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  2. Granulation (jewellery) - Wikipedia

    en.wikipedia.org/wiki/Granulation_(jewellery)

    The metals used in granulation are usually gold and/or silver alloys of high purity – alloys below 18 kt. gold and sterling silver being unsuitable. With each technique, the process begins with the making of the granules themselves. [2] The granules are made from the same material as the base to which they will be affixed.

  3. Gold parting - Wikipedia

    en.wikipedia.org/wiki/Gold_parting

    Invented by Emil Wohlwill in 1874, the Wohlwill process produces the highest purity gold (99.999%). It is an electrolytic process using pure gold for the cathode (or titanium as a starter cathode) and chloroauric acid (gold chloride-hydrochloric acid) as the electrolyte; this is made by dissolving gold with chlorine gas in the presence of ...

  4. Granulation - Wikipedia

    en.wikipedia.org/wiki/Granulation

    Plastic granulation and pelletizing line; extrusion, cooling, and cutting. In plastic recycling, granulation is the process of shredding plastic objects to be recycled into flakes or pellets, suitable for later reuse in plastics extrusion. In the first stage, plastic objects to be recycled are fed to an electric motor-powered cutting chamber ...

  5. Gold extraction - Wikipedia

    en.wikipedia.org/wiki/Gold_extraction

    The chloride process became obsolete with the development of the cyanide process. [22] [23] In 1887, John Stewart MacArthur, working in collaboration with brothers Dr Robert and Dr William Forrest for the Tennant Company in Glasgow, Scotland, developed the MacArthur-Forrest Process for the extraction of gold ores. By suspending the crushed ore ...

  6. Wohlwill process - Wikipedia

    en.wikipedia.org/wiki/Wohlwill_process

    The Wohlwill process is an industrial-scale chemical procedure used to refine gold to the highest degree of purity (99.999%). [1] The process was invented in 1874 by Emil Wohlwill. This electrochemical process involves using a cast gold ingot, often called a doré bar, of 95%+ gold to serve as an anode.

  7. Granular material - Wikipedia

    en.wikipedia.org/wiki/Granular_material

    The process stops when the surface inclination angle is equal to the angle of repose. The difference between these two angles, Δ θ = θ m − θ r {\displaystyle \Delta \theta =\theta _{m}-\theta _{r}} , is the Bagnold angle, which is a measure of the hysteresis of granular materials.

  8. Cupellation - Wikipedia

    en.wikipedia.org/wiki/Cupellation

    16th century cupellation furnaces (per Agricola). Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.

  9. Gold panning - Wikipedia

    en.wikipedia.org/wiki/Gold_panning

    "Panning out" ~ Stereoscopic view of print taken by the U.S. Geological and Geographic Survey of the Territories ~ circa 1874–1879 Gold panning is a simple process. Once a suitable placer deposit is located, some alluvial deposits are scooped into a pan, where they are then wetted and loosed from attached soils by soaking, fingering, and aggressive agitation in water.