High Temperature Muffle Furnace Silicon Molybdenum Rods for Fire Assay Gold Testing

This 1500℃ muffle furnace is the heating core of a fire assay laboratory. Fire assay runs on three high temperature steps — flux fusion at 1000–1200℃, cupellation at 900–950℃ and scorification — and every one of them depends on the same three things: the furnace can hold the set point, the whole crucible batch sits in an even thermal field, and the chamber atmosphere stays clean and oxidising. The unit delivers 1500℃ from eight silicon molybdenum heating rods arranged symmetrically around the chamber, holds ±5℃ with an S-type platinum-rhodium thermocouple, and gives you an 82 L working chamber with a pneumatic vertical lift door.

• 1500℃ from eight molybdenum disilicide rods: MoSi₂ elements keep their output at temperature and do not oxidise or sag the way resistance wire does, so the furnace can sit at 1150℃ fusion temperature all day without losing set point accuracy. The eight rods are placed symmetrically around the chamber so the radiated heat is even on all four sides, not just at the back wall.
• 82 L chamber, about five times the common 16 L lab furnace: the working chamber measures 295 x 485 x 575 mm. Twenty gold ore samples that would take a 16 L furnace several batches are fused in a single load, which cuts cycle time, energy cost and crucible handling risk at the same time.
• Pneumatic vertical lift door with foot pedal: the door rises vertically on an air cylinder and is operated by a foot switch, so both hands stay free for the crucible tongs or the loading cart and the operator's arms never reach across the furnace mouth. Vertical travel also keeps the door seal even, which is why the unit holds temperature better than a swing door after repeated opening.

• Fire assay flux fusion of gold, silver and PGM ore samples with litharge flux
• Cupellation of lead buttons on bone ash or magnesia cupels
• Scorification and annealing steps in precious metal assays
• Sulphide and refractory ore roast preparation before fusion
• High temperature ash determination, sintering and heat treatment work in the same laboratory

• Batch size decides throughput: an 82 L chamber changes the assay lab from batch-limited to shift-limited, which is usually the real bottleneck once the balance and cupellation stage are running smoothly.
• Independent cordierite-mullite chamber: the chamber is a separate refractory block rather than a lining cast into the frame, so flux spillage or thermal cracking is repaired by replacing the block instead of scrapping the furnace.
• Door design decides operator safety: foot-pedal vertical lift keeps the operator's face and arms away from the 1500℃ opening on every single load, hundreds of times a month.
• 25 kW input, 19 kW heating power at 460V three phase: sized to bring an 82 L chamber to fusion temperature without a long ramp, and the 460V three phase supply matches North American laboratory power.
• ISO 9001 production with OEM and ODM support: spare heating rods, thermocouples and door seals are supplied as separate service parts.

Send three details and we reply with the chamber layout, the fusion program settings and a quotation instead of a generic price list:

• Ore type and daily sample count — sulphide, oxide or refractory ore, and how many crucibles you run per shift
• Crucible diameter and fusion program — we confirm how many crucibles the 295 x 485 x 575 mm chamber takes per load
• Site voltage, phase and compressed air — 460V three phase is standard, 380V and 220V options are built to order, and the pneumatic door needs a compressed air line at your bench

• Export wooden case with shock blocking for the heating rods and refractory chamber
• English operation manual, wiring diagram and thermocouple calibration certificate supplied
• Spare MoSi₂ rods, S-type thermocouples, door seals and foot switches available separately