The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as th...The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as the collector has been investigated. The results show that the selectivity of these collectors for these three calcareous minerals falls in the order： DDDAC 〉 DDBAC 〉 DTAC. A significantly different flotation response of scheelite compared to the other two calcareous minerals was observed over the pH range from 7 to 8 for DDDAC as the collector. A concentrate containing 41.40% W03 could be produced from a feed mixture containing 23.22% WO3 at the DDDAC concentration of 4.0× 10^-4 mol/L. The WO3 recovery was 92.92% under these conditions. The results of zeta potential measurements suggest that electrostatic interactions are the main forces between DDDAC and the minerals. When the concentration of DDDAC is from 2× 10^-4 to 4×10-3 mol/L large differences in adsorption density, and adsorption kinetics, of DDDAC onto scheelite, calcite, and fluorite provide desirable conditions for achieving high selectivity.展开更多
Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation m...Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation mechanism of the fine cassiterite was investigated by adsorbance determination,electrophoretic mobility measurements and Fourier transform infra-red(FT-IR) spectrum checking.Results of the flotation experiments show that with SHA as a collector,the collecting performance is remarkably impacted by the pulp pH value as the floatability of cassiterite varies sharply when the pH changes,and flotation with SHA gives distinct maximum at about pH 6.5.Additionally,the floatability of cassiterite is determined by using SHA and TBP as collectors.The range of pulp pH for good floatability is broadened in the presence of TBP as auxiliary collector,and the utilization of TBP improves the recovery of cassiterite modestly.Moreover,the optimum pH value for cassiterite flotation is associated with adsorbance.The results of FT-IR spectrum and the electrophoretic mobility measurements indicate that the adsorption interaction between the collectors and the cassiterite is dominantly a kind of chemical bonding in the form of one or two cycle chelate rings due to the coordination of carbonyl group,hydroxamate and P=O group to the metal tin atoms,where the oxygen atoms contained in carbonyl group,hydroxamate and P=O group of the polar groups have the stereo conditions to form five-membered rings.In addition,the adsorption interactions of SHA and TBP on the surfaces of cassiterite are also dominated by means of hydrogen bonds.展开更多
美国收藏家查尔斯·兰·佛里尔(Charles Lang Freer,1856-1919)生活的晚年,购置了一批中国古代玉器,这批玉器绝大部分得自上海和纽约的商人之手,其中一部分据说出土于浙江省。1923年,佛里尔艺术藏品对外展出以后,这批具有特征...美国收藏家查尔斯·兰·佛里尔(Charles Lang Freer,1856-1919)生活的晚年,购置了一批中国古代玉器,这批玉器绝大部分得自上海和纽约的商人之手,其中一部分据说出土于浙江省。1923年,佛里尔艺术藏品对外展出以后,这批具有特征的玉器引起了人们的注意。展开更多
PT．Paradigma Putra Sejahtera（简称PT．PPS）成立于2001年，业务以打捞沉船为主。公司创始人Adi Agung Tirtamarta先生和Priyo Saryanto Brodjonegoro先生。Adi Agung Tirtamarta先生是一位艺术品收藏家（古陶瓷、古画和古代家具），...PT．Paradigma Putra Sejahtera（简称PT．PPS）成立于2001年，业务以打捞沉船为主。公司创始人Adi Agung Tirtamarta先生和Priyo Saryanto Brodjonegoro先生。Adi Agung Tirtamarta先生是一位艺术品收藏家（古陶瓷、古画和古代家具），Priyo S Brodjonegoro先生也是一位艺术品收藏家（古代家具和爪哇刀-波型刀）。展开更多
基金supported by the State Key Program of National Natural Science Foundation of China (No. 50834006)
文摘The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as the collector has been investigated. The results show that the selectivity of these collectors for these three calcareous minerals falls in the order： DDDAC 〉 DDBAC 〉 DTAC. A significantly different flotation response of scheelite compared to the other two calcareous minerals was observed over the pH range from 7 to 8 for DDDAC as the collector. A concentrate containing 41.40% W03 could be produced from a feed mixture containing 23.22% WO3 at the DDDAC concentration of 4.0× 10^-4 mol/L. The WO3 recovery was 92.92% under these conditions. The results of zeta potential measurements suggest that electrostatic interactions are the main forces between DDDAC and the minerals. When the concentration of DDDAC is from 2× 10^-4 to 4×10-3 mol/L large differences in adsorption density, and adsorption kinetics, of DDDAC onto scheelite, calcite, and fluorite provide desirable conditions for achieving high selectivity.
基金Project(50774094) supported by the National Natural Science Foundation of ChinaProject(2010CB630905) supported by the National Basic Research Program of China
文摘Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation mechanism of the fine cassiterite was investigated by adsorbance determination,electrophoretic mobility measurements and Fourier transform infra-red(FT-IR) spectrum checking.Results of the flotation experiments show that with SHA as a collector,the collecting performance is remarkably impacted by the pulp pH value as the floatability of cassiterite varies sharply when the pH changes,and flotation with SHA gives distinct maximum at about pH 6.5.Additionally,the floatability of cassiterite is determined by using SHA and TBP as collectors.The range of pulp pH for good floatability is broadened in the presence of TBP as auxiliary collector,and the utilization of TBP improves the recovery of cassiterite modestly.Moreover,the optimum pH value for cassiterite flotation is associated with adsorbance.The results of FT-IR spectrum and the electrophoretic mobility measurements indicate that the adsorption interaction between the collectors and the cassiterite is dominantly a kind of chemical bonding in the form of one or two cycle chelate rings due to the coordination of carbonyl group,hydroxamate and P=O group to the metal tin atoms,where the oxygen atoms contained in carbonyl group,hydroxamate and P=O group of the polar groups have the stereo conditions to form five-membered rings.In addition,the adsorption interactions of SHA and TBP on the surfaces of cassiterite are also dominated by means of hydrogen bonds.
文摘PT．Paradigma Putra Sejahtera（简称PT．PPS）成立于2001年，业务以打捞沉船为主。公司创始人Adi Agung Tirtamarta先生和Priyo Saryanto Brodjonegoro先生。Adi Agung Tirtamarta先生是一位艺术品收藏家（古陶瓷、古画和古代家具），Priyo S Brodjonegoro先生也是一位艺术品收藏家（古代家具和爪哇刀-波型刀）。
