Economic potential of glauconitic rocks in Bakchar deposit (S-E Western Siberia) for alternate potash fertilizer

Abstract This paper explores suitability of glauconitic rocks in the Upper Cretaceous Bakchar deposit in Western Siberia as alternate potash fertilizer. The K 2 O content of these glauconitic rocks varies from 2.5 to 4.1 wt.%, indicating their good potential as K-fertilizer for agronomic uses. According to the different compositional and textural characteristics, glauconitic rocks can be divided into three types, i.e., glauconitolite, glauconitic sandstone and glauconite-chamosite ooidal ironstone, with glauconite concentrations 58.5 wt.%, 25.7 wt.% and 24.6 wt.%, respectively. The intermediate size fraction of glauconitolite concentrates up to 90.4 wt.% of glauconite grains by using wet sieving. Magnetic separation further increases the concentration of glauconite grains for each type of rock samples, especially of glauconitic sandstone. Mixing of glauconitic products with soil increases the germination rate of oat seeds by up to 5.2%, the seedling height records an increase from 0.8% to 18.8%. Both untreated glauconitolite and its granulometric fraction result same rate of growth of oat seedlings. The results of this study suggest that the Bakchar glauconitic deposit can be used as a substitute potash fertilizer, with or without sieving and magnetic separation.