A novel smelting plant that produces ultra-low-carbon, high-grade ferrochrome at a fraction of the time it takes conventional facilities is being wet-commissioned at the African Chrome Fields (ACF) mine near the Zimbabwean town of Kwekwe, about 250 km south-west of Harare.

Completion of the wet commissioning is expected within the next two months.

The aluminothermic process that the new plant uses is the culmination of a multiyear development process that company executives say cost in excess of $2-billion, of which $40-million was channelled into actual plant construction.

The process starts with the extraction, in a kiln, of moisture from chromite concentrate trucked from the mine’s seven wash plants located across a 35 km radius. The dried concentrate is then fed into a batching plant and blended with 98% aluminium imported from South Africa. The blended ingredients are subsequently placed in a blast chamber and processed to produce ferrochrome with a chromite content of 64% to 65% and as little as 0.05% carbon, reportedly making the product’s quality one of the best in the world.

Unlike a conventional ferrochrome smelter, which takes about seven hours to convert chromite concentrate into ferrochrome using copious amounts of electricity, the ACF ferrochrome plant completes the conversion in a matter of minutes and uses minimal electricity. A baghouse that serves as a filtration system has been installed to capture chemical fumes from the production process to protect the environment.

Speaking to touring journalists from ten Southern African Development Community countries earlier this month, ACF mining and beneficiation manager Mark Beukes said the new plant would employ more than 60 Zimbabweans and that its output would be sold to a steel plant being built by Dinson Iron & Steel Company, a local subsidiary of China’s Tsingshan, a Fortune 500 company. Offtake arrangements with overseas entities would be pursued, he added.

The 60 Zimbabwean nationals to be employed at the aluminothermic plant when it reaches full production will be in addition to ACF’s current 550-strong staff complement. With the exception of nine South African expatriates, all are Zimbabweans who hail from the local area.

ACF explained that the aluminothermic plant had been “work in progress for the past seven years” and that it aligned with the Zimbabwean government’s push for local mineral beneficiation. In line with this policy, a ban on unbeneficiated mineral exports, including chromite concentrate, was imposed in 2019 and ACF has been unable to ship its output to overseas customers since then.

ACF has been operational in Zimbabwe since 2014 and has invested about $250-million in the country to date.

Its seven wash plants, which are of modular construction, process alluvial chrome ore with a 48% to 51% chromite content, which is second only to Kazakh ore, according to Beukes. The ore also has a very low silica content of less than 2%.

ACF produces 20 000 t to 30 000 t of chromite concentrate monthly at its Kwekwe claims, and the total reserves are sufficient to sustain operations for another 20 to 30 years.

To ensure the availability of sufficient water for its production processes and to prepare for a sustainable local economy when operations on the Kwekwe claims eventually cease, ACF is closing off a valley using overburden from mined-out areas to create a 21.2-million-litre dam.

Working with Zimbabwe’s parks agency, a local conservancy and nearby farmers, ACF aims to create a wildlife sanctuary boasting about 700 head of game and other animal species, with housing for the company’s employees to be converted into chalets when mining ends. To this end, Beukes said, ACF had established a nursery with about 5 500 seedlings that will be planted where the dam is being established and in rehabilitated former mining areas.