The Basic Research Of Extracted Calcium And Magnesium Compound From Dolomite

Dolomite is the important calcium magnesium resources on the surfaceof the earth. Extracted calcium and magnesium compound from Dolomitecan raised additional value of the minerals. so it has necessity of theoreticaland realistic significance to study on this subject.In this research light-burned dolomite collection dust was chosed asraw materials, two methods were used to extracted the calcium magnesiumcompound from it. The first method use ammonia chloride as infusion, Theconditions for extraction of the calcium ion from the light-burned dolomitecollection dust were studied. And the best extraction condition is reactiontime at15min and temperature at25℃. During carbonating process, Ifkeeping the calcium ion initial concentration at0.14mol/L, Carbonizationtemperature at20℃, carbonizationtime at13min，velocity of CO₂at0.1L·min^-1, The extraction ratio of Ca²⁺could to reach95%. The liquidwould be recycle after the carbonating process finished. During magnesiumoxide carbonating process, The best experimental condition is reactiontemperature at20℃， velocity of CO₂at0.1L·min^-1. At the samecarbonization time （1h）, compared with the once cathonation, the twicecathonation can raise the extraction ratio from36%to42%. Pyrolysisexperiment Showed Mg（HCO₃）₂part decomposition at50℃a ndbestthermal decomposition temperature at100℃. XRD data indicate that CaCO3is calcite crystalline phase. The chemical formula for light magnesiumcarbonate is4MgCO₃·Mg（OH）₂·5H₂O. T-G analysis is used to determine thecomponents and their contents of light magnesium carbonate and calciumcarbonate.The second use amine salt as infusion, CaO recover dibutylamine fromits salt. The extracted fluid is mixed with sulphuric acid and the nitric acidand calcium sulfate precipitate are formed. magnesium oxide dissolved with nitric acid. The high-purity Magnesium hydroxide was prepared byinhomogeneous precipitation method, using dibutylamine as the precipitatorintroduced by Directly add with Mg²⁺initial concentration at0.2-0.7mol/Land reaction temperature at50-70℃. The prepared Magnesium hygdroxidehave higher crystallinity and good filtering performance. Thethermodynamic and kinetic considerations of reaction system was discussedin detail. The sample was characterized by XRD、TG、FT-IR and surfacemorphography was observed with SEM.