are concentrated by froth flotation, while higher-grade ores are heated to 500–600 °C, the temperature at which stibnite melts and separates from the gangue minerals. Antimony can be isolated from the crude antimony sulfide by reduction with scrap iron: + 3 Fe → 2 Sb + 3 FeS The sulfide is converted to an oxide by roasting. The product is further purified by vaporizing the volatile antimony(III) oxide, which is recovered. This sublimate is often used directly for the main applications, impurities being arsenic and sulfide. Antimony is isolated from the oxide by a carbothermal reduction: 2 + 3 C → 4 Sb + 3 The lower-grade ores are reduced in blast furnaces while the higher-grade ores are reduced in reverberatory furnaces. Top producers and production volumes In 2022, according to the US Geological Survey, China accounted for 54.5% of total antimony production, followed in second place by Russia with 18.2% and Tajikistan with 15.5%. Chinese production of antimony is expected to decline in the future as mines and smelters are closed down by the government as part of pollution control. Especially due to an environmental protection law having gone into effect in January 2015 and revised "Emission Standards of Pollutants for Stanum, Antimony, and Mercury" having gone into effect, hurdles for economic production are higher. Reported production of antimony in China has fallen and is unlikely to increase in the coming years, according to the Roskill report. No significant antimony deposits in China have been developed for about ten years, and the remaining economic reserves are being rapidly depleted. Reserves Supply risk For antimony-importing regions such as Europe and the U.S., antimony is considered to be a critical mineral for industrial manufacturing that is at risk of supply chain disruption. With global production coming mainly from China (74%), Tajikistan (8%), and Russia (4%), these sources are critical to supply. European Union: Antimony is considered a critical raw material for defense, automotive, construction and textiles. The E.U. sources are 100% imported, coming mainly from Turkey (62%), Bolivia (20%) and Guatemala (7%). United Kingdom: The British Geological Survey's 2015 risk list ranks antimony second highest (after rare earth elements) on the relative supply risk index. United States: Antimony is a mineral commodity considered critical to the economic and national security. In 2022, no antimony was mined in the U.S. Applications Approximately 48% of antimony is consumed in flame retardants, 33% in