A comprehensive study of the compositions and properties of primary kaolins from the Sitnitsa and Dedovka deposits in the Republic of Belarus was performed. The mineralogical and chemical compositions, phase transformations during heating, dilatometric properties, and the properties of kaolin raw material were studied for individual fractions. A relation is established between the quality, structure, and physical-chemical properties, which made it possible to recommend the most effective methods of enriching the kaolin raw material studied.Increasing the production scales of building and facing rock, for which mainly magmatic rock from Belarus, specifically, the deposits in the Mikashevichi and Zhitkovichi salients, serve as the raw material, requires the use of overburden rocks, represented mainly by kaolins. In the Republic of Belarus there are no operating deposits of kaolin clays, so that the problems of creating a domestic mineral-raw materials base of kaolin raw material and developing technologies for its reprocessing and deep enrichment are very topical.It should be noted that kaolins from the Belorussian deposits differ by their structure and properties from high-quality kaolins from Ukraine and Russia. Four kaolin deposits (Sitnitsa, Dedovka, Berezina, Lyudenevichi) have been found on the territory of Belarus. These deposits are tied to sections of shallow bedding of crystalline rocks and are a product of the breakdown of gneisses, granite-gneisses, schists and granites and, as a rule, are primary and in individual cases secondary kaolins because of erosion and re-deposition. The considerable amount of mechanical inclusions, high content coloring oxides and other impurity components make for low quality of the raw material. Of greatest interest for practical use are kaolins from the Sitnitsa and Dedovka deposits.The Sitnitsa deposit lies in Brest Oblast. The kaolins represent the weathered crust of gneisses and granite-gneisses and they comprise a 2.0 -9.1 m thick (average 3.6 m) sheet bed. They lie under sandy-clayey deposits with thickness 12.0 -23.4 m. The proven reserves of primary kaolin-raw material in the Sitnitsa deposit comprise about 2.53´10 6 tons. The macroscopic primary kaolins in Sitnitsa comprise clayey rock of grey color, greasy feel and weakly chlorinated with large inclusions of feldspar-quartz fragments, biotite flakes, quartz grains, and feldspar. The eastern part of the deposit lies within a planned quarry of building rock, so that for obtaining kaolin as a by-product this section has been explored in detail [1].The Dedovka deposit lies in Gomel' Oblast and is represented by primary and secondary kaolins. The thickness of the deposit is 2.9 -53.9 m and the bedding depth is 29.7 -37.4 m. The overburden consists of sandy-clayey deposits. Secondary kaolins are embedded among glauconitequartz sands at depth 28.3 -33.0 m. The bed of secondary kaolins lies above the primary kaolins, repeating the latter's form, but it is somewhat larger with much thinner, 1.2 -5.4 m. These are yellow-grey...

The possibility of replacing imported refractory clays and kaolines, which are part of porcelain stoneware mix, with refractory clay materials of the Republic of Belarus, in particular quartz-pyrophyllite-kaolinite rock and kaolin of “Dedovka” and “Sitnitsa” deposits, was explored. Porcelainised stoneware body formulations of JSC “Keramin” (Minsk, Republic of Belarus) was taken as the basis. It was found that physico-chemical properties and operational characteristics of porcelain tiles comply with the requirements of EN 14411: 2014, when adding 2.5–15.0 wt.% quartz-pyrophyllite-kaolinite rock. Incorporation of quartz-pyrophyllite-kaolinite rock in percentage higher than 15.0 wt.% resulted in reduction in the total amount of the vitreous phase of porcelain stoneware, thus increasing water absorption, apparent porosity as well as reduces flexural strength and bulk density. The main crystalline phases in the synthesized materials were quartz and mullite. It was also revealed that imported kaolines could be completely replaced by kaolines of “Dedovka” and “Sitnitsa” deposits. In this, required physico-chemical properties and operational characteristics of porcelain tiles was maintained. SEM analysis revealed that specimens synthesized using considered kaolines show quite dense microstructures, with a high degree of vitrification. The gas phase in these materials was practically absent, the presence of only individual small irregular pores was found. XRD analysis indicated that the major phases were mullite, quartz, microcline and hematite. It was hematite that gives the obtained porcelain stoneware samples a dark gray color scheme. Thus, the use of domestic refractory clay raw materials provides import substitution and declining production costs.

No abstract

The article gives brief information about the most common kaolin raw deposits of the Republic of Belarus. Thermal and dilatometric characteristics of natural kaolins and kaolins enriched by clarification method of “Sitnitsa” and “Dedovka” deposits are studied in detail. It is found that these raw materials are industrially prospective in terms of its using in the production of silica-alumina refractories (semiacid and chamotte).

No abstract