Stainless Steel Slag - Sand

Steel slags are a by-product of stainless steel production that can be used to create a concrete like building material (carbinox carbstone). Two initiatives (VITO in cooperation with ORBIX) invented a process to make this concrete-like material, from steel slags, that captures CO2 in the production process.

Carbon dioxide emissions for regular concrete production are about 206 kg CO2/ m³ concrete. In stark contrast to these figures, the amount of carbon dioxide forever captured in a Carbinox Carbstone is about 208 kg CO2/ m³.

Steel slag is a glass-like by-product of the steel industry, that is leftover when metals and minerals are smelted and separated from the raw ore from which they are extracted. As an integral part of the extraction process of metal, slags are produced in large quantities but can be responsible for environmental damages.

VITO and ORBIX developed the Carbinox formula from recovered stainless steel slag. First, the left-over slag is pulverised into a fine powder to release the entrapped metals. The pulverised slag then reacts with dissolved carbon dioxide and becomes a stone-like material. Carbinox contains metal ions that react with CO2 to create carbonates which act as strong binding agents. As such, Carbinox can be used instead of cement - an environmentally harmful additive to concrete. It also acts as a carbon dioxide sink and prevents further CO2 emissions in the concrete manufacturing process.

VITO is an R&D organization specialized in clean technology and sustainable development.

VITO in cooperation with ORBIX invented the Carbstone process. The Carbstone process makes it possible to create a range of different products like roof tiles, clinkers and building blocks, while permanently sequestering CO2 in the process.

ORBIX is a company specialising in the recycling of slag from steel plants. They have been able to reclaim several materials from steel waste flows and convert them into metals and minerals to be used in the steel and construction industries.

Project by © Teresa van Dongen 2021