Using the right amount of reagents such as collector is critical in flotation. This not only helps recover the most of the value minerals but also improves concentrate grade and potentially reduce cost.
The first reaction to poor flotation is often to increase collector but that may further destroy the flotation performance.
Generally, the following rules apply:
Target a particle size that sufficiently liberates the valuable minerals.
Finer particles sizes require more collector due to the increased particles' surface area.
Coarser particles require less collector.
The collector dosage for the same ore and same P80 increases with higher feed grade.
Too high collector addition rate (over dosage) will lead to poor selectivity as other sulphide gangue minerals such as pyrite will also float.
Unexpectedly low recovery/concentrate grade can be due to low collector.
Insufficient concentration of dissolved oxygen hinders the xanthate collector adsorbtion.
If the concentrate grade increases with time before dropping down, the pulp doesn't have enough dissolved oxygen.
Too high concentration of dissolved oxygen may partially oxisise the valuable sulphide minerals and lower their flotatability.
Most importantly, assess the collector addition points and distribute the total dosage where necessary.
The guidelines for copper and nickel sulphides below are based on available online data and technical papers.
These are guidelines only and will need confirmation and optimisation since every ore is different with various ground particles size and surface chemistry.
Simply select the sulphide nickel or sulphide copper minerals, deposit type and head grade to see the results.
