New Life Innovations' Process
The separating and purifying of precious metals from other metals is called refining. Smelting is the separation of precious metal from non-metallic impurities.
New Life Innovations (NLI) is committed in using correct and accurate evaluation methods of all precious metal shipments from our valued customers. Our modern assay laboratory guarantees that all precious metals are tested using the most suitable methods of evaluation. Gold, silver, platinum, palladium and rhodium are assayed (determination of precious metal purity) in various ways to accurately and precisely evaluate each metal’s percentage of purity.
The method known as “fire assay” is the oldest known method of assaying gold and continues to be one of the most accurate. When gold is melted, a sample of the gold is taken, either by drilling through the poured bar or by capillary tube sampling while the gold is in a molten state. The sample is weighed very precisely, and the amount recorded. The sample is wrapped in assay lead foil along with a quantity of pure silver. This wrapped ball is placed in the furnace in a cupel (a special kind of disposable crucible). All the non-precious metals are absorbed by the hot cupel. The precious metal forms a button within the cupel. The cupel is removed from the furnace and the button is brushed to remove any remaining bits of the cupel. It is hammered flat, rolled thin and then heated in a porcelain crucible containing a weak nitric acid solution. The acid removes the silver, which is poured off and the silver recovered from solution. The gold is then rinsed in distilled water to remove any residual acid and then dried. The sample of gold is now at least 99.999% pure! The sample is then weighed again. The original weight of the impure sample is divided into the weight of the now pure sample. The result is the assay.