Abstract:

In order to promote the recycling of low grade gold resources，many conditional experiments about ore leaching，mudding degree，concentration of NaCN，sprinkling，obsorbency，permeability and  origin caustic con-sumption are carried out to study the cyanide leaching character and affecting factors，on the basis of research on chemical composition and ore character of low grade oxided gold ore.The results show that low grade gold ore in Tongguan area is a transitional type between primary ore and half oxidized ore which is of low oxidization level；it is a kind of ore which is hard to leach with undeveloped fracture and tight rock structure，and the natural gold is composed mainly of medium and coarse grain；it is also a kind of leachable ore with low level of harmful elements the leaching rate of which is 95.2% in a leachability test.The rate of 27 days leaching of -8 mm ore obtained from the conditional and composite column leaching experiments is 66%，which shows that the ore is leachable，and the leaching production technique conditions are 5 000 tons ore per heap，-8 mm fraction，3 m heap height，NaCN concentration is 0.03% to 0.06%，pH value is 10 to 12，the volume of sprinkling is 20～50 L/（m2·h） and the time of sprinkling is 30 days.The results of experiment show that the recycle rate of this kind of ore is low，benefit can be achieved only if it can be recycled as waste ore when bonanza is mined.Because this kind of low grade ore is pretty leachable，and the oxidation degree is low，the best way is all-slime cyanidation.

Key words: gold, cyaniding, leaching process scheme, experimental investigation