Recycling method and system for tin metal in nitric acid type tin returning waste water

Abstract

The invention provides a recycling method and system for tin metal in nitric acid type tin returning waste water. Through combination of a neutralizing method and a flocculence method, the system pH value is controlled within a certain range, then, metal ions are deposited through adding of a macromolecule flocculant, and the tin content in tin hydroxide products can be higher than 50%. Compared with the situation that only one method is adopted for conducting the tin returning waste liquid tin recycling treatment process, the usage amount of a needed alkaline solution and the usage amount of the needed flocculant are greatly reduced, the alkaline solution usage amount is about 1/2 of the traditional alkaline solution usage amount, and the flocculant usage amount is about 1/3 of the traditional flocculant usage amount.

Description

technical field [0001] The present application relates to the field of utilization of renewable resources and recovery of non-ferrous metals, and more specifically, to a method and system for recovering tin metal in nitric acid-type tin stripping wastewater. Background technique [0002] The tin stripping waste liquid is a kind of acidic wastewater produced in the production process of printed circuit boards. It contains a large amount of nitric acid, metal ions such as tin, iron and copper, as well as various organic substances such as copper corrosion inhibitors and tin suspension agents, which are directly discharged. It will not only cause waste of tin, but also seriously pollute the environment, causing great harm to human beings and the environment. The neutralization method is a traditional method for recovering tin in the circuit board tin stripping waste liquid, but the neutralization method in the prior art often has the defects of high precipitation pH and large a...

AI Technical Summary

Problems solved by technology

[0002] Tin stripping waste liquid is a kind of acid wastewater produced in the production process of printed circuit boards. It contains a large amount of nitric acid, tin, iron, copper and other metal ions, as well as various organic substances such as copper corrosion inhibitor and tin suspending agent, and is directly discharged It will not only waste tin into the environment, but also seriously pollute the environment, which is very harmful to human beings and the environment.

The neutralization method is a traditional method for recovering tin in the waste liquid of stripping tin from circuit boards, but the neutralization method in the prior art often has the defects of high precipitation pH and large amount of alkaline solution, and the tin obtained from the precipitation contains more The high content of iron, copper and other heavy metal ions caused the problems of low tin purity and low tin content, and the direct filtration performance was poor, and the production time cost was high, which seriously affected the recycling of tin. There are many deficiencies in metal recycling technology

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