Clay, kaolin test

This consists of zinc oxide in the form of a light, odourless, white powder. It may contain, as impurities, lead carbonate and sulphate and oxides of iron, cadmium and arsenic, and may be adulterated with chalk, barium sulphate and clay (kaolin). Besides the technical tests already described (see General Methods), the following tests and determinations are made. 

Both the Toth and Alcoa processes provide aluminum chloride for subsequent reduction to aluminum. Pilot-plant tests of these processes have shown difficulties exist in producing aluminum chloride of the purity needed. In the Toth process for the production of aluminum chloride, kaolin [1332-58-7] clay is used as the source of alumina (5). The clay is mixed with sulfur and carbon, and the mixture is ground together, pelletized, and calcined at 700°C. The calcined mixture is chlorinated at 800°C and gaseous aluminum chloride is evolved. The clay used contains considerable amounts of silica, titania, and iron oxides, which chlorinate and must be separated. Silicon tetrachloride and titanium tetrachloride are separated by distillation. Resublimation of aluminum chloride is requited to reduce contamination from iron chloride. 

Dispersant Activity Tests were conducted utilizing iron oxide and clay suspensions in order to establish the efficacy of the copolymers as dispersants for suspended particulate matter. Kaolin clay was used for the clay dispersion study. According to the procedure, separate 0.1% iron oxides and 0.1% clay suspensions in... 

Kaolin had little or no cracking activity, and catalyst activity as tested in the laboratory was directly related to silica-alumina gel content. However, the catalyst performed much better in commercial tests than anticipated from laboratory testing. Undoubtedly, this open structure encountered much less severe conditions at the outer surface of the microsphere during regenerations and made internal catalytic surfaces more readily available. This first of the so-called "semisynthetics" was called Nalco 783, and the matrix is still used in many forms some 28 years later.(7,13) Today it is estimated that some 200,000 tons/yr. of kaolin clay is used for cracking catalyst manufacture as reported by Georgia Kaolin Corporation.(24) Figure 10 shows the pore volume distribution for Nalco 783 and two other commercial semisynthetics from that period. 

Tests were conducted on soft and hard kaolin clays from Georgia, USA. Soft kaolins are relatively coarse-grained (coarser than 65% < 2 microns), found in Cretaceous age strata, and typically have low Ti02 contents (1-3%). The hard kaolins are fine-grained (finer than 80% < 2 microns), found in Eocene age strata and have higher Ti02 contents (2-8%). 

This paper is a contribution to the subject of thermal effects on the mechanical behaviour of clays. We concentrate here on the presentation of experimental results obtained on a Kaolin clay under triaxial conditions at two temperatures (22 °C and 90 °C), in view of determining the evolution of the shear yield surface with temperature. A new temperatureapparatus developed by the authors was used (Cekerevac et al. 2(X)3). Temperature effects were identified by comparing the results of tests... 

The strength envelope at critical state of Kaolin clay at ambient temperature shows a straight line, with a slope M = 0.8 that corresponds to a friction angle of ( ) =21°. Figure 3 combines the results of drained shear tests at critical state obtained at ambient and high temperatures (90°C). It is clearly shown that the strength envelope at critical state is independent of testing temperature. 

Some results of a comprehensive laboratory study using a temperature controlled triaxial cell has been presented. Thermal effects on the mechanical behaviour of a Kaolin clay were analysed by comparing tests at ambient (22 °C) and high (90 °C) temperatures. Several thermomechanical loading paths were used to gain insight into the effect of temperature on the behaviour of clays. The main conclusions drawn from this study are as follows ... 

Berg Method. See diver method. Berkeley Clay. A plastic, refractory kaolin from S. Carolina P.C.E.34. Berkovich Indenter. A 3-faced diamond pyramid for indentation hardness tests. 

Production of kaolin clay for use in rubber is dependent on the availability of tertiary deposits of kaolin (where 80% or more of the particles are less than 2 micrometers in diameter, based on laboratory sedimentation testing). 

Structural ceramics are generally brittle composite systems with a coarse micro structure consisting of two or more phases. Kaolinitic clays are used in the industrial production of structural ceramics. Thermograms from TG and DTA tests are shown in Fig. 19 for kaolin, a pottery mixture, brick... 

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