Iron Precipitation Slurry Tank Selection Hydromet
Iron Precipitation Slurry (Jarosite, Goethite, Hematite, and Ferric-Hydroxide High-Density-Sludge HDS at Zinc, Copper, Nickel, Cobalt, and Lead Hydrometallurgy Operations for Iron Rejection from Sulfate-Leach, Chloride-Leach, Pressure-Oxidation Autoclave-Discharge, and Electrolyte-Purification Streams via Jarosite Process at pH 1.5 + 95C, Goethite Process at pH 2.5-3.5 + 80-90C, Hematite Process at pH 1.0-2.0 + 200C Autoclave, and Ferric-Hydroxide Process at pH 4-5 + 25-50C at Trail British Columbia, Hudson Bay Mining Flin Flon, Glencore Brunswick + Kidd Creek + CCR + Nikkelverk, KGHM Glogow, Boliden Ronnskar + Odda + Kokkola, Vale Sudbury + Long Harbour + Onca Puma + Sorowako + Goro, Mt Keith + Kalgoorlie + Olympic Dam + Cawse + Murrin, and Global Zinc, Nickel, Cobalt Hydromet Refineries) — Tank Selection at Iron-Removal Reactor, Clarifier-Feed, Sludge-Thickener, and Adjacency Service
Iron precipitation slurry (jarosite, goethite, hematite, and ferric-hydroxide high-density-sludge HDS; CAS 12575-82-7 sodium-jarosite + 12595-94-7 ammonium-jarosite + 13473-90-0 ferric-nitrate + 1309-37-1 hematite Fe2O3 + 51274-00-1 goethite alpha-FeOOH + 1309-33-7 ferric-hydroxide; supplied as in-situ-generated process slurry from iron-removal reactor at the zinc + copper + nickel + cobalt + lead refinery; jarosite as KFe3(SO4)2(OH)6 + NaFe3(SO4)2(OH)6 + (NH4)Fe3(SO4)2(OH)6 alkali-iron-sulfate at jarosite process pH 1.5 + 95C; goethite as alpha-FeOOH iron-oxyhydroxide at goethite process pH 2.5-3.5 + 80-90C with seed-recycle to densify sludge; hematite as Fe2O3 iron-oxide at hematite process pH 1.0-2.0 + 200C autoclave at 30 bar O2 with seed-recycle; ferric-hydroxide as Fe(OH)3 amorphous gel at HDS process pH 4-5 + 25-50C with high recycle ratio; specific gravity 1.20-1.50 at typical 20-50% solids HDS slurry; pH 1-5 acid + 8-10 lime-trim depending on process; particle size D50 5-50 micron at jarosite + goethite and 10-100 micron at hematite densified seed; supplied internally to the refinery at 50,000-2,000,000-gallon iron-removal-reactor + clarifier-feed + sludge-thickener network; iron-bearing sludge is disposed at iron-residue stack + paste-tailings-stack + dry-stack-tailings + cement-stabilization facility per state-specific tailings code) is the dominant iron-rejection chemistry at modern zinc + copper + nickel + cobalt + lead hydrometallurgical refineries that recover base metals from sulfate-leach + chloride-leach + pressure-oxidation autoclave-discharge + electrolyte-purification streams across the global hydromet refinery market.
U.S. Process is internal to the refinery + iron-residue is disposed at iron-residue stack + tailings facility.
The eight sections below cite OSHA Hazard Communication 29 CFR 1910.1200 + 1910.1000 sulfuric-acid + heavy-metal PEL + MSHA 30 CFR 56/57 + EPA Method 6010 + 6020 ICP-OES + ICP-MS metal analytical + EPA Method 9040 pH + EPA NPDES + state-specific mining-discharge permit + EPA SPCC + state-specific tailings code + EPA RCRA Bevill exemption + Bureau of Land Management Mine Plan of Operations + State Reclamation Bond + State Aquifer Protection Permit + Title V Clean Air Act + ASTM E1915 + ISO 5667 sampling + state-specific iron-residue + paste-tailings code + International Council on Mining and Metals ICMM + ICMI + GISTM Global Industry Standard on Tailings Management framework at routine operating practice at North American + Latin-American + European + Asian + African zinc + copper + nickel + cobalt + lead hydromet refinery iron-precipitation operations.
1. Material Compatibility Matrix
Iron precipitation slurry at typical 20-50% solids jarosite + goethite + hematite + ferric-hydroxide + 1-50 g/L SO4 + 1-15 g/L H2SO4 free acid + Fe + Zn + Cu + Pb + Cd + As + Ni + Co matrix at site-specific composition + 25-200C is a corrosive abrasive acidic-iron-bearing process slurry with acid-corrosion + abrasion-wear + scaling + arsenic-stabilization considerations. Polymeric construction (HDPE + XLPE + PP + FRP vinyl-ester + CPVC) covers most iron-removal-reactor + clarifier + sludge-thickener service to 80C; pressure-oxidation hematite-process autoclave at 200C + 30 bar O2 calls titanium-clad + titanium-grade-2 + titanium-grade-7 alloy outside HDPE scope. Note operating-discipline considerations: arsenic-stabilization discipline (arsenic-bearing iron-precipitation sludge at copper + cobalt + nickel + lead refinery requires arsenic-stabilization in scorodite FeAsO4-2H2O or Fe(III)-As(V) coprecipitation phase to meet TCLP arsenic 5.0 mg/L + state-specific tailings As stabilization code; pH + Fe:As ratio + temperature control discipline at the iron-precipitation reactor stage is critical), heavy-metal-coprecipitation discipline (lead + cadmium + selenium + thallium + mercury coprecipitate with iron-hydroxide at HDS process; iron-residue characteristic-hazardous-waste classification per RCRA TCLP at site-specific evaluation; iron-residue stack stabilization with cement + lime is routine), abrasion-wear discipline (jarosite + goethite + hematite particle Mohs hardness 4-6 drives accelerated abrasion-wear at pump impeller + pipe elbow + clarifier rake at high-velocity transfer; abrasion-resistant elastomer-lined progressive-cavity + peristaltic + rotary-lobe pump + UHMW-PE or rubber-lined pipe-liner is standard at long-service equipment), and scaling discipline (gypsum CaSO4-2H2O scale at lime-trim downstream + jarosite scale at the iron-precipitation reactor surfaces drives buildup at heat-exchanger + transfer-pipe + valve seat; routine acid-cleaning at 1-3 month frequency is standard).
| Material | Iron Slurry @ 25C | Iron Slurry @ 90C | Notes |
|---|---|---|---|
| HDPE rotomolded | A | C | Standard at lower-temperature iron-removal-reactor + clarifier-feed + adjacency service across the 1,500-10,000-gallon range; temperature-derated above 60C; abrasion-resistant grade preferred |
| XLPE rotomolded | A | B | Standard at lower-temperature service + slightly improved temperature limit to 70C; not at 90C jarosite + goethite reactor service |
| Polypropylene (PP) | A | A | Standard at smaller iron-precipitation specialty + analytical-lab service to 90C |
| FRP vinyl-ester resin | A | A | STANDARD at jarosite + goethite + ferric-hydroxide reactor + clarifier + sludge-thickener service across the 50,000-2,000,000-gallon scale at temperatures to 95C |
| FRP polyester resin | A | C | Acceptable at lower-temperature service; not preferred at hot jarosite + goethite reactor |
| 304 stainless steel | C | NR | NOT recommended at iron-precipitation service due to acid + chloride attack at temperature |
| 316L stainless steel | C | NR | NOT recommended at hot iron-precipitation service; pitting + crevice corrosion |
| Duplex 2205 / 2507 | B | C | Acceptable at lower-temperature analytical-lab service only |
| Carbon steel uncoated | NR | NR | NOT recommended; rapid acid corrosion + iron-contamination |
| Carbon steel rubber-lined | A | A | STANDARD at primary iron-removal-reactor + clarifier-feed at hot jarosite + goethite + ferric-hydroxide service; natural-rubber or chlorobutyl-rubber liner |
| Titanium grade 2 / 7 | A | A | Premium at hematite-process pressure-oxidation autoclave at 200C + 30 bar O2; titanium-grade-7 (Ti-Pd) at chloride-bearing service |
| EPDM | A | A | Standard gasket + lining at iron-precipitation service |
| Viton (FKM) | A | A | Standard at higher-temperature pump + valve seat |
| Nitrile (Buna-N) | B | NR | Acceptable at brief contact only at low-temperature |
| HDPE 60-mil + 80-mil geomembrane liner | A | A | STANDARD at iron-residue-stack + paste-tailings + sludge-pond primary + secondary liner |
| UHMW-PE pipe lining | A | A | Premium abrasion-resistant pipe interior at high-velocity slurry transfer |
| Rubber-lined pipe | A | A | Premium abrasion-resistant pipe at long-service high-velocity transfer |
The dominant industrial pattern at North American + Latin-American + European + Asian + African zinc + copper + nickel + cobalt + lead hydromet refinery iron-precipitation operations is FRP vinyl-ester resin or rubber-lined carbon-steel construction at the larger 50,000-2,000,000-gallon iron-removal-reactor + clarifier-feed + sludge-thickener vessel, titanium-grade-2 + grade-7 at the hematite-process pressure-oxidation autoclave, and HDPE rotomolded tank at the 1,500-10,000-gallon process-water + reagent + sample + analytical-lab + adjacency service. OneSource Plastics' 5-brand HDPE network (Norwesco, Snyder Industries, Chem-Tainer, Enduraplas, Bushman) covers the typical 1,500-10,000-gallon hydromet-refinery process-water + reagent + sample + adjacency specification across the standard envelope; primary 50,000-2,000,000-gallon iron-removal-reactor + clarifier-feed + sludge-thickener vessel typically calls FRP vinyl-ester or rubber-lined carbon-steel construction outside our HDPE 5-brand scope; pressure-oxidation autoclave calls titanium-grade-2 + grade-7 outside our HDPE 5-brand scope. We refer those specifications to qualified FRP + lined-steel + titanium tank fabricators.
2. Real-World Industrial Use Cases
Zinc Hydromet Jarosite Process (Dominant Use at Zinc Refinery). Zinc refinery sulfate-leach circuit oxidizes ferrous-iron to ferric-iron + precipitates iron as alkali-jarosite KFe3(SO4)2(OH)6 + NaFe3(SO4)2(OH)6 + (NH4)Fe3(SO4)2(OH)6 at pH 1.5 + 95C reaction tank with potassium + sodium + ammonium counter-cation addition. Sites: Teck Trail British Columbia + Hudson Bay Mining Flin Flon Manitoba + Korea Zinc Onsan + Boliden Odda Norway + Glencore Sudbury + Nyrstar Balen-Wezel Belgium + Penoles Saltillo Mexico. Storage envelope: FRP vinyl-ester or rubber-lined carbon-steel jarosite-reactor + clarifier-feed + sludge-thickener at 50,000-2,000,000-gallon scale; HDPE rotomolded process-water + reagent at 1,500-10,000-gallon scale.
Zinc Hydromet Goethite Process. Zinc refinery goethite process precipitates iron as alpha-FeOOH iron-oxyhydroxide at pH 2.5-3.5 + 80-90C reaction tank with seed-recycle to densify sludge to 30-50% solids. Sites: Vieille Montagne Balen-Wezel Belgium + Outokumpu Kokkola Finland + Akita Iijima Japan. Storage envelope: same as jarosite.
Zinc Hydromet Hematite Process. Zinc refinery hematite process precipitates iron as Fe2O3 iron-oxide at pH 1.0-2.0 + 200C autoclave at 30 bar O2 with seed-recycle to produce dense sellable hematite product or stack-disposable hematite residue. Sites: Akita Iijima Japan + Hindustan Zinc Chanderiya India. Storage envelope: titanium-grade-2 + grade-7 autoclave + flash-tank typically OUTSIDE HDPE scope; HDPE rotomolded reagent + sample tank at adjacency 1,500-10,000-gallon scale.
Copper Hydromet Iron Removal. Copper SX-EW raffinate iron-bleed at 1-10% of total raffinate flow + autoclave-discharge sulfide-leach iron at copper-arsenic refractory concentrate is neutralized in HDS reaction tank with lime-slurry to pH 4-5 to precipitate iron as ferric-hydroxide + arsenic as scorodite at recycled-sludge ratio 5-10:1 to maximize sludge density to 30-50% solids. Sites: Freeport-McMoRan Morenci + Bagdad + Sierrita + Ray + Mission + Silver Bell Arizona + Tyrone + Chino New Mexico + Mexicana de Cobre La Caridad + Cananea Mexico + Pueblo Viejo Dominican Republic + Constancia Peru + Antamina Peru. Storage envelope: same as zinc + nickel.
Nickel + Cobalt Hydromet Iron Removal. Nickel + cobalt refinery iron-removal at sulfate + chloride leach circuit + electrolyte-purification at the cobalt + nickel + manganese + magnesium separation step uses goethite + ferric-hydroxide precipitation at pH 3-4. Storage envelope: same as zinc + copper.
Iron-Residue Stack and Paste-Tailings Disposal. Iron-residue at 50-70% solids dry-stack or paste-tailings disposal at the refinery iron-residue stack facility; cement-stabilization at 5-15% Portland-cement addition + lime + sodium-aluminate addition to immobilize arsenic + lead + cadmium + selenium per state-specific tailings code + GISTM framework. Storage envelope: HDPE 60-mil + 80-mil double-liner residue-stack + paste-tailings facility.
3. Regulatory Framework
OSHA 29 CFR 1910.1200 + 1910.1000 + 1910.1018 Heavy-Metal Standards. Iron-precipitation slurry with arsenic + lead + cadmium + selenium impurities triggers OSHA arsenic 1910.1018 + lead 1910.1025 + cadmium 1910.1027 + chromium-VI 1910.1026 + welding-fume + worker SDS + container labeling + PPE + medical-monitoring + biological-monitoring + emergency-shower-eye-wash discipline.
MSHA 30 CFR 56/57 Surface-and-Underground Mine Heavy-Metal Standard. MSHA 30 CFR 56.5001 + 57.5001 heavy-metal air-contaminant + biological-monitoring + supplied-air-respirator at iron-removal-reactor + clarifier + sludge-handling work above OSHA PEL.
EPA RCRA Subtitle C Characteristic Hazardous Waste TCLP. Iron-precipitation residue with elevated As + Pb + Cd + Se + Cr + Hg may classify as RCRA characteristic hazardous waste at site-specific TCLP per 40 CFR 261.24 D004 + D005 + D006 + D007 + D008 + D009 + D010 + D011 testing; iron-residue + paste-tailings stabilization with cement + lime + sodium-aluminate at site-specific recipe is routine to meet TCLP limits.
EPA RCRA Subtitle C Bevill Exemption. Mining-extracted ore + tailings + iron-residue generally qualify for Bevill exemption to RCRA Subtitle C under 40 CFR 261.4(b)(7) at most hydromet operations. Refinery + smelter + electrowinning + tankhouse spent-electrolyte may be subject to characteristic hazardous waste classification at site-specific evaluation.
EPA NPDES + State Mining Discharge Permit. Iron-precipitation effluent + residue-stack runoff discharge to surface water requires state-specific mining-discharge permit + NPDES outfall + state water-quality criterion compliance + Discharge Monitoring Report DMR submission framework.
EPA SPCC + State Tailings Code. Iron-bearing residue storage requires double-liner + leak-detection + secondary-containment per state-specific tailings code; iron-residue-stack + paste-tailings + clarifier-overflow + event-pond + stormwater-pond inventory + closure-plan + reclamation-bond.
Global Industry Standard on Tailings Management GISTM. ICMM + UNEP + Principles for Responsible Investment Global Industry Standard on Tailings Management adopted 2020 establishes 15 principles + 77 requirements covering tailings-facility integrity + Engineer-of-Record + Independent-Tailings-Review-Board + emergency-response + closure framework. Most major mining companies are GISTM signatories.
EPCRA + TRI Reporting. Hydromet-refinery TRI-reporting threshold per EPCRA 313 + 40 CFR 372 covers Cu + Pb + As + Cd + Cr + Ni + Hg + Zn + Se + sulfuric acid + heavy-metal releases at the refinery iron-precipitation + electrowinning + tankhouse + tailings facility annual reporting framework.
4. Storage System Specification
Iron-Removal Reactor and Clarifier-Feed Vessel (Outside HDPE Scope). Primary jarosite + goethite + ferric-hydroxide reactor + clarifier-feed + sludge-thickener at 50,000-2,000,000-gallon scale uses FRP vinyl-ester resin construction or rubber-lined carbon-steel construction with natural-rubber or chlorobutyl-rubber liner + 304 + 316L stainless mixer impeller at 50-150 rpm + acid-resistant baffle + lime-slurry-dosing-pump + recycled-sludge-pump + heat-exchanger to maintain 80-95C reaction temperature + acid-trim makeup. Construction at qualified FRP or lined-steel tank fabricator with NDE inspection + holiday-test on liner. This specification is OUTSIDE OneSource Plastics' HDPE 5-brand scope; we refer those specifications to qualified FRP + lined-steel tank fabricators.
Pressure-Oxidation Hematite Autoclave (Outside HDPE Scope). Hematite-process autoclave at 200C + 30 bar O2 uses titanium-grade-2 + grade-7 (Ti-Pd) clad construction + titanium-impeller agitator + titanium-clad heat-exchanger + titanium-clad flash-tank. Construction at qualified titanium-clad pressure-vessel fabricator with ASME Section VIII Division 1 + 2 + NDE radiographic + ultrasonic inspection. This specification is OUTSIDE OneSource Plastics' HDPE 5-brand scope.
Process Water and Reagent Makedown Tank (HDPE Scope). Process-water + sulfuric-acid-makedown + lime-makedown + sodium-carbonate + sodium-hydroxide + iron-seed + flocculant + sample + analytical-lab adjacency at the refinery uses 1,500-10,000-gallon HDPE or XLPE rotomolded vertical flat-bottom or shallow-cone-bottom atmospheric tank, 1.85 specific-gravity rated, mounted on level reinforced-concrete pad with secondary containment via integral catch-basin or external concrete-bermed pad sized to 110% of largest-tank volume; 3-4 inch flanged top fill + atmospheric vent; 2-3 inch flanged bottom outlet with full-bore PVC ball valve; 18-24 inch top manway; ultrasonic level transmitter; sample valve; opaque-pigmented HDPE for UV protection at outdoor service.
Iron-Residue Stack and Paste-Tailings Liner. Iron-residue-stack + paste-tailings + sludge-pond uses HDPE 60-mil or 80-mil double-liner construction with primary + secondary liner + leak-detection sump + GCL or compacted-clay subliner per state-specific tailings code.
Containment and Spill Pad. All iron-precipitation slurry + iron-residue + heavy-metal-bearing storage requires secondary containment per EPA SPCC + state-specific tailings code; concrete-bermed pad with HDPE primary + secondary liner + leak-detection sump + acid-resistant epoxy or polyurea topcoat.
5. Field Handling Reality
Handler PPE. Iron-precipitation slurry handling: chemical-resistant Tyvek or equivalent suit at any open-system work, double nitrile chemical-resistant glove at any contact, chemical splash goggles + face shield at any open-system handling, supplied-air respirator at iron-removal-reactor + clarifier + sludge-handling work above OSHA acid-mist + heavy-metal PEL, half-mask air-purifying respirator with acid-gas-cartridge + HEPA at routine open-system work, steel-toe boots with chemical-resistant overshoe, eye-wash + emergency shower per OSHA 29 CFR 1910.151 within 10 seconds of work area, cyanide-area + heavy-metal-area medical-monitoring + biological-monitoring per OSHA 29 CFR 1910.1018 As + 1910.1025 Pb + 1910.1027 Cd at affected work zone.
Arsenic-Stabilization Discipline. Arsenic-bearing iron-precipitation sludge at copper + cobalt + nickel + lead refinery requires arsenic-stabilization in scorodite FeAsO4-2H2O or Fe(III)-As(V) coprecipitation phase; pH 2-4 + Fe:As mole ratio 4:1 minimum + temperature 80-95C + ferric-iron-excess discipline at the iron-precipitation reactor stage drives stabilized-scorodite phase that meets TCLP arsenic 5.0 mg/L + state-specific tailings As stabilization code. Routine sludge-stability testing at the iron-residue stack with TCLP + extraction batch-test framework.
Abrasion-Wear Discipline. Jarosite + goethite + hematite particle Mohs hardness 4-6 drives accelerated abrasion-wear at pump impeller + pipe elbow + clarifier rake at high-velocity transfer; abrasion-resistant elastomer-lined progressive-cavity + peristaltic + rotary-lobe pump + UHMW-PE or rubber-lined pipe-liner is standard at long-service equipment; pipe-elbow inspection every 6-12 months at high-velocity transfer line.
Scaling Discipline. Gypsum CaSO4-2H2O scale at lime-trim downstream + jarosite scale at the iron-precipitation reactor surfaces drives buildup at heat-exchanger + transfer-pipe + valve seat; routine acid-cleaning at 1-3 month frequency with HCl or weak-acid soak is mandatory. Heat-exchanger CIP at 6-month frequency.
Heavy-Metal Coprecipitation Discipline. Lead + cadmium + selenium + thallium + mercury coprecipitate with iron-hydroxide at HDS process; iron-residue-stack stabilization with cement + lime + sodium-aluminate at site-specific recipe is routine to meet RCRA TCLP + state-specific tailings code. Site-specific mass-balance + impurity-budget tracking at the iron-precipitation reactor + clarifier + sludge-thickener stages.
Cargo-Tank Receipt of Process Reagents. Sulfuric-acid bulk receipt at 5,000-25,000-gallon FRP vinyl-ester storage + lime-slurry receipt at 5,000-25,000-gallon HDPE storage + sodium-carbonate + sodium-hydroxide + flocculant receipt at 1,500-10,000-gallon HDPE makedown. PPE + transfer-rate-monitoring + secondary-containment + emergency-deluge framework.
QC Sampling and Verification. Each iron-removal-reactor + clarifier + sludge-thickener + iron-residue + outfall sample collection: total + dissolved Fe + Zn + Cu + Pb + Cd + As + Se + minor metal per EPA Method 6010 + 6020 ICP, pH continuous + grab confirmation, ORP, conductivity, density, total-solids by gravimetric oven-dry, scorodite-stability by TCLP + extraction batch-test, particle-size by laser-diffraction.
Spill Response. Iron-precipitation slurry spill response: small-volume spill is contained at secondary-containment + neutralized in place with lime + sodium-hydroxide to pH 8-10 + transferred via vacuum-truck to event-pond. Large-volume spill triggers state-agency notification + NPDES exceedance reporting + downstream water-quality sampling + remediation per state mining permit + GISTM emergency-response framework.
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