Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigate...Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction（XRD）, scanning electron microscopic（SEM） analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^（-1） sulfuric acid, 0.5 g·g^（-1） ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.展开更多
China produces much tungsten metal every year. The tungsten deposits in China usually are low-grade and have complex mineralogy composition as well as many associated valuable elements. The associated elements include...China produces much tungsten metal every year. The tungsten deposits in China usually are low-grade and have complex mineralogy composition as well as many associated valuable elements. The associated elements include Sn, Mo, Bi, Cu, Pb, Zn, Sb, Be, Co, Au, Ag, Nb, Ta, Re, Sc, REE, Li, As, S, P and the nonmetallic minerals such as quartz, fluorite, feldspar, etc. Therefore, only the tungsten ore dressing is done in accordance with the ore properties based on the detailed and full process mineralogy study can the valuable elements be reasonably and fully recovered and the maximization of resource utilization as well as environment-friendly is achieved eventually. This paper summarizes the status quo of process mineralogy of tungsten and its associated elements in China, focuses on the process mineralogy studies on major tungsten ore types including tungsten-molybdenum associated ore, tungsten-tin polymetallic ore and tungsten-copper polymetallic ore, suggests the future process mineralogy research on tungsten and its associated elements.展开更多
The dual geochemical character of paragenesis and fractionation between gold, arsenic and antimony in micro-disseminated gold deposits in southwestern Guizhou is discussed in terms of spatial distribution of independe...The dual geochemical character of paragenesis and fractionation between gold, arsenic and antimony in micro-disseminated gold deposits in southwestern Guizhou is discussed in terms of spatial distribution of independent deposits, lateral and vertical enrichment, mineralization stage and factor and correlation analyses. Thermodynamic calculations of solubility and speciation of gold and antimony minerals indicate that gold is transported in hydrothermal solution as Au(HS) 2and antimony is mainly as Sb(OH)30 although HSb2S4 may be of increasing importance in acidenvironment at low temperatures during the late stage of mineralization. Changes in physico-chemical conditions hold the key to the association and fractionation between gold and antimony. Gold and antimony response differently to physicochemical variations because they are distinct from each other in soluble speciation and mineral solubility, leading to precipitation at different times and localities during hydrothermal evolution.展开更多
Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group invers...Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group inverses of the block matrices（ABCD）over a ring with unity 1 under the following conditions respectively： （i） B = C, D = 0,B#and（BπA0#both exist; （ii） B is invertible and m = n;（iii）A#and （D - CA#B）# both exist, C = CAA#, where A and D are m × m and n × n matrices, respectively.展开更多
基金Funded by the National Natural Science Fundation of China(51274158)the National Twelfth Five-Year Plan for Scientific and Technological Support(2013BAE04B03)the Scientific and Technological Support Project of Hubei Province(2015BCA251)
文摘Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction（XRD）, scanning electron microscopic（SEM） analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^（-1） sulfuric acid, 0.5 g·g^（-1） ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.
文摘China produces much tungsten metal every year. The tungsten deposits in China usually are low-grade and have complex mineralogy composition as well as many associated valuable elements. The associated elements include Sn, Mo, Bi, Cu, Pb, Zn, Sb, Be, Co, Au, Ag, Nb, Ta, Re, Sc, REE, Li, As, S, P and the nonmetallic minerals such as quartz, fluorite, feldspar, etc. Therefore, only the tungsten ore dressing is done in accordance with the ore properties based on the detailed and full process mineralogy study can the valuable elements be reasonably and fully recovered and the maximization of resource utilization as well as environment-friendly is achieved eventually. This paper summarizes the status quo of process mineralogy of tungsten and its associated elements in China, focuses on the process mineralogy studies on major tungsten ore types including tungsten-molybdenum associated ore, tungsten-tin polymetallic ore and tungsten-copper polymetallic ore, suggests the future process mineralogy research on tungsten and its associated elements.
文摘The dual geochemical character of paragenesis and fractionation between gold, arsenic and antimony in micro-disseminated gold deposits in southwestern Guizhou is discussed in terms of spatial distribution of independent deposits, lateral and vertical enrichment, mineralization stage and factor and correlation analyses. Thermodynamic calculations of solubility and speciation of gold and antimony minerals indicate that gold is transported in hydrothermal solution as Au(HS) 2and antimony is mainly as Sb(OH)30 although HSb2S4 may be of increasing importance in acidenvironment at low temperatures during the late stage of mineralization. Changes in physico-chemical conditions hold the key to the association and fractionation between gold and antimony. Gold and antimony response differently to physicochemical variations because they are distinct from each other in soluble speciation and mineral solubility, leading to precipitation at different times and localities during hydrothermal evolution.
基金Acknowledgements The authors were grateful to the referees for their constructive comments and suggestions. This work was supported by the National Natural Science Foundation of China （Grant No. 11371109） and the Education Department of Heilongjiang Province of China （No. 12541605）.
文摘Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group inverses of the block matrices（ABCD）over a ring with unity 1 under the following conditions respectively： （i） B = C, D = 0,B#and（BπA0#both exist; （ii） B is invertible and m = n;（iii）A#and （D - CA#B）# both exist, C = CAA#, where A and D are m × m and n × n matrices, respectively.
