Talc is our planet’s softest known mineral. All talcs are lamellar, chemically inert, organophilic and water repellent, but no two talcs are the same. Their unique properties bring added performance to a wide range of products and processes. Talc is also called steatite – or, in chemical terms, hydrated magnesium silicate. It is the main component of soapstone. Its crystals usually develop massive, leafy aggregates with laminar particles. Talc is practically insoluble in water and in weak acids and alkalis. It is neither explosive nor flammable. Although it has very little chemical reactivity, talc does have a marked affinity for certain organic chemicals, i.e. it is organophilic. Above 900°C, talc progressively loses its hydroxyl groups and above 1050°C, it re-crystallizes into different forms of enstatite (anhydrous magnesium silicate). Talc’s melting point is at 1500°C.
Talc is hydrated magnesium silicate. It generally occurs in two morphologies, either macro- or microcrystalline. Talc can have slightly differing compositions subject to the associated minerals in the ore body, but all talcs exhibit to a lesser or greater extent the following unique features: softness, hydrophobicity, platy ness and organophily. These properties can be further enhanced by careful and sometimes propriety processing and bring a number of specific benefits to a wide range of industries including paper, paints, plastics, ceramics, rubber, personal care and roofing. Present annual world talc production is about 5.7 million tonnes, extracted from some 250 deposits scattered across the globe. The term ‘talc’ covers over 500 products, each distinct by their nature, the proportion of by-minerals they contain and by their properties. Other minerals varying with talc vary according to the user industry: the two principal ones being carbonates and kaolin. People always think of talc as white, but it can also be grey, green, blue, pink and even black.
Mineral talc (Talc) or Magnesium Silicates (Magnesium Silicate) is the lowest hardness of any inorganic mineral.
The theory is based on the chemical composition is 63.5% SiO2, 31.7% MgO and 4.8% H2O.
With regard to its physical properties, talc has a specific gravity of 2.7, the lowest hardness of all the inorganic minerals (Mohs hardness : 1 ), with excellent heat resistance and good chemical stability. Nowadays world talc production stands at around 5.5 million tons per year, mined from about 250 deposits scattered across the globe. The term ‘talc’ covers over 500 products, each distinct by its nature, by the proportion of by-minerals it contains, and by its properties.