An anionic-cationic flotation of two Egyptian feldspar samples, representing Road Ashaab locality of the Eastern Desert of Egypt, was investigated on both laboratory and pilot plant scales. The pegmatites belong to th...An anionic-cationic flotation of two Egyptian feldspar samples, representing Road Ashaab locality of the Eastern Desert of Egypt, was investigated on both laboratory and pilot plant scales. The pegmatites belong to the alkali feldspar granite type, mostly microcline and orthoclase, KAL Si3O8 coarse grained rocks. Quartz, as the main gangue mineral, occurs in two forms as either free grains or as veins intercalating the feldspar crystals or, sometimes, intermingled with them. Iron, on the other hand, is found in three different forms as free magnetite embedded in the feldspar crystals, as microcrystalline crystals, or as magnetite filling cracks in the feldspar. Dissolution of magnetite to hematite is, sometimes, observed. Grinding of the feldspar samples to less than 0.25 mm followed by desliming was optimized in the laboratory, using a ball mill in closed circuit with the screen. Anionic flotation of the iron oxide impurity from the -0.25 + 0.03 mm ground product was successfully conducted using locally produced dodecyl benzene sulphonic acid—rice bran oil/kerosene promoter at pH 3. Cationic flotation of feldspar from this product was then carried out employing a locally produced quaternary ammonium salt in presence of HF acid, as a silica depressant and a feldspar activator at pH 3. Feldspar final concentrates assaying 80.8% - 89.5% feldspar mineral, 0.119% - 0.127% Fe2O3 and 16.84% - 18.65% Al2O3, were obtained at the optimum operating conditions that satisfy the requirements of the ceramic industry. Continuous 200 kg/h pilot plant runs were conducted using the appropriate equipment, based upon the laboratory findings to produce feldspar concentrates assaying 16.38% - 18.13% Al2O3, and 0.13% - 0.15% Fe2O3. Materials’ metallurgical balance and complete chemical analyses were shown.展开更多
<sup>29</sup>Si, <sup>27</sup>Al MAS NMR and IR spectra of monophase K-feldspars （sanidine, orthoclase and micro-cline） and Na-feldspars （monalbite, anorthoclase and low albite） in differen...<sup>29</sup>Si, <sup>27</sup>Al MAS NMR and IR spectra of monophase K-feldspars （sanidine, orthoclase and micro-cline） and Na-feldspars （monalbite, anorthoclase and low albite） in different structural states have been studied. The NMR and IR spectra of K-feldspars and Na-feldspars vary regularly along with their degrees of Si/Al ordering evolution. Si in orthoclase occupies T2m, T2o and T1m, and the high-temperature Na-feldspar （monalbite and anorthoclase） coincides in 29Si, 27Al NMR and IR spectra. Moreover, all the high-temperature Na-feldspars and sanidine have the same 27Al NMR and IR spectra.展开更多
文摘An anionic-cationic flotation of two Egyptian feldspar samples, representing Road Ashaab locality of the Eastern Desert of Egypt, was investigated on both laboratory and pilot plant scales. The pegmatites belong to the alkali feldspar granite type, mostly microcline and orthoclase, KAL Si3O8 coarse grained rocks. Quartz, as the main gangue mineral, occurs in two forms as either free grains or as veins intercalating the feldspar crystals or, sometimes, intermingled with them. Iron, on the other hand, is found in three different forms as free magnetite embedded in the feldspar crystals, as microcrystalline crystals, or as magnetite filling cracks in the feldspar. Dissolution of magnetite to hematite is, sometimes, observed. Grinding of the feldspar samples to less than 0.25 mm followed by desliming was optimized in the laboratory, using a ball mill in closed circuit with the screen. Anionic flotation of the iron oxide impurity from the -0.25 + 0.03 mm ground product was successfully conducted using locally produced dodecyl benzene sulphonic acid—rice bran oil/kerosene promoter at pH 3. Cationic flotation of feldspar from this product was then carried out employing a locally produced quaternary ammonium salt in presence of HF acid, as a silica depressant and a feldspar activator at pH 3. Feldspar final concentrates assaying 80.8% - 89.5% feldspar mineral, 0.119% - 0.127% Fe2O3 and 16.84% - 18.65% Al2O3, were obtained at the optimum operating conditions that satisfy the requirements of the ceramic industry. Continuous 200 kg/h pilot plant runs were conducted using the appropriate equipment, based upon the laboratory findings to produce feldspar concentrates assaying 16.38% - 18.13% Al2O3, and 0.13% - 0.15% Fe2O3. Materials’ metallurgical balance and complete chemical analyses were shown.
基金Project supported by the Foundation of Magnetic Resonance and Atom and Molecular Physics,Wuhan Institute of Phyiscs,Chinese Academy of Sciences
文摘<sup>29</sup>Si, <sup>27</sup>Al MAS NMR and IR spectra of monophase K-feldspars （sanidine, orthoclase and micro-cline） and Na-feldspars （monalbite, anorthoclase and low albite） in different structural states have been studied. The NMR and IR spectra of K-feldspars and Na-feldspars vary regularly along with their degrees of Si/Al ordering evolution. Si in orthoclase occupies T2m, T2o and T1m, and the high-temperature Na-feldspar （monalbite and anorthoclase） coincides in 29Si, 27Al NMR and IR spectra. Moreover, all the high-temperature Na-feldspars and sanidine have the same 27Al NMR and IR spectra.
