Multi‐stage wide‐angle hydrocyclone circuits for removing fine, high density particles from a low density soil matrix

Abstract

Simulations were performed for various hydrocyclone staging arrangements using experimental results from single‐stage wide‐angle hydrocyclone separations when processing fine (‐150 μm) particles in a 25 mm diameter hydrocyclone. Mixtures of fine quartz and magnetite or ferrosilicon of similar size ranges were used to represent low density (e.g., soil) and high density (e.g., heavy metal contaminant) particles, respectively. The staging arrangements included re‐treating the overflow and/or underflow streams in both once‐through and recirculating circuits. The results indicated that heavy metal recoveries greater than 95% with soil rejections over 90% could be obtained for the ferrosilicon/quartz system using a three‐stage circuit. Lower metal recoveries were obtained when processing the lower density magnetite.

Key words:

• Soil washing
• water‐only cyclone
• autogenous cyclone
• waste remediation
• process recycling.