World's Greenest Refiner - Hoover & Strong has been refining precious metals for over 106 years and we pride ourselves on utilizing environmentally-friendly refining techniques that always exceed federal, state and local environmental regulations.
In April 2012, SCS Global Services, a globally-recognized independent third party sustainability expert, certified us as a "Responsible Refiner". This certification confirms our ongoing commitment to the environment and to our customers who demand raw materials that are ethically sourced with minimal environmental impact.
DOWNLOAD THE HARMONY BROCHURE - This brochure includes additional information about our SCS certified green refinery and our responsible diamond sources and services.
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 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.
In the Mill and Jewelry Division:
- All clean manufacturing scrap from our operation is re-melted.
- Floor sweeps, sink sludge and mixed scrap are all refined.
- Cooling water from casting and melting is re-circulated within the plant.
- All copper and brass is recycled from the tool and die department.
In the Refining Division:
- Gold refining process reduces the quantity of waste products generated per ounce recovered by 75%.
- A newly developed platinum and palladium refining process reduces the quantity of waste products generated per ounce recovered by 60%.
- All furnace and chemical exhaust fumes are processed through a scrubber system that removes all harmful particulates, cleaning the air before it is released into the environment.
- The water treatment facility removes all harmful materials from our waste water before it is evaporated. Absolutely no waste water is discharged into the environment.
- All cooling water for our refining smelting furnaces is provided by a fully recycled, no-loss water cooling system.
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 a 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 a karat estimate. The scrap then moves to our smelting department.
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.
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 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 24k gold is plated onto the cathode. Both platinum and palladium remain in the electrolyte solution where they are later recovered.
This 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 quality 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 that 100% of our products are manufactured using only re-cycled gold. We at Hoover & Strong believe in taking care of our environment.
Refining To Fine Platinum
To compliment our 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 coworkers.
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 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.
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