Method of preparing laminar silicon by suspension heat exchange agglomeration method and its device

Abstract

A process for preparing granular laminated Si with delta-crystal form by suspended heat exchange-sinter-crystallizing method includes such steps as preparing natron solution, using clean hot air to treat it to become non-crystalline sodium bisilicate powder, grinding, heat treating in suspended state, loading in crystallizer, and sintering while crystallizing to obtain granular laminated Si, pulverizing, classifying by granularity, respective storing, and proportional mixing. Its apparatus is composed of suspended preheater, and fixed crystallizer or rotary crystallizer.

Description

technical field [0001] The invention relates to a process and device for preparing layered silicon (layered silicon is layered sodium disilicate phosphorus-free builder) by means of suspension preheating and suspension heat exchange sintering, and belongs to the field of inorganic salt application material manufacturing, specifically Said to be related to a kind of δ-crystal form as the main component, can be used as the preparation process of the layer silicon material of non-phosphorus builder and its device. technical background [0002] Phosphorus-free builder layer silicon was developed in the late 1980s. Compared with the currently widely used phosphorus-free builder 4A zeolite, its performance has obvious advantages. Compared with other phosphorus-free builders (such as sodium metasilicate, layer Silicate, sodium polyacrylate, nitrilotriacetic acid, sodium citrate and other materials) comprehensive comparison, layer silicon is a recognized, ideal phosphorus-free build...

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Problems solved by technology

There is following shortcoming in above-mentioned two kinds of techniques: (1) to raw material requirement height, the SiO of quartz sand Content will ≥ 99%, and liquid caustic soda needs the caustic soda prepared by expensive ion membrane method, and this just causes raw material cost too high; When adopting When the solid sodium silicate produced by the calcination method is used as a raw material, it often encounters the problem that the sodium silicate with the same chemical composition supplied by the same factory cannot produce crystalline layer silicon with the δ-crystal form as the main body under the same conditions, resulting in huge waste

(2) The production time is long, it is easy to make the product contain too much vitreous body, and the insoluble content of the final product exceeds the standard

(3) The reactant particles are easy to adhere to the inner wall of the equipment. In order to effectively prevent the reactant particles from adhering to the equipment, some people recycle a small amount of final products to separate the sintered reactants from the inner wall of the crystallization equipment. However, this method It is easy to affect the product quality

(4) The rotation of the rotary kiln requires too much power, which increases the power consumption

(5) Using a rotary kiln as a reactor has low thermal efficiency, resulting in high heat consumption of the product

In order to improve the thermal efficiency of the rotary kiln, someone abroad grinds the spray-dried powdered amorphous sodium disilicate into particles with a particle size of 1-50um, and then introduces it into a rotary furnace equipped with a moving solid device, that is, an indirect heating rotary kiln. Sintering, but this method requires the particle size to be too small, and the equipment is complicated at the same time. Although the thermal efficiency has been improved, the power consumption for grinding is also increased, and the rotary kiln is still a device with low thermal efficiency, and it cannot solve the problem of reactant particles. The problem of adhesion on the inner wall of the equipment

The sintering in the direct heating rotary kiln currently used in China not only has low thermal efficiency, but also has high requirements for fuel, which will increase the cost of the product

(6) It is difficult to realize large-scale chemical industrial production

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