard of industrial active copper oxide.According to XRD and SEM images,the main phase of the product is copper oxide,with irregular microspheres in morphology and particle size ranging from 0.1μm to 30μm.（3）The optimum conditions for the preparing sodium fluosilicate from waste glass etching liquor were determined as follows:reaction temperature 35℃,n（Na Cl）:n（H₂Si F₆）=2.1:1,reaction time 75 min,aging time 15 min,recrystallization liquid-solid ratio 75:1,3℃±1℃for 24 hours.The results of chemical analysis show that the purity of the product is more than 99.0%,and the indexe meet the requirements of type I superior product in industrial sodium fluosilicate standard.It can be seen from XRD that the main phase of the product is sodium fluosilicate.（4）The economic benefit estimation results show that the project of preparing active copper oxide from alkaline copper containing etching waste liquid can obtain good economic benefit;environmental protection analysis results show that the production process is a clean environmental protection process.