Study On The Preparation Process Of High-Purity Magnesium Oxide From Old Bittern In Lop Nor Saline Lakes

The Saline Lake of Lop Nor,Xinjiang,is the largest potassium Magnesium Sulfate subtype brine deposit developed in China to date.At present,the Saline Lake potassium resources have been used for large-scale exploitation,and the production of 1 million 600 thousand tons of potassium sulphate production system for adult production has been built.However,a lot of old brine brine produced by saltern spreading process is partially removed in the salt field,but the remaining part is not yet effectively utilized,and the waste is excluded.For the effective development of Lop Nor Saline Lake brine brine resources,improve resource utilization,based on China's Xinjiang Lop Nor Saline Lake old brine brine as the research object,according to the chemical brine brine magnesium ion precipitation reaction principle prepared precursor;according to the principle of chemical decomposition of precursor in high temperature,high temperature technology roadmap the way of calcining from Magnesium Oxide,studied Lop Nor Saline Lake brine preparation of high pure Magnesium Oxide.Magnesium oxide precursor was prepared by chemical precipitation from the brine.The optimum process conditions were as follows: Two-stage reaction was carried out using the two-stage precipitation method.In the first stage,90% of the theoretical amount of ammonia for used the precipitating agent.The ammonia addition time was10 min,and the reaction time was 20 min,and magnesium hydroxide was prepared at room temperature.In the second stage,100% of the theoretical amount of ammonium bicarbonate solution was used as the precipitating agent.The addition time was 10 min,and the reaction time was 20 min,and magnesium carbonatewas preparedat room temperature.After the two-stage reaction,the total precipitation rate of magnesium was90.2%.High purity Magnesium Oxide was obtained through the process of washing,drying and calcining of the precursors obtained from the two section of precipitation.A suitable calcination system has been determined.A precursor(magnesium hydroxide)is calcined 75min at 600 degrees in air,and the two precursors(basic magnesium carbonate)is calcined at 45min at 550 temperature.The purity of the obtained Magnesium Oxide products is above 98%,and the indexes are in line with the industrial light weight Magnesium Oxide standard(HG/T2573-2012).