Ammonium sulphate: Feedstocks
Why its inputs are almost free
What this tab covers What it is made from and what it feeds: the raw materials and energy per tonne with their share of cost (linked to the commodity table), who is low-cost and why, and the chemicals made from it.On paper AS is ammonia plus sulphuric acid: 0.26 t of ammonia and 0.74 t of acid (about 0.24 t of sulphur) per tonne. In practice most producers get both almost free as by-products of caprolactam, coke or flue-gas cleaning. That is why by-product AS sets world prices and synthetic plants run only where acid or ammonia has nowhere better to go.
Inputs per tonne
| Input | Quantity per tonne | Role | Share of cost | Source |
|---|---|---|---|---|
| N Nitrogen (ammonia) | 0.258 t per t (stoichiometry) | nitrogen | about 60-70% of synthetic AS raw material cost (indicative) | stoichiometry; USGS MCS 2026 |
| S Sulfur | about 0.24 t S (0.742 t H2SO4) per t | sulphate and sulphur nutrient | about 30-40% for synthetic AS (indicative) | stoichiometry; sulphur tile |
| Oil Crude oil | indirect | AS is a by-product of nylon 6 monomer | allocated cost near zero | indicative |
| Kc Coking coal | indirect | ammonia source from coking | allocated cost near zero | indicative |
| Gas Natural gas | about 8.5 MMBtu per t synthetic AS (0.258 x about 33 MMBtu/t NH3, indicative) | ammonia feedstock | via ammonia | nitrogen tile (indicative) |
Who is low-cost, and why
Chinese caprolactam and coke by-product AS is the lowest-cost supply because producers must move it. Synthetic producers are high on the curve unless they use spent acid. Freight is a large share of delivered cost for a 21% N product, which favours nearby by-product supply.