铬铁粉矿球团烧结新工艺及固结机理研究

Study of Chromite Fines Pellet Sintering and its Hardening Mechanism

对铬铁精矿进行了常规烧结及球团烧结试验研究,并揭示了固结机理。常规烧结结果表明,在最优条件下,烧结矿成品率为73.16%,利用系数1.17t/(m2.h),烧结矿转鼓强度61.03%,固体燃耗115.80kg/t;球团烧结实验表明:在最优条件下,烧结矿成品率为77.18%,利用系数1.47t/(m2.h),转鼓强度83.78%,固体燃耗107.32kg/t。与常规烧结相比,球团烧结显著改善了烧结矿产质量,降低了固体燃耗。固结机理研究表明,在常规烧结中,烧结过程形成的液相量仅有17.1%,故烧结矿强度差,产量低;而球团矿烧结中,表层呈单个球团,中下层呈葡萄状粘结构。球团烧结矿固结以铬铁尖晶石、镁铁尖晶石再结晶为主,液相量19%左右,孔隙率下降。球团烧结矿强度由固相固结和液相粘结共同维持,因此,烧结矿强度好、产量高。球团烧结工艺是强化铬矿粉烧结、降低烧结能耗的有效途径之一。

The normal sintering and pellet sintering of chromite fines was studied and the consolidation mechanism was revealed.Results of normal sintering showed that under the optimum conditions,yield of 73.16%,productivity of 1.17 t/（m2·h）,tumble index of 61.03% and solid fuel consumption of 115.80 kg/t were achieved.In contrast the pellet sintering of chromite fines under optimum conditions indicated better sintering performance proven by the following dexes yield of 77.18%,productivity of 1.47 t/（m2·h）,tumble of 83.78% and solid fuel of 107.32 kg/t respectively.Consolidation mechanism showed that in normal sintering process,the liquid phase was only accounted for 19% and higher porosity,resulting in weak sintering and lower productivity.With regard to micro pellet sintering,sinter from top and middle-lower bed is ding morphology,respectively.Recrystallization of ferro-chromium and ferro-magnesium spinel and some 19% liquid phase along with lower porosity play a significant role in consolidation of sinter made of chromite fines by micropellet sintering,leading to a strong sinter and higher productivity at lower solid fuel.Therefore,pellet sintering is an effective way to promote sintering of chromite fines at lower solid fuel consumption.