Boiling roasting method for processing gold arsenic ore abroad (5)

The ore in the furnace contains As2.85% , 53.6% , Fe 3.2% , Sb 0.1% and Au. 7 grams / ton. The boiling furnace diameter is 4.8 meters , using oil as fuel. Calcination temperature is 590 -650 °C . The exhaust gas discharged from the furnace is cooled to 175~ 200 °C As a result, a large amount of arsenic is condensed. The residual arsenic in the gas is collected into the scrubber during the wet purification process.

After Southern Rhodesia Mining Research Laboratory, establishing - a seat roaster boiling test apparatus, with which the arsenic-containing pyrite gold ore processing. The processing capacity of the device is 100 tons / day and night.

The industrial plant was commissioned in 1952 with a processing capacity of 600 tons / day and night. The flow of the device is shown in Figure 4 .    

Boiling roaster diameter 5 meters ,high 6 meters . It consists of two chambers, A and B. Depending on the amount of concentrate obtained, the working time of the roaster is between 14 and 16 hours per day and night . Concentrate ore contains 72~78% solids and 22~24% sulfur . A indoor furnace temperature is maintained at 588 °C Control the furnace temperature by spraying water on the boiling layer. Room B is mainly used to gradually cool the calcine. The temperature of room B is kept at 340~ 450 °C .

The arsenic grade in the calcine is 1.4% , sulfur 1% , gold 120~ 150 grams / ton.     The Soviet Union has not widely used boiling roasting to treat various refractory gold-bearing concentrates. However, a lot of research has been done on the calcination parameters of different ore materials in various deposits; from 1956 to 1957 , the Irkutsk branch of the National Institute of Rare Metals conducted the first two-stage boiling roasting laboratory test in the Soviet Union. . The calcined material was used "Dala Song" beneficiation plant arsenopyrite concentrate. Concentrate contains S23.5% ; As9.55% ; Fe23.3% ; Cul.13% ; Pb0.6%; Au 18.4 grams / ton ; Ag 6.2 grams / ton.

For the test, two laboratory-scale boiling roasters were designed and installed. 1 and paragraph for paragraph â…¡ sequentially fired roaster with these two.

Determining the optimum conditions for arsenic removal and retention of sulfur in paragraph I fired according to calcine the results are as follows:

Calcination temperature, °C     450~480

Unit processing capacity, tons / (m ² / day and night)       4.5~5.5

Unit consumption of air, m ² / (m ² / min)     3.5~4.0

Line speed of air, cm / sec              8

Was determined: Stage I at the time of firing, when the air consumption is sulfur and arsenic theoretically required combustion 85-90%, 85-90% arsenic can be excluded (i.e., the amount of baking to reduce arsenic sand 1.3 - 1.9% ), and the sulfur in the sulfide is actually all left in the calcine.

Calcine paragraph 1 after firing to firing in the firing furnace paragraph II. The best conditions selected according to the test results are as follows:

Calcination temperature, °C         580~620

Unit processing capacity, tons / meter ² · day and night      3.0~4.0

Unit consumption of air, meters 3 / m ² · minutes     5.5~6.0

Line speed of air, cm / sec     8.5~9.5

Gold recovery rate in calcination during cyanidation %     92~93

At the same time as the laboratory research, the Soviet Nonferrous Metallurgy Design Institute developed a preliminary design of the test furnace and roasting workshop for the boiling roasting of the arsenic pyrite concentrate in Dalazon.

The total area of ​​the designed rectangular two-chamber roaster is 4.2 meters ² ( 1.7 × 2.5 ), the day and night processing capacity is 18 tons. In 1960 , the Dalazon mine was built in advance, and a two-stage roasting device for flotation concentrate was installed and the test was started. According to the research results, the calcination conditions originally selected under laboratory conditions were used. The arsenic-containing concentrate used for the test contained S30.6% ; As9.6% ; Cu2.4% ; Pbl.1% ; Fe27.0% ; Au 60 grams / ton.

The fineness of the concentrate is 60%-0.074 mm and the humidity is 4~7% .

During the test, the device was found to have many structural disadvantages and many difficulties in the operation. However, as the researchers have demonstrated, satisfactory results have been obtained in the preferential oxidation of arsenopyrite. These results also confirm that the previous laboratory study data is correct.

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