Abstract:A direct heat transfer with blast furnace waste for heating water was introduced, which has been running for nearly 5 months in a iron and steel factory in China. The operation results showed that the new single channel heat exchanger without contact point could avoid corrosion and block problems caused by impurity in blast furnace waste water. The temperature of slag flushing water through the heat exchanger can be reduced to less than 55 ℃ which meets the requirement of flush slag process. The heating water temperature can be increased from 50℃ to 67.7℃ which meets the heating requirements. The economic and environmental benefits of the system are significant.