水菱镁石制备轻烧MgO粉的煅烧工艺研究

Preparation of light-burned MgO powder from hydromagnesite

以粒度3～5 mm的水菱镁石为原料,研究了煅烧温度(600、700、800、900和1 000℃)和保温时间(2、3、4和5 h)对轻烧MgO粉活性和热选(分别过孔径0.425、0.150和0.074 mm筛)降CaO率的影响。结果表明:1)轻烧MgO粉的活性随煅烧温度的升高及保温时间的延长均呈先增大后减小的变化趋势,拐点分别为800℃和3 h。2)热选降CaO率随煅烧温度的升高呈先减小后增大的变化趋势,拐点为800℃;随保温时间的延长呈先增大后减小的变化趋势,拐点为3 h;筛孔孔径越大,热选降CaO率越高。3)水菱镁石制备轻烧MgO粉的最佳工艺参数是900℃保温3 h煅烧,然后过0.425 mm筛热选。

Effects of calcination temperatures （600,700,800,900 and 1 000 ℃） and soaking times （2,3,4 and 5 h） on activity and hot selection （selected using 0. 425,0. 150 and 0. 074 mm screen,respectively） CaO reducing rate of the light-burned MgO powder were studied using hydromagnesite （3-5 mm） as the starting material. The results show that：1 ）with temperature rising or soaking time prolonging ,the activity of light-burned MgO powder firstly increases and then decreases,and the inflection point is 800℃ and 3 h, respectively ;2）CaO reducing rate firstly decreases and then increases （inflection point is 800 ℃）, or changes inversely with soaking time prolonging （inflection point is 3 h） ;the bigger the aperture of the screen is, the higher the CaO reducing rate is ;3）the optimum parameters to prepare light-burned MgO powder using hydromagnesite are calcining at 900 ℃,soaking for 3 h and screening at 0.425 mm.