Talc

General Category Silicate mineral Formula    (repeating unit) Mg₃Si₄O₁₀(OH)₂

 Strunz classification                                                     9.EC.05

 Crystal symmetry                                     Either monoclinic 2m or triclinic 1

 Identification Color                   Light to dark green, brown, white,grey

Crystal habit                      Foliated to fibrous masses, rare as platey to pyramidal crystals

 Crystal system monoclinic or triclinic^[2] Cleavage                 Perfect on {001}

basal cleavage Fracture             Flat surfaces (not cleavage), fracture in an uneven pattern Tenacity                                                      Sectile

 Sectile Mohs scale                             1 (defining mineral) hardness

Luster                                                     Waxlike or pearly

Streak                                                    White to pearl black

Diaphaneity                                            Translucent

Specific gravity                                        2.58 to 2.83 Optical properties Biaxial (-)

Refractive index                                                        n_α = 1.538 – 1.550
                                                                                  n_β = 1.589 – 1.594
                                                                                  n_γ = 1.589 – 1.600

Birefringence                                                                  δ = 0.051

 Pleochroism                                                           Weak in dark varieties Ultraviolet

 fluorescence                                               Short UV=orange yellow, long UV=yellow

Over 40 million tonnes deposits of talc have been identified in Niger, Osun, Kogi, Ogun and Kaduna states. The Raw Materials Research and Development Council (RMRDC)’s 3,000 tonnes per annum catalytic plant is the only talc plant in the country. The talc industry represents one of the most versatile sectors of the industrial minerals of the world. The exploitation of the vast deposits would therefore satisfy local demand and that for export.

Talc bulk from the mine is crushed in a jaw crusher and then screened in a rotary screen.  The oversized materials are milled in a hammer mill fitted with a cyclone.  The undersized materials from the hammer mill are fed into a pebble mill using ceramic grinding media.

Contamination and discolouration of talc may occur if conventional grinding media are used.  When the fineness of the talc from the pebble mill is satisfactory, the product is packed.

For contaminated talc, the product from the mill is fed into floatation cells and then to a hydrocyclone assembly for thickening.  For the badly discoloured talc or when high whiteness is required, the product from the floatation cells is bleached with acid before going through the cyclone.  The product from the cyclone is dewatered in a filter press and the cake so obtained is granulated in a disintegrator. The disintegrated talc is then dried in a flash dryer.

Finally, the dried talc is milled to the required particle size, weighed and bagged.

Talc as a vital raw material in the ceramics, cosmetics, paints, paper, pharmaceutical and tyre industries, enjoys a ready-made market for the high short-fall in supply.  With a high national demand of about 50,000 tonnes per annum, over 90% of the talc used by Nigerian industries is imported.

However, if the Nigerian talc is exploited and beneficiated properly, it would not only satisfy the local demand but could also be exported because of the abundant reserves in the country.

An estimated reserve of over 100 million tones of talc has been found in Niger, Osun, Kogi, Kwara, Ogun, Taraba and Kaduna States. There are only two medium size talc processing plants currently operating in Nigeria and both are located in Niger State.

Talc being the vital mineral in the ceramics, cosmetics, paint, paper, soap, rubber, fertilizer, pharmaceutical and tyre industries enjoys a ready made market for the huge shortfall in supply. In spite of the high national demand which is over 50,000 tonnes per annum, there is only one talc processing industry in the country which produces about 3,000 tonnes per annum.

Over 90% of the talc used in Nigerian industries is imported. Therefore, if Nigeria talc is exploited and processed properly, it would not only satisfy the local demand, but would also be ready for export because of the abundant reserves in the country