Synthesis And Study On The Properties Of Quartz And Zircon Composit MgO-CaO Material

Refractory material need have a certain size stability, high temperature resistant performance and corrosion resistance. High temperature equipment generally needs refractory material as lining, so the refractory material is an indispensable part of high temperature industrial. Along with the development of metallurgical technology, the demand for pure steel and high-grade steel, the continuous casting ratio increases gradually. the technology of refining outside the furnace is developing.The ladle of smelting clean steel need refine secondary molten steel, when it was laying up and delivering, which force the refractory material change, improve and develop for high-grade refractory materials. Calcium magnesium series refractory’s powerful superiority is attended gradually by people, which include high temperature resistance, good resistance to slag penetration ability, and also can purify liquid steel. In many oxide refractory materials, Ca O not only has high temperature resistance, but also pury liquid steel. So magnesium calcium series refractory is honoured as one of the four main develop direction of refractory materials in China in the 21 st century.Calcium magnesium series refractory has very many excellent properties, it also exist some problems, one of the most important problem is the free Ca O hydration. In order to enhance the hydration resistance of magnesium calcium series refractory,common methods are divided into the following kinds: the first is surface processing; the second is introduction of additives;the third is change the sintering technology. So far, the study found that the additives which is good for calcium magnesium series refractory hydration resistance include:Ba O,Sr O,Al2O3,Fe2O3,B2O3,Y2O3,Si O2,Cr2O3,Ti O2,Zr O2,Ca F2,rare earth oxides and its composites, etc. The method of improving the sintering technology generally includes two step sintering method and high temperature sintering.This subject uses light burned dolomite, light burned magnesite as main rawmaterials, quartz and zircon as additives. We will study the compactness, hydration resistance, microstructure and phase composition of samples, by using two step sintering method, adjusting the proportion of calcium magnesium and introducing different content additives. Each group of samples were sintered under different temperature.And the influence of properties on different sintering temperature is studied.The results showed that:The compactness of samples is best when w(Mg O) is 60%.The hydration resistance is closely related to w(Ca O).The influence of samples’ phase composition by adding quartz is great. C3S、C2S and C3MS2 emerges with the increase of quartz content.While the content of Ca O is gradually decrease and eventually disappear. Excess quartz is bad for samples.The hydration resistance of samples improve obviously by introduction of zircon.The best contend of zircon is different with w(Mg O).The property improvement is obvious by improving the sintering temperature,which can make grains of Mg O growing up significantly and reduce the inernal porosity of Ca O grain.