B) MICA POWDER

Mica Powder in various forms is obtained by grinding/breaking mica scrap, which is a slow, costly and extremely complicated process, because of the scrap being tough and having a plate like structure. Meticulous care and precaution has to be taken so that there is no deterioration of its natural brilliance, colour and properties.

1) MICA FOR WELDING ELECTRODES

Muscovite dry ground mica is well recognised for use in mild steel rutile based welding electrodes. In the manufacture of welding electrodes a core of steel wire is coated uniformly with a 'flux' comprising mica as a lagging compound. Mica is added to the 'flux' with which welding electrodes are coated as binders, extrusion agents and pigments to aid slag formation, weldpool protection and arc stabilisation. The mica coating provides two distinct types of protection to the welding rods. Firstly, it serves in forming a fusible slag and a good seal at the fusion zone on the arc. Secondly, it resists the action of heat, gaseous and other surrounding atmospheric oxidization. In fact, it is the nature of mica coating that largely determines the quality of a welding electrodes.

2) MICA FOR GYPSUM PLASTER BOARDS

Muscovite dry ground mica is light in weight, non-combustible, free flowing, chemically inert, resilient and non-abrasive. It have good thermal insulation properties and an excellent characteristics for sound absorption. Low shrinkage and coefficient of expansion, good dimensional stability, temperature stability, and extremely low water absorption are some of its additional outstanding features. All these properties makes mica an ideal product for use as a filler in light-weight fire-resistant pre-fabricated gypsum wallboard slabs and panels for building constructions, in place of asbestos, where thermal insulation and acoustic properties are of particular importance.

3) MICA FOR WALLBOARD JOINT CEMENTS

Dry ground muscovite mica is effectively used a cost-effective filler and surfacing agent in wallboard joint cement compounds to fill the joints between panels of wallboards, as well as, in the finished coating of ceilings in building constructions, because of its many functional and morphological surface characteristics. In this particular application, mica acts as a reinforcing pigment reducing penetration into porous surfaces, improving mixing and trowelling properties of jointing cements. High heat resistance, excellent mechanical and thermal strength, low moisture absorption, high surface leakage resistance, unusual chemical resistance and non-hygroscopic properties are some of the distinctive mica properties which makes it an useful ingredient for use in the above applications.

4) MICA FOR ACOUSTIC PRODUCTS

Muscovite mica powder is widely used as a filler in non-asbestos acoustic products for treatment of automobile under-bodies and noise protection systems because of its functional, morphological and surface characteristics. The addition of mica in acoustic compounds improves its material properties significantly, such as, improve heat and UV resistance, increase tensile and flexural strengths, reduce isotropic shrinkage and permeability, enhance the dielectric and insulating properties, better surface properties, etc. In fact, Mica is a unique mineral which offers the multiple advantage of noise and vibration absorption, reduces flammability, adds low temperature impact resistance, high thermal stability and multi-directional lateral reinforcement to composite plastic polymer compounds such as superior quality and excellent dimensional stability than mica.

5) MICA FOR ASBESTOS-FREE BRAKE LININGS

Mica has an outstanding electrical, thermal, mechanical and chemical properties. High heat resistance, excellent mechanical and thermal strength, low moisture absorption, high surface leakage resistance, unusual chemical resistance and non-hygroscopic properties are some of the most distinctive properties of mica. Mica particles are stronger than iron and are not brittle like other inert inert material. It serves to reinforce, stiffen, harden and strengthen the product and prevent microscopic ruptures, reduce warping, lower thermal expansion and conductivity. During the mixing process, the use of mica helps to achieve a more homogeneous mix. Due to platy nature and surface characteristics of mica, it tends to lock together under compression during wet or dry, cold or hot processes to form an effective plateform for the matrix of other materials in the formulation. As such, the benefit of mica for use as friction materials for asbestos-free brake linings, brake shoes, clutch discs, etc. is well recognised.

6) MICA POWDER FOR RUBBER & TYRE APPLICATIONS

It is suitably used as an anti-blocking, anti-sticking and anti-friction agents between the inner rubber and castings of rubber tyres for aeroplanes, automobiles and motor bikes. It is primarily used as a dusting agent and mold lubricants to prevent massing and adhesion of the rubber compounds during vulcanization and acts as a separating factor for the cores of the outer sheath. Besides, it prevents movement of sulphur while permitting air and moisture to escape during curing and helps create a uniform pore structure that leads to improve resiliency and reduced shrinkage.