Preparation of special silicon steel grade MgO from hydromagnesite  

作　　者：Xiangyang Zhou Shanni Li Jie Li Hongzhuan Liu Shangyuan Wu 

机构地区：[1]School of Metallurgical Science and Engineering, Central South University, Chang sha 410083, China [2]School of Biological Science and Technology, Central South University, Chang sha 410083, China

出　　处：《Journal of University of Science and Technology Beijing》2007年第3期225-230,共6页北京科技大学学报（英文版）

基　　金：the Science and Technology Program Project of Hunan Province, China (No.06SK2011).

摘　　要：A preparation technology of MgO powder used in special silicon steel from hydromagnesite mineral has been developed. The preparation technology includes the following steps： （1） calcining the hydromagnesite at 700-750°C for 1.5-2 h; （2） hydrating the calcined hydromagnesite to be slurry containing the solid-liquid ratio of 15-20 g？L？1; （3） acquiring Mg（HCO3）2 solution by carbonating the slurry, the carbonation temperature, CO2 pressure, and end point PH value of carbonation are less than 40°C, 0.4-0.6 MPa, and 7 respectively during the carbonation process; （4） preparing precipitated basic magnesium carbonate by thermally decomposing the Mg（HCO3）2 solution at 90-100°C; （5） obtaining the MgO product by calcining the precipitated basic magnesium carbonate at 850-950°C for 30-60 min, and adopting flowing nitrogen during the cooling process. By using this technology, more than 80wt% magnesium in hydromagnesite mineral can be extracted, and high-performance MgO products used in special silicon steel can be ob- tained.A preparation technology of MgO powder used in special silicon steel from hydromagnesite mineral has been developed. The preparation technology includes the following steps： （1） calcining the hydromagnesite at 700-750°C for 1.5-2 h; （2） hydrating the calcined hydromagnesite to be slurry containing the solid-liquid ratio of 15-20 g？L？1; （3） acquiring Mg（HCO3）2 solution by carbonating the slurry, the carbonation temperature, CO2 pressure, and end point PH value of carbonation are less than 40°C, 0.4-0.6 MPa, and 7 respectively during the carbonation process; （4） preparing precipitated basic magnesium carbonate by thermally decomposing the Mg（HCO3）2 solution at 90-100°C; （5） obtaining the MgO product by calcining the precipitated basic magnesium carbonate at 850-950°C for 30-60 min, and adopting flowing nitrogen during the cooling process. By using this technology, more than 80wt% magnesium in hydromagnesite mineral can be extracted, and high-performance MgO products used in special silicon steel can be ob- tained.

关 键 词：special silicon steel grade MgO hydromagnesite mineral CARBONATION end point pH value 

分 类 号：TF822[冶金工程—有色金属冶金]