Studying On The Preparation Of The Light Calcium Carbonate And Magnesium Oxide From Dolomite

In this dissertation, the preparation of light calcium carbonate and magnesium oxide were studied using dolomite as raw materials via the phase-transfer carbonization route.The main research and conclusions include:1. Taking the phase transfer ratio of calcium ions as the main index, MY was selected as the phase transfer reagent.2. Taking the activation grade of the calcined dolomite as the main index, the calcination conditions were investigated and optimized as follows:calcination time 1.5h, calcination temperature 950℃. The activation grade of the calcined dolomite was very high with mass loss rate of 45.7% under the optimized conditions.3. Taking the phase transfer ratio of calcium and magnesium ions as the main index, the phase transfer reaction conditions were investigated and optimized as follows:molar ratio of Ca2+ to phase transfer agent 1:1.5, solid-liquid ratio 1:10, reaction time 40 min and reaction temperature 20℃. Under the optimized conditions, the average phase transferring ratio of calcium ions can reach to 96.36% while that of magnesium ions only 2.43%.4. Taking the yield of the light calcium carbonate as the main index, the carbonation reaction conditions were investigated and optimized as follows: concentration of Ca2+ 0.38mol·L-1, carbonization temperature 35℃, the carbonization time 1.5h and the flux of CO2 100ml·min-1. The average yield of the light calcium carbonate was 95.46% under the optimized conditions.5. Taking the yield of the basic magnesium carbonate as the main index, the carbonation reaction conditions were investigated and optimized as follows: concentration of MgO 7.38g-L-1, carbonization temperature 20℃, carbonization time 120min and the flux of CO2 100mL·min-1. The average yield of the basic magnesium carbonate was 82.34% under the optimized conditions.6. Taking the mass loss rate of basic magnesium carbonate in the calcination as the main index, the calcination conditions were investigated and optimized as follows: calcination time 1h, calcination temperature 700℃. The mass loss rate of basic magnesium carbonate in calcination was 57.5% under the optimized conditions.