Sulfuric Acid Feed System Equipment for Lithium Hydroxide Plants

A sulfate-route lithium leach circuit — sulfuric acid roasting/leaching on mined spodumene ore concentrate to produce lithium hydroxide — runs concentrated sulfuric acid through several distinct equipment stages before it ever reaches the leach vessel. Each stage is its own spec problem.

Bulk Unloading & Storage

Bulk acid arrives by tanker truck or railcar and needs a real unloading pump — not a gravity connection improvised on-site. A sealless magnetic-drive pump avoids the mechanical seal that's usually the first failure point in continuous acid transfer duty; published sealless designs in this service run wide temperature ranges (roughly -60°C to +200°C) at PN16 pressure class, with a vortex or semi-open impeller specifically for solids-laden leach-circuit duty. A self-priming design that draws from the top of the tank avoids sidewall penetrations entirely — one less below-liquid-line fitting to leak.

The bulk tank itself is sized to delivery logistics, not just average daily use: it needs to hold at least one full delivery load plus a safety margin above minimum working level, checked against the tank manufacturer's published gallon-to-height ratio for the actual concentration on the certificate of analysis. Poly Processing's XLPE-with-OR-1000 antioxidant liner system, for example, publishes its own gallon/height rule for concentrated acid service — a tank sized past that ratio needs engineering review before fabrication, not just a bigger version of the same design.

Transfer Piping & Isolation Valves

Transfer piping and valves see more mechanical stress than the tank — velocity, elbows, turbulence, and dilution risk at every connection. Acid-only feed lines ahead of the leach vessel generally call for thermoplastic ball and diaphragm valves selected to the same concentration band as the piping around them (see the 93-98% sulfuric acid tank and piping material selection guide for the full breakdown by concentration). Downstream, once the stream is a solids-laden slurry, isolation shifts to a different valve geometry entirely — see the knife gate vs. ball vs. butterfly valve comparison for abrasive slurry for that decision.

One trap that catches submittals on either side of that line: a diaphragm or seal elastomer inside a valve can cap out at a temperature well below the pressure rating of the valve body itself. Confirm the elastomer manufacturer's published maximum temperature for your acid service and use that number — not the body rating — as the real operating limit.

Metering & Dosing Into the Leach Step

Feeding acid into a leach or roast-neutralization step is a different pump problem than bulk transfer. It needs a metering pump with a published, verifiable turndown ratio across the real batch profile, not a transfer pump throttled down — check the pump's rated maximum output at your actual discharge pressure, then confirm the minimum required flow still sits inside the manufacturer's published turndown ratio, not just above zero. Where the process moves further downstream into solvent extraction or electrowinning, the metering-pump technology choice changes again — see the SX-EW equipment guide for that stage specifically.

Sulfate-Route Leach vs. Direct Lithium Extraction (DLE)

A sulfate route and direct lithium extraction are not the same equipment problem. A sulfate route runs sulfuric acid roasting/leaching on mined ore concentrate; DLE pulls lithium directly out of brine with no acid-roast step. If your project is DLE, the piping and pump questions are different from everything above — see the direct lithium extraction guides on this site for that equipment instead of applying this page's acid-feed content to a brine circuit.

Frequently Asked Questions