Stibnite
Bulk flotation followed by sequential flotation of gold-bearing sulfides, and depression of stibnite. This method was practised at the Bradly concentrator (USA) and consisted of the following steps: first, bulk flotation of stibnite and gold bearing sulfides at pH 6.5 using lead nitrate (Sb activator) and xanthate; second, the bulk concentrate is reground in the …