| You have taken the plunge and sent your gold and | | | | At this point we have bullion bars which are not pure |
| other precious metal which is surplus to your | | | | gold, platinum or whatever precious metal is involved - |
| requirements in to a gold buyer and you have received | | | | we have an alloy or amalgam with a mixture of |
| your check but, aren't you interested in what happens | | | | precious and non-precious metal content. The bullion is |
| to your old pieces and scrap precious metals now? | | | | now melted again for further processing so that the |
| The scrap precious metal which is bought in from the | | | | separate metals can be extracted and when |
| public will now go through a refining process which will | | | | producing "fine gold", the Miller Process is used. |
| involve the metal being sorted, weighed and analyzed. | | | | After the bullion bars are melted, chlorine gas is then |
| This process involves checking and rechecking the | | | | introduced into the molten mixture which reacts with |
| metal at every step of the refining process, in a | | | | silver and non-precious metals to form solid |
| meticulous and documented fashion, because this is a | | | | compounds (known as "chlorides"). These float to the |
| necessary part of the requirement to satisfy | | | | top of the melt and are skimmed off for further |
| numerous regulations on purity control and for applying | | | | refining to extract the silver. What is left is at least |
| hallmarks. | | | | 98% gold and must now be further processed using |
| Smelting | | | | electrolysis. |
| Once logged in and checked, the scrap precious metal | | | | The result of electrolysing the gold melt is to produce |
| is transferred to the smelting department. Smelting is | | | | pure, 24k gold and a solution which contains platinum |
| the process by which the metal is heated and infused | | | | and palladium which is in turn extracted at a later |
| with a special additive, known as a flux, and the metal | | | | stage. |
| is melted. The flux allows for the metal to melt more | | | | This whole process generates only a quarter of the |
| easily and for the pure metal to be mixed thoroughly | | | | pollutants and waste products which traditional smelting |
| providing uniform purity level. | | | | operations generate, and a tiny fraction of the adverse |
| Once melted, the metal is poured into a mold and | | | | environmental impact that mining the gold from the |
| allowed to cool until solid again - this forms bullion bars | | | | ground creates. |
| which are then sampled and weighed. | | | | Platinum Refining |
| Assaying | | | | Platinum is an extremely valuable precious metal, more |
| Assaying is the process by which the bullion bars are | | | | valuable than gold at the moment but it also produces |
| analyzed to determine the level of precious metal in | | | | a large quantity of waste and extremely toxic |
| the bullion bars. Obviously, greater levels of precious | | | | pollutants. The "Column Process" greatly reduces the |
| metal make the bullion bars more valuable. The | | | | pollution and toxins which traditional platinum and |
| analysis takes the form of two samples taken from | | | | palladium refining generates. The metal mix is placed |
| each end of the bullion bar and these are put through | | | | inside a column with an acid solution which digests the |
| a "fire assay" test - it is this test which provides the | | | | precious metal, but because it is self-contained, there is |
| level of purity of the bullion bar. | | | | no excessive use of toxic acids and the creation of |
| Gold Refining: The Miller Process | | | | waste is minimized. |