Arsenopyrite is an FeAsS iron-arsenic sulfide. It can be closely associated with gold in some deposits, but the presence of arsenopyrite alone does not prove that an ore contains economically recoverable gold.
- Formula / structure
- FeAsS
- Ore role
- Important sulfide in some Au and polymetallic ores
- Preparation focus
- Identify and liberate the arsenic-bearing phase
What is Arsenopyrite and how does it occur in ore?
Arsenopyrite can occur with pyrite and other metallic sulfides. Ore texture and the actual host of gold are more important to flowsheet selection than visual identification of arsenopyrite alone.
How can arsenopyrite differ from pyrite in processing?
Both minerals may enter sulfide circuits, but arsenopyrite carries arsenic and may therefore need separate tracking for concentrate quality, environmental management and downstream metallurgy. Whether selective rejection is required depends on the processing objectives and concentrate-quality requirements.
Which behaviour matters during ore preparation?
Grinding should be sufficient to release arsenopyrite from quartz, pyrite or valuable phases. If gold occurs as very fine inclusions within arsenopyrite, the limit of mechanical liberation has to be established experimentally.
Arsenic-bearing dust and residues require separate health and environmental management. Chemical oxidation or leaching, where used downstream, is distinct from the mechanical preparation discussed here.
Which inputs should be verified?
- Arsenopyrite-to-pyrite ratio
- Mineralogical location of gold
- Arsenic distribution
- Liberation size
- Arsenic targets in concentrate and tailings
