introduction : Phosphate rocks are vital non-renewable resources and are essential components in agricultural fertilizers and phosphorous-based chemicals [1-4]. About 95% of the phosphate produced around the world is consumed in fertilizer industry [5, 6]. Phosphate deposits can be divided into three groups (і) sea sediments, (іі) igneous and (ііі) biogenetic deposits [7]. The distribution of phosphate resources in the world is approximated as follows: 75% from sedimentary marine deposits, 15-20% from igneous, metamorphic and weathered deposits, and 2-3% from biogenic sources [5-8]. A large proportion of the world's phosphate reserves are sedimentary deposits containing a considerable amount of carbonate minerals.
In terms of quality and P2O5 grade, phosphate can be divided into three groups: low - grade ores (12-16% P2O5, intermediate-grade ores (17-25% P2O5) and high-grade ores (26-35% P2O5). Deposits containing of 28-38% P2O5 are considered commercial grade deposits and have high economic value to mine and process [9]. .