A new type of laminar composite material has been developed by the bonding of ceramic and metal with a special agglutinate metal. A tube can be made of the laminar composite material and this tube can perform as an outer sheath of an immersion heater. Such heaters can be made to lager size and can be heated using a wide range of energy sources including electricity, gas and oil. Moreover this new heater tube is low cost and has a long working life, is convenient to use and requires little maintenance. This technology allows all kinds of zinc kettle to be heated by immersion heaters.