Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

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Gold leaching procedure (1 reply and 2 comments)

M
martie
7 years ago
martie 7 years ago

Hi there

I need help with a laboratory procedure for gold leaching with cyanide please

J
Jorge
7 years ago
Jorge 7 years ago
Like
2 likes by Mikhail and David

The Cyanidation testwork can comprise three tests to evaluate different levels of sodium cyanide (e.g. 0.5, 1.0 and 2.0 g/L). If you have not performed any cyanidation test in the past, you need an experienced person in the lab with you. The main steps of the cyanidation tests are listed below,

  • Each ore sample should be weighed and crushed to minus 10 mm
  • By riffling can be obtained ten 300-gram portions. These portions were used for head analysis, pulverizing and cyanidation tests
  • In order to determine the time required to obtain a specific particle size (e.g. 80% minus 200 mesh) it is necessary to grind several 300-grams portions at different times. Then, the time can be extrapolated to grind 300-grams portions to perform the Cyanidation test. In some labs, it is common to pulverize the sample
  • A 300-gram portion of pulverized ore is placed into a 1.0 liter beaker and the material is slurried with 750 mLs of distilled water. Also, it is possible to use a bottle instead of a beaker
  • The slurry is under agitation thoroughly using a mechanical device and the slurry pH is checked. The pH of the slurry is adjusted, as required, to between 10.5 and 11.0 with lime
  • Sodium cyanide is added according to the test (0.5, 1.0, 2.0 g/L), then the slurry is mixed throughout the duration of the test
  • The slurry can be checked at 1, 2, 4, 8, 24 and 48 hours for pH, free NaCN and Au
  • After completion of the leach period (48 hours), the slurry was filtered, washed and the final tailings are dried. The dry tailings are pulverized and submitted for gold assays.
M
martie
7 years ago

Thank you

J
Joeram
6 years ago

Jorge, Hi I am new to all this. I have tried smelts and acids. i have assay's. Ok I read this above. I have arsenic and sulfides with micro. If I add to much cyanide then more zinc is needed to precip. and could foul solution. How do i prevent this? and how to de-aerate solution? I was told grind pulp fine, mix in lime to raise ph to 10, add 3-5% cyanide, by weight or volume? Forced air and agitate for 48 hours, decant liquid add zinc, filter dry torch. Thats what i was told. But sine i have arsenic and sulfides, how much extra cyanide? Then I was told by another guy, after decant lower ph to 5 and use SMB. What is correct? I would appreciate any and all guidance. Thanks


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