1、英文文献翻译原稿：New Chloride Leaching Process for Gold Extraction from Refractory OresAbstract：The extraction process of gold and silver from the gold clay ore containing arsenic and manganese was investigatedWith the conventional techniquethe leaching rates of gold and silver are 7823 and 4902，respectivel
2、yTo eliminate the negative efects of arsenic and manganese on cyanidation and increase the gold and silver leaching rates，a novel catalyst was addedThe content of the catalyst used in the process was 8 gper 500 g org sample，the sample size was 60 prn andthe pH value was kept between l0 and 11Leachin
3、g with the catalyst for 3-5 h under certain conditions，the gold leaching rate increased to over 90 and the silver leaching rate increased to 80一90Th e catalyst can efectively liberate gold and silver from the enclosure of arsemc and manganese and the industrial experiment has great significance to t
4、he development and utilization ofthe gold clay ore containing arsenic and manganese.0.IntroductionFrom certain gold ores, known as refractory gold ores, the gold cannot be fully recovered by direct cyanide leaching. A major cause of this is the occurrence of much of the gold in such ores in highly d
5、isseminated form in sulfide, arsenide and sometimes antimonide minerals. Three methods have been developed for treatment of such refractory ores, each of which involves breaking down the sulfide and arsenide minerals by oxidation before cyanide extraction.In one method, the sulfide and related miner
6、als containing the gold are recovered by flotation, and roasted. The residues (S- and As-free) are then leached with cyanide. In a second, recently developed process, the flotation concentrates are aerated in slurry form in a medium containing Sand As-oxidizing microorganisms before being leached wi
7、th cyanide. In the third method, breakdown of the S- and As-minerals is achieved by oxidative treatment of the concentrate in an au toclave, followed by cyanide leaching.Method 1 is gradually being abandoned because of environmental pollution problems, and new plants in the USA, South Africa, Austra
8、lia and elsewhere tend to employ Method 2 or Method 3, which produce less severe problems of this type.There are two factors affecting the extraction rate: one is the elements existing in the gold ore, and the other is the method used in the extraction process. Much research has been devoted to conv
9、entional gold ores , while few works has been published on gold ores containing manganese and arsenic. The cyanidation process has been the most important process in the extraction of gold and silver for the past 100 years and the methods used to enhance the extraction rates in the cyanidation proce
10、ss have drawn much attention in recent years. Several researchers have studied the additive to enhance the leaching rates .Over the past 10 years, however, there have been a number of publications which indicate that the direct oxidative chloride leaching of gold from refractory gold ores may prove
11、to be an improvement on the methods now in use. These new developments were reviewed by F K Lerowski of the University of Witwatersrand in Johannesburg, at the International Conference on the Science and Technology of Gold at Hanau in Germany in June 1996 (1). They include:1 The use ofless volatile
12、chloride ion carriersIn the past, HCl has been used as the main chloride ion carrier in leaching solutions and HN03 (or C12) as the oxidant. This has limited leaching temperatures because high partial pressures of HCl lead to loss of Cl from the leaching solution. Partial substitution of HCI by AlCI
13、3 or ZnCl2 has been found to decrease dramatically these partial pressures of HCl, apparently as a result of the formation of AI and Zn chlorocomplexes. This has made the attainment of higher leaching temperatures and higher efficiencies possible. Decomposition of the refractory sulfides and arsenid
14、es occurs in the chloride leach solutions and their gold content made susceptible to cyanide leaching.The objective of this study was to analyze the interference characteristics of manganese and arsenic in the cyanidation process. The effect of a catalyst that could significantly enhance the leachin
15、g rate was also discussed and illustrated through experiments.2 The regeneration, in process, of nitric acid used as oxidantIn the chloride leaching reaction, the nitric acid is reduced to NO, the conversion of which back to HN03 is costly by conventional methods. A leaching in froth (LlF) process h
16、as been devised, however, which has been successfully applied on a laboratory scale for mineral graphite purification (2), zinc concentrate processing (3) and more recently for gold extraction from refractory gold ores.In this process, oxygen and oxides of nitrogen are the flotation carriers and a chloride solution containing HN03 is the reactive medium in which the hydrophobic particles of the ore are suspended. In operation, the outer walls of the
