PRECIPITATED SILICA

Description:
Precipitated Silica is composed of aggregates of ultimate particles of colloidal size that have not become linked in massive gel network during the preparation process. Precipitated silica prepared by the action of acid on a solution of soluble silicate is of fine controlled particle size & porous in nature. Precipitated silica powders have a more open structure with higher volume than dried pulverized gels. Amorphous silica is precipitated from super saturated solution obtained by concentrating an under saturated solution a hot saturated solution or generating Si(OH)4 of silica ester SiH4, SiS2, SiCl4 or Si. It was reported in 1640 that amorphous silica in the presence of excess alkali become a liquid & that subsequent neutralization of the liquid with acid caused precipitation of silica. The physical & chemical properties or precipitated silica vary according to the manufacturing process. Ultimate & aggregate particle size in silica’s precipitated from solution can be varied by reinforcement & control of suspension pH., temperature & salt content. The particle size in gynogenic silica’s is controlled by combustion conditions. The surface area as determined by nitrogen adsorption, is a function of particle size. Precipitated silica is used as filler for paper & rubber as a carrier & diluents for agricultural chemicals, as an ant caking agent, to control viscosity & thickness and as molecular sieve. The distinguishing feature of the growth of precipitated silica industry in India is that it has classifiably flourished in the small-scale sector. Readily available new materials low capital investment & high rates of return offer a distinct advantage to the small-scale manufacturers to venture into this field. So, we can better understand the growing demand of precipitated silica with the growth of end user industries.

PRECIPITATED SILICA

Description:

Product Profile Precipitated silica is silica produced by precipitation. Precipitated Silica is a versatile inorganic chemical which is used for reinforcement of rubbers and plastics, thickening and thixotropy of coating and paints, printing inks and cosmetics, antiblocking of plastic foils, free running and free flow of sticky solid and liquid substances, carrier for pesticides, insecticides, high temperature insulation, stabilizing of beer and silicon rubber. It imparts good finish, strength and balances at the required physico- chemical properties of the products. Product characteristics Appearance : White free flowing powder or lumps Water absorption value: 250% minimum Oil absorption value : 225% min. Moisture at 1100 C : 5-7 % Silica content SiO2: 88-90% Applications Precipitated silica is useful to enhance bond strength and as a reinforcing and thickening agent. Silica provides thixotropy, reinforcement and promotes adhesion as well as serves as extenders; therefore it raises quality and lowers cost. Silica prevents resin separation and the settling of pigments and heavy fillers. Precipitated silica has industrial applications in rubberized foot wear, paint, dyes, printing ink, and plastic products. Precipitated Silica is used to improve the tear strength due to its small particle size and complex aggregate structure. Precipitated Silica is used to improve pigment dispersion and acts as a parting agent and as absorbent to improve the flow and imparts a dry feel to the compound. Precipitated Silica is used in Railway Pads because it provides increased abrasion resistance and strength. In industrial rubber, precipitated silica confers superior strength and durability on industrial Rubber Belts and Rubber Hoses together with improved heat resistance and tear strength. Production Process The production of precipitated silica starts with the reaction of an alkaline silicate solution with a mineral acid. Sulfuric acid and sodium silicate solutions are added simultaneously with agitation to water. Precipitation is carried out under alkaline conditions. The choice of agitation, duration of precipitation, the addition rate of reactants, their temperature and concentration, and pH can vary the properties of the silica. The formation of a gel stage is avoided by stirring at elevated temperatures. The resulting white precipitate is filtered, washed and dried in the manufacturing process. Na2(SiO2)3.3(aq) + H2SO4(aq) ? 3.3 SiO2(s) + Na2SO4(aq) Market scenario The present demand for precipitated silica is estimated at 166.83 tonnes per annum. The demand is expected to reach at 402.03 tonnes by the year 2020. Precipitated silica is manufactured in India both in medium and small scale sector. Indian production is around 70,000 tonnes per annum.

PRECIPITATED SILICA

Description:

Precipitated silica is a silica (SiO2) produced by precipitation from a solution containing silicate salts. In 1999, more than 1M tons/y was produced, mainly for use in tires and shoe soles. Silica has two main varieties (a) Ground silica and (b) Processed silica. Ground silica is practically sand and is abundant in India and worldwide only the percentage of SiO2 varies from source to source. In general these are known as sands and are very cheap and usually used for glass making. It has very minimum use in rubber, however, can be used as heat resistant compound in rubber. It does not show any effect on cure. Processed silica is again SiO2 but in a purified form. This is obtained only after further processing from ground silica and in such process the percentage of SiO2 is increased considerably (>98%). Precipitated silica is a kind of processed silica only. In this method, silica is precipitated after acidification of alkaline silicate solution. There are three different types of reactions, possible: • The alkaline silicate solution flows into the acid solution. • The acid solution flows into the alkaline silicate solution. • The alkaline silicate solution and acid solution flows jointly into water or primary natural salt solution. CHEMICAL CHARACTERISTICS OF PRECIPITATED SILICA: SiO2 content Filler, softener and performance improvement in rubber and plastics. Cleaning, thickening and polishing agent in toothpastes for oral health care. Cleaning, thickening and polishing agent in toothpastes for oral health care. IEVE residue Tamped density DBP absorption Food processing and pharmaceuticals additive as anti-caking, free-flow, thickening agent and absorbent to make liquids into powders. BET Surface area pH value Food rheology modifier Defoamer component Drying loss Ignition Loss GLOBAL DEMAND Growth in manufacturing industry and high GDP growth in the emerging economies of India and China has led to growth in several end user segments such as automobiles, plastics and agriculture among others. On account of which, Asia Pacific has been dominating the global precipitated silica market both in terms of production and consumption and this trend is expected to continue during the forecast period. World demand to rise 5.6% per annum through 2018 Global demand for specialty silicas -- which include precipitated silica, silica gel, silica sol, and fumed silica -- is forecast to grow 5.6 percent per year through 2018 to 2.9 million metric tons, valued at just under seven billion dollars. This will represent an acceleration from the pace of the 2008-2013 period, as improved manufacturing levels in a stronger economic environment support faster gains in the developed countries of North America and Western Europe Global demand 1.6 million metric tonne per annum Global demand for speciality silicas such as precipitated silica, fumed silica, silica gel and silica sol will grow by 5.6% a year to 2.8 million metric tonne by 2016, according to the recent report from Freedonia Inc. GLOBAL PRODUCERS Important global producers include the following Evonik Rhodia PPG Industries Huber Tokuyama Glassvenset Specialty Chemical Products Madhu Silica,India