How silver refining works

What refining actually does

Almost no silver object is pure silver. Sterling is 92.5 percent silver and 7.5 percent copper; continental pieces are often 800 or 835; old coinage is commonly 900. Refining separates the silver from the copper and everything else, leaving fine silver at 999 parts per thousand. The copper does not come back, which is why refining deals are always priced on fine content, never on what the lot weighs on the scale.

Step one: testing the lot

The lot is weighed and its composition measured by XRF analysis at intake. This is the step that protects you: a canteen of sterling cutlery, a drawer of continental odds and ends and a bag of pre-decimal coins all reduce to one number, the grams of fine silver they contain. Knife handles are a known trap here: sterling-handled knives have steel blades and often a filled handle, so an honest intake weighs the silver actually present rather than the whole knife. You should see and agree the fine content figure before anything is refined.

Step two: separating the silver

Scrap silver is typically refined either chemically, dissolved in nitric acid and the silver then recovered from the solution, or electrolytically, where the impure silver is dissolved at one electrode and pure silver crystals grow at the other. Electrolytic refining is the standard route to consistent 999 purity. Either way the outcome is the same: the silver is collected, the copper and other base metals are left behind.

Step three: pouring the return

The fine silver is melted and returned as grain, small shot that is easy to weigh out for casting and alloying, or poured as a single stamped bar. Jewellers and casters almost always want grain; a bar suits someone consolidating family silver into one piece of metal they can hold.

How the fees work

This is toll refining: the metal stays yours, and the refiner charges a toll for processing it. Fees are a percentage of the fine silver content. Ours is 15 percent, taken in metal rather than cash. A worked example: 100 g of sterling contains 92.5 g of fine silver; our fee is 13.9 g; 78.6 g of 999 silver comes back to you as grain or a bar, with no invoice and nothing else to pay. The silver refining page has a calculator that shows the split for any weight and purity, valued at the live London price.

When refining beats selling

Refine when you want to keep the metal: casting grain for the bench, or a canteen you inherited turned into a bar rather than a cheque. If you want money, selling is the better tool: we buy sterling and other solid silver at published prices per gram. Not sure your silver is solid at all? Start with is my silver real? — plate is not worth refining and we will tell you so plainly.