Specialized laboratory

Danesh Banyan Company, the foundation of the Zarmehr Mining Industrial Group, was established in 1385 with a specialized laboratory for analyzing gold and silver in cans, products, and bars. It succeeded in obtaining the laboratory’s accreditation license from the Standards Administration in 1388 and operated as a partner laboratory of the Standards Administration from 1388 to 1403.

Since 1400, the requirements of the ISO 17025 standard have been established in the laboratory, and in March 1403, it succeeded in obtaining the international ISO 17025 certificate with the scope of determining the amount of gold in mines, determining the amount of gold by the coplasion method, and determining the quality of high-purity gold using ICP-OES. Considering the high importance it attaches to quality control of results, this laboratory has implemented an output data control process using methods such as using replicate samples from the grinding phase, using replicate samples from the powder phase, placing CRM RM, Blank, Replicate and Duplicate samples in each test, and sending interlaboratory samples.

The gold measurement test method in mines is carried out in accordance with the Standard 853 of the National Standards Organization of Iran. Samples entering the Zarmeh Laboratory for the analysis of precious metals and other metals are divided into three groups, which include core, trench and drill.

If the sample is in the form of a slice, it must first be broken into pieces, then divided, dried, and powdered by a divider. If the sample is in the form of a core, it must first be cut by the user, then broken into pieces, then divided, dried, and then powdered by a divider. If the sample is in the form of a drill, it must only be divided into pieces, then dried, and powdered.

The sample is powdered by a pulverizer to a size of about 100 microns and placed inside a sample bag, which is given a laboratory archive code. After this stage, the soil sample for the dissolution process is weighed with a specific weight on a scale with an accuracy of 0.1 gram and mixed with the dissolution aid. (It should be noted that the dissolution aid is an imported substance that was purchased in the early years, but with the efforts of the Research and Development Unit, its formula was indigenously prepared by Zarmeh experts and is now prepared in the Zarmeh laboratory.) After mixing the sample with the help of the solvent and soil, this mixture is homogenized and transferred to the solvent bottles. (The solvent bottles are also an imported product, and this product is also prepared by the laboratory with the efforts of the Research and Development Unit and the laboratory’s experts). The cans are placed in an electric melting furnace at a temperature of 950 degrees Celsius, and after the melting process is complete, the molten material is discharged from the cans into special cast iron containers. After the molten material cools, by inverting the cast iron containers, it is observed that a piece of lead has formed at the end of the container, and above it, a glass-shaped material called lead is seen. The lead is separated from the lead with a hammer.

The lead contains precious metals that have been collected from the molten sample. Then the cubic lead is placed inside the bone couplers (couplers are also imported goods that are produced in the laboratory with the efforts of the Research and Development Unit and the laboratory experts) which are placed inside the second furnace called the coupling furnace and are pre-heated to carry out the coupling process. After the coupling process is completed and the couplers are removed from the furnace, a silver-colored ball containing silver and gold will be formed. The couplers will be transferred to the acid wash. Then, the ball obtained from the coupling stage is transferred by forceps into a special cylinder. During the first stage of the acid wash process, the silver ball is completely dissolved. During the continuation of the acid wash process, the gold is completely dissolved in the royal acid. After the balloons are filled to volume, the gold concentration in the sample is read by an atomic absorption spectrometer.

This laboratory, equipped with advanced and sensitive analytical instruments such as ICP-OES, FAAS, GFAAS… and using the latest methods, is able to provide the following services:

• Analysis of gold, silver, palladium and platinum by the Fire Ace method
• Multi-element analysis with sample preparation in tetrahydrofuran and measurement using ICP-OES instrument
• Analysis of precious metals in high-grade concentrates
• Analysis of gold, silver and base metals in artifacts and swords
• Determining the purity of a gold bar
• Determining the purity of a silver sword
• Determining the amount of impurities in gold and silver bars
• Design and conduct gold processing tests from various mineral ores
• Design and conduct tests related to the extraction of gold and silver from mineral concentrates
• Analysis of base metals by acid dissolution and reading or atomic absorption.
• Carbon activity analysis
• Determination of sodium cyanide purity
• Analysis of gold and silver in loaded and unloaded carbons
• Analysis of gold, silver, and base metals in cyanide solutions
• Physical and chemical analyses of kaolin samples