Check Valves for Mining & Minerals

For slurry pump discharge: rubber-lined swing check valves with spring-assisted or weighted disc are the preferred choice in most mineral processing plants. The full-rubber lining (disc, seat, and body) ensures: (1) particles in the slurry do not damage the seating surfaces — rubber elastomers deform to seat around particles; (2) abrasion resistance — 12–20 mm natural rubber lining in the body and 12–15 mm on the disc face provides 3–5 year service life in iron ore, copper and coal slurry; (3) economical maintenance — the rubber disc and seat are replaceable as wear items without replacing the valve body. For ultra-high-pressure slurry pumps (above PN40) or coarse particle service where rubber-lined swings are impractical: specify hard-chrome overlay or ceramic-lined check valve. For very large bore (DN600–DN900) tailings pump discharge: dual plate rubber-seat check valves are preferred because the smaller individual disc size reduces dynamic forces and wear compared to a single large swing disc.

Slurry check valve wear minimisation strategies: (1) Velocity control — check valve disc and seat wear is proportional to velocity squared; if slurry velocity exceeds 3 m/s through the check valve, consider upsizing the line to reduce velocity to 1.5–2.5 m/s; (2) Disc angle — swing check disc at 20–30 degrees from vertical when fully open provides a more streamlined disc profile that deflects slurry rather than presenting a flat face to the flow; (3) Liner thickness — specify 12–16 mm natural rubber (Shore A 45–50 hardness) for slurry service vs the standard 6 mm for water service; harder rubber (Shore A 60+) is more abrasion resistant but loses particle-seating compliance; (4) Replaceable disc covers — specify vulcanised rubber disc covers as wearable field-replaceable items on the swing disc; these can be replaced in 2–4 hours without removing the valve from line; (5) Correct hydraulic design — avoid high-velocity slurry impingement directly on the check valve disc; install the valve downstream of a straight pipe section (minimum 5D upstream) to stabilise slurry velocity profile before the check valve.

No. Acid mine drainage (AMD) is typically pH 2–4, contains dissolved ferric iron, sulphate, and heavy metals — it is highly corrosive to carbon steel. For AMD service: (1) Natural rubber-lined carbon steel body — the rubber completely protects the steel body from chemical attack; verify rubber compound acid resistance (NR is resistant to pH 2–11; for pH below 2 or HF contamination, specify EPDM or Hypalon lining); (2) HDPE (High Density Polyethylene) body check valves — for AMD service above pH 1 at moderate pressures (PN10); all-plastic construction eliminates corrosion entirely; (3) Ductile iron with Neoprene or EPDM lining — for pH 2–5 AMD with low iron content; (4) SS 316L for low-corrosivity AMD (pH 3–5) — stainless is resistant to mild sulphuric acid below 10% concentration and below 25°C; (5) FRP (fibreglass-reinforced plastic) body check valves — for highly corrosive AMD at low pressure; lightweight, fully corrosion-proof. Do not use uncoated carbon steel, cast iron without lining, or bronze in AMD service — all will corrode rapidly, contaminate process solutions with dissolved metals, and fail structurally within months.