Correctly caring for your precious metal apparatus will provide a service life unrivalled by another other material. These simple guidelines will help you get the most out of your investment.
1600°C for ZGS 10% rhodium platinum 1 Kg Crucible
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1400°C for ZGS 5% gold platinum.
1450°C for 3% gold 10% rhodium platinum
When high temperatures are involved, avoid unknown substances as well as the following to prevent platinum being attacked:
Platinum vessels should always be cleaned after use.
Platinum tipped tongs are unsuitable for removing platinum vessels from acid leach solutions; the acid will attack the frames causing the shoes to loosen and detach. The labware shape and surface should be preserved for maximum life and inadvertent handling can cause distortions. Minor crucible distortions can be reshaped on a reshaping block with a plug inside, which is rotated slowly with a moderate pressure. The block and plug can then be used to store the crucible.
Our platinum apparatus can be used for evaporations with:
Fusions in platinum labware should be under oxidising conditions without organic substances. During fusion and cooling the material should only come in to contact with platinum or clean refractory materials. To enable solidified material to be removed without distorting the vessel it should be tilted while the melt is cooling. Common fusion agents that will affect platinum are:
Platinum apparatus is widely used for ignitions, with a low risk of damage when precautions are used:
Our platinum labware can be used for ignitions of the following precipitates:
Precipitates being ignited in a Gooch crucible should have full access to air, even without organic matter. Particular care should be taken with readily reducible compounds. For determining ash in organic materials, we recommend a shallow dish to ensure a large surface area is exposed. We advise particular care is taken when determining volatile matter in fuels. The non-oxidising atmosphere to prevent loss of free carbon can contaminate the platinum, particularly if the fuel is rich in sulphur or phosphorus compounds. When determining magnesium or phosphorus by the magnesium ammonium phosphate method, full access of air needs to be maintained in the heating process. The filter paper should be completely ashed before raising the temperature to completely decompose it to pyrophosphate. The ignition of ammonium arsenate requires even more stringent care to avoid damage.
Removing water or alcohol from electrodes by shaking them vigorously can cause bending at the junction of the stem and the gauze cylinder. Repeated bending and straightening will eventually cause a fracture. Instead, we recommend washing the electrodes in water, rinsing them in alcohol and drying them in warm air below 100°C. We don't recommend drying them in a Bunsen flame as this can cause the fine gauze wires to soften and sag and any deposit left may alloy with the platinum.
When used as cathodes for determining bismuth, cadmium, gallium, lead, mercury, tin and zinc the platinum should first be plated with copper or silver. This prevents superficial alloying with the deposited metal.
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1 Kg Crucible To ensure a long platinum vessel life when producing glass, all batch materials should be fully oxidised and silica-bearing refractory materials should be avoided. We recommend cleaning the vessel in 50% hydrofluoric acid at no more than 80°C. This may take several days - to speed up glass removal, occasionally remove the vessel from the acid and scrub soft glass residue away, ensuring your skin is protected.