Precipitated silica is a silica (SiO2) produced by precipitation from a solution containing silicate salts. In 1999, more than 1M tons/y were 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:
Ø SiO2 content
Ø Filler, softener and performance improvement in rubber and plastics.
Ø Cleaning, thickening and polishing agent in toothpastes for oral health care.
Ø Cleaning, thickening and polishing agent in toothpastes for oral health care.
Ø IEVE residue
Ø Tamped density
Ø DBP absorption
Ø Food processing and pharmaceuticals additive as anti-caking, free-flow, thickening agent and absorbent to make liquids into powders.
Ø BET Surface area
Ø pH value
Ø Food rheology modifier
Ø Defoamer component
Ø Drying loss
Ø 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