Device and method for preparing silica by taking sodium silicate as raw material

Abstract

The invention discloses a device and a method for preparing silica by taking sodium silicate as a raw material, and relate to the preparation of silica. The device comprises a sodium silicate solution storage tank, a high-pressure carbonization reaction / aging kettle, a gas compressor, a heat exchanger, a check valve, a back pressure valve, a pumping, filtering and cleaning machine, a slurry preparation tank, a dryer, a carbon dioxide storage tank and a temperature control system. The method comprises the following steps: dissolving solid sodium silicate in water, filtering the obtained object, then adding water into the obtained product so as to obtain a sodium silicate solution, pumping the sodium silicate solution into the kettle, and feeding carbon dioxide into the kettle so as to obtain silica gel; controlling the temperature and carbon dioxide pressure in the kettle, carrying out aging and pore fixing on the obtained product and removing the pressure in the kettle so as to obtain saliferous silica slurry, then transferring the saliferous silica slurry to the pumping, filtering and cleaning machine to carry out solid-liquid separation, washing a filter cake by using water, detecting filter liquor by using a saturated barium hydroxide solution, stopping washing until no precipitation exists, and washing the filter cake by using anhydrous ethanol; and adding ethanol into the filter cake, and stirring the obtained product so as to prepare slurry, and then drying and crushing the obtained object so as to obtain silica. The process is simple, and a subtranslucent silica product with a high pore volume and a large specific surface area is obtained conveniently.

Description

technical field [0001] The invention relates to the preparation of silicon dioxide, in particular to a device and method for preparing silicon dioxide by using water glass as a raw material. Background technique [0002] As an inorganic powder material, silica has the characteristics of small particle size, large specific surface area, high purity, non-toxic and harmless. In addition, it also has many unique physical and chemical properties, such as dispersibility, extinction, reinforcement, thickening and thixotropy, and insulation, etc., so it is widely used in petrochemical, pharmaceutical and chemical industries, daily Chemical industry, rubber industry, paint industry, plastic products industry, etc., such as catalyst or drug carrier, paint matting agent, rubber reinforcing agent, ink thickener, daily cosmetic filler, etc. Compared with ordinary silica, high-performance silica has the characteristics of large pore volume, large pore size, high specific surface area, an...

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Problems solved by technology

For the research on carbonization method, my country had industrial experiments on the preparation of white carbon black by bubbling carbonization method as early as the 1980s. Long, limited to technical level has not been applied to production

Later, many researchers developed the spray carbonization method, high gravity carbonization method, supercritical carbonization method, etc. These methods can effectively overcome the limitation of gas-liquid mass transfer and greatly shorten the time required for the reaction. Capacity, pore size, specific surface area and dispersion performance, etc. can not meet the requirements of high-performance products

[0005] The applicant disclosed in Chinese patent CN102020284A a method for preparing silica by coupling supercritical / subcritical carbonization reaction with supercritical drying technology. The maximum pore volume of silica prepared by this method can reach 2.6cm 3 / g, specific surface area up to 421m 2 / g, the product prepared by this method meets the requirements of high-grade matting agent in terms of pore volume and specific surface area, but its performance needs to be further improved in other fields such as thermal insulation materials, catalyst carriers, etc.

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