Technology for recycling biomass and making chromium slag harmless through waste heat of blast furnace slag

The invention provides a method for synchronously treating liquid-state blast furnace slag, chromium slag and biomass. According to the method, the biomass is heated and gasified through the blast furnace slag, then such catalysts as hazardous waste, namely the chromium slag, are utilized for conducting catalytic cracking on the biomass at the high temperature, the biomass is converted into low-molecular high temperature energy gas thoroughly under the condition of water vapor gasification, and the coking phenomenon occurring on the surface of the chromium slag is avoided. Meanwhile, the high temperature energy gas is utilized to heat the chromium slag, so that hexavalent chromium in the chromium slag is reduced into trivalent chromium, the energy gas is cooled at the same time, and CO2 and Cl in the energy gas are absorbed by alkaline matter in the chromium slag. By means of the technology, the chromium slag is made harmless and the blast furnace slag is cooled while energy is greatly saved, and meanwhile the high-grade energy gas is obtained.