Deep Beneficiation of Kaolin from the Tugan Deposit
Abstract Generated abstract
This paper addresses the low quality of the clay product obtained during hydrocyclone beneficiation of kaolinized sands from the Tugan deposit, where silty sand, iron oxides, and humic substances limit use in fine ceramics and as industrial fillers. The authors report a deep beneficiation scheme combining flotation to remove silty sand with subsequent sulfuric acid autoclave treatment to reduce iron content. Under the selected flotation conditions, the concentrate yield was 63.2 percent and contained 36.12 percent aluminum oxide, while autoclave treatment lowered iron oxide content to 0.57 percent and increased whiteness from 68 to 80 percent. The resulting kaolin is reported to meet chemical composition requirements for fine ceramic products and for fillers in the rubber and paper industries.
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DEEP BENEFICIATION OF KAOLIN FROM THE TUGAN DEPOSIT
S. A. BABENKO, L. G. LYUTOVA
(Presented by the scientific final conference of the Faculty of Chemical Technology)
The clay product separated in the process of beneficiation of kaolinized sands by means of hydrocyclones is of low quality, owing to its high content of silty sand (up to 15%), iron oxide (1.5–6.5%), and humic substances (0.2–8.0%). The presence in kaolin of iron compounds and humic substances gives the clays a grayish, pinkish, and dirty-brown color; therefore such clay cannot be used in the manufacture of fine-ceramic products or as a filler for the rubber and paper industries.
As a result of the investigations carried out, we have developed a technological scheme for deep beneficiation of kaolin from the Tugan deposit, including flotation of the kaolin and its subsequent autoclave treatment.
The purpose of the flotation experiments was to separate the kaolin from silty sand. Kaolin flotation was carried out in a mechanical-type machine with a chamber capacity of 1 l and an impeller speed of 2000 rpm.
The following flotation regime proved optimal: S:L = 1:4, sulfuric acid consumption 0.8 kg/t, collector ANP—consumption 0.9 kg/t. The concentrate yield in this case was 63.2%. The chemical composition of the concentrate (Table 1) indicates its high quality (aluminum oxide content 36.12%).
Table 1
Chemical composition of kaolin flotation products
| Product name | l.o.i. | SiO₂ | Al₂O₃ | TiO₂ | Fe₂O₃ | CaO | MgO |
|---|---|---|---|---|---|---|---|
| concentrate | 12.30 | 48.58 | 36.12 | 1.26 | 1.16 | 0.49 | 0.89 |
| tailings | 3.01 | 86.90 | 4.05 | 1.57 | 1.21 | 0.22 | 0.76 |
| feed product | 8.87 | 62.00 | 24.25 | 1.38 | 1.17 | 0.39 | 0.84 |
Deferrization of the clay product was carried out by the chemical method according to the method proposed by Romanikevich and Gerasimova. The clay raw material was treated with sulfuric acid in an autoclave under pres-
under a pressure of 2 atm for two hours. After autoclave treatment, the clay was washed with water until traces of iron and sulfur were removed from the wash waters. Autoclave treatment made it possible to reduce the iron content in the kaolin concentrate to 0.57%. This increased the degree of whiteness from 68 to 80%. The consumption of sulfuric acid was 50 kg/t of kaolin.
After flotation and autoclave treatment, Tugan kaolin, in terms of its chemical composition, meets the requirements imposed on kaolins for fine-ceramic products and the requirements for fillers for the rubber and paper industries.