The difference between calcined clay and calcined kaolin
Generally speaking, the strengthening effect of hard, clay on hardness, elongation strength, tensile strength or wear resistance is larger than that of soft clayBut the hard clay and soft clay (hard Claysoft clay) is mixed with rubber as raw material mixed hardness, tensile strength training plus sulfur product for compliance, which can not be a clear division, but hard clay particles were relatively small, at 2 below for more than 80%, soft clay is about 50%. The proportion of around 2.6. The general kaolin is acidity, pH value is about 4~5, but also the use of alkali or amine treatment, the pH value tends to alkaline. Kaolin better than calcium carbonate in the tensile strength and hardness increase and mechanical strength has good performance, but the degree of poor white, permanent compression deformation, and sulfur is slow (because of the pH value of 4.5.5, delay the sulfur addition tendency), glycerol, ethylene glycol, can amine (Glycol) as activating agent to improve the properties of sulfur. The clay at suitable temperature (600~800 DEG C) loses water of crystallization calcination (OH) the crystal structure collapse, in order to improve live Because the free ion (ion) is adsorbed and fixed, the insulation effect can be improved, and the treatment can decompose the organic matters and increase the whiteness, and because the size is neat, the dispersion is good
Also known as clay kaolin clay, clay, generally translated, is a content of kaolinite origin rocks have reached more than the amount of which is the final product of granite and feldspar weathering, is the main component of hydrated aluminium silicate. Catalpo rubber old called crushing natural product is refined, the price is low.
Calcination can also make the crystal structure of kaolin changes (mainly caused by hydrogen bonding and crystal water removal layer), from the original ordered lamellar crystal structure of kaolin into disordered metakaolin, the exposed parts of the original crystal layer group, and due to remove water of crystallization, type and quantity of surface active the increase (the type changed from -OH to Si-O, Al-O and part of the remaining -OH), the reaction activity increased.Calcined kaolin can lead to particle size increased, while the decrease of surface area, adsorption decreased, but the decrease of surface energy, to improve the dispersibility of kaolin, and the amorphous structure became loose, but also can improve the dispersion of calcined kaolin after dehydroxylation. Usually by grinding or fine chemical surface modification as rubber plastic and other reinforcing filler of white smoke.Shvarzman replace some found that when the amorphous phase in the kaolin is more than 55%, according to the ASTM618 standard can be used as an active filler.
