At AFX Holdings we offer top of the range products for copper mining applications. In the below blog piece you will find out in which copper mine applications our products are used.

Applications where our products are used in the copper mining process include:

 

Copper recovery from direct acid leaching; Chalcocite and Bornite ores or concentrates

Crusher plants

Peristaltic pumps: Transfer of crusher slime thickener underflow to milling plant. Transfer of spillage to milling plant.

Milling Plants

Agitator for surge tank before thickener. P3 or F3 impeller blades can be used.

Thickener plant

Peristaltic pumps: Transfer of thickener underflow to the surge tank at the copper leaching plant.

Agitator for surge tank uses P3 impeller blades.

Copper acid leaching plant

Leach reactors agitators can use P3 or F3 impellers, in acid environment materials 316 SS or SAF 2205, or rubber lining can be considered. Sparge ring can be provided if required.

Copper recovery from refractory; Chalcopyrite ores and concentrates

Crusher plants

Peristaltic pumps: Transfer of crusher slime thickener underflow to milling plant.

Transfer of spillage to milling plant.

Thickener plant

Peristaltic pumps: Transfer of thickener underflow to surge tank at copper leaching plant.

Agitator for surge tank with P3 impeller blades.

Autoclaves

High pressure and temperature treatment of ore or concentrates. Agitators for autoclaves are specialised. P4 impellers for gas dispersion and aeration are used.

Iron removal

Agitators for high efficiency gas dispersion agitators with P4 impellers. Bull horn sparging systems to handle large volumes.

Neutralisation

SX raffinate to neutraliasation plant for pH adjustment.

Special agitators for neutralisation.

Copper leaching from ore and concentrates

Leaching of copper from sulphide ores can follow two different routes;

  1. For Chalcocite and Bornite the copper is normally easily liberated and leached with sulphuric acid following a typical sulphuric acid leach in tank reactors. This procedure can be applied to both run-of-mine ore and flotation concentrates.
  2. For Chalcopyrite the ore can be classified as refractory and the copper cannot be leached directly with sulphuric acid. For these ores the copper is recovered through an autoclave oxidation process and then followed by the normal SX and electrowinning steps.

Direct leaching of copper from Chalcocite and Bornite is conducted in mechanical agitated reactors, varying in size as required by throughput and residence time. The specification for the mechanical agitators will be to efficiently suspend solids and to thoroughly mix the sulphuric acid reagent and the ore particles. For this type of duty, the Afromix P3 or the F3 impeller system is recommended. These impellers produce high volumes of flow per unit power and in the case of the P3 impeller, they can handle viscous ores and gas when required.

Due to the acidic environment and low pH, materials of construction of the shaft and blades will be 316 stainless steel or in some cases even SAF 2205. Under certain conditions rubber lining could also be considered, but this would need to be confirmed with the client.

For this operation typically a ring sparge can be installed if air is required for the reaction.

Iron Removal

The majority of base metal leaching plants recovering the final metal through the solvent extraction process will incorporate an iron removal step. The iron is removed through a selective precipitation process of the ferric iron at a controlled pH level.

After the initial metal leaching process the iron is present as ferrous iron and an oxidation step is introduced to oxidise the ferrous iron to ferric iron for removal before precipitation.

For this process the oxidation is done through the introduction of large volumes of air in the presence of sulphur dioxide. For handling large volumes of air, the conventional ring spargers that are fitted below the impeller could result in flooding of the impeller and reduced efficiency. AFX has developed the eight point bull horn sparger to handle such high volumes. On a typical ring sparge the impeller would flood around 7% of the impeller pumping capacity. With this system that number is increased to 21%.

This sparge is low maintenance and can handle very high gas rates. In the application air is being used as a carrier gas for the reaction. Gas is injected downward towards the floor of the tank. As the gas begins to rise the agitator draws in the gas and holds it down.

Unlike conventional ring sparges the gas bubbles are not that fine when they are injected into the mixture but this is compensated for by the large gas hold up from the impeller and sparge combination. Thus if SO2 was not being added and rather SMBS you will still get the desired efficiencies.

As a result of these new developments high gas volumes can now be efficiently handled in the iron removal processes for base metals and has led to three successful installations in the DRC that was done by AFROMIX.

Give our team at AFX Holdings a call and we will find the best products for your copper mining processes.

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