1. The Brazilian fertilizer chain — pumping points
The Brazilian fertilizer industry operates in three distinct stages with very different pumping requirements. The first is raw-material handling: sulfuric acid (97-99%), phosphoric acid (52-54% P₂O₅) and anhydrous ammonia. The second is intermediate production — DAP, MAP, ammonium sulfate, urea, granulated NPK and liquid NPK. The third is dispatch and final formulation — including liquid solutions for foliar application and suspensions for fertigation.
FB Bombas operates across all three stages, with clear scope differentiation: concentrated acids (stage 1) require special materials at the edge of the standard catalog; liquid and molten intermediates (stage 2) are natural territory for FBCN stainless and FBE; dispatch and formulation (stage 3) are broadly covered by FBCN in lined cast iron or 316 stainless.
| Product | Stage | Recommended material | FB line |
|---|---|---|---|
| Sulfuric acid 98% | Raw material | Super-duplex (out of scope) | — |
| Diluted phosphoric acid 30% | Process | 316L stainless | FBCN |
| Ammonium sulfate (solution) | Intermediate | 316 stainless | FBCN |
| Molten urea (132 °C) | Intermediate | 316L stainless with heating jacket | FBE |
| Liquid NPK (solution) | Final product | 316 stainless | FBCN |
| Glycerin (biodiesel/agro by-product) | Viscous by-product | Carbon steel | FBE |
2. Liquid NPK and suspensions — where FBCN 316 stainless is the choice
Liquid NPK is an aqueous solution of N (urea, ammonium nitrate), P (monoammonium or diammonium phosphate) and K (potassium chloride or sulfate) with total concentration between 28% and 35%. pH ranges 5.5 to 7.0 and salinity is high — a combination that progressively attacks carbon steel and requires AISI 316 stainless for service life above 5 years.
For liquid NPK transfer between tanks, loading to tank trucks and inline blending dosage, FBCN in 316 stainless construction with type-21 mechanical seal (ceramic × graphite × viton) and AISI 304 spring covers 90% of applications. For suspensions with undissolved solids (fine mineral fillers), switch to semi-open impeller and widen the radial clearance, keeping the casing in stainless.
3. Molten urea — territory of FBE with thermal jacket
Urea melts at 132.7 °C and beyond that point becomes a viscous liquid (~3-5 cP) with rapid crystallization tendency as soon as temperature drops below 110 °C. Conventional centrifugals suffer from crystallization under low rpm or shutdowns — the impeller literally "locks" in place. The technical solution is a gear pump with heating jacket that keeps the product fluid during operation and controlled shutdowns.
FBE with jacket for saturated steam at 6 bar (~165 °C) or thermal fluid at 180 °C serves molten urea in internal transfer of prilling or humid granulation plants. 316L stainless construction is mandatory — cast iron contaminates the product and generates unstable ammonium carbamate. For larger granulation systems (>20 ton/h), consider two FBE in parallel with VFD for maintenance without plant shutdown.
4. Dilute sulfuric and phosphoric acids — standard-catalog limits
Sulfuric acid in intermediate concentrations (10-70%) is the most aggressive regime in the fertilizer industry — both 316L stainless and carbon are inadequate, and duplex 2205 is the minimum material. Above 93%, paradoxically, carbon steel becomes viable again (passivation by ferrous sulfate) — but the 10-93% range requires super-duplex 2507 or Hastelloy alloys.
FBCN in duplex 2205 is available on consultation for specific projects. For concentrations above 70% and for industrial phosphoric acid in high concentration (>50% P₂O₅), the honest technical recommendation is to specify a supplier specialized in super-duplex/Hastelloy alloys (FB Bombas can refer partners). For process dilutions (sulfuric acid <10%, phosphoric <30%), FBCN 316L stainless serves and is the correct cost-benefit choice.
5. Regulatory standards and safety in fertilizer plants
Brazilian fertilizer plants operate under a restricted set of standards: NR-15 (unhealthy activities), NR-20 (safety in flammables and combustibles — relevant for molten urea and ammonia), NR-23 (fire protection), NBR 14725 (FISPQ — chemical product safety data sheet) and MAPA regulations for fertilizer registration. ABNT NBR 13902 specifically addresses pumps for industrial chemical service and is the reference standard for datasheets.
For classified areas (Zone 1 and Zone 2 per IEC 60079), the pump motor must be Ex-d or Ex-e certified by an accredited Brazilian body (INMETRO). FB Bombas supplies the motor-pump set already configured for the correct class from the datasheet — the customer specifies zone, gas and temperature, FB delivers complete compliance documentation.