PSI - Issue 13

Igor Bunin et al. / Procedia Structural Integrity 13 (2018) 1971–1976 Author name / Structural Integrity Procedia 00 (2018) 000–000

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3.3. Effect of HPEMP on electrical properties minerals The electrokinetic potential of fluorite (8.8 mV, reference sample) shifted to the region of negative values upon electropulse treatment of the minerals, due to modifications in the charge state (recharge) of the mineral particle surfaces: −6.1 mV (  treat t 10 s), and −16.5 mV ( ~ treat t 100 s). Calcite and scheelite were characterized by an increase in the absolute ζ -potential of the investigated samples in the region of negative values. Changes in the ζ -potential for calcite were −6.2 mV (reference sample), −19.5 mV (  treat t 10 s). For scheelite, they were −20.6 mV (reference sample) and −25.4 – −26.8 mV ( ~ treat t 30–100 s). The HPEMP effect on the electrostatic potential ( V ) of the mineral surfaces of thin sections (KPFM) generally corresponded to the pattern of changes in the ζ -potential of mineral particles: a reduction in the electrostatic potential of scheelite and fluorite surfaces and the shift of scheelite V to the region of negative values. For example, changes in the electrostatic potential ( V ) for fluorite were 9.8 V (reference sample), and 0.5 V (  treat t 50 s). Variations in mineral flotation activity were estimated from the variations in the contact angle of wetting (Ө°) of the thin section surfaces (using the example of calcite, one of the minerals that complicate obtaining marketable scheelite concentrates from enriched ores) and on the output (extraction) of mineral particles into the flotation foam product. Short-term (  treat t 10 s) electropulse treatment of calcite resulted in higher hydrophobicity of the mineral surfaces (an increase in the contact angle of wetting, from 79° to 84°). Increasing the dose of electromagnetic radiation (  treat t 30–150 s) resulted in a steady decline of Ө°, from 79–80° to 73°. 4. Conclusion The experimental results proved applicability of the pulsed energy effect to stimulate softening of rock-forming minerals of diamond-bearing kimberlites and to preserve the wholeness of diamond crystals in ore-grinding circuits due to reduced time of kimberlite rock processing in autogenous mills. We established an efficient mode of electromagnetic pulse processing (  treat t 30–50 s) for the flotation of Ca-bearing minerals, and conditions of reagent flotation optimized for the extraction of scheelite that ensure an 8% increase calcite, a 6% increase in the extraction of fluorite, and a 10–12% increase in the extraction of scheelite. Our results testify to the great potential of using pulsed energy effects to improve the efficiency of the flotation enrichment of Ca-bearing minerals. Acknowledgements This work was supported by the RF President’s grant for the state support of leading scientific schools of the Russian Federation, Academician V.A. Chanturiya’s School NSh-7608.2016.5. References Aditya, S., Tapas, K., Samir, K., Arun, K., 2017. Pre-Treatment of Rocks Prior to Comminution – A Critical Review of Present Practices. International Journal of Mining Science and Technology 27 (2), 339–348. Bunin, I., Ryazantseva, M., Samusev, A., Khabarova, I., 2017. Composite Physicochemical and Energy Action on Geomaterials and Aqueous Slurries: Theory and Practice. Gornyi Zhurnal (Mining Journal) 11, 77–83. Chanturiya, V., Bunin, I., Lunin, V., Gulyaev, Yu., Bunina, N., Vdovin, V., Voronov, P., Korzhenevskii, A., Cherepenin, V., 2001. Use of High Power Electromagnetic Pulses in Process of Disintegration and Opening of Rebellious Gold-Containing Raw Materials. Journal of Mining Science 37 (4), 427–437. Chanturiya, V., Bunin, I., Ryazantseva, M., Filippov, L., 2011. Theory and Application of High-Power Nanosecond Pulses to Processing of Mineral Complexes. Mineral Processing and Extractive Metallurgy Review 32 (2), 105–136. Parker, T., Shi, F., Evans, C., Powell, M., 2015. The Effects of Electrical Comminution on the Mineral Liberation and Surface Chemistry of a Porphyry Copper Ore. Mineral Engineering 82 (10), 101–106.