Composite phase-change catalyst for preparing quartz and use

Abstract

This invention relates to a phase change catalyst for calcining quartz prepares cristobalite and application. A composite phase changes catalyst of prepared cristobalite, which characteristic lie in that it is composed of KCl powder and MoO3 powder composition with mass ratio: 5-10:1-5. the application of the prepared cristobalite composite phase changes catalyst, its feature lie in: the composite quartz powder mixed composite phase change catalyst to get batch, the enter quality of composite phase changes catalyst is 6% - 15% of quartz powder quality; the batch heat on the speed of 2degree centigrade-10degree centigrade per minute to 1300degree centigrade and insulated for six hours, get products of the quartz phase more than 94%. The composite catalyst used for calcining quartz to prepare cristobalite, the transited temperature reduce (1300degree centigrade) from quartz to cristobalite, and its conversion rate is more than 94%, composite phase change catalyst used little.

Description

technical field [0001] The invention relates to a phase change catalyst for preparing cristobalite by calcining quartz and its application. Background technique [0002] A flux generally refers to a substance that reduces the softening, melting or liquefaction temperature of its substance. According to chemical properties, it can be divided into: (1) basic fluxes with calcium oxide and magnesium oxide as the main components; (2) acidic fluxes with silica as the main components; (3) fluorite, oxide A neutral flux with aluminum as the main component. [0003] Mineralizers are additives added to promote the solid-phase reaction effect of aluminosilicates. The mineralizer promotes the phase transition and lattice structure of the product, and its function is to form a solid sol with the reactant during calcination, activate the crystal lattice of the reactant, and facilitate the transformation of the product to a layered crystal form. It should be pointed out that a small amo...

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Problems solved by technology

[0005] At present, there are four kinds of additives that are reported in domestic literature and have been put into practical application in the production of cristobalite: one is the addition of metal oxides, see (Wang Jinshu, et al. Research on conversion rate of quartz to α-cristobalite [J]. China Ceramics, 1992 (6 ): 1-5), it is reported in the paper that alumina is an ideal phase-change catalyst, and when the addition amount is 4%, the conversion rate at 1320°C is the highest at 42.2%; the second type is the widely used lime in current production— Iron (CaO+FeO) or iron-lime (FeO+CaO) mineralizer, the former is more widely used, the addition amount is: about 2.5% of CaO, FeO (Fe 2 o 3 ) 0.5-1.0%, usually added in an amount of 3-4%; the third is to use fluorine-containing compounds as mineralizers, which can greatly accelerate the conversion of quartz, and the conversion rate can reach 85% at 1400 ° C; the fourth for Li 2 O, Na 2 O, K 2 O and other alkali metal oxides, this kind of mineralizer not only reduces the high temperature performance of bricks, but also the salts of these compounds will precipitate on the surface of bricks when dry, resulting in different mineralization inside and outside the bricks, easy to crack, Therefore, it is generally not suitable as a mineralizer

[0006] The main defects of the above methods are: 1. The addition of additives is too large, which affects the purity of cristobalite; 2. The conversion rate is low; 3. The addition of additives will affect product performance

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