Know About The Chemical Properties Of Magnesia Cupel

 

Know About The Chemical Properties Of Magnesia Cupel

Do you know about the use of magnesia cupel? If you are interested in the experiment, I'll tell you some things about it. The features of our new products- High purity Magnesia cupel: High temperature, good thermal conductivity, corrosion resistance, high melting purity, long life.

 

An experiment of grey blow:

The magnesia cupel placed in a muffle furnace, close the door at 900-1000 ºC 15-20 minutes to remove the volatile matter and organic matter, will lead buckle into the magnesia cupel ash blowing. When the molten lead all peeling, slightly open, temperature should be controlled (not less than 800 ºC in order to avoid the occurrence of lead oxide coagulation) at 800-850 ºC. When the lead oxide is absorbed by all the magnesia cupel, there's a flash of gold and silver alloy grain immediately, quickly remove the magnesia cupel to cool. Remove the gold particles; small hammer flat the next step to be determined procedures.

Magnesia cupel is absorbed lead oxide (or bismuth oxide) porous refractory vessel with ash blowing lead button (or bismuth buckle) when. There are three common magnesia cupels: cement gray dish, ashes - and magnesia cement gray magnesia cupel dish.

 

① Cement dust pan with 400,500 No. of portland cement, plus 8 to 12% of water, mix, pressed on gray dish machine. Portland cement composition contains CaO60 ~ 70%, A1 2O3 4 ~ 7%, SiO2 l9 ~ 24%, Fe2O3 2 ~ 6%. Cement is inexpensive common materials. Cement gray dish hard, not easy to crack, but the precious metal after the loss of two larger than when the ash blowing.

② Magnesia cupel and ashes - cement dust pan with sheep bones burning ashes, ground, and then get burned, including organics must all be removed. Its composition was 90% calcium, 5.65% calcium oxide, 1% magnesium oxide, 3.1% calcium fluoride. Fineness of ashes is less than 0.147mm, 0.088mm which should account for more than 50%. Made with pure ashes loose magnesia cupel can be used for coarse gold, crude gold ash blowing. Assay analysis generally mixed magnesia cupel ashes and cement, ashes and cement mix in different proportions, plus 8 to 12% water, dish machine in the gray repression. Different people do different test results, some believe 3: 7 Well, there are believed to be four: 6 or 5: 5 good. Ashes - harder than pure cement gray ashes magnesia cupel dish, but, more than cement gray fluffy dish. With ashes - cement gray magnesia cupel to blow, the loss of gold, silver dish smaller than the gray cement. Preparation of the ashes of more trouble to go through burning, ground several procedures to be made.

③ The calcined magnesia cupel ground, require more than 63% by 0.074mm sieve of 0.2 ~ 0.1mm particles does not exceed 20%. End of magnesia to pressure in the ground after a few days, or else have to place long after agglomeration. Take 85 parts and 15 parts of finely ground magnesite No. 500 cement, mix, add 8 to 12% water pressure made ​​the dish. When the blow with the loss of precious metals made ​​magnesia gray magnesia cupel is smaller than the first two.