Method for synthesizing light calcium-silicate thermal insulation material

Abstract

The invention discloses a method for synthesizing xonotlite-type calcium silicate. The method includes the following steps that reinforced fibers are dispersed into a calcium-silicate solution with the specific concentration and module, lime milk is added, then ordinary-pressure hydrothermal synthesis is carried out, a sodium hydroxide solution is replaced, and C-S-H gel-type calcium silicate fineparticles are obtained; filtering and washing are sequentially carried out, water is added into the obtained C-S-H gel-type hydrated calcium silicate for adjusting the concentration, then a high-pressure dynamic hydro-thermal synthesis reaction is carried out, and a xonotlite-type light calcium silicate product is finally obtained. By means of the method, the problems that in the prior art, whena quartz sand solid raw material is directly used as a silica raw material and directly participates in the reaction, the reaction activity degree is low, energy consumption is high, and the crystal effect of the product is low are solved; the problems that the reinforced fibers are unevenly dispersed in a xonotlite-type thermal insulation material, and the moisture content and the strength are uneven after the material is subjected to pressing filtration forming are solved. In addition, recycling and cyclic utilization of the sodium hydroxide solution are achieved.

Description

technical field [0001] The invention relates to the technical field of calcium silicate thermal insulation materials, in particular to a method for synthesizing lightweight calcium silicate thermal insulation materials. Background technique [0002] The main chemical composition of lightweight calcium silicate insulation material is xonotlite, and its molecular formula can be expressed as: 6CaO·6SiO 2 ·H 2 O. The material is dynamically hydrothermally synthesized from a mixture of lime and silica at a certain Ca / Si molar ratio at 150°C to 400°C. Its structure belongs to the monoclinic system, and the microstructure of xonotlite is prism-like crystals or fibers. shaped aggregates. [0003] The application of lightweight calcium silicate thermal insulation materials is developing very rapidly. The main reason is that compared with other inorganic thermal insulation materials, xonotlite materials have many excellent characteristics, such as light weight, fire prevention, hig...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a method for synthesizing light calcium silicate thermal insulation material under the high temperature and high pressure dynamic hydrothermal synthesis method using fly ash desilication lye, reinforcing fiber and milk of lime, in order to solve the existing traditional technology When using quartz sand as a raw material for production, the liquid-solid ratio in the reaction process is high, the reaction time is long, and the required temperature is high, which leads to high material consumption and energy consumption, and the crystallization reaction of raw materials in the hydrothermal synthesis reaction process is not good. Completely, the crystallization degree of xonotlite crystals obtained is poor, and at the same time, it solves the problem that a large amount of alkali residue in the material cannot be effectively removed when the desilication alkali solution is used as a raw material to participate in the reaction, and also solves the problem that the fiber in the material cannot be effectively removed. The problem of uneven dispersion

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