In the first six months after the calciner was put into production, it was calcined under conditions of excess air ( from 50% to 100%) . Â The resulting calcine is bright red. The gold recovery from this calcination is not high during the cyanidation process.
The roasting method was later changed. Initially , the calcination is carried out under conditions of a small excess of air and an exhaust gas having an oxygen content of about 1% . As a result, the obtained calcine was chocolate color. Under this calcination condition, the gold content in the residue after the blasting of the calcine is low.
"KapaTOH" beneficiation plant that the existence of a large excess of air in the upper deck if boiling roaster space, then the fine particles in suspension concentrate has created favorable conditions for the flow of air. As a result, a temperature much higher than the temperature of the boiling layer can be formed on the surface of these particles. Therefore, the calcine particles ( dust ) are melted. This has an adverse effect on the gold recovery rate in the next - step cyanidation treatment. Therefore, the excess oxygen remaining in the upper portion of the boiling layer during calcination cannot melt the calcine. This is - the point is an important condition when necessary to improve the recovery of gold cyanide process.
Tenth obviously, when the calcine is chocolate, the highest gold recovery, drug consumption is also minimal.
It is also obvious that the two-stage roasting effect is the best. This is because the amphoteric gold ore can be decomposed in a reducing atmosphere under two-stage calcination conditions, and the sulfur-containing hot calcined sand is re-fired in an atmosphere containing excess air until reddish brown baking is obtained.
The processing capacity of the roaster for every day and night was originally set at 60 to 70 tons of concentrate, which actually only reached 30 to 35 tons of concentrate, and only worked 14 to 16 hours per day and night . When the furnace is shut down, the material layer can maintain its original temperature for a long time. This eliminates the need for an auxiliary oven for the roaster prior to furnace opening. It is certain that the calciner can be maintained for 36 hours without the need for an oven.
When the roaster is in operation, about 60% of the material is discharged through the furnace door, and about 40% is taken away from the furnace.
Exhaust gas dedusting system consists of two diameters
The total dust removal rate of the gas is 99% or more. Listed in the table is the composition of the solid product of concentrate and concentrate calcination when obtaining chocolate-colored calcine.
The gold recovery rate during cyanidation is 97.5% , and the gold grade in cyanide leaching residue is
US concentrator is a few foreign enterprises with gold. The plant directly calcined the gold - arsenic ore with a boiling roaster at a capacity of 75 tons per hour .
The market of LNG (Liquefied Natural Gas) is booming worldwide during the past years. The transportation of LNG over long distances, generate a great demand of cryogenic pipeline facilities, including cryogenic valves.
Due to high performance of the cryogenic valves, materials with outstanding mechanical properties in crygenic environments are required. The body and trim materials should pass the impact test at a specific temperature. Other designs also include: extended bonnet to make sure the temperature of stuffing box remains at a relative higher interval; relief port or by-pass system to prevent abnormal pressure rising which could destroy the pipe facilities; etc.
Kolink cryogenic valves (low temperature valves) include: crygenic gate valves, crygenic globe valves, crygenic check valves and crygenic ball valves, with material range of LCB, LF2, LC1, LC3, 304, 316, and temperature range of -46 ~ 196°C.
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