A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluor...A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluoric acid can quickly dissociate berylum ore powder directly at low or room temperature with more than 99%dissociation rate.The solubility of AlF_(3),FeF_(3) CrF_(3) and MgF_(2),is low.Coupled with common ion effect,99.9%-purity beryllium products can be prepared without chemical purification.For high-purity beryllium products of grade 4N or higher,they can be prepared through the superior property that the pH intervals of iron,chromium,and other hydroxide precipitates are distinctly different from those corresponding to Be(OH)_(2),precipitates.This new method can be used to prepare most of the beryllium products that are prepared by modern beryllium metallurgy.展开更多
The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization mo...The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization model of spinel was established to calculate the effects of basicity(the mass ratio of CaO to SiO_(2))and P_(2)O_(5) on crystal growth rates and precipitation patterns.Based on the crystal size distribution(CSD)theory,the size distribution and growth mechanisms of spinel crystals in alkaline vanadium slag at different temperatures were investigated.The results revealed that,at a cooling rate of 5 K/min,the mean grain size of spinel increased from 12.77 to 21.52μm as the temperature decreased from 1748 to 1598 K,with spinel growth being controlled by the interface.At 1548 K,the spinel particle size reached 31.04μm,indicating a supply-controlled growth mechanism as the temperature decreased from 1598 to 1548 K.Increased P_(2)O_(5) content hindered the crystal growth,while an increase in basicity promoted nucleation and growth.Furthermore,MnCr_(2)O_(4) preferentially crystallized and grew in alkaline vanadium slag.展开更多
The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the p...The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the production practice of steel-belt furnaces.Furthermore,the kinetics of oxidative volatilization was elucidated using differential thermal gravimetric analyses and non-isothermal analysis methods.The results indicated that the oxygen concentration and the temperature were pivotal variables in the oxidative volatilization process.Notably,the volatilization efficiency of antimony was 97.25%under optimal conditions.Moreover,the kinetic control stages were divided into chemical reaction control(440-490°C),internal diffusion control(500-550°C),and chemical reaction control(560-580°C).These stages corresponded to activation energies of 16.40-18.79,120.86-195.96,and 24.00-28.31 kJ/mol,respectively.展开更多
Potassium hydroxide(KOH)was introduced into the molybdenite roasting process to convert molybdenum(Mo)and sulfur(S)into water-soluble potassium molybdate(K_(2)MoO_(4))and potassium sulfate(K_(2)SO_(4)).Roasting with a...Potassium hydroxide(KOH)was introduced into the molybdenite roasting process to convert molybdenum(Mo)and sulfur(S)into water-soluble potassium molybdate(K_(2)MoO_(4))and potassium sulfate(K_(2)SO_(4)).Roasting with a 1.8-fold excess of KOH at 400℃ for 3 h enabled the leaching of over 99%of Mo from the molybdenum calcine using water.A precipitation method involving potassium–magnesium(K-Mg)salts was proposed for impurity removal.Under the conditions of pH 11,30℃,excess coefficient of 1.7 for Mg salts,and a duration of 1 h,98.37%of phosphorus(P)was removed from the K_(2)MoO_(4) solution.With post-purification,over 99%of Mo crystallized upon adjustment of pH to 1.Subsequently,S and K were recovered as K_(2)SO_(4) fertilizer from the crystalline mother liquor.An environmentally sustainable approach was proposed to conduct molybdenite production and ensure the efficient recovery of both Mo and S.展开更多
基金National Key Research and Development Program of China(2021YFC2902301,2021YFC2902302)。
文摘A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluoric acid can quickly dissociate berylum ore powder directly at low or room temperature with more than 99%dissociation rate.The solubility of AlF_(3),FeF_(3) CrF_(3) and MgF_(2),is low.Coupled with common ion effect,99.9%-purity beryllium products can be prepared without chemical purification.For high-purity beryllium products of grade 4N or higher,they can be prepared through the superior property that the pH intervals of iron,chromium,and other hydroxide precipitates are distinctly different from those corresponding to Be(OH)_(2),precipitates.This new method can be used to prepare most of the beryllium products that are prepared by modern beryllium metallurgy.
基金supported by the National Natural Science Foundation of China(No.51974047)the Natural Science Foundation of Chongqing,China(No.cstc2022ycjh-bgzxm0003)the Large Instrument Foundation of Chongqing University,China(No.202303150239)。
文摘The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization model of spinel was established to calculate the effects of basicity(the mass ratio of CaO to SiO_(2))and P_(2)O_(5) on crystal growth rates and precipitation patterns.Based on the crystal size distribution(CSD)theory,the size distribution and growth mechanisms of spinel crystals in alkaline vanadium slag at different temperatures were investigated.The results revealed that,at a cooling rate of 5 K/min,the mean grain size of spinel increased from 12.77 to 21.52μm as the temperature decreased from 1748 to 1598 K,with spinel growth being controlled by the interface.At 1548 K,the spinel particle size reached 31.04μm,indicating a supply-controlled growth mechanism as the temperature decreased from 1598 to 1548 K.Increased P_(2)O_(5) content hindered the crystal growth,while an increase in basicity promoted nucleation and growth.Furthermore,MnCr_(2)O_(4) preferentially crystallized and grew in alkaline vanadium slag.
基金supported financially by the National Natural Science Foundation of China(No.52074362)。
文摘The substitution of traditional blast furnaces with steel-belt furnaces for antimony smelting was proposed.The influence of various parameters on the oxidative volatilization of stibnite was studied according to the production practice of steel-belt furnaces.Furthermore,the kinetics of oxidative volatilization was elucidated using differential thermal gravimetric analyses and non-isothermal analysis methods.The results indicated that the oxygen concentration and the temperature were pivotal variables in the oxidative volatilization process.Notably,the volatilization efficiency of antimony was 97.25%under optimal conditions.Moreover,the kinetic control stages were divided into chemical reaction control(440-490°C),internal diffusion control(500-550°C),and chemical reaction control(560-580°C).These stages corresponded to activation energies of 16.40-18.79,120.86-195.96,and 24.00-28.31 kJ/mol,respectively.
基金financially supported by the National Natural Science Foundation of China(No.52174340)the National Key Research and Development Project of China(No.2022YFC2904505)the Hunan FURONG Scholars Project and the Basic Science Centre of the National Natural Science Foundation of China(No.72088101)。
文摘Potassium hydroxide(KOH)was introduced into the molybdenite roasting process to convert molybdenum(Mo)and sulfur(S)into water-soluble potassium molybdate(K_(2)MoO_(4))and potassium sulfate(K_(2)SO_(4)).Roasting with a 1.8-fold excess of KOH at 400℃ for 3 h enabled the leaching of over 99%of Mo from the molybdenum calcine using water.A precipitation method involving potassium–magnesium(K-Mg)salts was proposed for impurity removal.Under the conditions of pH 11,30℃,excess coefficient of 1.7 for Mg salts,and a duration of 1 h,98.37%of phosphorus(P)was removed from the K_(2)MoO_(4) solution.With post-purification,over 99%of Mo crystallized upon adjustment of pH to 1.Subsequently,S and K were recovered as K_(2)SO_(4) fertilizer from the crystalline mother liquor.An environmentally sustainable approach was proposed to conduct molybdenite production and ensure the efficient recovery of both Mo and S.
