Intensification of Basic Processes in Separation of Difficult Diamond-Bearing Raw Materials

The article describes the theoretical and experimental research data on possibility to improve the quality of the end concentrates of float-and-sink, X-ray luminescent, adhesive and froth separation. The method of nitride hardening is proposed for ferrosilicium grain surface with the hardened layer depth in the range of 30–60 nm for reducing ferrosilicium corrosion rate by 2.7 times at the preserved process properties. The necessity of adding the primary float-and-sink flotation circuit with two-stage magnetic separation to decrease the yield of rough concentrates and to improve their quality owing to removal of 29–95% of siderite. The optimized composition of luminophore-bearing modifying agent ensures complete recovery of earlier unrecoverable diamonds in concentrate at the maximum kimberlite yield of 2.5%. The workbench test processing of difficult diamond-bearing raw materials proves the possibility of incremental diamond concentration in adhesive and froth separation (by 14.0% and 12.7%, respectively), and in the cycle of finishing operations in X-ray luminescent separation (by 25.3%) owing to modification of surface properties of diamond crystals using physicochemical methods and energy deposition.