Refractory Clays of the Tugan Deposit
Abstract Generated abstract
This paper evaluates refractory clays from the Tugan deposit in Western Siberia as a potential local raw material for regional refractory and metallurgical plants. It describes their occurrence as a byproduct of placer concentration and characterizes their color, chemical composition, mineralogy, and ceramic behavior using chemical analyses, dye tests, thermal analysis, X-ray analysis, and firing tests. The clays are predominantly kaolinitic with minor hydromica, have compositions comparable to high-grade refractory clays, and show refractoriness of 1710 to 1740 degrees with acceptable shrinkage, strength, and water absorption characteristics. The authors conclude that Tugan clays meet technical requirements for class A and B fireclay products and could reduce dependence on imported refractory clays in Western Siberia.
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REFRACTORY CLAYS OF THE TUGAN DEPOSIT
P. G. USOV, E. A. GUBER
(Presented by Professor, Doctor of Chemical Sciences A. G. Stromberg)
In the territory of Western Siberia, significant deposits of high-grade refractory clays have not yet been found. This raw material is brought to plants from remote regions of the Union, from Kazakhstan, from the Urals, and in individual cases even from Ukraine. Therefore, the search for local nearby raw-material resources is of great practical importance for refractory, metallurgical, and other plants of Western Siberia. The demand for refractory clays is increasing considerably with the fulfillment of the seven-year plan for 1959–65, under which a significant expansion of the existing metallurgical plants of Western Siberia and the construction of a powerful metallurgical base are envisaged, based on the iron-ore deposits of Siberia and Kazakhstan discovered in recent years.
For the plants of Western Siberia, the Tugan deposit may be a local source of high-grade refractory clays. In working the placers of this deposit, refractory clays are waste products of the concentration process. Under the projected scheme of industrial concentration, the clays are separated out and may be used as an independent raw material. Development of the clays of the Tugan deposit will almost completely free all plants of Western Siberia from importing them from remote regions of the Union and will serve as an example of the comprehensive utilization of all useful products of the deposit. Since they are wastes of the concentration process, the Tugan clays will be cheaper in cost than any specially mined clays.
The clays from most of the workings are white in color, and in smaller quantities there are clays colored light gray, pinkish, and yellowish. The light-gray coloration of the clays is due to the presence in them of carbonaceous matter in a finely dispersed state; the pinkish and yellowish coloration is due to the presence of organic and inorganic colloids. After calcination the natural differences in color disappear; they are replaced by a single yellowish tone, the intensity of which is directly related to the content in the clay of titanium dioxide and iron oxide. In composition, the clay substance itself, within the limits of the thickness of the productive bed over the extent of the entire explored deposit, is fairly constant and corresponds to the compositions of the best grades of refractory clays.
Their chemical compositions vary within the following limits: SiO$_2$—from 44.8 to 50.2%; TiO$_2$ from 0.59 to 1.61%; Al$_2$O$_3$ from 30.90 to 36.92%; Fe$_2$O$_3$ from 1.19 to 5.35%; CaO from 0.57 to 0.93%; MgO from 0.31 to 1.01%; loss on ignition from 11.14 to 14.52%; H$_2$O from 1.20 to 3.17%.
Table 1
| Components | 3—3 | 4—4 | 5—5 | 6—6 | 7—7 | 8—8 | 9—9 | Average for the area |
|---|---|---|---|---|---|---|---|---|
| SiO₂ | 46,02 | 45,58 | 46,90 | 45,86 | 47,09 | 48,43 | 46,79 | 46,73 |
| TiO₂ | 1,21 | 0,59 | 0,87 | 1,27 | 1,65 | 1,26 | 1,16 | 1,14 |
| Al₂O₃ | 35,88 | 36,42 | 35,38 | 34,59 | 34,14 | 32,03 | 31,45 | 34,27 |
| Fe₂O₃ | 1,63 | 2,07 | 1,80 | 2,31 | 2,26 | 2,84 | 4,71 | 2,52 |
| CaO | 0,66 | 0,78 | 0,59 | 0,68 | 0,68 | 0,79 | 0,86 | 0,71 |
| MgO | 0,36 | 0,73 | 0,43 | 0,53 | 0,42 | 0,62 | 0,64 | 0,53 |
| alk. | 12,84 | 12,79 | 12,16 | 12,35 | 11,87 | 11,45 | 11,11 | 12,18 |
| H₂O | 1,38 | 1,21 | 1,81 | 2,09 | 1,81 | 2,49 | 2,93 | 1,82 |
| Sum | 99,98 | 100,17 | 99,94 | 99,68 | 99,92 | 99,91 | 99,65 | 99,90 |
Table 1 gives the chemical compositions of the clays, averaged by section lines, of the central South Aleksandrovsk area of the deposit.
The mineralogical composition of the clayey material is predominantly kaolinitic, with a small admixture of hydromicas, which are clearly established by staining with standard dyes. Chrysoidine stains all samples yellow, and in some an orange shade is recorded. When hydrochloric acid is added, all precipitates become orange. Methylene blue stains the clayey material violet with a blue shade, which does not change when potassium chloride is added. Chrysoidine in aqueous and hydrochloric-acid media, and methylene blue in aqueous medium, are incompletely adsorbed by the precipitates. Benzidine stains the precipitates of all samples a pale blue color, characteristic of the presence of hydromicas.
The kaolinitic composition of the clayey material is established by thermal and X-ray analyses, shown in Figs. 1 and 2.
Ceramic properties of the clays
The ceramic properties of the Tugan clays vary within the following limits: forming moisture from 28 to 30%, plasticity number from 11,0 to 15,0; drying shrinkage from 7,0 to 9,0%; cohesion about 3,5 kg/cm²; bonding capacity with 60% sand is 1,5 kg/cm² and with 80% sand is 0,0. The refractory properties of the clay are given in Table 2.
Table 2
| Property | 800 | 900 | 1000 | 1050 | 1100 | 1150 | 1200 | 1250 | 1300 | 1320 |
|---|---|---|---|---|---|---|---|---|---|---|
| Firing shrinkage, % | 1,29 | 2,15 | 3,85 | 4,50 | 6,00 | 7,50 | 10,7 | 11,6 | 12,4 | 12,4 |
| Total shrinkage, % | 8,90 | 9,00 | 10,6 | 11,2 | 12,6 | 14,0 | 17,0 | 18,0 | 18,7 | 18,7 |
| Water absorption, % | 30,9 | 30,5 | 29,5 | 27,2 | 17,2 | 12,1 | 7,70 | 3,50 | 0,05 | 0,05 |
| Mechanical compressive strength, kg/cm² | 74 | 81 | 110 | 116 | 161 | 243 | 262 | 350 | 400 | 400 |
| Mechanical bending strength, kg/cm² | 6 | 10 | 14 | 16 | 22 | 31 | 51 | 70 | 70 | 70 |
| Shard color | white | white | white | white | white | white | gray, white | gray, white | gray, white | gray, white |
Fig. 1. Thermograms of clays.
Fig. 2. X-ray diffraction patterns of clays.
The refractoriness of products made from Tugan clays varies within the range from 1710 to 1740°. The clays of the Tugan deposit have a melting interval of 460–490°. On firing they produce a body of uniform yellowish-white color, without specks, melt-outs, or other defects. In composition and properties they meet the technical requirements for raw material for refractory fireclay products of classes “A” and “B.”