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cdocastThe CDOCAST fire assay cupellation furnace is designed for the cupellation stage of precious metal assay, where lead and base metals are oxidized and absorbed by cupels while gold and silver remain as a clean assay bead.
Compared with a standard box furnace, this cupellation furnace is built with controlled oxygen supply, high-temperature uniformity, lead oxide fume exhaust and laboratory safety protection for repeatable gold and silver fire assay results.
Designed for cupellation, not general heat treatment. The furnace helps maintain an oxidizing atmosphere and remove lead oxide fumes during fire assay.
A fire assay cupellation furnace is a high-temperature laboratory furnace used after fusion in the traditional gold and silver fire assay method. The lead button is placed in a porous cupel and heated under an oxidizing atmosphere.
During cupellation, lead and other base metals oxidize into litharge (PbO) and are absorbed by the cupel. Gold and silver remain as a metallic bead for weighing or further chemical separation.
For laboratories, the key point is repeatability. Stable temperature, controlled oxygen flow and reliable exhaust directly affect cupellation speed, bead cleanliness and assay consistency.
For gold mining laboratories, refineries, jewelry assay labs, universities and research institutes.
Dual oxygen flowmeters help the operator adjust oxidizing atmosphere during cupellation.
A top-mounted exhaust chimney helps discharge PbO fumes generated in the cupellation stage.
PID control, uniform heating and stable chamber insulation support repeatable fire assay work.
The cupellation furnace is used after sample fusion. It is not used to replace the full fire assay workflow, but it is the key machine for the lead button oxidation stage.
The air-cooled double-wall housing helps keep the external surface temperature below 45°C during continuous operation.
The electrically controlled pneumatic lifting door reduces operator effort and supports stable loading during assay work.
The top chimney is designed to remove lead oxide fumes produced during cupellation and connect with laboratory exhaust treatment.
The CDO-CP cupellation furnace uses an intelligent PID programmable controller with up to 30 heating segments. This helps laboratories create repeatable heating curves for gold assay and silver assay work.
U-shaped silicon carbide heating rods are installed on both sides of the chamber for fast heating, temperature uniformity and easier maintenance. The chamber uses vacuum-formed high-purity alumina fiber with multi-layer insulation to reduce heat loss.
Touch screen control supports programmable heating and easier operation for laboratory technicians.
| Item | Specification | Buyer Note |
|---|---|---|
| Model | CDO-CP | Standard laboratory cupellation furnace model. |
| Furnace Type | Fire Assay Cupellation Furnace | Designed for gold and silver fire assay cupellation stage. |
| Maximum Operating Temperature | 1150°C | Suitable for common cupellation operation. Higher temperature requires upgraded heating elements. |
| Temperature Control Range | 50-1150°C | Programmable temperature control for laboratory workflow. |
| Chamber Dimensions | 300 × 200 × 200 mm | Confirm cupel size and loading quantity before quotation. |
| Power Supply | AC 380 V | Voltage can be confirmed according to local electrical standard. |
| Temperature Sensor | Type K thermocouple, 0-1200°C | Stable temperature feedback for cupellation control. |
| Temperature Control Accuracy | ±1°C | Important for repeatable assay conditions. |
| Temperature Uniformity | ±5°C within effective working zone | Helps reduce differences between cupel positions. |
| Heating Rate | Up to 15°C/min, adjustable | Slow heating down to 1°C/h can be programmed when needed. |
| Heating Elements | U-shaped silicon carbide heating rods | Side-mounted design supports uniform heating and easier replacement. |
| Chamber Material | Vacuum-formed high-purity alumina fiber | Lightweight insulation with good thermal cycling resistance. |
A normal box furnace is mainly used for heating, sintering, annealing or general laboratory heat treatment. It may not provide controlled oxygen flow or a dedicated exhaust path for lead oxide fumes.
A cupellation furnace is built around the fire assay process. It supports oxidizing atmosphere control, stable chamber temperature, cupel loading and exhaust discharge during lead button oxidation.
±1°C control accuracy and up to 30 programmable heating segments support repeatable fire assay cupellation.
Independent oxygen flowmeters help adjust the oxidizing atmosphere according to cupellation requirement.
The top exhaust chimney helps remove lead oxide fumes and can connect with laboratory fume treatment systems.
U-shaped silicon carbide heating rods provide fast heating, stable temperature and long service life.
Double-layer air-cooled structure helps reduce surface temperature and improve operator safety.
CNC machining, phosphating, powder coating and high-temperature baking improve durability and corrosion resistance.
To select a suitable fire assay cupellation furnace, the buyer should confirm the actual laboratory workflow instead of only asking for price.
CDOCAST can customize chamber size, voltage, controller configuration, gas flow arrangement and exhaust connection according to the laboratory requirement.
If a higher operating temperature is required, heating elements can be upgraded to silicon carbide or molybdenum disilicide, but the equipment cost will be higher.
For safety, laboratories should plan cupellation furnace exhaust together with local ventilation and environmental treatment requirements.
It is used for the cupellation stage of gold and silver fire assay. The furnace oxidizes lead and base metals under a controlled oxidizing atmosphere, leaving a precious metal bead for weighing or further analysis.
A cupellation furnace has controlled air or oxygen supply and an exhaust system for lead oxide fumes. A normal box furnace is mainly for general heating and usually is not designed specifically for fire assay cupellation.
The standard maximum operating temperature is 1150°C, with a control range from 50°C to 1150°C. If a higher temperature is required, the heating element configuration must be upgraded.
Yes. CDOCAST can supply cupels in different materials and sizes according to sample type, cupellation method and laboratory requirement.
Yes. The fire assay cupellation furnace is mainly used for gold and silver assay, especially in gold mining labs, refineries, jewelry assay labs and research laboratories.
Please provide chamber size requirement, operating temperature, cupel material and dimensions, gas or oxygen supply condition, waste gas treatment requirement, power supply and expected sample batch size.
The standard warranty is one year. Spare parts, heating elements and technical support can be discussed according to the project requirement.
Send your cupel size, sample quantity, chamber size requirement, operating temperature and exhaust treatment plan. CDOCAST can recommend a suitable fire assay cupellation furnace configuration for your laboratory.