Boiling roasting method for processing gold arsenic ore abroad (2)

The beneficiation plant flotation concentrate gives the diameter 3.7 meters In the concentrator, it is then fed into a rotary vacuum filter. This gives the material to the 1830x 1830 mm Inside the slot. The slurry ( 80% solids ) is pumped into the feeder and fed into the gun feeder (the position is opposite to the discharge kiln and higher than the boiling level of the roaster) 610 mm ). The flow of the entire roaster is shown in the figure above.

Roaster is - external cylindrical body size 2640 × 5490 mm, which is lined with refractory insulating brick 75 mm thick and 225 mm thick. The body of the boiling layer is 2030 mm and the boiling layer is 1270 mm. The structure of the hearth is similar to that of the concentrator. During the roasting process, the boiling layer temperature is 700 °C , This will ensure the highest gold recovery. If the boiling layer temperature exceeds 725 °C Water spray can be used to lower the temperature. The processing capacity of the roaster is 12 to 15 tons of pulp per day and night . When shutdown is stopped while feeding, but it should continue to ten minutes into the air to the furnace, which purpose is to remove the furnace gas space and the exhaust gas purifying gaseous compounds of arsenic and arsenic to prevent agglomeration in the nozzle.

The furnace is running stably. Ten years only three times a shutdown. The purpose of the shutdown is to perform inspections and minor repairs to the lining.

The concentrate having a calcination at the beginning of the operation of the calciner has a particle size of 60% to 325 mesh. Later, the ore dressing plant installed an auxiliary grinding machine to achieve a grinding fineness of 87%-325 mesh. Reducing the size of the concentrate increases the dust yield from 40% to 50% , resulting in blockage of the discharge tube of the precipitator.

When processing fine concentrates, the heat reserve in the boiling layer is less than when the coarse concentrate is processed. This situation is particularly noticeable when the furnace is shut down. The fine-grained concentrate layer cools much faster than the coarse-grained concentrate layer. When calcining the coarse concentrate, the time to lower the layer temperature lasts for 36 hours. Then the furnace can start working without the need for an auxiliary oven. When the fine material is fired, the temperature drop is stopped for more than 12 hours. This requires an auxiliary oven to make the furnace work better.

Calcination of concentrates can increase gold recovery rates prior to cyanidation in the concentrator.

Canadian businesses started up in 1949 - the seat boiling roaster. Mixed flotation concentrate for roasting containing Au 230 grams / ton, S 24% , As 6.5% , Sb 0.43% , Ni 0.33% , Fe29% .

The boiling roaster was also designed by Dow. Roaster is - in diameter 5 meters ,high 7 meters The cylindrical body of the furnace. The bottom of the furnace is equipped with a steel strip screen (or furnace) with a thickness of 16 mm. Lined with grate above - refractory cement layer 100 mm thick. The boiling layer height is 1625 mm. The furnace is built with 230 mm thick refractory bricks. The height of the refractory brick lining is the same as the height of the boiling layer.

The upper part of the roaster casing is made of 115 mm thick refractory bricks. The flotation concentrate containing 78-80% solids is directly pumped from the thickener into the upper part of the furnace (through the intermediate slurry tank).

The roaster can handle 75 tons of concentrate every day and night .

Calcination temperature is 565 °C The calcined sand contains As : 2.3~2.9% , S : 0.7~0.8% . Exhaust gas passes through the dust collector and passes through 38 meters The high chimney is discharged into the air.

The boiling recovery of the flotation concentrate prior to cyanidation increases the gold recovery from 80% to 90.2% .