As part of our comprehensive overview of all of the different kinds of refining that jewellers can make money back from, let’s delve into the categories of floor sweeps, carpets, and the (little-known) sludge.
Read on for descriptions of these, as well as best practices in collecting, storing and submitting your refining to maximise your payout:
FLOOR SWEEPS
This refinable material category includes sandpaper, sanding disks, tissue paper, polishing wheels, rubber wheel grindings, cotton pieces, plastics, vacuum dust, buffs, brushes, emery paper, metals lost during lapping and setting, felts, and miscellaneous workshop debris including grimy mop heads, cotton wool, wet wipes, paper towels, vacuum bags and filters.
How to look after your floor sweeps refining:
Floor sweeps are low yield material, which necessitate a more involved precious metals extraction process and longer refining times and should be stored separately to bench sweeps.
How we recover precious metals from your floor sweeps:
This process is different and more time-consuming than the previous. The sweep is spread out in a large tray. A full description of the contents are recorded and the sweep is photographed. The material is incinerated, calcined, milled and sieved leaving us with a fine powder. A sample of the powder is sent to an independent assay laboratory. Flux is added to the powder which is smelted in our gas furnace and poured into an ingot. This is drilled for assay and sent to the laboratory for refining. The precious metals recovered must be equal to the expected yields calculated from assay.
Refining turnaround time for floor sweeps:
- Our turnaround time for floor sweeps is 15 working days as this is a long and involved process.
- Please note this timeframe does not include time spent in transit to our Cape Town refinery.
CARPETS
Carpets that have been lying under benches, polishing or casting areas are valid sources of precious metal recovery, but are one of the lowest grades of refining and are very time-consuming to refine.
How to look after your carpets refining:
Depending on your work output, it’s best to only send in carpets that have been in your workshop for approximately 5 years. These should be supplied with as little rubble or other debris that might accompany their removal.
How we recover precious metals from your carpets:
This process is different and more time-consuming than the previous ones. The carpet is cut in to small pieces for processing, and then the material is incinerated, calcined, milled and sieved leaving us with a fine powder. A sample of the powder is sent to an independent assay laboratory. Flux is then added to the powder, smelted in our gas furnace and poured into an ingot which is drilled for assay and sent to the laboratory for refining. The precious metals recovered must be equal to the expected yields calculated from assay.
Refining turnaround time for carpets:
- Turnaround times for carpet: 15 -20 working days.
- Please note this timeframe does not include time spent in transit to our Cape Town refinery.
- Please allow for longer turnaround if the job is extremely large.
SLUDGE
Sludge is a bad smelling, goopy compound that looks like black mud. It collects in sink traps and wastewater treatment systems, and is an overlooked category of refinable material. If you’re not collecting sludge, you could be pouring substantial amounts of money down the drain. This is an easy DIY installation that CPM is happy to advise you on, or simply have our ready-made sink trap product installed.
How to look after your sludge:
Don’t wash your hands or any dishes or foodstuff in the basin that your sink trap is fixed to. The fine metals stick to the soapy, oily or greasy residue which floats on top, and will eventually be flushed down the drain, evading the sink trap system’s filters.
How we recover precious metals from your sludge:
Sludge is spread out on to trays and dried. Flux is then added to the powder, smelted in our gas furnace and poured into an ingot which is drilled for assay and sent to the laboratory for refining.
Refining turnaround time for sludge:
- Turnaround times for carpet: 15 working days.
- Please note this timeframe does not include time spent in transit to our Cape Town refinery.
PLEASE DON’T SEND THE FOLLOWING, AS WE DO NOT REFINE:
- Plating solutions
- Solutions from ultrasonic cleaners – these must be removed by a specialist waste company and MAY NOT be discarded down the drain.
- Silver Nitrate, Mercury, computer parts, stainless steel or amalgam.
- Please remove all precious stones from refining beforehand as we do not sort/remove these
- Please remove from your refining batches anything flammable or explosive including aerosol cans, lighters and batteries; domestic waste like foodstuff (or dirty nappies!), tin cans or metal items like knives, files and tools; and light bulbs
