Research On The Recovery Process In The Cords Of Scrap Tires

A large number of waste tires generated due to the sharp increase in the number of vehicles in the world. If waste tires cannot be handled properly. It will cause serious harm to the natural environment. How cost-effective recovery of useful metals from scrap tires is an important problem faced in using renewable resources recovery. Therefore, this paper has carried on the system research to the recycling process of waste tyre cord. It has certain theoretical significances and practical values.There is a brass plated layer on the steel cord surface. The coating is mainly through cyanide method and thermal diffusion method to plait. The copper content of the brass plated is to be controlled between61% and65%, the coating thickness range is between0.2and0.4μm. The remaining component is zinc. To determine the experimental program of the coating removal, the removal methods of the copper plating and the zinc coating of steel substrate were separately investigated. Eventually, ammonia leaching as the removal process of the brass coating of steel cord surface was presented.By the thermodynamic analysis of the ammonia leaching removal process of brass plated steel cord, we can see four influencing factors in the removal programs of the brass plated of steel cord surface by using the ammonia leaching:temperature, ammonia concentration, treatment time, liquid-solid ratio. Different values of these four factors could cause different effects of the removal of the brass coating.By using orthogonal experiment to optimize the design process, design1shows that ammonia/water is the main factor, temperature is secondary factor. The best combination of optimum conditions was selected from a variety of programs of orthogonal combination: ammonia/water1:3; temperature90℃; liquid-solid ratio8:1; time70min. Design2shows that temperature is the main factor. The best combination of varieties of combinations was be selected:the temperature of90℃; ammonia/water1:5; liquid to solid ratio24.5:1; time30min. Through the experiment1and experiment2, we can see:liquid-solid ratio8:1, ammonia/water1:5, temperature90℃, when the time30min, the removal rate of copper ion is good. That means using ammonia leaching to remove brass plated of steel cord is most thorough.