MATERIALS TESTE kaolin

The extraction techniques in current use in most laboratories throughout the world are still based on the kaolin-acetone procedures of Albert (A2) and Loraine and Brown (L8) or the tannic acid method of Johnsen (Jl). There is little information in the literature regarding the reliability criteria of these methods. Loraine and Brown tested the accuracy of their kaolin-acetone method in a series of recovery experiments in which a reference material prepared from urine, HMG-20A, was added to urine and recovered the end point of the bioassay was the mouse uterus test for total gonadotropic activity. The mean percentage recovery was 76,... 

The fatty acid derivatives give a very good performance on calcium carbonate but are inferior on kaolin. The results of mechanical testing show that the ease of dispersion and mechanical properties of fillers are governed by interactions with the matrix polymer. Thus, mechanical testing of the filled material must be carried out before the best coating can be selected for a given polymer. 

The present research aims to develop a type of element permitting electric field relaxation, consisting of constituent materials graded for electric permittivity. The constituents used are titamium oxide and kaolin. 15 combinations of titamium oxide and kaolin in differing relative proportions were produced by a vacuum filter prcess, and tests were conducted to measure the permittivity and conductivity of each. 

Mineral microfillers have been tested in a plasticized starch matrix [CAR 01]. For example, micrometric particles of kaolin have been incorporated by extrusion. Due to a significant compatibility between the matrix and the filler, we note an increase in the glass transition temperature, a reduction in water absorption and an increase in the rigidity of the material. However, with the corresponding filler contents, these composites no longer satisfy the standards of biodegradation (at least 90% of the material has to be degraded). 

Nevertheless, for waste paper recycling the plateau values of the isotherm are not decisive. With 0.2% dosage of the cationic polymer and 1 % stock consistency, the initial concentration is only 20 mg/1. Due to the steeper slope of the adsorption isotherm on the fillers, the polymer should preferentially be adsorbed on the fillers. Figure 5 shows the flotation recovery of all three solid materials — calcium carbonate, kaolin, and cellulose. These flotation tests were performed with pure systems. The solid content was the same as in waste paper recycling 1 and 0.2% for fibers and fillers, respectively. At a concentration of 20 mg/1, the recovery of kaolin is higher than 90%, while 70% of calcium carbonate are floated. However, with the same initial concentration the recovery of the cellulose fibers is below 20%. In comparison with the adsorption isotherms it can be concluded that the adsorbed amount of the cationic polymer is too low in order to hydrophobize the cellulose surface. Thus, the cationic polymer is a selective collector with respect to filler pigments. This fact has been confirmed by flotation tests with synthetic mixtures of cellulose and fillers [30]. 

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