Gold ore technology for raw ore roasting carbon slurry

Mine ore features are: high arsenic-containing, antimony-containing, carbon, finely-wrapped ore gangue mainly composed of limestone, dolomite, alkaline minerals, less metal-containing sulfide minerals, insufficient support with gold, using The flotation gold selection process has low technical indicators and belongs to difficult ore. Due to the influence of sulfur and arsenic, environmental protection issues are more prominent.

In the production practice, the direct ore processing of the ore and the gold pulping process are used to obtain better technical specifications, which lays a foundation for the utilization of difficult ore.

First, the ore roasting process

Second, the process characteristics

The ore roasting process, which handles difficult ore, shows many advantages. It has strong adaptability to changes in raw ore, reliable roasting technology, and can be applied in a wide range of harmful impurities such as arsenic, carbon and sulfur in raw ore. The ore roasting process can make full use of the alkaline gangue in the ore, and arsenic and sulfur can be used to calcine and solidify arsenic and sulfur, thereby reducing the content of harmful impurities in the soot, achieving non-polluting flue gas emissions, and facilitating the treatment of flue gas.

The raw ore roasting carbon slurry method is used to extract gold, remove the flotation operation link, and the process structure is simple, and the index is better than the traditional process of flotation of the original ore and flotation of the fine gold cyanide leaching. According to the test of the geological department, the flotation recovery rate is 80%, the leaching rate of concentrate roasting leaching is only 80%, the total recovery rate is only 64%, the raw ore direct roasting carbon slurry method to raise gold, the gold recovery rate can reach 82%. , increased by 18%.

The flue gas treatment is simplified and the environment is improved. Compared with the direct roasting of the original ore, the content of SO2 and As2O3 in the flue gas of the concentrate roasting is high, the concentration of SO2 in the flue gas is generally 5% to 10%, and 60% in the ore. 80% of As enters the flue gas in the form of As2O3. Therefore, in the dust collection, it is necessary to use a relatively high-temperature flue gas treatment device such as a high-temperature electric dust removal and a bag filter.

Raw ore roasting, arsenic and sulfur due to the existence of a large number of alkaline gangue, arsenic and sulfur are basically fixed in the roasting, dust collection only needs to use gravity dust collection and wet dust collection and other simple dust collection facilities can meet the requirements.

Third, the original ore roasting arsenic, sulfur fixation

An important feature of raw ore roasting is that the primary gold ore contains a large amount of alkaline gangue such as limestone and dolomite. It participates in the reaction during the roasting process, absorbs sulfur and arsenic in the ore and remains in the roasting sand, and basically does not enter the soot recovery. The system achieves a "self-cleaning" roasting effect.

Sulfides such as pyrite roasting:

4FeS2 (solid) + 11O2 (gas) = ​​Fe2O3 (solid) + 6SO2 (gas)

2FeAsS(solid)+6O2(gas)=Fe2O3(solid)+As2O5(gas)+2SO2(gas)

Limestone and dolomite decomposition:

CaCO3/MgCO3 (solid) = CaO / MgO (solid) + CO2 (gas)

SO2 fixed:

2CaO/MgO(solid)+2SO2(gas)+O2(gas)=2CaSO4/MgSO4 (solid)

As fixed:

3CaO/MgO(solid)+As2O5(gas)=2Ca3(AsO4)2/Mg3(AsO4)2(solid)

Fe2O3 (solid) + As2O5 (gas) = ​​2FeAsO4 (solid)

CaO in raw ore: 8.4%

MgO: 2.6%

S: 1.66%

As: 0.61%

The content of CaO and MgO is higher than the weight ratio required for the reaction of solid sulfur and solid arsenic. It can fully meet the required values ​​of sulfur-fixing and solid-arsenic reactions. The self-cleaning effect of the roasting flue gas of solid sulfur and solid arsenic is basically achieved.

After testing, the calcination temperature was increased from 600 °C to 800 °C. With the decomposition of alkaline gangue, the sulfur fixation rate of the calcine increased from 8.9% to 69.2%, and the solid arsenic rate increased from 55.8% to 75.4%.

Test Results:

to sum up

1. For gold-bearing ore that is difficult to float, the effect of gold extraction by raw ore roasting carbon slurry is better, especially for refractory ore with high arsenic content in ore.

Second, the alkaline gangue in the ore can be used to fix sulfur and solid arsenic. The environmental protection treatment process is relatively simple, and the roasting soot is easy to reach the discharge standard.

Third, because the flotation operation is not used, the process is reduced, the process flow is relatively simple, the operation, control and management are relatively convenient, the leaching index is relatively high, the production cost is low, and the operation effect is relatively good.

Fourth, the investment is small, the construction speed is fast, and the production time is short.

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