A kind of calcium and magnesium sulfate double salt cementitious material and its preparation method and application

Abstract

A calcium-magnesium sulfate double salt cementing material and a preparation method and application thereof; the double salt cementing material comprises the following components: calcium and magnesium sulfate double salt, active magnesium oxide and mineral powder; wherein the calcium and magnesium sulfate double salt is kiln smoke The desulfurized calcium and magnesium double salt powder discharged from the gas desulfurization process, or the waste calcium and magnesium double salt powder formed by treating industrial waste sulfuric acid with dolomite, or the industrial by-product gypsum slag after heating and dehydration in the presence of magnesium sulfate. Calcium and magnesium double salt powder; other mineral powders include fly ash, limestone powder, dolomite powder, building gypsum, etc. The invention not only provides a new technology for economical and efficient utilization of flue gas desulfurization products, industrial waste sulfuric acid and phosphogypsum, but also the prepared double salt cementitious material has excellent physical and mechanical properties, and is characterized by fast setting, high strength and water resistance. Well, multiple social benefits such as environmental protection, economy, and new materials have been achieved. The preparation method of the calcium-magnesium sulfate double-salt cementing material of the invention is simple and feasible, and has low energy consumption.

Description

technical field [0001] The invention relates to a calcium-magnesium sulfate double-salt cementing material and a preparation method and application thereof, belonging to the field of inorganic gelling materials and building materials. Background technique [0002] In the field of inorganic gelling materials, they are generally divided into two categories: hydraulic and air-hardening gelling materials. Commercial cements such as Portland cement, aluminate cement and sulphoaluminate cement are hydraulic cementing materials; various building gypsums are air-hardening cementing materials. Their essential difference is that the main hydrates of hydraulic cementitious materials are highly stable in water, so the slurry made of this type of cement and water can develop and maintain its microstructure and physical and mechanical properties in water; The main hydrates of hard gelling materials have poor water stability and are soluble. Therefore, the slurry made of such gelling mate...

AI Technical Summary

Problems solved by technology

This has led to a comprehensive utilization rate of less than 30% of the industrial by-product gypsum, that is, about 120 million tons of industrial by-product gypsum are stacked and stored every year, which not only causes waste of resources, but also contains some soluble acid Substances, these acidic substances in stacking and storage will pollute the water and soil environment

However, the production of sulphoaluminate cement requires high-grade bauxite as a key raw material, and bauxite is not only an important raw material for the alumina and electrolytic aluminum industries, but also has a small storage capacity and a small distribution area. Therefore, this The popularization and application of a technical invention is also subject to relatively large restrictions

Chinese patent CN201610034309.1 discloses a technical scheme of using low-grade bauxite to prepare low-carbon cement clinker, but the proportion of calcium sulfate in cement mass is less than 15%

Although there are some technical solutions and equipment for recycling waste sulfuric acid, industrial waste sulfuric acid has the characteristics of complex impurity components, high treatment costs, huge total volume and scattered industries, which brings great difficulties to resource utilization and harmless treatment.

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