Brazil and Colombia have large reserves of coal. Those reserves in Brazil are located predominantly in the south and the main reserves in Colombia are located in the north. Despite the relative ease of exploitation, t...Brazil and Colombia have large reserves of coal. Those reserves in Brazil are located predominantly in the south and the main reserves in Colombia are located in the north. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, these countries are developing projects and partnerships aiming to qualify this mineral resource, adding quality to the final product of the processing plants. In this scenario, the processing of Brazilian and Colombian coal in flotation columns appears as a promising alternative, having been successful in mineral systems containing fine particles. The paper aims to study the overall process of column flotation for a specific Brazilian coal and a specific Colombian coal. The material used in this study consists of fine coal from Brazil （Copelmi） and Colombia （Cerrejon）. The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The two coals were floated using a negative bias in a 5 cm diameter conventional flotation column of 5 m high. Flotation parameter investigated included air velocity in the range 0.6 to 1.5 cm/s. For all runs, a constant negative bias of-0.25 cm/s and a pulp concentration of 8% w/w were used. For Cerrej6n coal, 300 g/ton of frother and 907 g/ton of collector was used, whereas for Copelmi coal, 600 g/ton of frother and 1,815 g/ton of collector was employed. The frother was a commercial Aerofroth 65 （AF65）, whereas the collector was Kerosene. For the Colombian coal, in general, yield, organic recovery, ash recovery and water recovery decreased with the increasing air rate. However, for Brazilian coal the air rate had no significant effect. For Colombian coal, the highest yield （60% w/w） and organic recovery （69% w/w） were obtained at the lowest air rate （0.6 cm/s）.展开更多
Greece, in relation to many other countries of similar size, is very advantageous for the mineral wealth it possesses. Great variety, mostly industrial and metallic minerals, and energy mineral raw materials such as l...Greece, in relation to many other countries of similar size, is very advantageous for the mineral wealth it possesses. Great variety, mostly industrial and metallic minerals, and energy mineral raw materials such as lignite, are in its subsoil. The probable and proven reserves of most of the mineral resources of Greece are unknown, as detailed investigations （e.g., drillings, measurements, analyses, etc.） are lacking. In our assessment the total value of the reserves is about ε1.5 trillion and is four times its total debt （ε360 billion）. The total value of the indicated reserves of the Industrial Minerals ＆ Rocks is ε60 billion. The total value of the indicated reserves of the Metallic Minerals is ε72 billion. The total value of the indicated reserves of the Energy Mineral Raw Materials is ε1,362 billion, of which ε268 billion belong to the lignites which are exploited for decades to produce only electricity. The indicated oil reserves are 10 billion barrels with current value of E685 billion and the corresponding of natural gas 3.5 trillion m3 with current value of ε409 billion.展开更多
文摘Brazil and Colombia have large reserves of coal. Those reserves in Brazil are located predominantly in the south and the main reserves in Colombia are located in the north. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, these countries are developing projects and partnerships aiming to qualify this mineral resource, adding quality to the final product of the processing plants. In this scenario, the processing of Brazilian and Colombian coal in flotation columns appears as a promising alternative, having been successful in mineral systems containing fine particles. The paper aims to study the overall process of column flotation for a specific Brazilian coal and a specific Colombian coal. The material used in this study consists of fine coal from Brazil （Copelmi） and Colombia （Cerrejon）. The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The two coals were floated using a negative bias in a 5 cm diameter conventional flotation column of 5 m high. Flotation parameter investigated included air velocity in the range 0.6 to 1.5 cm/s. For all runs, a constant negative bias of-0.25 cm/s and a pulp concentration of 8% w/w were used. For Cerrej6n coal, 300 g/ton of frother and 907 g/ton of collector was used, whereas for Copelmi coal, 600 g/ton of frother and 1,815 g/ton of collector was employed. The frother was a commercial Aerofroth 65 （AF65）, whereas the collector was Kerosene. For the Colombian coal, in general, yield, organic recovery, ash recovery and water recovery decreased with the increasing air rate. However, for Brazilian coal the air rate had no significant effect. For Colombian coal, the highest yield （60% w/w） and organic recovery （69% w/w） were obtained at the lowest air rate （0.6 cm/s）.
文摘Greece, in relation to many other countries of similar size, is very advantageous for the mineral wealth it possesses. Great variety, mostly industrial and metallic minerals, and energy mineral raw materials such as lignite, are in its subsoil. The probable and proven reserves of most of the mineral resources of Greece are unknown, as detailed investigations （e.g., drillings, measurements, analyses, etc.） are lacking. In our assessment the total value of the reserves is about ε1.5 trillion and is four times its total debt （ε360 billion）. The total value of the indicated reserves of the Industrial Minerals ＆ Rocks is ε60 billion. The total value of the indicated reserves of the Metallic Minerals is ε72 billion. The total value of the indicated reserves of the Energy Mineral Raw Materials is ε1,362 billion, of which ε268 billion belong to the lignites which are exploited for decades to produce only electricity. The indicated oil reserves are 10 billion barrels with current value of E685 billion and the corresponding of natural gas 3.5 trillion m3 with current value of ε409 billion.
