Closed furnace model to reduce Zimasco emissions, improve efficiency

Michael Magoronga

KWEKWE-BASED ferrochrome producer Zimasco has completed the construction of furnaces seven  and eight, which will see the company reducing emissions and improving efficiency.

The Zimasco High Carbon Ferrochrome Smelter Establishment Project has been tracked under successive 100-day cycles of the RRI (Rapid Results Initiative) of priority projects identified by the Second Republic.

The project dovetails with the Government’s goal to achieve a US$12 billion mining industry milestone under the National Development Strategy 1 (NDS1).

As part of the project, Zimasco has refurbished Furnaces one and two, which are now operational as semi-closed furnaces, while the old furnaces — 3, 4, 5, and 6 — have been turned off.

Each furnace contributes to the multi-million dollar initiative differently, based on specific technical settings.
According to Zimasco chief operations officer, Namatai Mapfumo, each of the four furnaces is an upgrade from the previous 18MVA furnaces, allowing for a production output of 43 800 tonnes of ferrochrome alloy per annum, compared to the last 36 000 tonnes.

“The new furnaces conserve heat and direct it more efficiently to the smelting process, thereby demanding less power per unit production output. The furnaces’ chemical reactions are more complete, increasing efficiency,” said Mapfumo.

With the new furnaces in operation, the visual intrusion from the chimneys is mitigated, with only minor visible smoke emissions.

In addition, Zimasco plans to harness and purify off-gases from the closed Furnaces seven and eight for use as fuel for the Sintering Shaft Furnace, a move that will significantly reduce the amount of off-gases released into the atmosphere and thus help reduce the company’s carbon dioxide emissions.

The semi-closed and closed furnaces are also more energy-efficient, consuming seven to 10 percent less power per tonne of ferrochrome produced compared to the open furnaces.

Zimasco has traditionally worked closely with strategic partners like Zesa, mining contractors and suppliers of key inputs.

In 2023, the company partnered with the National Railways of Zimbabwe to repair 100 wagons and three locomotives.

Of the targeted 100 wagons, 51 have already been repaired, with work in progress on the remainder. The three locomotives are still under repair by NRZ engineers and technicians, due to issues with the long lead time for receipt of spares from overseas suppliers, Mapfumo said. —[email protected]