The road to climate neutral metal production

Elkem is among the world's cleanest metal manufacturers. Still, we emit around 2,54 million tonnes of carbon per year (2018 numbers). Production of silicon and ferrosilicon takes place in electric arc furnaces where quartz, which consists of silicon and oxygen, is mixed with carbon at a high temperature.

This leads to a chemical reaction process that releases the oxygen from the quartz to produce pure silicon, but also CO₂ emission. Due to prohibitive costs, as well as challenges related to sustainability of biocarbon, Elkem mainly uses fossil coal as reduction material.

By replacing fossil coal with charcoal produced from sustainable biomass, the production processes could become carbon neutral. Studies have shown that charcoal (and woodchips) can perform even better than fossil coal in the chemical reaction, and at the same time reduce our carbon footprint.

CNMP

In 2015, Elkem initiated a research programme called Carbon Neutral Metal Production (CNMP). The concept of CNMP is to produce charcoal in the same production facility as ferrosilicon or silicon production, connecting this to an energy recovery unit, to produce electricity from the excess heat.

In an optimal situation with 100% biocarbon use and optimal energy recovery, such a plant would become both CO₂ and energy neutral, delivering enough electricity to run the electric arc furnaces. The concept would thus integrate the forest industry with metal production, producing new, circular value chains.

The initial R&D project of the CNMP programme was funded by the Research Council of Norway and concluded that with existing furnace technology, we can reduce energy consumption by over 50 per cent with considerable reduction of fossil CO₂ emissions.

Furthermore, the project also showed that the economic margins and risk are significantly dependent on the performance of the pyrolysis technology, both in terms of quality, commercial viability and energy yield.

Our conclusion was that further research is needed, to ensure successful realisation of carbon neutral metal production. Therefore, several projects have been initiated to improve process integration, process performance and charcoal quality.

Two of the projects are research projects co-funded by the Norwegian Research Council (awarded approximately 25 mill NOK in 2017-2018).

Research projects

PyrOpt will look into pyrolysis of wood optimised for production of energy and tailor-made biochar for silicon production. The project is a collaboration with SINTEF and Papir & Fiberinstituttet. The project will look into resource-effective production of high quality charcoal.

Elkem’s long-term goal is that charcoal will replace fossil coal in the production of speciality silicon, as well as standard silicon and ferrosilicon production.

SiNoCO₂ is a project looking into silicon production with no CO₂ emissions through the closing of silicon and ferrosilicon furnaces. If successful, closed furnaces would emit CO instead of CO₂, enabling further industrial use of the off gas.

Closing the furnaces could also be a step towards developing processes prepared for carbon capture. The project is conducted in collaboration with scholars at NTNU and SINTEF in Trondheim

Elkem is committed to reduce our climate footprint, and we are in a hurry. Hence, we are committed to projects such as the pilot for testing industrial scale production of fit-for-purpose charcoal, based on commercially available technology.

Such production would not be able to replace all fossil carbon, due to the quality of the charcoal, but would be an important step on the way towards our 2030 target of 40% biocarbon. The main barriers are commercial viability and availability of sustainable biomass at competitive prices.

The project, called Norwegian Wood, has explored the possibilities for building a pilot plant in Norway based on Norwegian biomass. So far, the main barriers have been commercial.

To become commercially viable, a pyrolysis plant would need to sell the significant amounts of heat, in the form of steam, to other industrial actors. In addition, long-term contracts for wood at predictable prices would have to be available for biocarbon to be a competitive raw material for Elkem.

So far, promising research has come out of the CNMP programme, strengthening our resolve and belief that the CNMP concept will secure our license to operate and provide products that are essential in the low carbon society.