Limestones have been one of the major economic sources in state’s economy and becoming more and more important in recent years. They are mainly exploited for crushed stone, dimension stone and micronized calcite prod...Limestones have been one of the major economic sources in state’s economy and becoming more and more important in recent years. They are mainly exploited for crushed stone, dimension stone and micronized calcite production including lab-grade CaO with high purity. Although some of the applications require fairly simple value-adding processes such as crushing and/or sizing, some may require rather complicated processes such as calcination and coating.展开更多
Optical cathodoluminescence microscopy (CLM) can provide very useful information both on mineral zoning formed during crystal growth and on variations in chemical composition of sphalerites which is reflected by their...Optical cathodoluminescence microscopy (CLM) can provide very useful information both on mineral zoning formed during crystal growth and on variations in chemical composition of sphalerites which is reflected by their visible colors. Gem quality sphalerite crystals associated with dolomite, calcite and fluorite having 3 different visible colors - green, honey and brown - were studied to compare their mineral chemistry and CL characteristics. Electron microprobe analyses indicated essentially no significant differences in terms of major components. Although the common CL-quencher ferrous iron contents of all three were lower than 0.25 wt %, none of the sphalerites cathodoluminescenced: two (brown and honey) were non-CL, the green sphalerite showed very week CL in faint brown color. Other trace elements that were analyzed include Fe, Cd, Mn, Ag, Hg, In, Bi, Cu, Ge, and Ga. Fe, Cd, Ga and Cu were relatively higher than the others. Most significant differences with respect to the common trace elements include honey colored sphalerites are essentially Fe- and Cd-poor but rich in Ga, green sphalerites are Fe- and Cd- rich but poor in all the others, and brown sphalerites are rich in Cd. No conclusive relation between non-CL behavior of all three sphalerites and their trace element chemistry was established, however; low quantities of common CL activators in sphalerite crystal structures such as Mn, Cu, and In were the main cause of the non-CL behavior.展开更多
文摘Limestones have been one of the major economic sources in state’s economy and becoming more and more important in recent years. They are mainly exploited for crushed stone, dimension stone and micronized calcite production including lab-grade CaO with high purity. Although some of the applications require fairly simple value-adding processes such as crushing and/or sizing, some may require rather complicated processes such as calcination and coating.
文摘Optical cathodoluminescence microscopy (CLM) can provide very useful information both on mineral zoning formed during crystal growth and on variations in chemical composition of sphalerites which is reflected by their visible colors. Gem quality sphalerite crystals associated with dolomite, calcite and fluorite having 3 different visible colors - green, honey and brown - were studied to compare their mineral chemistry and CL characteristics. Electron microprobe analyses indicated essentially no significant differences in terms of major components. Although the common CL-quencher ferrous iron contents of all three were lower than 0.25 wt %, none of the sphalerites cathodoluminescenced: two (brown and honey) were non-CL, the green sphalerite showed very week CL in faint brown color. Other trace elements that were analyzed include Fe, Cd, Mn, Ag, Hg, In, Bi, Cu, Ge, and Ga. Fe, Cd, Ga and Cu were relatively higher than the others. Most significant differences with respect to the common trace elements include honey colored sphalerites are essentially Fe- and Cd-poor but rich in Ga, green sphalerites are Fe- and Cd- rich but poor in all the others, and brown sphalerites are rich in Cd. No conclusive relation between non-CL behavior of all three sphalerites and their trace element chemistry was established, however; low quantities of common CL activators in sphalerite crystal structures such as Mn, Cu, and In were the main cause of the non-CL behavior.
