Steel pickling solution recycling device and process based on Fenton oxidization

Abstract

The invention discloses a steel pickling solution recycling device and process based on Fenton oxidization. A pickling bath achieves circulation of a pickling solution through a circulating pump and is connected with an acid pickle bath, a plastic microballoon filtering device, a freezing crystallization kettle and a solid-liquid separation device in sequence. The freezing crystallization kettle is connected with a refrigerating machine, and the freezing crystallization kettle or the solid-liquid separation device is connected with the pickling bath through a backflow pipeline. According to the pickling solution, H2SO4 serves as basic acid, a Fenton reagent serves as an oxidizing agent, and HF serves as a penetrating agent. Metal sulfate in waste liquid is separated out by crystallization by increasing the sulfuric acid concentration of the pickling solution and reducing temperature, recycled through a solid-liquid separation technology, and prepared into nickel matte capable of being sold, and free acid in acid pickle circulates and flows back into the pickling bath after being collected. According to the steel pickling solution recycling device and process, no nitric acid is included, a series of environmental problems that yellow fume comes out of an acid pickling workshop, and nitrogen is included in waste water is thoroughly solved, and good economic benefits are achieved through recovery of metal and recycling of waste acid.

Description

technical field [0001] The invention relates to a pickling solution for metal surface treatment, in particular to a steel pickling solution recycling device and a process thereof. Background technique [0002] When steel is made into various plates and profiles by hot rolling, its surface will be covered by O in the air under high temperature conditions. 2 Oxidation produces black and yellow tight oxide layers. Whether it is to improve the appearance and corrosion resistance of steel, or for subsequent processing such as cold rolling, drawing, coating or cladding, it must be pickled. Usually, the mixed acid pickling process is used to remove the oxide scale on the surface, and the acid solution mainly includes HNO 3 , HF, HCl, H 2 SO 4 etc., the concentration range is 5-20%. In order to improve the pickling speed, the acid concentration of the acid solution is usually higher, and it is heated at the same time, and the temperature range is 40-80°C. Metals and metal oxid...

AI Technical Summary

Problems solved by technology

Most of these pickling waste liquids are disposed of as pickling sludge in the form of neutralization and precipitation, which not only causes great pressure on the ecological environment and human health, but is also a huge waste of resources

A small number of enterprises use resin exchange and other methods to recycle waste acid in wastewater, but there are still problems such as low recovery efficiency, high recovery cost, and a large amount of heavy metals in pickling sludge, which has not completely solved the problem of pickling solution. Recycling to realize resource utilization of pickling process

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