The Refining Process – Technical Articles

Shipment Arrives
The moment your scrap shipment is weighed in at our refining division, it is entered into our computerized refining flow system. The shipment is checked and double-checked through every step of the refining process. Each lot, regardless of size, receives the same careful attention to ensure you a maximum return. If there is any weight discrepancy between your stated weight and our scales, you are called before the scrap continues through our system. Our refining coordinator then records a description of the scrap, and estimates weight loss due to any non-metallic material and a karat estimate. The scrap then moves to our smelting department.

Smelting
Clean scrap (benchsweeps and filings for example) is mixed with a special flux and then melted. The flux makes the melt more fluid and homogeneous. The melt is then poured into a mold, the metal settles to the bottom and the slag created by the flux remains on top taking some of the non-metallic impurities with it. After smelting, the bars are returned to the vault to be weighed and sampled. The bullion remains in the vault until you have been paid for your scrap.

Assaying
After your bullion has been weighed, drill samples are taken from each end of the bullion. This sample is fire assayed in duplicate to determine the precious metal content of the refining shipment. The assay lab does a miniature refining process on multiple samples to determine the precious metal content. The bullion karat is actually determined by the percentage of fine gold remaining following the assay process. The results of the assays must agree. If they do not, the bar is remelted to ensure that it is homogeneous and then resampled and reassayed.

Sweeps
Sweeps require more involved processing than clean scrap. It would be impractical to melt down a sweep because of its large volume and low grade gold content. The sweep is first burned at a low heat to incinerate the combustible material. It is then milled into a fine powder and sifted. By producing a fine blended powder, the sweep is made homogeneous. A representative sample is taken and assayed to determine the fine gold content.

Refining To Fine Gold
After completion of the assay process, the value of the scrap shipment is determined
and you, our customer, are paid. The metal is then ready to be refined into its precious
metal components.

Hoover and Strong has invested in a new refining process known as the “Miller” process.
Bullions from smelting are melted in a furnace. Chlorine gas is then bubbled through the
liquid metal, turning silver and base metals into solid chlorides. These float on top of the
melt and are skimmed from the surface to undergo a secondary refine to reclaim any silver. Once the process is complete, the remaining liquid metal is at least 98% pure gold. This is cast into anodes and electrolytically refined by submerging into a gold-based solution. During this process, fine or 24kt gold is plated onto the cathode. Both platinum and palladium remain in the electrolyte solution where they are later recovered.

This new gold refining process has several advantages over the previous method. Our processing capacity has increased by 100%! As a refiner, once we settle with you, the
customer, we own the gold. As all jewelers know it then becomes an expense because it is
not “working” for us during the refining process. As a consequence, the longer the refining
process takes, the more expense we incur. By increasing our capacity and throughput, we
save money because the gold is in “limbo” for a shorter period of time. These savings help
us remain highly competitive in our pricing structure – we pass them on to you.

The other exciting feature of this new process is that we have reduced the quantity of
waste products generated during gold refining by 75%. Other gold refining methods – using aqua regia for example – create significant amounts of waste products. By converting to the Miller process, liquid waste has been drastically reduced and chlorine gas is scrubbed and filtered out by our air control system, making us one of the most environmentally friendly refiners in the country.

All our refined gold is used to make our mill products, findings, castings and finished
jewelry. This means a high percentage of our products are manufactured using only recycled gold. We at H&S believe in taking care of our environment.

Refining To Fine Platinum
To compliment our new Miller process for refining gold, we’ve also upgraded our platinum and palladium refining process. Our previous process was also slow and produced significant quantities of waste product. We have now installed a new “column refining”
system. The platinum or palladium to be refined is processed into a suitable form and
placed inside the columns where it undergoes a digestion process. Column refining is a
closed system and not just environmentally friendly for waste products; it also ensures the safety of our co-workers.

Once the platinum or palladium have digested, the remaining liquid is the secondary process in retrieving the fine metals. The overall new process recovers metal three times as quickly as the old process, and generates 60% less acid waste per ounce recovered. These financial gains can again be passed on to you, the customer, by keeping our charges low and competitive.

Our Commitment To Environmental Responsibility
Hoover & Strong guarantees that it processes, handles, stores and ships all hazardous material with procedures that meet or exceed federal, state and local environmental regulations. Our treatment facility removes all harmful materials from water with a chelation process before it is evaporated. No waste water is discharged into the environment without being fully treated beforehand. The scrubbers in our air control system remove harmful particles from the furnace exhaust before the air is released back
into the environment. Our new refining processes create up to 75% fewer waste products than standard refining techniques. Our ongoing commitment to improving our environmental responsibility ensures that you have complete legal protection regarding our refining procedures and the handling of any related hazardous material or waste. Don’t assume all refiners are in compliance with these laws. You could be held responsible.

Hoover and Strong is proud to supply all of our products in EcoGold that does not harm communities, workers and the environment. We sell mill products, findings, castings, semi-mounts, finished jewelry and refining services. Over half of our gold is purchased from jewelers and recycled in our environmentally friendly refinery. We then use this gold to manufacture our mill products, and from there the rest of our product range. Our self-sufficiency makes us the most eco-friendly and responsible refiner and supplier of
metal to the jewelry trade, bar none.

The balance of our gold is purchased from other environmental friendly refineries, and mines that follow these guidelines:
• Appreciation of basic human rights outlined in international conventions and law.
• Free, prior and informed consent of communities affected by mining operations.
• Provide safe working conditions, respect for workers rights and labor standards.
• Keep operations out of areas of armed or militarized conflict, protected areas, fragile ecosystems or
other areas of high conservation value.
• Do not force communities off their land, dump mine waste into water or generate sulfuric acid.
• Disclose information about social and environmental effects of projects.

Our Commitment To Security
Hoover and Strong is committed to safeguarding the precious metals entrusted to us. Our Refining Division is an isolated wing with access limited to refining employees. All incoming packages are delivered to the wing where they are logged into the refining flow system. The packages are then taken to our vault where they are opened under security’s surveillance. Hoover and Strong’s security exceeds the industry standard. We do this for our peace of mind, as well as yours, our refining customer.