Method for preparing geopolymeric material from bentonite

Abstract

The invention discloses a method for preparing a geopolymeric material from bentonite. The method comprises the following steps of: uniformly mixing the bentonite with an excitant I, wherein the granularity of a solid phase in a mixture is less than or equal to 10 percent of the mass ratio of 200-mesh screen residues, and the mass ratio of the excitant I to the bentonite is 0.1-0.25; (2) calcining the mixture obtained in the step (1) at the high preserved temperature of 700-1,000 DEG C for 2-4 hours, and regrinding a calcining product to obtain chamotte powder, wherein granularity of the chamotte powder is less than or equal to 10 percent of the mass ratio of 200-mesh screen residues; and (3) doping an aqueous solution of an excitant II into the chamotte powder obtained in the step (2), mixing uniformly, compacting by vibrating, and preserving in a wet state at the temperature of 60-95 DEG C to obtain the geopolymeric material, wherein a water cement ratio, i.e., the mass ratio of theaqueous solution of the excitant II to the chamotte powder is 0.2-0.4; and the mass ratio of a solid phase in the excitant II and the non-calcined bentonite is 0-0.05. The method plays a remarkable role in expanding raw material sources, reducing cost, enhancing use convenience, and the like.

Description

Technical field [0001] The invention belongs to the field of preparation of novel cement materials, and particularly relates to a method for preparing geopolymeric materials by using bentonite. Background technique [0002] Geological polymer materials (referred to as geopolymers), also known as mineral polymer materials, geopolymeric cement, alkali-activated cement, etc., are an eco-friendly silico-alumina inorganic material that has been developed in recent years and is expected to replace Portland cement. Cementitious material. It mainly refers to zeolite-like three-dimensional aluminosilicate mineral polymers containing a variety of amorphous to semi-crystalline. The typical preparation procedure is: silico-alumina raw materials → calcination activation → soluble alkali metal aluminosilicate dissolution activation → 20-120 ℃ heat preservation and curing. The geopolymer has rich sources of raw materials, low carbon emissions, low expansion and contraction rate, low permeabi...

AI Technical Summary

Problems solved by technology

However, the use of geopolymeric materials to replace Portland cement still faces some major problems: ①Limitation of raw materials. From the perspective of composition, aluminosilicate raw materials with the most abundant content in the earth’s crust can be used as natural raw materials for geopolymers, but the actual Kaolin is the only one that has been studied the most and can produce geopolymers with sufficient strength; the composition and structure of silicon-alumina solid wastes are very different, making it difficult to use them on a large scale

② The preparation cost is high. When preparing geopolymers from natural raw materials, calcined pretreated high-quality kaolin and alkali silicate activators are raw materials with high cost; when preparing geopolymers from industrial solid waste, although pre-calcination is not required , but the activator used is the same as the natural mineral raw material, and its cost still needs to be reduced

③Using hygroscopic and reactive strong alkaline salts as activators and a two-component system make it inconvenient to store and use, and the environmental risk is greater

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