The specific objectives were to (i) obtain arsenopyrite particles of the size fraction 150-250 μm by removing fines adhering to the surface, and (ii) clean the surface of crushed particles to remove oxide species of Fe, As and S, without altering the stoichiometry of the mineral.
It was found that some fine crystals adhered with each other during spraying by electrostatic and van der Waals forces, and the particle size became larger.
Surface cleaning of arsenopyrite consisted of two steps: 1. Removal of fine particles adhered to the surface: particles significantly smaller than the sieved range can be electrostatically bound to the surface of larger particles.
Sieved samples are then cleaned in various ways to remove fine particles adhering to the mineral surface and oxidation products prior to use.
Ground pyrite exhibits a wide range of sizes from very fine particles adhering to the surfaces of larger individual grains, to small particles scattered among the larger grains.
It is found that: the errors associated with large time-step integration do not cause statistically significant errors to the bulk behavior; rolling resistance is a necessary model component; and the outlet flow from the drum is sensitive to fine material adhering to the outlet creating a thick coating that narrows the outlet gaps.
In a previous work [21], PANI/graphite nanosheet composites were synthesized, and fine polyaniline particles adhered on the surfaces of graphite nanosheets.
Preexisting S0 impurities as unaccounted reaction products are a source of experimental uncertainty, as are adhered fine grains of pyrite and its oxidation products.
Additionally, the new procedure was more efficient at removal of fine particles of adhered pyrite and its oxidation products and did not appear to affect the particle size distribution, the specific surface area, or the properties of grain surfaces.
The main objective of pyrite pretreatment procedures is the removal of preexisting impurities (e.g., oxidation products, adhered fine particles), which may bias experimental results or otherwise affect reaction rates.
