Study On The Enhanced Dissolution And Mechanism Of MgO-containing Calcium Aluminate Clinker

MgO,one of the impurities contained in calcium aluminate clinker when dealing with low-grade aluminum resources,will react with CaO,Al₂O₃ and SiO₂.And the compound20CaO·13Al₂O₃·3MgO·3SiO₂?Q phase?will be formed,which will decrease alumina leaching property and self-disintegrating ratio of the clinker.The negative effect of MgO can be reduced when a small amount of Na₂SO₄ was added,but there still were problems of low alumina dissolution rate,high dissolution conditions and so on during the dissolution process.In this paper,MgO-containing calcium aluminate clinker was prepared under the raw material conditions of C/A=1.4,A/S=3,MgO 2%,Na₂SO₄4%?in mass?.The dissolution of clinker was enhanced by ultrasonic,two-stage and microwave,and the enhanced-dissolution properties and mechanism were studied.The results show that:?1?Alumina dissolution performance of MgO-containing calcium aluminate clinker was excellent.The best industrial dissolution conditions were that:dissolution temperature70?,Na₂O_C 120 g·L^-1 and dissolution time 30min,liquid solid ratio 5.The alumina dissolution ratio that obtained under these conditions was 91.58%and the content of alumina in the solution was 61.21 g·L^-1.?2?The dissolution temperature,and content of Na₂O_C and the dissolution time reduced when dissolution was enhanced by ultrasonic and microwave;the content of Na₂O_C reduced and the alumina content of solution increased when dissolution was enhanced by two-stage.?3?The mechanism of enhanced-dissolution was as followed:the particle size of dissolution slag reduced,the liquid-solid mass transfer was accelerated,the reaction rate increased when dissolution was enhanced by ultrasonic and microwave;The clinker was dissolved twice when dissolution was enhanced by two-stage,which was equivalent to increasing the concentration of the dissolution solution.