Possible reagents to use are Collector-SIBX, Activator if needed- Lead Nitrate, Frother-MIBC.

Options-possibly float Sb and treat tails of float in a CIL circuit to get the gold.

Your problem:

Treatment of 525# particles with 3ppm au, 1.8% sb.

Answer:

•Size of particle:

525# is too fine to float. Surface charge, Vander valve equation, plays a major role in flotation.

Many times it was difficult to do. Have you tried micro bubble flotation? If not we can test it and give results at free of cost, with microscopic tests.

•Magnet separation at 20000 gauss:

if Au, Sb are found feebly magnetic, then we can try HGMS.

•Differential flocculation:

we may try this to depress either gangue or valuables to separate them and settle particles to get clean separation.

Gravity separation:

It is ruled out, at such fine size of 525#.

• Hydrocyclone:

Yes we can try pencilcyclones.

•Last option:

Leaching of gold, Sb, to be tried R&D. We call heap leaching. Or pressure leaching if found economical.

•You need to spell out associated waste minerals to suggest new technologies.

I worked in antimony/gold deposit and flotation plant. In tailings/flotation slimes we had 0.18 gpt of antimony and 0.35 gpt of gold. In some cases we got 3.5 gpt off gold (heavy fraction from manual panning. Tailing outflow was 200mesh (11%); 170mesh (22%); 120mesh (49%); 60mesh (18%)

of course we were doing tests to recover some gold - both from the mine tailings and from the foundry processing - tailings were not effective, but Sb-foundry cumulated gold in clinker (even 30 gpt/ppm).

Sb content 1.8% in tailings is content of regular Sb-deposit - if this Sb-content is sending into tailings, it is "untypical". If you have those Sb-problems, forget gold content (3 ppm) at fraction 550 mesh (25 microns).You have great problem with setting of you flotation/processing plant.

I did more tests of flotation; the granulometry of the first test was 65% passing mesh 200.

Now I’m doing with granulometry 77% passing mesh 200 and the recovery increase 10% so I have 70% recovery of gold, the recovery of Sb is still low 33%.

Remember this material is old flotation's tail of stibnite with gold values.

This material is old flotation tail of Stibine with gold values (maybe the head's flotation in plant was 8% Sb or more). We want to gold recovery by flotation (now we have a recovery 70% of gold) then maybe roasting tests to finally cyanidation and recovery gold.

Your flotation tests (70% gold recovery vs. 33% antimony recovery) are compatible with my deposit - it was no problem to produce quality mono mineral Sb-concentrate (52-53%), but gold was extra, because older mineralization stage was pyrite-arsenopyrite one with gold and younger mineralization stage was almost mono-mineral stibnite one. Flotation process successfully separatedboth. Roasting pyrite-arsenopyrite is forbidden because of ecology.

You may have some liberation, surface contamination or grinding problems. It also may be impossible to separate/upgrade them by flotation as is. To make sure you address the right issue and set a realistic recovery target it is the best to look at the matter of the tails and do mineralogical study: liberation analysis and gold/Sb deportment. It will save you a lot of blindly done test work and open your eyes on methods to handle the tailings/ore.

You have 1.8% and Sb 3g/t Au, get the liberation issue sorted. For this to work you will need effective gravity unit if some of the gold is gravity recoverable gold. Looking at the Sb & Au recovery of 30% and 60% respectively I think you need to get detailed mineralogical information because with sulphides present on your leach feed you will recover far less than 60% unless this material does not contains sulphides but rather oxide. There are three main antimony minerals which is gudmundite, berthierite and stibnite the latter being common. All these minerals are sulphides. How was the float test work conducted? If you have the first two in higher fraction your ore then this explains roughly your 30% recovery.

As I suspect you have oxidized Sb minerals and SbOx on the Au surface that prevent them floating. Measures can be taken accordingly.

You could send me your samples to study to prove whether it is liberation/overgrinding or the surface issue and give more info on your flow sheet.

Flotation results seem to be good from old tailing pond. In general the surface properties alter due to weathering and become difficult in selectivity.

Today many have tried heap leaching of tailing and were successful. After flotation, tailing you may try for extraction of pyrite using low pH pulp and try. Though this may be poor in quality but it contains recoverable gold interlocked.

Have you done any diagnostic leach work to verify alkalinity controls and where the gold reports? With so much Sb and other heavy elements, a blind mineralogical study might be difficult to interpret (low statistics), but diagnostic leach will provide far more insight and lead to a focussed mineralogical solution.