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Fire Assay Electric Furnace

    Fire assay is considered the most reliable method for accurately determining the content of gold, silver, and platinum-group metals (except osmium and ruthenium) in ores or concentrates. In order to simplify the experimental operation, Juxing kiln combined with the specific needs of the Academy of Geological Sciences, the electric furnace was improved to create a set of experimental equipment related to Frie Assay.

   The equipment is specifically composed of an electric furnace body, crucible rack, and line feeding rack. The size can be customized according to the number of crucibles and actual demand.

    The furnace is normally used under 1400 degrees centigrade.

  *It is essential to discuss your application with us to ensure the suitability of the material for use in this equipment. 

Main operation steps:

  • Sampling, including minerals, refined products, debris, etc., requires the careful collection of representative samples. Because precious metals are often present in minerals in irregular dispersion, it is often necessary to extract a representative sample with a large amount of the mineral, and finally, the sample must be carefully crushed.

  • Melt sample, add appropriate flux to the sample, such as pulverized sodium carbonate, borax, silicate, lead monoxide, etc., and then heat the sample and flux to melt. Lead monoxide is reduced to metallic lead, which sinks to the bottom of the container with the precious metal, and when it cools it becomes a metallic pellet containing the precious metal and a lot of metallic lead, as well as other metallic impurities. The slag produced by the reaction is discarded.

  • The pot is then tested for gold by placing pellets containing precious metals and lead in a pot made of pure porcelain, which is then heated in a special GWDL electric oven that provides a strong oxidizing atmosphere. The lead and other metal impurities in the pellets are oxidized, and the resulting lead oxide and other metal oxides become slag or impregnated into the pores of the oven. Only the gold and silver are not oxidized and remain metallic, separate from the lead and other metal oxides. Remove the oven from the GWDL furnace and allow it to cool slowly. The resulting balls can be washed and dried and used as samples, or they can be made into thin sheets by hammering or rolling.

  • The total weight of gold and silver can be measured by weighing the sample containing gold and silver.

  • Separation of gold and silver, the silver can be dissolved by treating the sample containing gold and silver with hot dilute nitric acid.

  • Weighing, after removing silver only gold samples after washing, drying and then weighing, you can measure the weight of gold.

Standard specifications

  • Crucible dimension(top side diameter: 92mm, bottom side diameter: 59mm. thickness 7mm. height 140mm)

  • Furnace chamber: 600*700*300 can be placed crucible 30 pieces.

  • Furnace chamber: 600*900*300 can be placed crucible 40 pieces

  • Furnace chamber: 600*1050*300 can be placed crucible 50 pieces.

*Content may be subject to modifications or corrections

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