Effects of calcium flux on fluxed pellets strength
XU Zixuan1, JIANG Xin2, HE Jia2, WANG Xiaoai3, XIE Yunfei2, SHEN Fengman2
1. School of Computer Science and Engineering, Northeastern University, Shenyang 110819, Liaoning, China; 2. School of Metallurgy, Northeastern University, Shenyang 110819, Liaoning, China; 3. Materials Technology Research Institute, HBIS Group, Shijiazhuang 050023, Hebei, China
Abstract：In recent years, under the influence of environmental protection policies, the technology development of fluxed pellets has received widespread attention. Limestone and burnt lime were used as calcium fluxes, and influence law and action mechanism of flux type and flux addition amount on the compression strength of green pellets, preheated pellets and fired pellets were systematically studied. The experimental results show that, whether limestone or burnt lime is used, the compression strength of green pellets increases first and then decreases with the increase of basicity. When the basicity R=1.0, the compression strength is the highest. The compression strength of preheated pellets decreases with the increase of basicity. Prolonging the preheating time and increasing temperature can improve the compression strength of preheated pellets. When the roasting temperature is 1 200 ℃, the compression strength of fired pellets decreases with the increase of basicity. The basicity increases from 0.06(no calcium flux, natural basicity)to 2.0, the compression strength of limestone pellets and burnt lime pellets decreases from 2 212 N to 1 070 N and 1 010 N per pellet, respectively. When the roasting temperature is 1 250 ℃, the compression strength of fired pellets increases first and then decreases with the increase of basicity, and reaches the peak when basicity R=0.5. Under the experimental conditions, the optimum basicity of fluxed pellets is R=0.5, the roasting temperature is 1 250 ℃, and the roasting time is 20 min. Because the CO2 produced by the decomposition of carbonate has greater adverse effect on the internal structure of pellets than H2O produced by the decomposition of hydrated lime during roasting process of pellets, the effect of burnt lime as the calcium flux of fluxed pellets is better. The research content can provide theoretical basis for the selection of suitable calcium flux, basicity and roasting temperature parameters for the production of fluxed pellets.
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2023, Vol. 33 
