Danzhang Liu,Xiaoqing Weng,Yanfeng Jin,Richard M. Kasomo,Shunfu Ao,Hongqiang Li
Feldspar is a typical sesquioxide which is associated with phosphate ore. It can greatly prevent the formation of calcium sulfate crystals during the wet process of phosphoric acid production, resulting in the loss of P 2 O 5 , and therefore lowering the phosphoric acid recovery. To achieve the selective separation of feldspar from phosphate ore, we first tried using a new Gemini quaternary ammonium salt as the collector in conjunction with a reverse flotation approach. The flotation tests of single minerals and artificially mixed minerals were employed to investigate the collecting ability and selectivity of the collector, the adsorption mechanism was also evaluated by means of zeta potential measurements and molecular dynamic calculations. The flotation results demonstrate that the collector showed a strong harvesting effect and selectivity on feldspar rather than fluorapatite . When the Gemini concentration was set at 7.5 × 10 −6 mol/L, the P 2 O 5 grade could reach 31.69% with a corresponding recovery of 77.57%, indicating that Gemini collector could suitably be used as a potential chemical to achieve the effective removal of feldspar from phosphate ore. The results obtained from zeta potential measurements and molecular dynamics simulations indicate that the adsorption of Gemini collector on feldspar was more pronounced compared to that on fluorapatite surface and the interaction between Gemini and both minerals was mainly ascribed to electrostatic interaction . This work aims to provide a reference for using Gemini as collector combined with reverse flotation approach to achieve the effective removal of sesquioxide from phosphate ore and further enhance the quality of phosphate fertilizers .
White phosphorus (P 4 ) is an essential raw material for the production of phosphorus chemicals. The conventional carbothermal reduction process used to extract P 4 from phosphate rock is known as energy intensive and environmentally polluting, posing obstacles to meeting the urgent global demands for clean production and carbon neutrality . Moreover, the low product purity restricts its application in high-value industries. This paper presents an original approach that is both simple and coke-free for extracting high-purity P 4 . The method involves electrolyzing dissolved phosphate rock in molten CaCl 2 at a mild temperature. We undertake an in-depth investigation into the dissolution behavior of phosphate rock in molten CaCl 2 and the electrolysis behavior of the melt. The experiments demonstrate the rapid dissolution of phosphate in the rock when exposed to molten CaCl 2 , reaching saturation within a short time (e.g., within 10 min at 850 °C). The dissolution of phosphate shows a preference over silicates present in the phosphate rock. The electrochemical reduction of PO 4 3− in molten CaCl 2 is electrochemically reversible, as observed at potential scan rates not exceeding 0.20 V s −1 . The obtained P 4 product through electrolysis is of higher purity compared to the industrial-grade commercial product produced via carbothermal reduction. The implementation of pre-electrolysis can further improve the purity of the product and the current efficiency of the electrolysis process. The theoretical electricity and carbon consumption in the electrolysis method are estimated to be 9.12 kWh and 0.53 kg, respectively, for every 1 kg of P 4 produced. These values are lower than the conventional carbothermal reduction process. This cutting-edge electrolysis method represents a paradigm shift towards a more sustainable development of the phosphorus chemical industry, thereby showcasing its potential for revolutionizing the field.
This study investigates the role of Na 2 SO 4 as an inorganic regulator in enhancing the flotation separation efficiency of apatite from dolomite by mitigating the adverse effects of interfering ions. Micro-flotation tests revealed that adding 3 × 10 −4 mol/L Na 2 SO 4 significantly increased the recovery of dolomite from 77.52 % to 91.26 %, while reducing the recovery of apatite by 16.31 %. The MgO content in the mixed concentrate rose from 9.69 % to 15.05 %, with its removal rate increasing from 54.76 % to 82.53 %. Importantly, the loss rate of apatite in the mixed concentrate was reduced by 33.37 %. Characterization techniques and solution properties analysis elucidated the mechanism: Na 2 SO 4 prevents the formation of precipitates between interfering ions and sodium oleate (NaOL), reducing NaOL adsorption on apatite surfaces while enhancing and evenly distributing NaOL adsorption on dolomite surfaces. molecular dynamics simulations further showed that Ca 2+ and Mg 2+ promote NaOL agglomeration, whereas Na 2 SO 4 disperses NaOL uniformly in solution. This study provides an innovative for enhancing the anti-interference ion ability of flotation reagents.
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