Chromium
Used to impart corrosion resistance and improve hardenability, chromium is a key material in the production of stainless and specialised steels.
Chromium (Cr)
Chromium is a hard steel-grey metal used in various industries due to its excellent strength and corrosion resistance. It is primarily used in the production of stainless-steel and nonferrous alloys. Chromium is also used in the production of super alloys, pigments, and chemicals used to process leather.
Chromite ore deposits are highly concentrated in South Africa and Kazakhstan, which combined hold over 95 percent of the world’s reserves. South Africa accounts for more than 60% of exports of chromium. China – as the biggest producer of stainless steel in the world – is the largest importer of chromium.
While chromium can be found in many valence states, much attention is given to its hexavalent form Cr(VI), which is toxic. This form is used in many industrial applications and is associated with air, water and soil pollution, posing health risks to affected communities.
In addition to these environmental and social impacts, virtually all chromium is produced in countries that are perceived as suffering from widespread corruption. Also, chromite mining in Afghanistan supports the Taliban government, which has severely curtailed the rights of women and is widely perceived internationally as illegitimate.
Main Uses and Attributes
Chromium is a hard, silvery metal with a blue tinge. Although it occurs in many minerals, chromite is the only commercially exploited ore.1 Chromium exists in a number of valence states, of which the trivalent (III) and hexavalent (VI) states are the most stable. While chromium metal and trivalent chromium, Cr(III), are considered non-toxic, hexavalent chromium, Cr(VI), which can be used in multiple industrial applications, is toxic and carcinogenic. According to the European Chemicals Agency (ECHA), chromium trioxide that is used in industrial electroplating processes is a “substance of very high concern” (SVHC).2
Most of the chromium ore consumed worldwide is used in electroplating and steel production. Of the chromite ore produced, 92% is used by the metallurgical industry, and of that 95% is used to make stainless steel.3 It is used to impart corrosion resistance to steel and to improve hardenability, wear-resistance, and high-temperature strength. There is no substitute for chromium in stainless steel or in superalloys. The chromium-containing material used in steel is called ferrochromium, which is derived from chromite. Ferrochromium can be further refined into chromium metal used in electroplating and other applications.
Chromium is used to produce specialised steel for wind, solar, hydro, geothermal and nuclear energy generation. A landmark study by the World Bank identifies chromium as a critical element for realising a low-carbon future.4
The mineral chromite is employed extensively as a refractory material. Other chromium compounds are used as tanning agents, with an estimated 75-80% of all leather tanned using chrome.5 However, the waste effluent from chromium tanning is toxic and the ICDA reports that consumer pressure is leading to increasing use of metal-free alternatives. Chromium compounds are also used as industrial catalysts and pigments, specifically in bright green, yellow, red and orange colours.6
Key Countries
South Africa
Kazakhstan
Supply Chain Risk
TDi assesses Chromium for key risks affecting the security of supply, and for its association with artisanal and small-scale mining.
Country Governance Risks
Chromium's association with countries experiencing:
Association with ESG issues
TDi Sustainability's data rates Chromium's association with the following issues as high or very high: