| My Homeland has abundant high-sulfur bauxite resources,and the development and utilization of these bauxite resources can alleviate the shortage of bauxite resources and high dependence on foreign countries.However,the sulfur in high-sulfur bauxite will have a serious impact on the alumina production process,so the problem of desulfurization is imminent.The microwave desulfurization has attracted people’s attention because of its low temperature,short-time high efficiency,and good desulfurization effect.Therefore,this paper uses the microwave method to study the desulfurization effect of high-sulfur bauxite under microwave roasting conditions and the dissolution effect of the desulfurized roasted ore Bayer method to dissolve alumina.At the same time,the microwave sintering conditions of high-sulfur bauxite are studied.The phase change of the material and the dissolution effect of the clinker normal pressure and low temperature alkali-soluble alumina provide a reference for the development and utilization of high-sulfur bauxite.High-sulfur bauxite microwave roasting desulfurization test results show that microwave roasting desulfurization of high-sulfur bauxite can achieve better desulfurization effect.Roasting at 600℃for 20 min can remove the total sulfur content of bauxite from 3.88%to 0.23%,the desulfurization rate reaches 95.11%.Compared with the roasting time,the roasting temperature has a more significant influence on the desulfurization rate.When the roasting temperature is increased from 100°C to 600°C,the desulfurization rate can be increased by about 30%on average,and the roasting time is extended from 2 min to 20 min.Only an average increase of about 12%.High-sulfur bauxite ore after microwave roasting and desulfurization,the Bayer process high-pressure dissolution test results show that the microwave roasting temperature also has a significant influence on the dissolution rate of alumina.As the microwave roasting temperature increases,the relative dissolution rate of alumina is the first After the increase,there is a downward trend.After the microwave roasting temperature is higher than 400℃,a large amount of corundum（Al2O3）phase will appear in the roasted ore,resulting in a decrease in the relative dissolution rate of alumina.The dissolution conditions of roasting ore by Bayer process are close to industrial production conditions:roasting temperature is 400℃,roasting time is 20min,caustic soda concentration is 265g/L,dissolution temperature is 260℃,dissolution time is 60min,and the relative dissolution rate of alumina is 94.07%.The clinker sintering and clinker dissolution test results show that:during the clinker sintering process,a more complicated phase transformation process occurs,generating sodium metaaluminate,sodium ferrite,nepheline,sodium aluminosilicate,calcium aluminosilicate,Phases such as calcium ferrite and calcium titanate.Sintering conditions,dissolution conditions and residual sulfur in the clinker all affect the dissolution of alumina from the clinker to varying degrees.The best low-temperature and atmospheric pressure dissolution conditions for the sintering method are:clinker roasting at 1000°C,alkali ratio 1.3,calcium ratio 2,dissolution temperature 85°C,dissolution time 15min,caustic alkali concentration 42.6g/L,and carbon alkali concentration 8g/L,the dissolution rate of alumina at this time is 90.87%. |
