Ammonia-water neutralization with sulfuric acid to ammonium sulfate — a BRINE process flowsheet
A 2 wt% ammonia water (a scrubber or coke-oven bleed) is neutralized with 20 wt% sulfuric acid to pH 6.0. The neutralizer solves the acid dose (drawn from the acid supply, the rest returned) on the aqueous speciation (NH4+ pKa 9.25), so at pH 6 nearly every ammonia molecule is protonated and the dose lands at half a mole of sulfuric acid per mole of ammonia: the stream leaves as ammonium sulfate solution, reported from the speciation. The heat of neutralization is the ammonium dissociation enthalpy, 52.2 kJ per mole of ammonia protonated (110 kW here), and the outlet is adiabatic, so the liquor warms by about 12 K.
Modeling assumptions & limitations
- 1Only the proton-transfer heat is carried; diluting concentrated acid releases much more on its own, which is why a dilute acid is dosed here
- 2The aqueous package treats ammonia as non-volatile, so the ammonia a warm, alkaline liquor loses to the air is not shown; and
- 3Activity coefficients are B-dot, a screening model above about 1 mol/kg ionic strength.
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- Rigorous BRINE thermodynamics, solved by the same engine every simulation runs on.
- 1 unit operations modeled: Neutralizer.
- Focus areas: Neutralization, Ammonia, Ammonium sulfate, Wastewater.
- Thermodynamics
- BRINE
- Components
- water, ammonia, h2so4
- Unit operations
- Neutralizer
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Read the step-by-step guideReproduce this exact result from Python — the real client.get_example() → run_and_wait() path, not a mockup.
from flowsim.sdk import FlowSimClient
client = FlowSimClient()
example = client.get_example("ammonia-water-neutralization")
sim = client.create_simulation(example["title"], example["flowsheet"])
result = client.run_and_wait(sim["id"])
print(result["status"]) # "converged"
streams = client.streams(sim["id"])Related models
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Battery cobalt recovery: leach, neutralize, D2EHPA Mn SX, Cyanex 272 Co SX, electrowinning
Spent NMC111 black mass is leached in sulfuric acid with the acid consumption tracked (lithium as Li₂SO₄, each transition metal as its sulfate), so the pregnant leach solution carries the residual free acid a real leach leaves. A neutralizer then titrates that liquor with 20 wt% caustic to pH 4.0 on the aqueous speciation: the caustic dose is solved, not assumed, and the heat of neutralization (55.8 kJ per mole of acid neutralized) warms the liquor; the caustic header is the supply, and what the titration does not take is returned. Two solvent-extraction circuits on the pH-isotherm chemistry follow, the common NMC arrangement: D2EHPA at pH 4.0 takes manganese into the organic while cobalt and nickel stay behind, and Cyanex 272 at pH 5.0 then takes cobalt and rejects nickel and lithium to the raffinate. The Cyanex 272 isotherms are one published measurement (Liu et al., Metals 11 (2021) 401: 0.4 M in ShellSol D70, 40 C, sulfate; pH50 cobalt 4.15, nickel 6.06), and the 1.9 pH-unit gap between them is why the cobalt organic carries about 0.6% of the nickel, against about 3% with D2EHPA at the same cobalt recovery. The loaded cobalt organic is stripped into a dilute sulfuric strip liquor, and that advance electrolyte goes to cobalt electrowinning: Faraday's law at a 90% current efficiency, 90% of the cobalt plated as cathode cobalt, the anode's oxygen and the 10% of the charge that evolves hydrogen reported as cell gas, and one mole of sulfuric acid regenerated per mole of cobalt plated.
Acid-mine-drainage neutralization: staged lime precipitation
Acidic, metal-laden mine water (dissolved ferric iron, aluminium, nickel and zinc over a sulfate background) is cleaned in a two-stage lime-neutralization circuit — the classic hydrometallurgy / water-treatment precipitation train. Stage 1 doses to pH 4.5, where ferric iron (Fe(OH)3, pKsp 38.6) and aluminium (Al(OH)3, pKsp 33.0) drop out as a sludge while the base metals stay dissolved; stage 2 raises the liquor to pH 9.5, where nickel (Ni(OH)2) and zinc (Zn(OH)2) precipitate, leaving a clarified effluent. Both stages are the new precipitator unit op wrapping the codebase's CRC-cited metal-hydroxide solubility-product chemistry (thermo/electrolytes.hydroxide_precipitation) — dose to a pH setpoint, read off what drops out — the same selective-precipitation workflow a real neutralization plant runs.
Quench-converter ammonia synthesis loop
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