DETERMINATION OF THE COMPONENT COMPOSITION OF A SERIES OF CALCIUM-CONTAINING DEPOSITS AND TECHNOLOGICAL RECOMMENDATIONS FOR THEIR UTILIZATION

Abstract

Abstract. A comprehensive analysis of samples of calcium-containing mineral raw materials from deposits in Russia (Bryansk), Kazakhstan (Beineu, Shetpe, Zhanakorgan), and Uzbekistan (Fergana) was carried out to assess their suitability as precursors of calcium oxide used in technologies for the remediation of oil-contaminated soils. The study employed methods of X-ray phase analysis (XRD), elemental analysis, and infrared spectroscopy (FTIR). By the XRD method, the phase composition of the samples was established and their semi-quantitative evaluation was performed. Based on the obtained data, the samples were classified into three groups: 1) calcium oxide–hydroxide (Bryansk, Beineu, Fergana), characterized by a high content of CaO (76.1-92.5%) and Ca(OH)₂ (7.5–19.0%); 2) calcium hydroxide (Zhanakorgan), representing almost pure Ca(OH)₂ (99.6%); 3) carbonate (Shetpe), consisting of calcite CaCO₃ (>98%). FTIR results confirmed the presence of the identified phases. Elemental analysis showed high purity of most samples in terms of calcium (>52% CaO in normalized form). The sample from Bryansk contains an increased amount of silica (SiO₂ ≈ 4%). Technological recommendations for the use of the raw materials are proposed. The Beineu-1 and Beineu-2 samples, containing 92.5% and 81.0% CaO, respectively, were identified as the most promising raw materials for the energy-efficient production of active CaO.