Resourceful treatment process for silicon carbide pickling wastewater

Abstract

The invention discloses a resourceful treatment process for silicon carbide pickling wastewater, and the resourceful treatment process mainly adopts a process route of taking single membrane electroosmosis+ precipitation+ filtration as a pickling wastewater resourceful treatment technology. On the premise of not introducing extra chemical agent, separation of acid and metal ions in sulfuric acid pickling wastewater can be effectively realized, so that the iron content in the sulfuric acid pickling wastewater is guaranteed to be reduced to be lower than 10mg / L from 500mg / L, the iron recovery rate is 90% or higher, and the acid recovery rate is 99% or higher. According to the resourceful treatment process, no other impurities are newly introduced, and 3g of concentrated sulfuric acid with concentration being 98% only needs to be added into every liter of the recycled sulfuric acid pickling wastewater, so that the acidity of the recycled sulfuric acid pickling wastewater is supplemented to be 3%, and therefore, wastewater recycling can be realized. Meanwhile, simple substances and / or compounds are generated by the treatment process, so that zero release can be realized, clean production is guaranteed, and resource recycling of wastewater and iron is realized, and therefore, very good economic and environmental benefits are generated.

Description

technical field [0001] The invention relates to a pickling waste water treatment process, in particular to a silicon carbide pickling waste water recycling process, which is suitable for recycling pickling waste water resources in the silicon carbide industry. Background technique [0002] Silicon carbide is the basic raw material for refractories, abrasives and photovoltaic industries. There are more than 500 silicon carbide enterprises in my country. During the production of silicon carbide powder, it is necessary to use sulfuric acid solution to remove iron impurities in silicon carbide powder, and a large amount of pickling wastewater is generated in this process. The main pollutants of pickling wastewater are waste acid mainly sulfuric acid and various iron ions (Fe 2+ , Fe 3+ )Wait. The pH value is around 2, and the iron ion concentration is between 50 and 500mg / L. [0003] If the pickling wastewater is not treated properly, the harms that can be caused are: 1. It ...

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Problems solved by technology

[0003] If the pickling wastewater is not properly treated, the hazards will be: 1. It will corrode sewer pipes and reinforced concrete structures, etc.

2. It will hinder the growth and reproduction of aquatic organisms

3. Waste water infiltrates into the soil, which will cause soil calcification after a long time, destroy the loose state of the soil layer, and affect the growth of crops

4. Iron ions in wastewater will accumulate in organisms and cause harm to organisms and human health

[0005] The main disadvantages of the traditional process are: ①It needs to consume a large amount of neutralizing agent calcium oxide or caustic soda, plus electricity and labor, etc., and the treatment cost is as high as 5 yuan / ton of water; ②Wastewater can only be discharged up to the standard, and the salt content of wastewater is too high to be Achieving reuse, resulting in a large waste of water resources; ③ a large amount of waste residue generated in the process of wastewater treatment, the main components are calcium sulfate and iron hydroxide, the separation of various active components is too difficult, most of them are landfilled, waste a large amount of land resources

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