Buttweld elbows, tees, reducers and caps for high-pressure acid leach (HPAL) refineries, rotary kiln electric furnace (RKEF) smelters and the captive power plants that run them. Duplex, super duplex, 904L, Alloy 20 and Hastelloy C-276 for acid and slurry service; WP91, WP22 and WPB for steam. Small batches of exotic grades, no minimum order, shipped from India to Indonesia and the Philippines.
HPAL dissolves nickel and cobalt from limonite ore in sulphuric acid at roughly 250–270 °C inside pressure autoclaves. Almost every circuit around the autoclave combines acid, solids and temperature, so piping fails by corrosion, erosion or both. These are the areas where we are asked for fittings most often.
Thickened ore slurry is preheated with recycled flash steam and pumped by high-pressure pumps into the autoclave. Feed lines see high pressure and abrasive solids, and heater vent and steam lines carry acidic condensate. Heavy-wall WPB is common before acid addition; duplex and 904L appear where condensate or acid carry-over is expected.
Leached slurry is let down through choke valves into flash vessels. Flashing, high velocity and hot acid make this the most severe service in the plant. Titanium and lined construction dominate here; steel and nickel alloy fittings are used on flash steam, vent and lower-temperature connections where the designer specifies them.
Counter-current decantation thickeners separate leach liquor from residue, and limestone slurry neutralises free acid and removes iron and aluminium. Lines are large, acidic and full of solids. 316L, 317L and duplex 2205 are typical for metal piping; large-bore lines are often rubber-lined carbon steel or HDPE.
Most HPAL refineries burn sulphur to make their own acid and recover steam from the waste-heat boiler. Strong-acid circulation, acid coolers, dilution points and product lines each need a different grade: carbon steel at low velocity, Alloy 20 and 904L for hotter or more dilute acid, and Cr-Mo or WPB for the steam side.
Purified liquor is neutralised with magnesia to precipitate mixed hydroxide (MHP). Service is close to neutral but abrasive, and chlorides can build up in recycled water. 316L is typical, with duplex 2205 where chlorides or temperature rise.
Plants that refine MHP into battery-grade nickel and cobalt sulphate add re-leach, solvent extraction and evaporative crystallisation. Hot, mildly acidic sulphate liquor with traces of chloride points to 316L, 317L, 904L or duplex 2205, and Alloy 20 or C-276 for the more acidic streams.
Ferronickel and nickel pig iron lines need large volumes of cooling water for furnace shells, electrode systems and tapholes, plus fuel, furnace off-gas, nitrogen and compressed air lines. Closed-loop cooling water and gas service are usually carbon steel (WPB); 304L or 316L for treated water; duplex 2205 or super duplex 2507 where seawater or brackish water is used for cooling.
Industrial parks run their own coal-fired units and, increasingly, gas or LNG-fired plants. Main steam and hot reheat use WP91 (P91) or WP22 (P22) depending on steam conditions; feedwater, cold reheat and auxiliary steam use WPB. All Cr-Mo fittings are heat treated in-house and supplied with heat treatment records and hardness results.
The table shows typical industry practice, not a guaranteed or recommended selection. Final grades depend on acid strength, chloride level, temperature, solids and the plant designer's corrosion review. We supply to the grade on your line list.
| Service | Typical grades | Specification |
|---|---|---|
| Autoclave feed slurry (before acid) | WPB heavy wall; duplex 2205 | A234 / A815 |
| Autoclave internals, acid injection, hottest flash service | Titanium or lined construction (not supplied by us) | — |
| Flash steam, heater vents, acidic condensate | 904L, duplex 2205, super duplex 2507, Alloy 20 | A403 / A815 / B366 |
| CCD and neutralisation slurry | 316L, 317L, duplex 2205 | A403 / A815 |
| Strong sulphuric acid (93–98%), low velocity | WPB; Alloy 20 or 904L where hotter | A234 / B366 / A403 |
| Dilute acid and dilution points | Alloy 20, Hastelloy C-276 | B366 |
| MHP precipitation | 316L, duplex 2205 | A403 / A815 |
| Nickel and cobalt sulphate liquor, crystallisers | 316L, 317L, 904L, duplex 2205 | A403 / A815 |
| Seawater cooling | Duplex 2205, super duplex 2507 | A815 |
| RKEF cooling water, fuel and off-gas | WPB; 304L or 316L for treated water | A234 / A403 |
| Captive power main steam and hot reheat | WP91, WP22 | A234 |
| Feedwater, cold reheat, auxiliary steam | WPB, WP11 | A234 |
Titanium (and titanium-lined steel) is used in some autoclave, acid injection and hot flash service because few other metals survive hot, oxidising sulphuric acid with chlorides. We do not make titanium fittings. We make steel and nickel alloy buttweld fittings for the rest of the plant, which is where most of the fitting count sits.
We ship by sea from Indian ports in seaworthy wooden cases, with bevel ends protected and every piece marked with heat number, grade and size. For Indonesian nickel regions — Morowali, Weda Bay, Obi and Pomalaa — we quote CFR or CIF to the port or forwarder you name, usually via a main transhipment hub, and can consolidate several grades into one shipment. Philippine deliveries go to Manila, Davao or the port nearest your site. Commercial invoice, packing list and certificate of origin come with every shipment.
No. Titanium is used in some autoclave, acid injection and hot flash service, and we do not manufacture titanium fittings. We supply steel and nickel alloy buttweld fittings for the rest of the plant: duplex and super duplex, 316L, 317L, 904L, Alloy 20, Hastelloy C-276, Inconel 625 and 825, and carbon and Cr-Mo steels.
Typical practice is 316L or 317L for neutral to mildly acidic nickel sulphate liquor and MHP slurry, with duplex 2205, 904L or Alloy 20 where acidity, chlorides or temperature are higher. Material selection belongs to the plant designer; we supply to the grade on your line list and can comment on alternatives.
EN 10204 3.1 inspection certificates as standard, and EN 10204 3.2 with a third-party inspector you nominate. Fittings are manufactured at our group facility, Arshya Engineers and Fabrications Pvt Ltd, which holds ISO 9001, ISO 14001, ISO 45001, PED (TÜV Rheinland), AD 2000 HP 0, EN 764-5, IBR and ASME U-Stamp approvals.
Yes. There is no minimum order, and small batches of exotic grades such as 904L, Alloy 20 and C-276 for shutdowns and spares are a normal part of our work. We quote in USD, EUR or INR and ship to the Indonesian or Philippine port you name.
Also see: 317L · WP22 / P22 · Power generation · Chemical process · 904L in sulphuric acid · Product catalogue (PDF)
Include fitting type, size, schedule, grade, certificate and delivery port. WhatsApp +91 86552 00777 or call +91-022-4481-8932.
