Our fire assay crucibles are high-quality and are suitable for multi-use. They have highly consistent dimensional tolerances and mechanical strength that makes manual and automatic handling very safe and efficient.
Customization is also available for any requirement to shape, size and so on. We can even mold logo, model no. or other signs onto the bottom of crucible if it is required by customer.
Gem40 40g Fire Assay Crucible
For Continental crucibles, our standard range offering, these crucibles will last 4-5 fusions (depending on ore type and flux formulation).
Drill core samples (or others) are received at the laboratory, crushed, milled and dried in the oven. Samples are then separated into bags, tagged and weighed.
Next, the samples are prepared for the fusion process, which requires a reducing environment and so the samples are mixed with flux, a carbon source (coal dust) and litharge (PbO).
The samples are then placed into a fusion/ refractory crucible, ready to go into the furnace. The high tempareture (1000 – 1200°C) melts the sample while the flux fuses with the gangue (non-precious material) and the now liquid lead collects all the precious metals. The newly-formed Pb-Au-Ag-PGE concoction migrates to the bottom of the crucible due to its high density.
As cooled lead sample is then separated from the glass waste (slag) with a hammer, and placed in a porous bone ash (MgO) crucible, ready for the cupellation step.
The sample is then placed in a muffle furnace at around 1000°C. The lead oxidises with the aid of the inflowing air from the furnace muffle and then immediately melts and is absorbed into the crucible, leaving behind what is known as a precious metal prill.
The prill is then analysed for its precious metal content through dissolving it in aqua regia (a mixture of hydrochloric and nitric acid) and the concentrations determined by spectroscopic methods (AAS, ICPAES, ICPMS).
Eventual detection limits are in the region of parts per billion but accuracy is usually in the region of 3 -5% for this metallurgical analytical technique.
L.O.I(loss on ignition)
Precious Metal Analysis
Fire assay crucible
SiO2 + Al2O3
Automatic molding equipment
ISO 9001 SGS
Many stocks , delivery time around 5-10days . by sea or by air as customer request
Delivery & Service:
Timely delivery each time. Provide reliable service and responsible for each customer with each product. Our target is to satisfy every customer with the best service.
Wooden Case Dimension (mm)
7000 square meters work shop
Automatic production line
Longer working life
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