富氧条件下高精粉配比对烧结指标及冶金性能的影响

Effect of high magnetite concentrates ratio on sintering index and metallurgical properties under oxygen-enriched conditions

为了深入研究富氧条件下磁铁矿配比对烧结矿烧结指标和冶金性能的影响,采用烧结杯试验、还原和软熔设备研究了不同磁铁矿配比下的烧结指标、还原性、低温还原粉化与软熔特性。试验结果表明,随着磁铁矿粉配比由0提升到56.4%,小于10 mm粒级烧结矿所占比例下降,大于40 mm粒级烧结矿所占比例有较大的波动,烧结料面富氧后成品烧结矿所占比例增加;垂烧速度由22.35 mm/min下降到15.87 mm/min,成品率先由73.88%升高到79.08%,后又下降到77.49%,利用系数在矿粉A配比为32.4%时达到最高,转鼓指数由59.26%上升到76.09%,收缩率和烧损随着矿粉A配比提高显著降低;富氧和增加磁铁矿配比共同导致烧结时间延长和转鼓指数的提升,随着矿粉A配比由0增加到56.4%,烧结矿的还原性由88.51%下降到82.13%,烧结矿的低温还原粉化指数由74.70%升高到了80.75%,软熔温度上升,软熔区间有下移趋势,且软熔区间变窄,滴落速度整体上呈现出下降趋势,熔滴滴落量降低,熔滴特性的变化主要是由于烧结矿中w(MgO)/w(Al2O3)提高而导致的。配矿结构为影响冶金性能变化的主要因素,大于富氧对烧结矿冶金性能的影响。烧结过程料面富氧且富氧率为25%时,磁铁矿配比不宜超过32.4%。

In order to investigate the effect of magnetite proportioning on the sintering index and metallurgical properties of sintered ore under oxygen-rich conditions in depth,the sintering index,reducibility,low-temperature reduction pulverization and soft fusion characteristics under different magnetite proportioning were studied using sinter pot experiments,reduction and soft fusion equipment.The experimental results showed that as the magnetite powder ratio increased from 0 to 56.4%,the percentage of less than 10 mm particle size sintered ore decreased,the percentage of more than 40 mm particle size sintered ore had large fluctuations,and the percentage of finished sintered ore increased after oxygen enrichment of the sintered material surface;the vertical sintering speed decreased from 22.35 mm/min to 15.87 mm/min,the yield increased from 73.88%to 79.08%,and then decreased to 77.49%,the utilization coefficient reached the highest at powder A ratio of 32.4%,the drum index increased from 59.26%to 76.09%,shrinkage and burn loss decreased significantly as powder A increased;Oxygen enrichment and increased magnetite powder ratio together led to longer sintering time and increased drum index,and as powder A ratio increased from 0 to 56.4%,the reduction of sintered ore decreased from 88.51%to 82.13%,the low temperature reduction pulverization index of sintered ore increased from 74.70%to 80.75%,the soft melting temperature increased,the soft melting interval had a downward trend and the soft melting interval became narrower,the drip rate showed an overall decreasing trend and the melt drop drip volume decreased,the changes of melt drop characteristics were due to the increase of the chemical composition of sintered ore mainly w(MgO)/w(Al2O3)caused.The structure of ore distribution is the main factor affecting the change of metallurgical properties,which is greater than the effect of oxygen enrichment on the smelting performance of sintered ore for gold.In summary,when the sintering process material surface is oxygen-rich and the oxygen-rich rate is 25%,the magnetite proportion should not exceed 32.4%.