Efficient calcium thioaluminate type bulking agent and its preparing process

Abstract

The invention is an improvement to the production process of the CAS type expansion agent. In the improved process, the calcination and mixing of gypsum materials are divided into two processes to complete. Calcium sulfate clinker is prepared by calcining limestone, gypsum and bauxite in a rotary kiln, and then the clinker and gypsum are mixed and ground, and an appropriate amount of limestone is added to form a CAS-type expansion agent, which not only maintains the performance of the CAS-type expansion agent Moreover, it greatly reduces the alkali content and production cost, and finds a process route suitable for my country's national conditions for the production of domestic high-quality expansion agents.

Description

technical field [0001] The invention belongs to the improved design and matching production process of a concrete expansion additive, in particular to the improvement of the production process of a calcium sulfoaluminate type expansion agent. Background technique [0002] Obtaining a certain degree of expansion in the early stage of hardening is an important means to improve the performance of concrete. For this reason, countries all over the world are competing to develop various types of expansive cements and expansive agents. Although there are many chemical substances that can cause the expansion of concrete through corresponding chemical reactions, there are mainly three reactions of expansion agents that have been applied so far: CaO hydration to Ca(OH) 2 , MgO hydrates to Mg(OH) 2 , to generate calcium sulfoaluminate hydrate. Due to the instability of CaO and MgO itself and the chemical reaction process in the expansion process, CaO and MgO are rarely used at prese...

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Problems solved by technology

[0004] Domestic research since the 1970s has proved that CAS expansion agent has superior performance, but the price and cost are too high. Electric furnace melting method calcination cannot be applied in China, and it is difficult to realize it with low-cost rotary kiln technology.

In the mid-1970s, expansion agents with alunite and anhydrite as the main components appeared in China. Although the cost was low, their performance was unstable, the expansion cycle was long, the alkali content was high, and the dosage was high. Compared with CAS expansion agents, their performance was still inferior. There is a big gap

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