Separation Of Impurities And New Process Of MgO-CaO Clinker

MgO-CaO refractory has caused widespread attention because of its excellent properties.However, the biggest problem of MgO-CaO refractory is sintering of calcium magnesium clinker（MgO-CaO clinker）and the hydration of f-CaO. Meanwhile, high-quality resources are nearlyexhausted after many years of exploiting. Therefore, how to use dolomite as raw materialsefficiently to prepare high-calcium MgO-CaO clinker with excellent properties makes greatsense.In this work, the preliminary work on the preparation of MgO-CaO clinker has beenresearched through the following aspects:Using dolomite as raw material,the thermal decomposition of dolomite were studied bychemical analysis, comprehensive thermal analysis, X-ray diffraction. The effects of granularity、light burning temperature on impurities separating on have also been studied based on thermalseparation principle. Studies showed that the thermal decomposition of dolomite reacted withtwo steps. The decomposition temperature of MgCO₃was about780℃.while CaCO₃decomposed at900℃. the content of SiO₂and Fe₂O₃in dolomite could be decreased effectivelythrough separation and little impaction was made on Al₂O₃. Furthermore, comparing theeffection of impurity removal by light sintering,2#dolomite was the best and then1#dolomitewhile3#dolomite was the worst for its high impurity content.Using dolomite of different particle size as raw material, the effect of activity degree on thesintering properties of MgO-CaO clinker were studied by changing light burning temperatureand sintering temperature. The result shows dolomite insulted for2h at1000℃indicated themost activity. MgO-CaO clinker calcinated at high temperature has the best character. Theas-prepared MgO-CaO clinker reach to optimal sintering property by processing at1600℃for3h.MgO-CaO clinker were synthesized by new process which combined one-step calcinationwith two-step calcination. High-calcium MgO-CaO clinker with bulk density as3.35g/cm3, inwhich the mass fraction of CaO was about56%are synthesized by changing the proportion ofraw dolomite and slaking product.Using dolomite as raw material,The effect of additives and the content of magnesium onsintering property of MgO-CaO clinker were studied though two-step calcination process, Theresult showed that addition of V₂O₅,MgCl₂and Ba（OH）₂could promote the sintering ofMgO-CaO clinker and their optimum addition were all0.5%. MgCl₂can easily soluble in water.Comparing the effection of promoting the sintering character of the samples, MgCl₂withsolution state are better than MgCl₂powder. The addition of magnesite could obviously improvethe sintering property of MgO-CaO clinker. And when the amount of magnesium is60%, thesample have the best sintering property.