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.