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-...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.展开更多
For an algebraically closed field F of characteristic different from 2 and a field K satisfying that for all a,b∈K,a^(2)+b^(2)=0 if and only if a=b=0,we extend the notion of superderivations to special graded local s...For an algebraically closed field F of characteristic different from 2 and a field K satisfying that for all a,b∈K,a^(2)+b^(2)=0 if and only if a=b=0,we extend the notion of superderivations to special graded local superderivations,graded local superderivations and local superderivations.Applying matrix theory,we establish a calculation method for local superderivations.Then we determine all the special graded local superderivations of Heisenberg superalgebras of even center over F and graded local superderivations and local superderivations of Heisenberg superalgebras of even center over K.Finally,we determine all the special graded local superderivations,graded local superderivations and local superderivations of Heisenberg superalgebras of odd center over F.展开更多
基金the Science and Technology Program Project of Hunan Province, China (No.06SK2011).
文摘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.
基金supported in part by the National Natural Science Foundation of China(12061029)Natural Science Foundation of Hainan Province(120RC587)the Natural Science Foundation of Heilongjiang Province of China(YQ2020A005).
文摘For an algebraically closed field F of characteristic different from 2 and a field K satisfying that for all a,b∈K,a^(2)+b^(2)=0 if and only if a=b=0,we extend the notion of superderivations to special graded local superderivations,graded local superderivations and local superderivations.Applying matrix theory,we establish a calculation method for local superderivations.Then we determine all the special graded local superderivations of Heisenberg superalgebras of even center over F and graded local superderivations and local superderivations of Heisenberg superalgebras of even center over K.Finally,we determine all the special graded local superderivations,graded local superderivations and local superderivations of Heisenberg superalgebras of odd center over F.
