The paper presents studies on the production of a high-alumina aggregate with an Al2O3 content of 75% based on fine-grained corundum dust generated by grinding fused corundum. Finely dispersed corundum powder is a by-product and due to the low Al2O3 content (93 – 95%) is not used in further production. It is proposed to obtain high-alumina aggregate without joint grinding of the components. Aggregate was obtained by pressing through a “false grain” from a mixture of kaolin and corundum dust in a certain ratio. The samples firing was carried out at a temperature of 1700°C. The phase composition of the obtained aggregate is represented by 46 – 51% corundum, 45 – 49% mullite. The water absorption of such chamotte is 14 – 16%, open porosity is 33 – 35%, apparent density is 2230 – 2290 kg·m−3. Now, it was not possible to obtain a high-density filler grade ZML and ZMK that meets the requirements of GOST 23037 – 78. The production flow chart of high-alumina chamotte based on kaolin and corundum dust should include a joint fine grinding of the components, or a separate grinding of corundum dust until it passes completely through the 0.063 mm mesh.

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High-alumina chamotte with an Al2O3 content of more than 62% is a desirable raw material to produce high-alumina refractories. The production of high-alumina aggregate (chamotte) is carried out in various ways, using plastic or semi-dry technology for briquetting from commercial alumina and refractory clay. When grinding fused corundum, the dust containing 93–95% Al2O3 is formed; it is currently a substandard material. It is of interest to involve this waste product in the production of high-alumina chamotte. The developed technology allows obtaining the desirable material and utilizing production waste. In this project the briquetting parameters to produce high-alumina chamotte using corundum waste and refractory enriched kaolin were determined.

The properties of red low-melting clay with the aim of its use in the production of building ceramics are investigated. The presented sample of clay raw materials by mineral composition refers to kaolinite clays with mixed-layer formations in the form of illite and ferruginous montmorillonite with Na-, Ca- and Mg-interlayer hydrated exchange cations. It is characterized by an average content of free SiO2 (10 – 25%). The clay is medium plastic with a low content of coarse inclusions, it refers to medium raw materials. Clay is medium-drying, medium-sensitive to drying, non-sintering. Mechanical strength during firing at a temperature of 900°C is 27.5 MPa. When firing samples in the temperature range 900 – 1050°C, a significant black core is formed. At a firing temperature of 1050°C, swelling of the samples occurs. Considering the properties of this clay, it cannot be recommended to produce face and ordinary building bricks. However, the studied clay can be used to produce expanded clay. The introduction of 0.5% of spent technical oil allows to get the expansion coefficient of 3.83. The temperature range of expansion is 1050 – 1170°C. The density of expanded clay granules in this case is 560 kg·m−3.

When fused corundum is crushed, a finely dispersed powder is formed with an Al2O3 content of 93–95%, in the form of substandard material. It is advantageous to utilize this powder to obtain high-alumina chamotte with Al2O3 content of more than 62%. High-alumina aggregate (chamotte) was obtained by semi-dry technology with intermediate briquette molding from a mixture of corundum dispersed powder and enriched kaolin. Based on a final Al2O3 content of 65 wt. % the batch composition of the mass to produce a high alumina aggregate (chamotte) was calculated. From a mixture of dispersed corundum powder and kaolin moistened with a 5–7% technical lignosulfonate solution with a density of 1050 kg·m−3, a briquette was formed at a specific pressing pressure of 15–20 MPa. The briquette was fired at a temperature of 1700°C. The fired briquette had a strength of 164 to 193 MPa. The water absorption of briquettes was 11–12%. The phase composition of the briquette is represented mainly by corundum and mullite. The enriched kaolin did not show sintering effect on fine corundum.