Eli5: How is petroleum used to make fertilizer when it doesn’t have any of the three key ingredients?

308 views

I was taught synthetic fertilizers are made of oil, which are a mix of hydrocarbons…. but fertilizers are made of nitrogen, phosphorus, and potassium.

In: 5

2 Answers

Anonymous 0 Comments

Nearly all synthetic nitrogen fertilizers are produced by distilling pure nitrogen from air, then “burning” it in hydrogen extracted from the methane in natural gas. That process results in the production of ammonia.

Sulphur fertilizers *can* be produced as a byproduct of the oil refining process. Sulphate is a common impurity in some oil that needs to be removed. In the US, this often is the result of refining oil imported from Venezuela, which has one of the highest sulphate levels of oil produced anywhere in the world. Sulphate itself is a fertilizer.

Potassium fertilizers don’t come from oil – most of them are produced from potash, which is a mineral that is mined.

If any of the ingredients in a fertilizer comes from a non-organic source then it will often be labelled as “synthetic” – which many people see as synonymous with coming from oil.

So if you’re in the US, the non-organically derived nitrogen in your fertilizer almost certainly came by mixing natural gas and air. The non-organic sulphur *probably* started out as an impurity in oil that was pumped out of Venezuela and refined along the US Gulf Coast. The non-organic potassium was mined as potash in Alberta, Canada.

You are viewing 1 out of 2 answers, click here to view all answers.