Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency ...Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency of processing is caused by gold ore characterization and evaluation of gold ore preparation process is not implemented. In this study, the conditions of gold ore deposits have a thin thickness （vein）. These gold ore deposits have an economic value if they are developed by traditional gold mining. The objective of the research is to identify and characterize gold ore as well as to analyze the optimum condition to obtain the perfect gold mineral liberation degree. Research methods include characterization of gold ore geology, sampling for test preparation using rod mill （amalgamation）, gold mineral liberation using time variables and number of rods. After the grinding process, grain size analysis is performed with various mesh sizes, and the analysis of each fraction uses a polarization microscope. The results show that gold ore minerals are associated with pyrite, chalcopyrite, galena and gangue minerals. Gold minerals are fully liberated at a certain size. The results of this research are very useful for the gold ore grinding process to obtain an efficient gold processing.展开更多
Rare earth elements （REEs） that are key to new technologies and green innovations are critical to life in modern societies. China continues to dominate the global REEs market despite several international trade disp...Rare earth elements （REEs） that are key to new technologies and green innovations are critical to life in modern societies. China continues to dominate the global REEs market despite several international trade disputes and market fluctuations. Pressured by an increasingly difficult situation, the Chinese government has been carrying out industry restructuring and has introduced regulatory reforms in recent years to promote the healthy develop- ment of the rare earth industry. This paper reviews the literature on the development of the rare earth industry and analyzes the reform policies, combining this with an analysis of relevant macroeconomic data. It discusses the current status of China＇s rare earth industry, the progress of industrial restructuring and the main problems the rare earth industry faces. The paper discusses the evolution of rare earth policies from that of ＂open production and open supply＂ to that of ＂limiting low quality development but encouraging export of high quality rare earths＂ and then to ＂integrating rare earth resources trade＂. Six key policies, including those for export quotas, export duties, environmental laws, resource utilization technology, industry consolidation and stockpiling, are discussed in detail. Policy suggestions based on this discussion are put forward concerning the treatment of small rare earth mines in China： firstly, robust efforts to prevent illegal mining must always be maintained; secondly, it is certain that the formation of large-scale conglomerates should be accelerated in the near future; thirdly, the management of key sections should be reinforced; fourthly, support for technological innovation and the development of the applications industry should continue; fifthly, specific rare earths laws and regulations should be greatly improved. The paper also puts forward some suggestions on revisions to improve mineral resources law： firstly, China must increase the market access threshold and suppress low-end excess production capacity; secondly, the new environmental protection verification must be developed for all rare earth enterprises; thirdly, minimum required indicators for the development and utilization of rare earths resources must be implemented in China. These recommendations can serve as a reference for efforts to promote the sustainable development of China＇s rare earth industry.展开更多
文摘Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency of processing is caused by gold ore characterization and evaluation of gold ore preparation process is not implemented. In this study, the conditions of gold ore deposits have a thin thickness （vein）. These gold ore deposits have an economic value if they are developed by traditional gold mining. The objective of the research is to identify and characterize gold ore as well as to analyze the optimum condition to obtain the perfect gold mineral liberation degree. Research methods include characterization of gold ore geology, sampling for test preparation using rod mill （amalgamation）, gold mineral liberation using time variables and number of rods. After the grinding process, grain size analysis is performed with various mesh sizes, and the analysis of each fraction uses a polarization microscope. The results show that gold ore minerals are associated with pyrite, chalcopyrite, galena and gangue minerals. Gold minerals are fully liberated at a certain size. The results of this research are very useful for the gold ore grinding process to obtain an efficient gold processing.
基金National Key Research and Development Program of China(2016YFA0602802)National Natural Sciences Foundation of China(71633006)Project granted from National Geological Library of China(cg12016067A1)
文摘Rare earth elements （REEs） that are key to new technologies and green innovations are critical to life in modern societies. China continues to dominate the global REEs market despite several international trade disputes and market fluctuations. Pressured by an increasingly difficult situation, the Chinese government has been carrying out industry restructuring and has introduced regulatory reforms in recent years to promote the healthy develop- ment of the rare earth industry. This paper reviews the literature on the development of the rare earth industry and analyzes the reform policies, combining this with an analysis of relevant macroeconomic data. It discusses the current status of China＇s rare earth industry, the progress of industrial restructuring and the main problems the rare earth industry faces. The paper discusses the evolution of rare earth policies from that of ＂open production and open supply＂ to that of ＂limiting low quality development but encouraging export of high quality rare earths＂ and then to ＂integrating rare earth resources trade＂. Six key policies, including those for export quotas, export duties, environmental laws, resource utilization technology, industry consolidation and stockpiling, are discussed in detail. Policy suggestions based on this discussion are put forward concerning the treatment of small rare earth mines in China： firstly, robust efforts to prevent illegal mining must always be maintained; secondly, it is certain that the formation of large-scale conglomerates should be accelerated in the near future; thirdly, the management of key sections should be reinforced; fourthly, support for technological innovation and the development of the applications industry should continue; fifthly, specific rare earths laws and regulations should be greatly improved. The paper also puts forward some suggestions on revisions to improve mineral resources law： firstly, China must increase the market access threshold and suppress low-end excess production capacity; secondly, the new environmental protection verification must be developed for all rare earth enterprises; thirdly, minimum required indicators for the development and utilization of rare earths resources must be implemented in China. These recommendations can serve as a reference for efforts to promote the sustainable development of China＇s rare earth industry.
