• In addition, the company has launched a pilot plant for arsenic copper processing with a  view to producing high-purity copper cathodes and obtaining high-grade gold and silver residue.

At PERUMIN 36, Raúl Benavides, director of Compañía de Minas Buenaventura, explained that the company has two new challenges, the first of which is the production of high-purity manganese sulfate for the manufacture of storage batteries required by the energy and automotive industries.

He stated that, at the Río Seco Industrial Processor, located in the province of Huaral, in the Lima region, an investment of US$ 275,000 has been made for the construction of a pilot plant with a production capacity of 100 kg per day. The innovative process of this plant will facilitate the production of battery-grade manganese sulfate, a product with high purity standards.

According to Benavides, Buenaventura currently processes manganese-containing concentrates from the Uchucchacua mining unit to produce monohydrated manganese sulfate, a raw material used in plant nutrition, steel manufacture, batteries and pigments, benefiting both the domestic market and national agriculture.

In this way, the Río Seco Industrial Processor, equipped with a 60-ton per day sulfuric acid plant and an 80-ton per day crystallization plant, has the capacity to produce 22 metric tons of manganese sulfate per year. Nevertheless, it suspended activities in 2022 due to the shutdown of Uchucchacua.

On the other hand, Raúl Benavides added that Buenaventura's second challenge is the treatment of leach residues from arsenic copper concentrates for sulfur extraction, gold and silver recovery, and sulfuric acid production. The latter will serve as a raw material for the eventual production of superphosphates.

Under this premise, he explained that another pilot plant was implemented at Rio Seco Industrial Processor, dedicated to arsenic copper processing, mainly from the El Brocal mining unit, producing 25 tons of metallic copper and precipitating scorodite, the only stable arsenic residue produced at an industrial level.

Furthermore, he said that Buenaventura plans to develop the Río Seco Copper Plant, where the hydrometallurgical process of leaching copper and arsenic concentrates will be used to extract high-purity copper cathodes and simultaneously obtain a high-grade residue of gold, silver, and arsenic in the stable form of scorodite crystals.

According to Benavides, the metallurgical project, located in the Huaral and Chancay districts of the Lima region, is estimated to have an investment of US$410 million and a production of 40,000 tons of copper cathodes. In 2022, it obtained the approval of the Environmental Impact Assessment and completed the closure plan as part of the feasibility study.