The Separation Of Lithium And Magnesium And The Preparation Of Magnesium Hydroxide Flame Retardant Use The Calcined Magnesium Slag From Salt Lake

In view of the Salt Lake Resources, the market potential and the major problems in the production of Mg(OH)2 flame retardants, the papers make a systematic study and explore for the separation of lithium and magnesium and the preparative of the Mg(OH)2 flame retardants,which come from calcine magnesium slag. Through research the mechanism of the preparation process of magnesium hydroxide, we found the reasons that low-purity,long reaction time,unevenly size,. and to identify ways to improve.The study of the separation of lithium and magnesium. In the atmospheric pressure, through the single-factor test, we determined the best conditions: reaction time is 1.5h, reaction temperature is 40℃, size is 200 mesh, Ratio of solid to liquid is 1∶5, 2mol/L NaOH solution for the reaction system of 15ml/100g. Under these conditions, the extraction rate of lithium would reached 90%, magnesium is less than 0.1 g/L in the filtrate.. In the atmospheric pressure, through the single-factor test, determined the best conditions of hydrat reaction which is prepared Mg(OH)2: size of MgO is 200 mesh, reaction times 2h, Ratio of liquid to solid is 10∶1, hydration temperature is 70℃. Above these conditions, wo can make the purity products of Mg(OH)2, which is small and uniform size. The purity can reach 98%,the specific area is 18 m2/g , the gumming is higher, and the product qualifications almost meet the standard of fire-retardant level.Based research on preparation mechanism of Mg(OH)2 via hydration method, the subject has found that it can accelerate by increasing the activity of MgO to decrease the activation energy of hydrated reaction, and heightening hydrated reaction temperature or enlarging stirring speed to promote molecular energy. In the crystallization process of Mg(OH)2, inhomogeneous nucleation mainly occurs, which lead to low purity and non-uniform size, but the influence of inhomogeneous nulcation can be reduced by introducing surface modifier or using High Shearing Emulsor.Takeing use of the calcined magnesium slag from salt lake, the subject synthesized fire-retardant level Mg(OH)2 via hydration preparation at atmosphere presure, and MgO hydration and modification of Mg(OH)2 can take place at same time. The preparation craft is simple and production cost is low. Achievements in scientific reseach set foundation to commercial process of hydration preparation of fire-retardant level mafnesium hydrate using magnesite.