Method for removing silicon dioxide in water

Abstract

The invention discloses a method for removing silicon dioxide in water. The method mainly comprises the following steps: (1) adding alkali for pretreatment to colloidize silicon dioxide, calcium and magnesium impurities in water; (2) electro-flocculation reaction precipitation: using an aluminum plate, an iron plate or an aluminum-iron mixed plate as a positive plate for electrolysis to generate an aluminum hydroxide or ferric hydroxide flocculant, after adsorption and alkali treatment, forming silica and calcium, and the magnesium impurities colloid particles, and performing co-deposition; 3)air flotation and impurity removal: floating waste water processed in the step 2) to remove impurities, and removing silica particles and other impurities which are difficult to precipitate in the water; and 4) membrane filtration: filtering the waste water processed by the step 3) by a membrane filtration apparatus, and realizing deep filtering treatment on the silica impurities in water. The whole process removes silicon dioxide thoroughly and maturely, and the process design is reasonable and coherent, also effectively removes calcium and magnesium impurities in the water, improves the quality of the processed clear water, and improves the recovery and application value of the processed water, has strong resistance to shock loading, and has good industrial application prospects.

Description

technical field [0001] The invention relates to the field of water treatment, in particular to a method for removing silica in water. Background technique [0002] With social progress, industrial development and population surge, the problem of environmental pollution is increasing, especially the pollution of water resources, which makes the fresh water resources available to human beings very small. Scientists predict that by 2025, two-thirds of the world's population will face severe water shortages, and may even be threatened by insufficient domestic water supply. In order to solve the shortage of water resources, all countries in the world have turned to the all-round and sustainable use of water resources for the overall strategy of water resources. How to improve the primary use efficiency of water and the reuse efficiency of water has become an important task in all walks of life. [0003] In industrial water, many industries are limited by silica in water, from t...

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Problems solved by technology

[0004] At present, for this kind of wastewater treatment, there are no examples of resource utilization at home and abroad. The existing methods include coagulation, chemical flocculation, ion exchange membrane and other single removal methods.

Among them, the traditional chemical flocculation method is easy to cause secondary pollution, and cannot achieve the purpose of deep removal of silica. Ion exchange membrane treatment is not only expensive but also requires high quality of influent water.

Moreover, the above-mentioned single treatment method is due to the variable content of silica and other impurities in the water during the actual water treatment process, resulting in a large operating load of the silica removal device and weak impact load resistance, resulting in an unsatisfactory final silica removal effect.

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