Kaolin production methods

The 2eohtes are prepared as essentially bindedess preformed particles. The kaolin is shaped in the desired form of the finished product and is converted in situ in the pellet by treatment with suitable alkaU hydroxide solutions. Preformed pellets of 2eohte A are prepared by this method. These pellets may be converted by ion exchange to other forms such as molecular sieve Type 5A (1). ZeoHtes of higher Si02/Al202 ratios, eg, 2eohte Y, can be obtained by the same method, when sodium metasiUcate is incorporated in the preshaped pellets, or when acid-leached metakaolin is used. 

In a second set of experiments, -74 pm size kaolin particles were leached with hot alkaline solutions to study the conversion of kaolinite to various sodium hydroaluminosilicate compounds (Table III) under different leaching conditions. In each experiment, 15 g. of kaolin was leached with 120 ml. of alkaline solution. The solid reaction product was recovered by filtration, washed with water, dried in an oven at 95 C, and analyzed by XRD. Although this method of analysis identified the minerals present, it could provide only an approximate indication of the relative proportions of the various minerals present. The amount of quartz was particularly difficult to assess because the method of detection was very sensitive to this mineral. Therefore, the results are reported only in terms of major, minor, and trace quantities present in the product as indicated by XRD (Table IV). Because the small amount of titania in the kaolin was apparently not affected by even the most rigorous leaching conditions, the product always contained a trace of this material and no further mention seems necessary. 

With capillary casting, the demands placed on ball clay and kaolin producers are the same as with traditional bench casting. Additionally, faster casting and firmer casts are also required. The methods used to address these needs can be defined as similar to those of battery casting. Custom slurry products seem to offer the potential to improve performance in this area. 

The aspect ratio of the final flake products depends upon the origin of the mica and the processing method. Large flake pegmatite mica and wet milled mica can have aspect ratios in excess of 100. By contrast, processed mica flakes from schist and kaolin deposits tend to have aspect ratios in the area of 30 to 60. 

The authors number was offered earlier [43] the new method of polymerization-filled compositions on the basis of UHMPE processing - powder billet ram extrusion, allowing to prepare rod-like products with mechanical properties high level. The studies, carried out on systems UHMPE-kaolin, UHMPE-Al, shown [2], that at large draw ratios X a componors strengthening reduction occurs. The obtained result comparison with the data by ex-trudates UHMPE and its compositions with smaller kaolin contents fracture [43] allows to suppose, that fracture stress extreme change can be connected with the filler availability. The Ref [44] is devoted to this question clarification. 

In the second method, the required amounts of alumina and kaolin are fused in an electric arc furnace at about 1750°C. This method gives rise to a higher-purity mullite. The fused product contains >95% mullite, the remaining being a mixture of alumina and glass. 

The most straightforward way to produce brick in this class is to use 50% AI2O3 or 60% alumina aggregates (i.e., bauxitic kaolin or andalusite). Another way to produce these classes of products is to use a mixture of bauxite and fireclay. This latter method has been termed the bauxite dilution method. In other words, bauxite (at 88% AI2O3) is diluted with calcined fireclay and raw clay (at 40% AI2O3) to produce the required alumina content Properties of these types of refractories are given in Table 9. 

---