Butterfly Valves for Mining & Minerals

Vajra Industrial Solutions supplies rubber-lined butterfly valves for mining slurry service from DN100 (4 inch) to DN1200 (48 inch), with special designs available to DN2000 for large tailings distribution mains. Standard sizes: DN100–DN400 with wafer-lug design (between-flange) and ANSI Class 150 / PN10–16 rating; DN400–DN800 with double-flange (lug or full face) and PN10–16; DN900–DN1200 with double-flange and geared operator, PN6–10. Available liner materials: Natural Rubber (NR), EPDM, Neoprene (CR), Hypalon (CSM) for specific chemical resistance requirements. Disc options: SS 316, Hard Chrome SS, HVOF tungsten carbide for high-abrasion applications. Gear operators: manual gearbox (bevel gear, handwheel) for all sizes; electric actuator for remote or automated operation. Contact Vajra with slurry properties (solids content, particle size, specific gravity, pH) for recommended liner and disc material selection.

Yes, with correct selection. Lime slurry (calcium hydroxide, Ca(OH)₂, typically 5–30% concentration) is highly abrasive due to crystalline calcium particles, has high pH (11–13), and tends to build scale deposits on valve internals. For lime slurry butterfly valves: (1) Natural rubber (NR) liner — provides good abrasion resistance for lime crystalline particles; (2) Neoprene or EPDM liner — alternative for pH 11–13 environments; (3) Hard chrome overlay disc — lime particles (Mohs hardness 3) will erode bare stainless disc faces within months; hard chrome extends disc life 3–5×; (4) Full bore design — minimise constriction to reduce lime particle velocity at the disc edge; (5) Lime scale prevention: flush the valve with clean water before shutdown to prevent lime precipitation and solidification around the disc while it is closed — lime can set hard in a closed valve; specify a body flush connection (1/2 inch NPT drain/flush port) for this purpose. For lime slurry above 30% concentration or lime with coarse aggregate: HVOF tungsten carbide disc coating is recommended for maximum service life.

Rubber-lined butterfly valves for mining slurry service are typically rated PN6–PN25 (6–25 bar maximum allowable pressure). Standard pressure ratings: PN10 (10 bar / 145 psi): most common for tailings disposal, slurry pump discharge at low-to-medium head systems; PN16 (16 bar / 232 psi): slurry pump systems with higher head, water distribution from elevated reservoirs; PN25 (25 bar / 360 psi): high-pressure slurry systems in deep mine dewatering and high-head pump circuits. Above PN25 in slurry service: rubber-lined butterfly valves are generally not used — the rubber liner under high differential pressure can extrude or deform at the disc edge; above PN25, specify knife gate valves or pinch valves for slurry, or ball valves with abrasion-resistant lining for smaller sizes. All pressure ratings are for ambient temperature (20°C) service; derating applies above 80°C — verify with Vajra's technical team for high-temperature slurry applications.