Metso optimises copper melting and refining

Metso has introduced the next generation of its anode furnace, ideal for refining blister copper or melting and refining high-grade secondary copper into anode copper.

The typical fire refining process sees an anode furnace capable of treating blister copper into anode copper. This is done through air oxidation and reduction by a reductant such as natural gas in order to purify the copper.

However, this process poses various challenges for the industry, including copper being over oxidised, energy wastage and the wear of the furnace shell. It also needs to be flexible to integrate secondary materials.

To address these issues, Metso manufactures and sells the Outotec anode furnace, which offers benefits such as reduced operating expenses due to its efficiency in heating and processing, reduced emissions, ease of maintenance, and high-risk prevention.

The latest iteration of the anode furnace features the latest innovations in process safety and ease of maintenance, improving impurity removal capabilities and the flexibility to treat secondary materials. It also uses two new methods for reducing carbon emissions (CO2).

“When it comes to CO2 emissions, the new anode furnace is unique,” Metso senior sales manager, anode casting and anode furnace technologies Miikka Marjakoski said.

“The process is fully prepared to utilise direct hydrogen reduction in the hydrogen gas ready variant. However, if the customer has no opportunity to switch to hydrogen use at present, Metso can also provide the technology to significantly increase the current gaseous hydrocarbon reductant efficiency with a steam-gas reduction system.

“Combining this with oxyfuel combustion at the burners, the total reduction in CO2 emissions is demonstrably significant compared with traditional processes. This has also been proved through LCA (life cycle assessment) calculations.”

Metso’s scrap melting furnace variant of the anode furnace allows users to treat secondary raw materials by using integrated burners for melting.

“The Outotec scrap melting furnace yields great flexibility in treating any mixture of molten copper from upstream processes and high-grade secondary copper feed directly into the anode furnace,” Marjakoski said.

“It can be used as a stand-alone melting furnace utilising solely secondary raw materials, making the product a go-to choice for primary and secondary smelters alike.”

The next generation of Metso’s anode furnace is part of the Metso Plus portfolio, which is considered to be more energy- or water-efficient than the industry benchmark.

In other news at Metso, the company has introduced its new integrated copper electrowinning plant.

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