Effect of parameters on reduction behaviour of preheated converter sludge pellets in grate-rotary kiln process

Abstract

Effects of parameters including temperature, time and coal ratio on the reduction behaviour of preheated iron-bearing converter sludge pellets in a simulated rotary kiln are studied through orthogonal tests. ANOVA analyses show that reduction time and temperature have remarkable influence on the metallisation degree, occupying 55.02 and 30.08% of the total contribution, while temperature is the most significant factor affecting the compressive strength, with 90.98% contribution. The metallisation degree increases with the increasing time from 1.5 to 2.5 h, and first increases and then decreases with the increasing temperature from 1000 to 1100°C. The compressive strength increases with the increasing temperature. Under the optimal condition of temperature 1050°C, time 2.5 h, coal ratio 1.3, the metallisation degree is 72.92%, and the compressive strength is 1310 N/p, which satisfies the requirement of iron burden for blast furnace.

Advanced converter sludge utilization technologies for the recovery of valuable elements: A review

“…And then, the pellets are introduced in the reactor and are reduced by the carbon in CS and the addition reductant (anthracite or coke breeze) under the temperature to prepare metallized pellets. Hu et al [40] investigated the effects of temperature, reaction time and coal ratio on the reduction behavior of preheated iron-bearing CS pellets in a 5, the results indicated that with the carbon ratio of 1.3 under the temperature of 1050°C for 2.5 h, the metallization rate achieved 72.92% with the corresponding compressive strength of 1310 N, which satisfied the requirement of the iron burden for the blast furnace. After reduction, the obtained metallized pellets have the metallization rate over 90%, and the high temperature softening performance of the pellets is similar to that of ordinary sinter.…”

“…Xia et al [20] Results of the metallization degree and compressive strength of the pellets. [40] NO. 4.…”

Comprehensive Utilization of Iron-Bearing Converter Wastes

“…It can be speculated that if the first drying time is not long enough, cracking rate of pellets will go up during the second drying section caused by the excessive expansion force generated through rapid and intense vaporization of residual moisture in the interior of pellet at high temperature and flow rate. Actually, moisture evaporation is a dynamic balance of liquid water gasification and vapor condensation, and evaporation rate is the difference of these two reactions [25]. It follows that the moisture evaporation velocity depends on the temperature and the pressure difference between saturated and ambient vapor.…”

“…In this chapter, performances of pellets prepared from the BOF sludge are briefly presented at first and then studies on drying characteristics and reduction behavior under different conditions are introduced and compared to provide scientific guidance for recycling of secondary iron-bearing resource from BOF wastes [24][25][26].…”

Influence of MgO on the oxidation and induration of Hongge vanadium titanomagnetite pellets

“…However, it is difficult to recover titanium from the BF slag in a cost-effective manner due to its low titanium content and complex chemical composition [9]. For the past few decades, various approaches utilizing coal have been used to improve the utilization of VTM [10][11][12][13][14][15][16][17][18]. Zhao et al [10] studied the reduction of vanadium and chromium during the isothermal reduction of HVTM and their effects on the elemental distribution in the subsequent magnetic separation.…”