ZIRCAR Refractory Composites, Inc. produces a comprehensive line of advanced high performance ceramic-ceramic composite materials and related products. Our materials are used around the world in the most demanding thermal, structural and electrical insulating applications ranging in temperatures from 600°C(1112°F) to 1650°C(3002°F). For over twenty-five years, we have been a problem-solver working with our customers to resolve their thermal management problems. We have developed products that have become industry standards for induction melting, forging and heat treating applications, investment casting, glass processing, hot pressing, as well as many high temperature electrical applications.

Application:  Aluminum Reduction Cell Crust Breaker Insulation

Products: Refractory Sheet Type RS-100 and Refractory Sheet Type RS-101 Cylinder

Application Information: ZIRCAR Refractory Sheet Type RS-100 Board and Type RS-101 Cylinders are used as structural and electrical insulation to support the crust breaker in aluminum reduction cells. In aluminum reduction cells aluminum ore (bauxite) is reduced to aluminum metal via an electrolysis process. In this process, bauxite is mixed with cryolite and electricity is applied. During the process, the aluminum ore is reduce to primary aluminum metal. The reduction cell consists of essentially a pot for containing the molten aluminum with electrodes positioned at the top. During the reduction process, a hard shell forms on top of the molten aluminum. This shell must be broken prior to removing the molten aluminum. After reduction of the ore to metal, the crust breaker smashes the crust so that a suction tube can be lowered into the molten aluminum to pump it off.

Benefits: The major benefits associated with using RS-100 are numerous.

High flexural strength and high toughness which facilitates bolting without cracking.

RS-100 replaces Duratec HT board, which is no longer available. Duratec was a strong, rigid, calcium silicate based insulation with a maximum use of approximately 100pcf (1600 Kg/m). Duratec’s bending strength was approximately 3100psi (22 MPa) and compressive strength at 2% deformation was approximately 14,000psi (98 MPa). Duratec HT was a strong but brittle material. It would not flex well during the bolting process often resulting in failure of the piece. Due to the composite nature and toughness of RS-100, it has a certain amount of "give" when bolted.

Although RS-100 is expensive than Duratec was, RS-100 has proven be cost effective.

RS-101 cylinders are used as an electrical insulator around the bolts in the crust breaker. Although this material is not applied in a structural manner, it is used for its electrical insulating properties.



ZIRCAR Refractory Composites, Inc.

P.O. Box 489

Florida, NY, 10921 USA

Phone:  (845) 651-2200                          Fax: (845) 651-1515 
email: sales@zrci.com