Stainless steel pickling mixed waste acid liquid pretreatment system and technology

Abstract

The invention discloses a stainless steel pickling mixed waste acid liquid pretreatment system. The stainless steel pickling mixed waste acid liquid pretreatment system comprises a graphite cooler, amixing tank, a settling tank, a press filter, a pretreated acid collecting tank and a high-pressure rinsing device, wherein the graphite cooler is used for cooling waste acid liquid; the mixing tank is provided with a stirring device, and an inlet of the mixing tank is connected with an outlet of the graphite cooler so as to flocculate the cooled waste acid liquid; an inlet of the settling tank isconnected with an outlet of the mixing tank so as to perform solid-liquid separation on the waste acid liquid; an inlet of the press filter is connected with a sludge outlet of the settling tank so as to filter sludge for further solid-liquid separation; an inlet of the pretreated acid collecting tank is connected with a waste acid liquid outlet of the settling tank and a waste acid liquid outletof the press filter so as to collect the pretreated waste acid liquid; and an inlet of the high-pressure rinsing device is connected with industrial water, and an outlet of the high-pressure rinsingdevice is connected with the inlet of the press filter to rinse a filtered sludge cake so as to reduce the acid content of the sludge cake. The stainless steel pickling mixed waste acid liquid pretreatment system provided by the invention increases the recycling rate of free acid in the waste acid liquid, and facilitates recycling of metal oxide.

Description

technical field [0001] The invention relates to the technical field of waste acid recovery, in particular to a stainless steel mixed acid pickling waste acid liquid pretreatment system and a process thereof. Background technique [0002] Iron and steel enterprises or stainless steel processing enterprises use a mixture of nitric acid and hydrofluoric acid to treat the surface of stainless steel (chromium and chromium-nickel gold), special-purpose alloys (such as nickel-based alloys) or special metals (such as titanium, zirconium) plates and bars. Pickling is carried out to remove the iron oxide scale on the metal surface to meet the requirements of metal material processing. This waste acid solution is usually treated and acid regeneration by spray roasting mixed acid regeneration unit. However, the waste acid solution often contains a large amount of metal oxide sludge, especially the content of metal oxide sludge in the waste acid solution of the hot rolling mill is very ...

AI Technical Summary

Problems solved by technology

If these waste acids enter the mixed acid regeneration unit directly, it will cause damage to the equipment of the regeneration unit, blockage of pipelines, etc., which will greatly affect the stability of the system, increase the workload of operation and maintenance, and reduce the service life of the equipment.

[0003] In order to prevent the sludge from damaging the regeneration system, this part of the acid-containing sludge is usually discharged directly to the wastewater treatment station for neutralization treatment. This method of treatment is not conducive to the recovery of metal oxides, but also reduces waste acid. Recovery of free acid, and at the same time, it is easy to cause nitrogen oxides to exceed the standard in the process of wastewater discharge

Images