Ecocem uses slag, a residue of steel production, instead of clinker made by heating limestone at extreme temperatures. This reduces the need for fossil fuel energy and constitutes Ecocem’s primary commercial advantage. But when global industries shut down like dominoes in the face of Covid-19, it became a problem. In commentary to accounts for 2020 just filed by the group’s Dublin-based parent, Ecocem Materials, directors described the chain reaction:  “After a strong start to 2020, the Covid pandemic had a significant impact on business from March. The steel industry reduced production in response to reduced demand from car manufacturing. This…