Froth flotation of scheelite has regained new focus since the 2010s and research regarding floatability and reagents has made great progress over the years. The main objective was and remains the selective flotation o...Froth flotation of scheelite has regained new focus since the 2010s and research regarding floatability and reagents has made great progress over the years. The main objective was and remains the selective flotation of scheelite from other calcium-bearing minerals, in particular calcite, fluorite and apatite. Due to similar properties, most attempts have limited success or only specific application(linked to a type of ore or a location). This article aims at reviewing all general physical-chemical information on froth flotation of scheelite, including electrokinetic properties, influence of p H and already existing reagents as well as ones still under examination. It appears that chelating or mixed collectors and modified versions of sodium silicate and quebracho hold great promise for scheelite flotation, while the use of said depressants and/or promoters seems inevitable.展开更多
Two Tahiti lime （Citrus latifolia Tan.） experiments were carried out to evaluate the performance of eight standard rootstocks on two different soil locations at Tecoman Colima, Mexico. Rootstocks were selected by th...Two Tahiti lime （Citrus latifolia Tan.） experiments were carried out to evaluate the performance of eight standard rootstocks on two different soil locations at Tecoman Colima, Mexico. Rootstocks were selected by their tolerance to Citrus tristeza virus （CTV） and acceptable adaptation to semi-add hot tropics environment. The first trial was planted in ＂Cerrito de Aguilar＂ （CA） location which had sandy-loam soil with a fluctuant water table at 100 cm depth. The second experiment was planted in ＂Crucero Tecoman＂ （CT） on a sandy deep soil with no water table restriction. At CT location the best Tahiti lime growth, yield and fruit quality were observed on Alemow rootstock. The same combination at CA showed a poor performance and was affected by diseases due to high moisture conditions by the superficial water table. Taiwanica, Swingle citrumelo and Rangpur lime rootstocks were less productive than Alemow, but showed a good adaptation and acceptable yield on both soil conditions. Among them, Swingle citrumelo was a promising rootstock because it showed standard tree growth, good yield and excellent fruit quality. Swingle citrumelo also showed an acceptable performance on soil with high presence ofPhytophthora sp. and moderate levels of calcium carbonate （near to 3,500 ppm）. Taiwanica and Rangpur lime performed well during the six years of the experiment, but trees began to be affected by root diseases. Better performance of most Tahiti lime/rootstocks were found on sandy depth soil than on superficial wet soils.展开更多
A premium composite grey element model is established and used for objective evaluation of fabric hand. Fabric hand is regarded as a grey system and the model is composed of fabric mechanical properties, which are pri...A premium composite grey element model is established and used for objective evaluation of fabric hand. Fabric hand is regarded as a grey system and the model is composed of fabric mechanical properties, which are primary hand attributes. Based on comparison with a standard model, fabric hand can be objectively evaluated.展开更多
基金the financial support of the Optim Ore projectthe European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642201
文摘Froth flotation of scheelite has regained new focus since the 2010s and research regarding floatability and reagents has made great progress over the years. The main objective was and remains the selective flotation of scheelite from other calcium-bearing minerals, in particular calcite, fluorite and apatite. Due to similar properties, most attempts have limited success or only specific application(linked to a type of ore or a location). This article aims at reviewing all general physical-chemical information on froth flotation of scheelite, including electrokinetic properties, influence of p H and already existing reagents as well as ones still under examination. It appears that chelating or mixed collectors and modified versions of sodium silicate and quebracho hold great promise for scheelite flotation, while the use of said depressants and/or promoters seems inevitable.
文摘Two Tahiti lime （Citrus latifolia Tan.） experiments were carried out to evaluate the performance of eight standard rootstocks on two different soil locations at Tecoman Colima, Mexico. Rootstocks were selected by their tolerance to Citrus tristeza virus （CTV） and acceptable adaptation to semi-add hot tropics environment. The first trial was planted in ＂Cerrito de Aguilar＂ （CA） location which had sandy-loam soil with a fluctuant water table at 100 cm depth. The second experiment was planted in ＂Crucero Tecoman＂ （CT） on a sandy deep soil with no water table restriction. At CT location the best Tahiti lime growth, yield and fruit quality were observed on Alemow rootstock. The same combination at CA showed a poor performance and was affected by diseases due to high moisture conditions by the superficial water table. Taiwanica, Swingle citrumelo and Rangpur lime rootstocks were less productive than Alemow, but showed a good adaptation and acceptable yield on both soil conditions. Among them, Swingle citrumelo was a promising rootstock because it showed standard tree growth, good yield and excellent fruit quality. Swingle citrumelo also showed an acceptable performance on soil with high presence ofPhytophthora sp. and moderate levels of calcium carbonate （near to 3,500 ppm）. Taiwanica and Rangpur lime performed well during the six years of the experiment, but trees began to be affected by root diseases. Better performance of most Tahiti lime/rootstocks were found on sandy depth soil than on superficial wet soils.
文摘A premium composite grey element model is established and used for objective evaluation of fabric hand. Fabric hand is regarded as a grey system and the model is composed of fabric mechanical properties, which are primary hand attributes. Based on comparison with a standard model, fabric hand can be objectively evaluated.
