SPMP developed the concept of a modern antimony roasting and gold plant in 2012, to be the first western-world minor metal primary smelter in nearly 40 years.
The SPMP Smelter converts primary sulphide concentrates, produced in mines from almost every region around the world into finished antimony, a strategic minor metal. At full capacity, SPMP will produce 20,000 tonnes of antimony products (metal and trioxide) and 50,000 ounces of gold per annum.
In July 2019, SPMP announced production of its first antimony metal, and in November that year, the company proudly celebrated the sale of its first batch of gold doré.
Antimony is considered a minor, critical and strategic metal.
It is an important mineral commodity with a range of industrial applications. With the surge of its industrial demand in the recent years, it was tagged as a critical and strategic metal of the modern industry. Antimony has consistently ranked high in European and US risk lists for supply of chemical elements or element groups required to maintain the current economy and lifestyle.
It is a silvery-white semi-metal that is brittle and is a poor conductor of heat and electricity. But when mixed into alloys, it imparts desired alloy properties such as strength, hardness, and corrosion resistance.
The largest applications for metallic antimony (Sb) is in alloy with lead and tin such as lead antimony plates in lead-acid batteries. Antimony is widely used in the plastics industry as a flame-retardant material which includes printed circuit boards, electrical and electronic.
Antimony can be used as a primary or secondary (synergist) flame retardant for various materials such as plastics, textiles, foams, households, wood etc. When antimony is combined with certain other compounds the synergistic effect creates flame retardant properties.
Antimony is alloyed in the grids of lead-acid batteries to improve their castability, corrosion resistance, and strength. The resultant alloy also increases the electrochemical stability of lead – which is essential for batteries’ cycle life. Research suggests expansion in the use of antimony for high energy density batteries as an alternative to lithium-ion batteries.
Antimony compounds are used as a catalyst to produce polyethylene terephthalate (PET) polymers, and as a heat stabilizer in polyvinyl chloride (PVC). As a heat stabilizer, antimony prevents polymers from degrading when subjected to high temperature conditions or when exposed to UV light.
Antimony compounds are added as an additive to glass batches as decolorizing (for color) and fining or degassing agents (for removal of gas bubbles during glass melting process). As an example, antimony compound is used during manufacturing of high-quality glass for mobile phones.
Antimony compounds are utilized in porcelain enamels mainly as opacifiers and to provide acid resistant property.
SPMP’s Doré is a Cu-Au alloy bar, typically with a high gold content resulting from the removal of metallic and non-metallic impurities. These bars require further refinement before the metal can be used as raw material for producing gold items.
This material is a by-product generated from the desulfurisation of flue gases produced during the conversion of antimony ore to metal. With its relatively high degree of purity compared to natural gypsum it is widely used in the manufacturing of gypsum panel products, cements, wallboards, and glass. Environmental agencies recommend the use of this type of gypsum as it promotes sustainability and is ecologically beneficial.