Ash Fusion Test Furnace

What is the Ash Fusion Test Furnace?

An ash fusion furnace heats prepared ash cones and records their deformation temperatures for coal and coke characterization. It is chosen when ash fusibility data are required for fuel specification and boiler operation.

Overview

The ash fusion furnace is designed around a viewing system and a controlled reducing or oxidizing atmosphere. Ash cones prepared to a standard shape are placed in the hot zone and heated at a defined rate while an operator or camera watches through a window, recording the deformation, softening, hemispherical and fluid temperatures. The furnace reaches 1500 to 1600 C with resistance or silicon carbide elements, and the atmosphere is set by gas flow to reproduce oxidizing or reducing conditions, since ash behavior differs between them. Multi-hole hearths hold several cones at once, and a programmable controller follows the specified heating rate. Uniformity and a clear, unobstructed view are essential so the recorded temperatures are reliable.

How does it work?

An ashing furnace heats a sample in a crucible until organic matter burns away and only mineral residue remains. A programmable controller raises temperature in stages, often with an initial low-temperature char stage to avoid flaming and loss of light ash, followed by a higher ignition stage for complete combustion. Air enters through the door gap or dedicated ports to supply oxygen, while combustion gases exit through a flue or extraction duct. Ceramic fiber or firebrick insulation and resistance or silicon carbide elements give uniform temperature across the hearth, and a type K or N thermocouple with PID control holds the setpoint. After the hold, the furnace cools and the crucible is weighed to constant mass, so reproducibility of temperature and atmosphere directly controls the result.

What are the key features?

• Viewing window or camera for cone observation
• Temperature range to 1500 to 1600 C
• Controlled oxidizing or reducing atmosphere
• Multi-hole hearth for several cones
• Programmed standard heating rate
• Type B or S thermocouple for high temperature

What are the technical specifications?

A typical ash fusion test furnace configuration offers maximum temperature of 1500–1600 C, heating rate of 5–15 C/min, atmosphere of Oxidizing or reducing, cones per batch of 3–5, observation of Window with camera or visual and thermocouple type of Type B or S. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Ash Fusion Test Furnace is used in coal ash fusibility determination, coke ash characterization, boiler slagging assessment, fuel blending studies and biomass ash behavior. Across the wider Ashing Furnaces class, laboratories also deploy it for food and feed ash content, coal and fuel ash determination and residue on ignition in pharmaceuticals.

Which standards and certifications apply?

Relevant standards and methods include IEC 61010-1, IEC 61010-2-010, ASTM D3174, ASTM D1857, ISO 1171, ISO 540, USP <281> and Ph. Eur. 2.4.14. Certification candidates for this model are CE, ISO 9001 manufacturing and RoHS; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the furnace on a heat-resistant surface with clearance and connect a vent or extraction duct, since combustion produces smoke, carbon dioxide and sometimes corrosive vapours. Use only crucibles and trays rated for the temperature and the sample chemistry. Run a low-temperature char stage before the ignition stage to avoid flaming, and never open the door at full temperature. Check and clean the hearth after each batch, since ash and flux residues attack the lining. Calibrate the control thermocouple and verify uniformity periodically, and record every ashing cycle together with crucible weights for traceability.

How do I select the right Ash Fusion Test Furnace?

Select the ash fusion furnace when deformation temperatures of ash cones must be recorded under controlled atmosphere for coal, coke or biomass work. General ashing furnaces cannot provide the viewing or atmosphere control. In the RFQ, specify top temperature, atmosphere control, cone capacity, viewing method and standards compliance.

How does it compare with other Ashing Furnaces variants?

Choose an ashing furnace when the result is expressed as ash or residue and the ignition atmosphere controls the outcome. Set the maximum temperature from the method, usually 550 C for food and feed ash, 600 to 800 C for residue on ignition, and up to 1000 C for some fuels. Match chamber volume to sample count, and prefer good uniformity and programmable staging, since a slow char stage prevents ash loss. Decide whether a larger chamber, ash fusion capability or microwave heating suits the workload. Verify that the furnace vents combustion gases safely, and confirm power, extraction and calibration options before ordering.