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ArticleName Recycling of Angren coal mining tailings to obtain humic acids and bacterial-humic fertilizers
DOI 10.17580/or.2022.05.07
ArticleAuthor Isokov M. U., Alimov R. S., Almatov I. M., Soatov S. A.

University of Geological Sciences (Tashkent, Uzbekistan):

Isokov M. U., Vice-Rector, Doctor of Geological and Mineralogical Sciences


Institute of Mineral Resources UGN (Tashkent, Uzbekistan):
Alimov R. S., Head of Laboratory, PhD in Technical Sciences,
Almatov I. M., Senior Researcher, PhD in Technical Sciences,
Soatov S. A., Junior Researcher


Coal processing at the Angren deposit in Uzbekistan has led to accumulation of a huge amount of coal tailings, for which an effective and economically viable recycling technology is required. For this purpose, a waste-free technology has been developed, which includes two-stage tailings processing. At the first stage, the tailings are treated with NaOH or KOH hydroxide at the rate of 5–8 g/100 g with the solid/liquid ratio of 1 : 5 for 30 minutes at 80 °C. The humic acid extracts are then filtered, the suspension is adjusted to pH 6.5–7, and dehydration to 50 % moisture is performed to obtain a humate paste. At the second stage, the growth medium is first prepared. First-stage cake is then inoculated with a solution containing an overgrown bacterial medium at a solid/liquid weight ratio of 1 : 3, with the total organic matter present in the form of rice screenings. The resulting mix is placed in waterproof tanks with a layer of up to 2 m and kept for 7–9 days, with six treatments a day. With the mass fraction of bound humic acids (HA) in the residual cake of 13.77 %, bacterial treatment with nine days of cultivation in the active phase results in 11.98 % of free HA passing into the liberated form (available to plants).

keywords Сoal mining waste, hydraulic dump, zero waste technology, humic preparations, bacterial-humic fertilizers, cake, bacterial medium

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