After consulting with customers, Anderman Ceramics and partner Jyoti Ceramic Industries identified a need for a suitable refractory coating compound that can withstand high temperatures and control the erosion and corrosion of refractory linings, monolithics, ceramic fiber boards, modules and steel shells. These requirements initiated a project to develop a suitable refractory coating compound with the desired features.

Product Development

After several years of collaboration in a state-of-the-art R&D laboratory, a team of scientists and technicians developed Zircoat, a zirconia-rich compound specially formulated to withstand high temperatures and control erosion and corrosion of refractory linings. The compound is also ideal for sealing cracks and performing emergency repairs. In most cases, the result of using Zircoat is a reduction in thermal energy loss and a subsequent saving in fuel costs; based on installations to date, savings are proving to be in the region of 30%.

Zircoat was originally developed as a way to improve the performance of in-house kilns by increasing their life and efficiency. Zircoat materials have since found applications in many high-temperature environments, helping to reduce operating costs and increase refractory life.

With zirconia as the main ingredient, Zircoat is able to provide a high-temperature, ceramic refractory coating capable of working at temperatures up to 1,800°C while offering resistance to chemical and physical attack. Protection is also offered to the mortar joints, which are often the weakest part of the system. By providing an additional insulation layer, the material allows for significant energy savings. Vigorous testing at temperatures ranging from 1,300°C to 1,780°C in electric and gas-fired kilns has demonstrated the excellent performance of Zircoat for extending the life of refractories and steel shells.

These specially formulated coatings have been developed for easy application. Zircoat comes in a dry powder state and is simply mixed with water to form the required consistency. The product can be applied by trowelling, brushing or spraying onto clean, dust- and grease-free surfaces. Once set, Zircoat produces a gas-tight surface without spalling or cracking, and provides a reliable barrier, protecting and increasing the life of the surface being protected.

Primary Characteristics

Zircoat adheres well to a range of materials, including metals (except aluminum), refractory brick, monolithics, castables and ceramic fiber modules. It can be applied and used in many different industries and on a variety of different components, including kiln and furnace doors and walls, industrial incinerators, chimneys, domestic log burners, crucibles, and more. Zircoat prolongs life for refractories and is particularly effective for uses in industries where high-temperature resistance is essential, such as the ceramic/glass and chemical industries.

The coating is available in two grades: Zircoat HT and Zircoat M. Zircoat HT is used for high-temperature refractories and has the ability to withstand temperatures up to 1,800°C. Zircoat M is ideal for low-temperature refractories, fiber modules, ferrous and nonferrous metals (except aluminum) and has the ability to withstand temperatures up to 1,500°C.

Zircoat can be applied in thicknesses of 1-25 mm (thicker coatings should be applied in layers). Typically, 3-5 mm thickness provide suitable protection.

A Case Study

Zircoat M was chosen as the ideal solution for a gas-fired tunnel kiln renovation. The project involved the major renovation of a 115-m-long, gas-fired tunnel kiln in a large international ceramic manufacturing facility. Zircoat was chosen by the customer as a means of increasing the life of the refractories.

Zircoat M was applied (2,500 kg) by brush on the kiln walls and ceiling. The coating was also applied to the kiln cars and burner nozzles, as these areas are prone to degradation.

Prior to the installation of the coating, the facility typically used 400 kg of propane per day. Results after the coating application showed a fuel savings of just over 30%; periodic inspection of the refractories reveal that the coating is providing a good protection, and the condition is such that an increase in service life can safely be predicted. The customer calculated a payback period for the Zircoat coating of only nine months to reach a return on their investment.