Processing method for recycling wastewater of aluminum industry

Abstract

The invention relates to a production wastewater recycling treatment method in the aluminum industry, comprising: firstly, implementing the first pretreatment to wastewater for purifying the wastewater, then concentrating and diluting the wastewater through electrodialysis concentration treatment, and then making the concentrated solution return to the alumina production after the Na2O content therein reaches 100g / l through the low temperature membrane distillation concentration treatment after the concentrated solution is pretreated secondarily, and the produced water serves as washing waterof alumina products. The treated concentrated solution can return to the alumina production, the produced diluted solution can meet the standards of production process water, and can be used as washing water of products, meanwhile, the recovery of Na2O and process water in the production wastewater can be realized, thereby reducing the discharge of wastewater, guaranteeing the clean production, protecting the environment, also reducing the process water consumption, effectively allocating precious water resources, and saving water resources.

Description

Technical field [0001] The invention relates to a treatment method for the reuse of wastewater from aluminum industry production, which is used to treat the wastewater from aluminum industry production to form recycling. Background technique [0002] All alumina production plants in my country adopt wet process, and a large amount of production wastewater is produced during the production process, which mainly comes from equipment cooling, sealing water, circulating water and other fluids, water treatment wastewater, and plant life drainage. The chemical composition of wastewater Very complicated, the main ingredient is Na 2 CO 3 , NaOH, NaAl(OH) 4 , Na 2 SO 4 Etc., the ions that exist in the state of anion and cation are Al(OH) 4 - , OH - , CO 3 2- , SO 4 2- , SiO 3 2- , Cl - , N a + , Ca 2+ , Mg 2+ , Fe 3+ , Fe 2+ Wait. [0003] The composition of production wastewater is complex, with high alkali, aluminum ions and suspended solids. In fact, most of the pollutants contained in it...

AI Technical Summary

Problems solved by technology

[0004] At present, the main method of recycling these production wastewater is to concentrate the production wastewater, and after sedimentation and filtration, part of the wastewater is directly pumped to alumina production for processes that do not require high water quality, such as large circulating water systems Water replenishment, spray cooling outside the clinker kiln, etc., part of the waste water is added back to the red mud washing process for alumina production for red mud washing. However, because the waste water contains 5-7g / l Na 2 O, resulting in a decrease in the washing efficiency of red mud, an increase in the amount of washing water, and an increase in the amount of water entering the alumina production process, resulting in an increase in steam consumption and causing many adverse effects on the subsequent production of alumina