The final step in many mining operations is to dewater the recovered concentrate to a shippable, smelter-ready moisture level. An automatic concentrate filter press takes copper, gold, lead, zinc, or iron concentrate at 30-50% solids and delivers a cake at 86-92% solids — meeting smelter moisture limits (typically 8-10% for copper) and maximizing per-tonne shipping value.
Why Mining Concentrate Needs a Specialized Press
Mining concentrates are dense (specific gravity 4.5-5.5 for copper, 7+ for gold-bearing pyrite), fine (80% under 75 µm), and very abrasive. They also represent significant economic value — every percentage point of moisture removed equals saved shipping cost and avoided smelter penalty. A general-purpose chamber press works, but a purpose-built concentrate press includes specific enhancements:
- Membrane (diaphragm) plates for squeeze step to push moisture below 10%
- Air-blow core blow at end of cycle to remove residual liquid from feed channel
- Auto cake-knocking for tough sticky cakes (gold concentrate especially)
- High-pressure cloth wash (100-150 bar) to prevent fine-mineral blinding
- 304/316L stainless or duplex frame for chloride-containing concentrates
Concentrate-Specific Process Considerations
Smelters charge moisture penalties above their spec (8-10% for copper, 6-8% for gold). They also penalize chloride content above 0.05-0.10%, so a cloth-wash step that allows freshwater cake-rinse improves payback. For more on mining filtration broadly, see mining filter press applications. For dewatering of tailings (the waste side), see our mining tailings dewatering filter press article.
Common Concentrates Processed
- Copper concentrate — 25-30% Cu, target 8-9% moisture for smelter shipping
- Gold pyrite concentrate — typically 30-100 g/t Au, dewatered before pressure oxidation or roasting
- Lead-zinc concentrates — separated Pb and Zn concentrates, both dewatered separately
- Iron ore concentrate — magnetite or hematite, dewatered for pellet feed
- Nickel sulfide concentrate — high-temperature pressure leach feed
- Molybdenum concentrate — byproduct of copper flotation
- Tin and tungsten concentrates — gravity-separated, very dense
Specifications & Customization Options
- Filter area: 50 – 1,500 m² per press
- Plate size: 1500 / 1800 / 2000 mm
- Filtration pressure: 8-12 bar
- Squeeze pressure: 16-25 bar (water or air)
- Cloth: Heavy-duty polypropylene monofilament, 10-25 µm
- Cake discharge: Vibration motors + pneumatic knockers for sticky concentrates
- Cloth wash: Auto traversing high-pressure lance (100-150 bar) every 2-5 cycles
- Frame: Heavy carbon steel epoxy-coated; duplex stainless for seawater-process plants
FAQs
How much moisture reduction does the membrane squeeze provide? For mineral concentrate, squeeze typically removes another 30-40% of residual moisture — taking a 14% chamber-only cake to 8-9% squeezed cake, right at the smelter spec.
What’s the typical cycle time? 30-60 minutes total for copper concentrate. Gold pyrite concentrate is slower (60-90 min) due to fine particle size and consequent cake resistance.
How important is filtrate clarity? Critical — every milligram of fines in the filtrate is lost concentrate. Mining-grade presses target filtrate suspended solids under 100 mg/L, which usually means new filter cloth with the right micron rating and proper precoat or polymer use.
Need a concentrate filter press for your mine? Talk to Senjie with your concentrate grade, particle-size distribution, daily t/h, and target moisture — we’ll spec the right concentrate press with membrane squeeze and automation.