China Clay

Product NameChina Clay
CAS1332-58-7
MFH2Al2O8Si2.H2O
MW258.16
EINECS310-194-1
MOL File1332-58-7.mol

Chemical Properties

Melting point	1750 °C
Density	2,6 g/cm³
bulk density	470kg/m3
refractive index	1.6200
storage temp.	no restrictions.
solubility	Practically insoluble in diethyl ether, ethanol (95%), water, other organic solvents, cold dilute acids, and solutions of alkali hydroxides.
form	Powder
color	75-96, Hunter Brightness
PH	6-7 (50g/l, H2O, 20℃)(slurry)
Water Solubility	insoluble H2O, dilute acids and alkali hydroxides [HAW93]
Dielectric constant	1.8 - 2.8（0.0℃）
Stability	Stable. Substances to be avoided include strong oxidizing agents.
Cosmetics Ingredients Functions	ANTICAKING ABSORBENT ANTI-SEBUM BULKING OPACIFYING VISCOSITY CONTROLLING COLORANT ABRASIVE BINDING SKIN CONDITIONING
InChI	InChI=1S/2Al.O5Si2.2H2O.2O/c;;1-6(2)5-7(3)4;;;;/h;;;21H2;;/q2+1;-2;;;;
InChIKey	NLYAJNPCOHFWQQ-UHFFFAOYSA-N
SMILES	[Si](=O)(O[Al]=O)O[Si](=O)O[Al]=O.O.O
EPA Substance Registry System	Kaolin (1332-58-7)

Safety Information

Safety Statements	22-24/25
OEB	B
OEL	TWA: 10 mg/m3 (total)
WGK Germany	-
RTECS	GF1670500
TSCA	TSCA listed
HS Code	25070090
Hazardous Substances Data	1332-58-7(Hazardous Substances Data)

MSDS

Provider	Language
ACROS	English
SigmaAldrich	English
ALFA	English

Usage And Synthesis

Description

China Clay, scientifically known as kaolin, is a soft, white clay mineral that originates from the decomposition of feldspar.The most abundant deposits are in China (hence the name), the United States, Brazil, and the United Kingdom.

China Clay.png

Chemical Properties

China clay occurs as a white to grayish-white colored, unctuous powder free from gritty particles. It has a characteristic earthy or claylike taste, and when moistened with water it becomes darker in color and develops a claylike odor. It is stable and chemically unreactive under ordinary conditions.

Physical properties

Kaolin is a white, soft, plastic clay mainly composed of fine-grained plate-like particles. It has a high fusion point and is the most refractory of all clays.

Occurrence

China Clay is one of the most common minerals; it is mined, as kaolin, in Australia, Brazil, Bulgaria, China, Czech Republic, France, Germany, India, Iran, Malaysia, South Africa, South Korea, Spain, Tanzania, Thailand, United Kingdom, United States and Vietnam.China Clay occurs in abundance in soils that have formed from the chemical weathering of rocks in hot, moist climates; for example in tropical rainforest areas.

Uses

China Clay is used as a filler and coating for paper, and in the manufacture of refractories, ceramics, cements, fertilizers, chemicals (especially aluminium sulphate), catalyst carrier, anticaking preparations, cosmetics, insecticides, paint, source of alumina, adsorbent for clarification of liquids, electrical insulators.

Preparation

China Clay is extracted from kaolinized granite by washing it out with powerful and remote water hoses. The clay stream is then pumped to the separation plant where sand and mica are removed. The purified clay is filtered when wet and then dried. The very fine powder is formed by milling.

Safety

Purified China clay (kaolin) has a long history of safe use in cosmetics. Further supporting its safety, kaolin has been generally recognized as safe (also known as GRAS status) by the US FDA as a direct food additive.

Structure and conformation

China clay is described as a 1:1 clay mineral consisting of two layers joined through an apical oxygen. One layer is known as the siloxane layer and consists of silicon tetrahedra joined in an hexagonal array. This layer is coupled to a gibbsite-like layer consisting of octahedral aluminium bonded to four OH units and two oxygen atoms. These layers are joined as sheets to other layers and may form a large set of clay layers known as a kaolinite book.