SODIUM MAGNESIUM SILICATE
Scientific name: sodium magnesium silicate
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SODIUM MAGNESIUM SILICATE: is a synthetic silicate clay with a composition mainly of magnesium and sodium silicate.
Function(s): Binder; Bulking Agent; BINDING; VISCOSITY CONTROLLING
Mined from the earth, this clay-like ingredient serves as a thickener and texture modifier used to stabilize formulas while offering astringent properties.
Synthetic magnesium silicates are white, odorless, finely divided powders formed by the precipitation reaction of water soluble sodium silicate(water glass) and a water soluble magnesium salt such as magnesium chloride, magnesium nitrate or magnesium sulfate. The composition of the precipitate depends on the ratio of the components in the reaction medium, the addition of the correcting substances, and the way in which they are precipitated.
The molecular formula is typically written as MgO:XSiO2, where X denotes the average mole ratio of SiO2 to MgO. The product is hydrated and the formula is sometimes written MgO:XSiO2•H2O to show the water of hydration.
The very large active surface makes synthetic magnesium silicate useful for a wide variety of applications: purifying adsorbent (polyols, animal and vegetable oils), chromatography, dry cleaning, sugar, resins, odors); filler (rubber, ceramics, paper, glass, refractories); anti-caking agent (salt);catalyst; catalyst carrier; absorbent[dubious – discuss] (crude oil spills); filter medium.
The U.S. Food Chemical Codex, JECFA, and other monographs for Food Grade synthetic magnesium silicate specify a mole ratio of 2MgO:5SiO2. The most common use for Food Grade synthetic magnesium silicate is as an active filter aid for adsorption of color, free fatty acids and other polar compounds from used frying oils. Various national and international regulations allow use of this material as an anti-caking agent in a wide variety of powdered foods.
When used as a food additive, it is safe to ingest synthetic magnesium silicate. In 1990, the safety of synthetic magnesium silicate was reviewed by the Scientific Committee on Food (SCF) together with that of silica and the other metal alkali silicates. The SCF noted that “the available data, including a number of short-term studies in two species, appear to substantiate the biological inertness of those compounds”. The SCF established a group Acceptable Daily Intake (ADI) not specified for silicon dioxide and the alkali metal silicates.
Not to be confused with MAGNESIUM SILICATE aka Talc
Talc (derived from Persian: تالک tālk; Arabic: تلك talk) is a mineral composed of hydrated magnesiumsilicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. In loose form, it is the widely used substance known as talcum powder. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage, and the folia are non-elastic, although slightly flexible. It is the softest known mineral and listed as 1 on the Mohs hardness scale. It can be easily scratched by a fingernail. It is also sectile (can be cut with a knife). It has a specific gravity of 2.5–2.8, a clear or dusty luster, and is translucent to opaque. Talc is not soluble in water, but it is slightly soluble in dilute mineral acids. Its colour ranges from white to grey or green and it has a distinctly greasy feel. Its streak is white.
Talc powder is a household item, sold globally for use in personal hygiene and cosmetics. Some suspicions have been raised about the possibility its use promotes certain types of diseases, mainly cancers of the ovaries and lungs (it is in the same 2B category in the IARC listing as mobile phones and coffee) although this is not widely recognised as an established link.
The studies reference, by subject: pulmonary issues, lung cancer, and ovarian cancer. One of these, published in 1993, was a US National Toxicology Program report, which found that cosmetic grade talc containing no asbestos-like fibres was correlated with tumour formation inrats (animal testing) forced to inhale talc for 6 hours a day, five days a week over at least 113 weeks. A 1971 paper found particles of talc embedded in 75% of the ovarian tumors studied.
The Occupational Safety and Health Administration and National Institute for Occupational Safety and Health have set occupational exposure limits to respirable talc dusts at 2 mg/m3 over an eight-hour workday.
One particular issue with commercial use of talc is its frequent co-location in underground deposits with asbestos ore, which often leads to contamination of powdered talc products with asbestos fibres. Stringent quality control since 1976 (separating cosmetic and food-grade talc from "industrial" grade talc, which is allowed a certain portion of asbestos contamination) has mostly eliminated this issue, but it remains a continuing hazard requiring mitigation in the mining and processing of talc.
The US Food and Drug Administration (FDA) considers talc (magnesium silicate) to be generally recognized as safe (GRAS) for use as an anti-caking agent in table salt in concentrations smaller than 2%.
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