As the deterioration trend of ironmaking raw materials is difficult to change,carbon-bearing pellets pro-vide the possibility for low-carbon ironmaking.Using biomass as a clean and renewable carbon source with zero-car-bon emission for the preparation of carbon-bearing pellets reductants has become one of the development trends for energy-saving and carbon-reducing production in iron and steel enterprises.Nowadays the key factor limiting the ap-plication of carbon-bearing pellets is their poor high temperature strength,so it is of great significance to study how to improve the high temperature strength of carbon-bearing pellets.Therefore,the effects of molding pressure,wa-ter addition,roasting system and binder types on the biomass carbon-bearing pellets were investigated using Dashihe powder as iron-containing raw material and biomass pyrolysis carbon as reductant.The results show that the strength of carbon-bearing pellets first increases and then decreases with the increase of molding pressure and water addition,and the optimum value is 16 MPa for molding pressure and 8％for water addition.With the increase of re-duction temperature,the strength of biomass carbon-bearing pellets decreases first and then increases,and 900-1 000 ℃ is the temperature range with the weakest strength due to the volume expansion caused by lattice distor-tion.In the later stage,with the increase of temperature,the metal iron gradually converges into sheets,and the strength and metallization rate are gradually increases.The metallization rate can reach 84.84％at 1 200 ℃.When using bentonite and sodium silicate as the binder,the strength is poor at normal temperature,and the high tempera-ture strength can be improved to a certain extent by increasing the binder addition amount.But the sodium silicate contains alkali metal Na,which is not conducive to the blast furnace.When using standard cement as the binder,the strength at normal temperature and high temperature are both poor,and the production efficiency is low.The strength of organic binder CMC is high at normal temperature,but it is easy to decompose at high temperature,and the pellets strength is poor at high temperature.The strength at normal temperature and high temperature can be obtained at the same time by composite binder,and the requirements of raw materials for different furnaces can be meet by adjusting the addition.
biomasscarbon peak-carbon neutralhigh strength carbon-bearing pelletsbinderhigh temperature strength
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