Melting crucibles for non-ferrous metallurgy

precious metals and special alloys

Ζirconia Silicate (Zircon) Crucibles, Melting Crucibles For Non-Ferrous Metallurgy, Precious Metals And Special Alloys

Zirconium Silicate ( ZrSiO4) or Zircon has unique and outstanding properties as a refractory material. It has no definite melting point and dissociation into zirconia and silica begins at 1550°C with little physical change apparent until 1700°C. Its favorably low thermal expansion properties and lack of crystalline inversion give it a higher thermal endurance than other ceramic refractory materials.

One of the major uses of Zircon crucibles is in the glass making laboratory. When glassy or siliceous slags are present in your melt t-ceramics Zircon crucible is the solution. Zircon crucibles are often used for melting platinum-group alloys. Their strength and resistance to high temperature makes them right for those special “dirty refining” applications. Zircon crucibles are also suitable for metal melting and casting since the cast metal does not stick to the crucible even at high temperature. Zircon crucibles performs well with many non-ferrous metals and alloys, especially Aluminium. Zircon is not “wetted” by Aluminium, so is relatively unreactive.

Basic properties of the material

Features:

• 1550 C max. service temperature
• 64% wt. Zirconia and Hafnia, 35% wt. Silica
• Exceptional thermal shock resistance, suitable for fast thermal cycling
• Superior performance against molten material
• Extended life – low cost
• Low reactivity - excellent chemical resistance to corrosion from chemicals, especially resistant against alkali material
• Low porosity and exceptionally fine surface finish enhance cleaning from heat treatment residuals and prevents chemical attack
• High mechanical strength and wear resistance
• Consistent dimensional control

The crucible material has the following requirements:

• corrosion resistance, resistance to melts and slags;

• mechanical strength;

• high purity material;

• resistance to thermal shock (heat resistance);

• refractoriness;

• shape stability and preservation of strength up to the maximum working temperature.

The choice of crucible material usually depends on the composition of the material to be melted, as well as the specific operating conditions.

We offers crucibles from the following materials:

• corundum (Al2O3 content not less than 98%);

• zirconium dioxide with various stabilizers (ZrO2);

• corundum-zirconium composite (Al2O3 + ZrO2);

• corundum-periclase composite (Al2O3 + MgO);

• corundum-carbide-silicon composites (Al2O3 + SiC);

• aluminosilicate compositions (Al2O3 + SiO2);

• ceramics based on amorphous silica (brand AMK-00, 01, 02, SiO2 content not less than 99.98%);

• graphite and graphite-containing materials.

Crucibles are made according to the standard nomenclature, and according to customer’s drawings.