Synthetic method of calcium silicide
Upload Time:
2022-05-31
1. Calcium silicide with higher purity can be obtained by direct melting of elemental silicon and calcium. But the operation has to be done in two steps. The first step: Mix the pure calcium chips and pure silicon powder evenly, put them in a hard biscuit-fired porcelain boat, quickly put the porcelain boat into the quartz reaction tube, pass CO2 into the tube, the porcelain boat has been heated to 1000 ℃, In just a few seconds, the mixture melts and the reaction proceeds violently. The porcelain boat was taken out, the product CaSi coagulated immediately, and it was pulverized. CaSi is a porous block, lead-grey and metallic luster. Step 2: Mix the CaSi with the calculated amount of Si powder evenly, place it in a nickel boat, and heat it to 1000°C in a H2 flow. Heating was required for 15h because the last stage of the reaction proceeded slowly. 2. Mix pure CaO and silicon with appropriate fluxes CaF2 and CaCl2, and melt at 1400 °C to obtain CaSi2. The CaSi2 thus obtained is mixed with a large amount of silicon.

1. Calcium silicide with higher purity can be obtained by direct melting of elemental silicon and calcium. But the operation has to be done in two steps.
The first step: Mix the pure calcium chips and pure silicon powder evenly, put them in a hard biscuit-fired porcelain boat, quickly put the porcelain boat into the quartz reaction tube, pass CO2 into the tube, the porcelain boat has been heated to 1000 ℃, In just a few seconds, the mixture melts and the reaction proceeds violently. The porcelain boat was taken out, the product CaSi coagulated immediately, and it was pulverized. CaSi is a porous block, lead-grey and metallic luster.
Step 2: Mix the CaSi with the calculated amount of Si powder evenly, place it in a nickel boat, and heat it to 1000°C in a H2 flow. Heating was required for 15h because the last stage of the reaction proceeded slowly.
2. Mix pure CaO and silicon with appropriate fluxes CaF2 and CaCl2, and melt at 1400 °C to obtain CaSi2. The CaSi2 thus obtained is mixed with a large amount of silicon.
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