Acid lixiviation based recycling treatment method of aluminum circulating coagulation sludge

Abstract

The invention provides an acid lixiviation based recycling treatment method of aluminum circulating coagulation sludge. The method is characterized by comprising the following steps of: dehydrating sludge to reduce water content of the aluminum circulating coagulation sludge to be lower than 80%; drying and baking; carrying out acidifying treatment: adding mixture of water and acid to adjust pH value of sludge slurry to 3, controlling reaction temperature to be 38 DEG C and agitating sludge and acid in mixed liquid so that the sludge and the acid sufficiently contacts; separating and purifying; and finally, filtering, evaporating and crystallizing to obtain crystal aluminum salt with a flocculation effect. According to the acid lixiviation based recycling treatment method of the aluminum circulating coagulation sludge, a large part of water and aluminum in the sludge is converted into a flocculating agent and impurities are further removed by separating to purify the flocculating agent, thereby improving the recycling of an aluminum salt flocculating agent, greatly reducing sludge disposal cost and further reducing COD (Chemical Oxygen Demand), pH value, residual organic matters and chromaticity of the sludge wastewater; and therefore, the aim of recycling is realized, the subsequence biochemical treatment is easy to implement and the damage of wastewater discharging to the environment is reduced.

Description

technical field [0001] The invention relates to a recycling treatment method of aluminum circulation coagulation sludge by an acid leaching method, which is suitable for safe and effective treatment of sludge produced in industrial waste water treated with an aluminum salt coagulant. Background technique [0002] Aluminum salt is a coagulant widely used in drinking water and industrial water treatment in my country, and about 70% of waterworks use aluminum salt as a coagulant. Since the water treatment sludge contains a large amount of aluminum salt, if it is directly discharged into the water or landfilled, it will cause great harm to the environment and human health. Therefore, it is of great significance to carry out the research on the resource recovery and utilization of aluminum salt coagulant in water purification sludge to realize the recycling of coagulant resources, prevent and control environmental pollution and protect people's health. [0003] At present, the r...

AI Technical Summary

Problems solved by technology

The three methods have their own advantages and disadvantages. The cost of the acid-base regeneration method is relatively low, but the separation effect is not good, and the purity of the regenerated coagulant is low; the ion exchange extraction regeneration method is difficult to extract because the silicate easily forms a third phase. It goes smoothly, but the cost of regeneration treatment is relatively high; the composite membrane regeneration method is still only in the laboratory research stage

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