What is Talc ?
Talc is the softest mineral (occupying place 1 in the Mohs hardness scale) known on our planet earth.
It is a hydrated magnesium silicate [Talc chemical formula is Mg3Si4O10(OH)2 ]. Also known as Steatite. It is the main component of soapstone. Its crystals usually develop massive, leafy aggregates with laminar particles.
Synonyms of Talc includes soapstone, steatite, silicates, Talcum powder etc
Its silicate layers lie on top of one another without having a chemical bond but are bound to each other by weak Vander Waals forces. This structure gives talc the platy appearance and its characteristic greasy or soapy feeling – hence the name “soapstone”.
Talc is the world’s softest mineral. Although all talc ores are soft, platy, water repellent and chemically inert, no two talc is quite the same. Talc is a vital part of everyday life. The magazines we read, the polymers in our cars and houses, the paints we use and the tiles we walk on are just some of the products that talc enhances.
Talc is a hydrated magnesium sheet silicate with the chemical formula Mg3 Si4 O10 (OH)2. The elementary sheet is composed of a layer of magnesium-oxygen/hydroxyl octahedra, sandwiched between two layers of silicon-oxygen tetrahedra. The main or basal surfaces of this elementary sheet do not contain hydroxyl groups or active ions, which explains talc’s hydrophobicity and inertness.
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 steatite (anhydrous magnesium silicate). Talc’s melting point is 1500°C.
The size of an individual talc platelet (= a few thousand elementary sheets) can vary from approximately 1 micron to over 100 microns depending on the deposit. It is this individual platelet size that determines a talc’s platyness or lamellarity. A highly lamellar talc has large individual platelets whereas a microcrystalline talc’s platelets are much smaller.
The elementary sheets are stacked on top of each other, like flaky pastry, and, because the binding forces (known as Vander Waal’s forces) linking one elementary sheet to its neighbours are very weak, the platelets slide apart at the slightest touch, giving talc its characteristic softness.
Related minerals :
Talc ores also differ according to the type and proportion of associated minerals present. They can be divided into two main types of deposits: talc-chlorite and talc-carbonate. Talc-chlorite ore bodies consist mainly of talc (sometimes 100%) and chlorite, which is hydrated magnesium and aluminium silicate. Chlorite is lamellar, soft and organophilic like talc. It is however slightly less water repellent than talc. Talc-carbonate ore bodies are mainly composed of talc carbonate and traces of chlorite. Carbonate is typically magnesite (magnesium carbonate) or dolomite (magnesium and calcium carbonate). Talc-carbonate ores are processed to removed associated minerals and to produce pure talc concentrate.
Talc properties :
Talc is lamellar, platy, organophilic, water repellent with special thermal and mechanical properties. It has a high capacity for absorbing organic substances. It is also acid & alkali-resistant, chemically inert and non-toxic. Talc has neither aroma nor taste. This makes it a very essential mineral in our day-to-day life.
Talc’s properties (platyness, softness, hydrophobic & organophilic nature and inertness) provide specific functions in many industries.
● Agriculture and Food: Talc is an effective anti-caking agent, dispersing agent and die lubricant and therefore contributes to more efficient functioning of animal feed and fertilizer plants. In premixes and agricultural chemicals, talc makes an ideal inert carrier. Talc is also used as an anti-stick coating agent in a number of popular food products and processes including chewing gum, boiled sweets, cured meats, and for rice polishing. In olive oil production, it increases yield and improves the clarity of the oil.
● Ceramics: Talc is a phyllosilicate which imparts a wide range of functions to floor and wall tiles, sanitary-ware, tableware, refractory and technical ceramics. In traditional building ceramics (tiles and sanitary-ware), it is used essentially as a flux, enabling firing temperatures and cycles to be reduced.
In refractory applications, chlorite- rich talc is transformed into cordierite to improve thermal shock resistance. For steatite ceramics, microcrystalline talc is the most appropriate. During firing , talc is transformed into steatite, which possesses electro-insulating properties, while very low-iron-content talc is particularly suitable for use in frit, engobe and glaze compositions.
● Coatings: Talcs confer a whole range of benefits to coatings. In interior and exterior decorative paints, they act as extenders to improve hiding power and titanium dioxide efficiency. Talc’s lamellar platelets make paint easier to apply and improve cracking resistance and sagging. They also enhance matting. In anti-corrosion primers, talc is used to improve corrosion resistance and paint adhesion. They also bring benefits to inks, jointing compounds, putties and adhesives.
● Paper: Talcs are used in both uncoated and coated rotogravure papers where they enhance printability and reduce surface friction, improving productivity at the paper mill and print house. They also improve mattness and reduce ink scuff in offset papers. Used as pitch control agents, talc “clean” the papermaking process by adsorbing any sticky resinous particles in the pulp onto their platy surface s, thereby preventing the agglomeration and deposit of these stickies on felts and calenders. As opposed to chemical pitch-control products that pollute the process water, talc is removed together with the pulp, enabling the papermaker to operate more easily in closed-circuit. In specialty papers, such as colored papers or labels, talc helps to improve quality and productivity.
● Personal Care: As it is soft to the touch and inert, talc has been valued for centuries as a body powder. Today it also plays an important role in many cosmetic products, providing the silkiness in blushes, powder compacts and eye shadows, the transparency of foundations and the sheen of beauty creams. In pharmaceuticals, talc is an ideal excipients, used as a glidant, lubricant and diluents. Soap manufacturers also use talc to enhance skin care performance.
● Plastics: Talcs impart a variety of benefits to poly-propylene, for instance higher stiffness and improved dimensional stability in automotive parts (under-the-hood/bonnet, dashboard, bumper interiors and exterior trim), household appliances and white goods. Advanced milling technology is required to obtain the finest talc without diminishing the reinforcing power of their lamellar structure. Talcs are also used for linear low density polyethylene (LLDPE) antiblocking and as a nucleating agent in semi-crystalline polymers. In polypropylene food packaging applications, talc is a highly effective reinforcing filler.
● Rubber: Talcs reduce the viscosity of rubber compounds, thereby facilitating the processing of molded parts. They also improve extrudate qualities, increasing production rates and enhancing UV radiation resistance of exterior parts such as automotive profiles. In sealants and gaskets, they provide good compression resistance, whilst in pharmaceutical stoppers, they create a barrier against liquids. In cables, talc functions as insulators and in tyre manufacture they make excellent processing aids.
Talc Chemical Properties/Composition
|MgO||: 30.0 – 32.5%|
|SiO2||: 64.0 – 66.0%|
|CaO||: 1.5 – 2.5%|
Talc Physical Properties
|Appearance||: White fine smooth powder|
|Sp. gravity||: 2.7 to 2.9|
|Bulk density||: 0.5%|
|Oil absorption value||: 35 to 40%|
|Hardness||: 1 (Mohs)|
|Moisture & Volatile matter||: 0.5% by wt. (105 deg.C)|
|Water soluble matter||: Max 0.5%|
|PH of 10% aqueous solution||8 to 10 (ASTM D 1208-65 BS 1795.)|
Minimum 88% combined magnesium calcium silicate.
Talc Industrial Applications & Uses :
Talc in Paper :
Gives smoothness, brightness to paper & partially replaces TiO2. Also acts as pitch absorber, talc “clean” the papermaking process by adsorbing any sticky resinous particles in the pulp onto their platy surfaces, thereby preventing the agglomeration and deposit of these stickies on felts and calenders. As opposed to chemical pitch-control products that pollute the process water, talc is removed together with the pulp, enabling the papermaker to operate more easily in closed-circuit.
Talc in Paints :
Highly recommended for wood finishes, primers, putties, undercoats, architectural finishes, water based coatings. Its laminar structure helps in better corrosion protection and also improves exterior durability of paints. Recommended for exterior paints.
Talc for Ceramics :
Talc improves resistance to thermal shocks and gives superior electrical properties. It gives greater toughness to speak plugs and switch boards. It also improves dry pressing resistance of ceramic bodies.
Talc in Foundries :
Used in mould making and for final finish.
Talc for Plastic & Rubber :
Used in variety of application as reinforcement filler.
Talc for Cosmetics :
Super fine talc powder is used in cosmetic for its smooth silky finish. Read More..
Talc Price in India (Our suggested talc grades):
|Talc Grades / Model no.||VT – 98L500||VT – 92L20||VT – 92L10||VT – 92H500||VT – 90H500||VT – 90M500||VT – 92L500||VT – 86L500|
|Product Name||Low calcium high whiteness talc powder||Industrial talc powder for plastics||Industrial talc powder for cosmetics||Industrial talc for Paints & Rubber||Talc powder Filler & Extender||Standard quality talc powder||High quality Talc powder||Industrial Talc powder|
|Moisture (%)||> 0.5%||> 0.5%||> 0.5%||> 0.5%||> 0.5%||> 0.5%||> 0.5%||> 0.5%|
|pH||8 to 10||8 to 10||8 to 10||8 to 10||8 to 10||8 to 10||8 to 10||8 to 10|
|Oil Absorption||36 to 38||36 to 38||36 to 38||40 to 42||40||39 to 40||38 to 40||40 to 42|
|Particle Size||500 mesh||20 micron||10 micron||500 mesh||500 mesh||500 mesh||500 mesh||500 mesh|
|Top cut (micron)||40 micron||50 micron||40 micron||50 micron||50 micron||50 micron||50 micron||50 micron|
|SiO2||64% – 66%||64% – 66%||64% – 66%||56% – 60%||56% – 60%||55% – 58%||55% – 58%||53% – 55%|
|MgO||30% – 32%||30% – 32%||30% – 32%||29% – 30%||29% – 30%||28% – 30%||28% – 30%||27% – 28%|
|CaO||> 1%||> 1.5%||> 1.5%||10% – 11%||10% – 11%||5%||2% – 3%||8% – 11%|
|Fe2O3||> 1%||> 1%||> 1%||> 3%||> 3%||2% – 3%||1% – 3%||1% – 3%|
|LOI||7% – 10%||7% – 10%||7% – 10%||7% – 9%||7% – 9%||7% – 8%||7% – 8%||7% – 8%|
|Automotive paints & Coatings; Plastic products; masterbatches; Cosmetics; Pharmaceuticals industry||Automotive paints & Coatings; Plastic products; masterbatches; Pharmaceuticals industry||Cosmetic grade for high finishing and gloss.||Industrial paints; Primers; PVC and other plastic products; Rubber industry||As a filler in all kinds of paints, Rubber & cosmetics industry||As a filler & extruder in all kinds of paints, Rubber & cosmetics industry||As a reinforcement filler in Paints, Paper & Rubber industry||As filler in Paper & Pulp; Detergent and Soap industry|
|Details||Extremely lamellar, ultrafine talc with enhanced purity and high specific surface area||Extremely lamellar, ultrafine talc with enhanced purity and high specific surface area||Extremely lamellar, ultrafine talc with enhanced purity and high specific surface area||Highly lamellar, superfine, free flowing talc powder.||Highly lamellar, superfine, free flowing talc powder.||Our standard filler grade talc, caters to all types of industries||A naturally occurring, stable, physically and chemically inert talc product with a natural structure. Generally used as fillers / extruders.||A naturally occurring, stable, physically and chemically inert talc product with a natural structure. Generally used as fillers / extruders.|
Apart from above grades we develop tailor made talc to meet the specific requirement of our clients. Our R&D is also working on ultra-fine Talc powders to develop many new products with exciting possibilities.
|Packaging & Delivery Details:|
|Packaging:||50 kg pp bag; 1ton/bag; 1*20 container, can load 25-27 MT or upon clients’ requirement|
|Delivery:||within 5 – 20 days (depending upon the delivery location) after receiving the deposit|