Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished acco...Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished according to their telations to the bedding:one is distributed along the bedding and the.other cuts across the bedding.Sn and sulfide orebodies associated with K-feldspare are mostly characterized by laminated ore structure. Microscopic examinations of K-feldspar-bearing rocks,in conjunction with X-ray diffraction,chemical composiion and cathodoluminescence data for K-feldspars,as well as their telations to mineralization,the authors consider that the K-feldspare are of authigenic origin,subordinate to the epigenetic stage of diagenesis,They resulted from the reaction of mixed,deep-seated,circulating underground hot waters rich in K,Al and Si with argillaceous carbonates during the Indo nesian orogenic movement.It is suggested more attention should be paid to the effect of authigenic K-feldspars on Sn mineralization.In the meantime the event related to circulating underground hot waters should also be taken into account so as to provide new clues to blind ore prospecting.展开更多
The suitability of Oreke dolomite in Kwara State, Nigeria as a raw material for the manufacturing of refractories was investigated. The Oreke dolomite samples were mingled with feldspar, clay, and quartz to form a ble...The suitability of Oreke dolomite in Kwara State, Nigeria as a raw material for the manufacturing of refractories was investigated. The Oreke dolomite samples were mingled with feldspar, clay, and quartz to form a blend. The fifteen (15) Blend samples were moulded and analyzed for their chemical, physical and mechanical properties. The characterization was carried out in accordance with American Society of Testing and Material (ASTM). The blend samples were tested for various refractory properties such as bulk density, porosity, cold crushing strength, linear shrinkage, refractoriness and others like water absorption and compressive strength. The chemical composition of the Blend was determined, using X-Ray Fluorescence Spectrometer and the result shows that Silica is 60%, Alumina is 11.5%, Iron Oxide is 0.48%, Calcium Oxide is 10%, Magnesium is 6.4%, Alkali is 10.4%, and Loss of Ignition of the sample is 15.28%. The addition of 10%-12% quart contents with dolomite of 20%-25% contents complements the percentage of silica in the blend thereby improving the properties of the blend. The strength characterization shows that the Compressive Strength (mean value) of the blend samples is 5.65 N/m2 with respect firing temperature. The strength classification varies between medium to high and was found to satisfy the allowable standard values for the production of refractory wares.展开更多
文摘Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished according to their telations to the bedding:one is distributed along the bedding and the.other cuts across the bedding.Sn and sulfide orebodies associated with K-feldspare are mostly characterized by laminated ore structure. Microscopic examinations of K-feldspar-bearing rocks,in conjunction with X-ray diffraction,chemical composiion and cathodoluminescence data for K-feldspars,as well as their telations to mineralization,the authors consider that the K-feldspare are of authigenic origin,subordinate to the epigenetic stage of diagenesis,They resulted from the reaction of mixed,deep-seated,circulating underground hot waters rich in K,Al and Si with argillaceous carbonates during the Indo nesian orogenic movement.It is suggested more attention should be paid to the effect of authigenic K-feldspars on Sn mineralization.In the meantime the event related to circulating underground hot waters should also be taken into account so as to provide new clues to blind ore prospecting.
文摘The suitability of Oreke dolomite in Kwara State, Nigeria as a raw material for the manufacturing of refractories was investigated. The Oreke dolomite samples were mingled with feldspar, clay, and quartz to form a blend. The fifteen (15) Blend samples were moulded and analyzed for their chemical, physical and mechanical properties. The characterization was carried out in accordance with American Society of Testing and Material (ASTM). The blend samples were tested for various refractory properties such as bulk density, porosity, cold crushing strength, linear shrinkage, refractoriness and others like water absorption and compressive strength. The chemical composition of the Blend was determined, using X-Ray Fluorescence Spectrometer and the result shows that Silica is 60%, Alumina is 11.5%, Iron Oxide is 0.48%, Calcium Oxide is 10%, Magnesium is 6.4%, Alkali is 10.4%, and Loss of Ignition of the sample is 15.28%. The addition of 10%-12% quart contents with dolomite of 20%-25% contents complements the percentage of silica in the blend thereby improving the properties of the blend. The strength characterization shows that the Compressive Strength (mean value) of the blend samples is 5.65 N/m2 with respect firing temperature. The strength classification varies between medium to high and was found to satisfy the allowable standard values for the production of refractory wares.
