Valves for Mining & Mineral Processing

For slurry service, the two most common choices are knife gate valves and pinch valves. Knife gate valves use a metal blade that cuts through the slurry to close; they are suitable for isolation (not throttling) and work well for slurries with fine to medium solids. Pinch valves use a flexible rubber sleeve that pinches closed — there are no internal metal parts to erode, making them ideal for highly abrasive coarse slurries. The choice depends on solids size, abrasivity, pressure, and whether on/off or throttling control is needed.

Acid mine drainage (AMD) can reach pH 1–2 with high concentrations of dissolved iron, copper, zinc, and sulphate. Carbon steel and cast iron corrode rapidly. Suitable materials include: HDPE (polyethylene) for low-pressure lines and valve linings; PVDF (polyvinylidene fluoride) for higher pressure and broad chemical resistance; natural rubber or Linatex lining for moderate acid concentrations; FRP (fibreglass-reinforced plastic) for large-diameter low-pressure applications. For valve bodies, ductile iron with HDPE or PVDF lining is a cost-effective solution for most AMD circuits.

A knife gate valve uses a hardened blade (SS 420, SS 316, or polyurethane-coated) that slides down through the flow path and seats against a rubber or polymer seat liner — it physically cuts through thick slurry or fibrous media. A pinch valve works by externally compressing a flexible elastomeric sleeve (rubber tube) until it closes — no metal contacts the process fluid, giving excellent abrasion resistance. Knife gate valves generally handle higher pressures (up to PN 16) and are better for on/off isolation; pinch valves offer better throttling capability and longer sleeve life in highly abrasive service.

Yes. Carbon-in-pulp (CIP) and carbon-in-leach (CIL) gold extraction circuits use dilute sodium cyanide (NaCN) at pH 10–11. We supply SS 316L ball valves and butterfly valves with EPDM seats for cyanide service, and PTFE-sleeved plug valves for sampling and chemical dosing points. All wetted components are compatible with NaCN and NaOH. Safety data sheets and material compatibility certificates are provided. We are experienced in supplying to gold, silver, and copper SX-EW operations in India and internationally.