Method for preparing high-modulus sodium silicate

Abstract

The invention discloses a method for producing high-modulus sodium silicate at low temperature and normal pressure. The method comprises the following steps: the activated silicon dioxide from fly ash-typed industrial waste is leached by caustic lye of soda to produce low-modulus sodium silicate solution, the solution is decomposed by carbonation to prepare silicic acid (SiO2nH2O), then the silicic acid, the low-modulus sodium silicate and / or sodium hydroxide solution are mixed at the modulus index required by the final sodium silicate products and stirred to dissolve at temperature lower than liquid boiling point, therefore, the high-modulus sodium silicate is produced. Compared with the existing drying and wet methods for producing sodium silicate, the method of the invention has the advantages of wide raw material resources, low cost and energy consumption, no pollution; the method can be used for producing the sodium silicate with any modulus (M) from 1 to 4, in particular to the high-modulus sodium silicate, and has great industrialized generalization and application value.

Description

technical field [0001] The invention relates to the comprehensive utilization of fly ash industrial waste and the preparation of inorganic salt---sodium silicate, which belongs to a technology for preparing high modulus sodium silicate from fly ash industrial waste. Background technique [0002] Sodium silicate is often called sodium silicate or sodium silicate. It is an inorganic salt product with a wide range of applications. It is mainly used in detergents, soap making, packaging, precision casting, welding electrode production, coatings, building materials and Metallurgy and other industries are also the basic raw materials for the production of silica gel, molecular sieve and white carbon black. One of the characterization indicators of sodium silicate solution is the modulus, that is, SiO in sodium silicate solution 2 and Na 2 The mass ratio of O, currently the use of high modulus sodium silicate solution occupies a dominant position. [0003] The manufacturing meth...

AI Technical Summary

Problems solved by technology

Among them, the dry method is to mix quartz sand with soda ash or sodium sulfate, and carry out a melting reaction in a high-temperature furnace at 1400-1500 ° C for 6-7 hours. The material is moved to the dissolving tank and dissolved with hot steam. The steam pressure is about 0.4MPa. The dissolved material is discharged into the clarification tank for a long time to settle naturally or filter to remove the residue. The clarified supernatant is then pumped to the evaporation tank. The sodium silicate product is concentrated in the concentrator to the required concentration. Its advantage is that sodium silicate with various moduli can be produced, such as M being 0.5-4.0, especially high modulus sodium silicate with M>2.5. The disadvantages are high energy consumption and heavy pollution

Like the dry method, the wet method also needs to remove the residue and then evaporate and concentrate to obtain the product. Its advantage is that it avoids high temperature reaction, but it has the disadvantage of high raw material consumption and only low modulus sodium silicate can be prepared.

[0004] In addition, industrial waste such as fly ash has not been fully utilized in the prior art to prepare high modulus sodium silicate regardless of wet or dry methods