Research on Activity Characteristics on Composite Cementitious Materials Based on Phosphogypsum

The physical and chemical characteristics of each of phosphogypsum-based silicon and aluminum composite materials were tested and analyzed. By means of ratio test, it is proved that the range of composite materials' compressive strength is 1.46MPa to 2.78MPa along with the range of the ratio in 1: 1: 4.7 to1: 1: 8. The experiments of active characteristics of composite materials were designed in method of activity ratio K-a value, whose results showed that in early stage, a small amount of hazardous substances in composite materials, such as soluble phosphorus, fluorine and so on, will inhibit free proliferation about the activity of SiO2 and Al2O3, while in medium and late stage, the K-a value that showing a inflection point at the age of 28 days has a relationship with the OH-density in alkaline environment. And temperature, an important factor affecting the K-a value of composite materials, was set 80 degrees C as an optimal temperature in reactions. In a word, by calculating the K-a value, the degree of activity features affected by the external environment was followed by Temperature> Activation time> Fineness. The research could provide theoretical guidance for large-scale application of utilizing industrial solid waste to fill goaf so that ensure the safety of mines. (C) 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Capital University of Economics and Business, China Academy of Safety Science and Technology.