In the aggregates industry, any effluent stream that has <100mesh (150µm) fractions is a very good candidate for a UFR, with excellent ROI if the materials are marketable. In the coal industry, certain effluent streams may contain valuable coal due to inefficiencies in the process.
Frac Sand Plants reject amounts of sand that cannot be used in the range of specification products most often in the <140 mesh (105µm), which are fractions left over from the 70x140 production. Any Industrial Sand Plant making tight specifications is likely to reject recoverable fractions to waste given their relatively low value compared with the core products. Covering up valuable reserves with ever-increasing pond space does not make economic sense when a UFR can significantly reduce the amount of fractions reporting to the pond.
Feed from the processing plant effluent stream is directed to the UFR sump. The slurry is then pumped at a relatively high pressure to multiple Hydrocyclones using a McLanahan rubber lined Pump. The Hydrocyclones recover most of the +400 mesh (38µm) fractions as partially dewatered underflow, which is in turn directed to the Dewatering Screen. The Dewatering Screen further dewaters the Hydrocyclone underflow to a conveyable/stackable product that is essentially drip-free even though the moisture content may exceed 20%. The recovered material is conveyable and stackable and is suitable for multiple industries, including sand, iron ore, coal recovery, ash, industrial sands, frac sand, and more. Any particles passing through the Dewatering Screen surface are recirculated through the Hydrocyclones to recover these fractions, forming a closed circuit.
After initially starting in the fines recovery business with 4” (100mm) Hydrocyclones, McLanahan Corporation quickly migrated to 9” (225mm) and 12” (300mm) units to reduce wear and, more importantly, to eliminate plugging of the apex on the Hydrocyclones. For every Hydrocyclone that is blocked, 100% of that portion of the feed goes directly to waste. If you have a 20 Hydrocyclone cluster and one Hydrocyclone blocks, then 5% of the flow remains untreated. It doesn’t take long for another and then another Hydrocyclone to block, and before you know it, you have less than 50% of the flow going direct to the pond.
When you analyze the difference in predicted recovery performance between the 9” and 12” (225mm and 300mm) units and a 4” (100mm), it is barely measurable in terms of total recovery. If you compare the losses in the real world, it is significantly higher with the smaller units when blockages occur. We have converted other manufacturers' 4” clusters with our larger Hydrocyclones, resulting in significant savings, maintenance costs and overall improved performance.