Solid wastes generated by the metallurgical industry contribute significantly towards the enhancement of environmental pollution. The handling, utilization, and safe disposal of these solid wastes are major concerns f...Solid wastes generated by the metallurgical industry contribute significantly towards the enhancement of environmental pollution. The handling, utilization, and safe disposal of these solid wastes are major concerns for the world. Dolochar is such a solid waste generated by the sponge iron industry. Investigations were carried out on the physical, mineralogical, and chemical characteristics for the efficient utilization of dolochar. The detailed studies on physico-chemical properties and petrography were carded out by optical microscopy, X-ray diffraction （XRD）, and scanning electron microscopy （SEM）. Characterization studies revealed that the dolochar consists of quartz （free as well as locked）, free lime, Fe particles, and Ca or Mg and/or Ca＋Mg＋Fe oxide phases. The washability data of-300 ~m dolochar samples indicated that clean coal with 41wt% ash at 18% yield can be produced from dolochar with 78wt% ash. The studies further suggested that the liberation of the dolochar is hard to achieve for clear separation. The dolochar is observed to have high ash fusion temperature and the un- burned carbon can be best utilized for power generation.展开更多
利用磁选和浸出技术从印度一水硬铝石样品中除铁,采用扫描电镜、电子探针显微分析仪和X射线衍射等定量矿物学评价技术进行深入的矿物学表征研究。结果表明,极细的赤铁矿颗粒与其他几种矿物相以复杂的方式结合在一起;即使粒度小于38μm,...利用磁选和浸出技术从印度一水硬铝石样品中除铁,采用扫描电镜、电子探针显微分析仪和X射线衍射等定量矿物学评价技术进行深入的矿物学表征研究。结果表明,极细的赤铁矿颗粒与其他几种矿物相以复杂的方式结合在一起;即使粒度小于38μm,仍有约60%的赤铁矿未被解离出来;这个粒度也是物理分离过程去铁的极限。湿式强磁选研究表明,只有49%的铁可被除去。进一步的草酸浸出研究表明,在固液比0.05:1、温度90°C、时间120 min、酸浓度1 mol/L的条件下,可除去约76%的铁。铁在草酸中的溶解受化学反应控制,计算的活化能为35.15 k J/mol。展开更多
The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and si...The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO2 and A1203 levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO2, and 5.28wt% A1203 with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO2, and 6.80wt% A1203, when NazSiO3 with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.展开更多
The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficia...The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficiation plants. Under statistically determined optimum conditions, which include a temperature of 900°C, a reductant-to-feed mass ratio of 0.35, and a reduction time of 30–45 min, the roasted mass, after being subjected to low-intensity magnetic separation, yielded an iron ore concentrate of approximately 64 wt% Fe at a mass recovery of approximately 71% from the feed iron ore slime assaying 56.2 wt% Fe. X-ray diffraction analyses indicated that the magnetic products contain magnetite and hematite as the major phases, whereas the nonmagnetic fractions contain quartz and hematite.展开更多
基金the Odisha State Pollution Control Board,Bhubaneswar,India
文摘Solid wastes generated by the metallurgical industry contribute significantly towards the enhancement of environmental pollution. The handling, utilization, and safe disposal of these solid wastes are major concerns for the world. Dolochar is such a solid waste generated by the sponge iron industry. Investigations were carried out on the physical, mineralogical, and chemical characteristics for the efficient utilization of dolochar. The detailed studies on physico-chemical properties and petrography were carded out by optical microscopy, X-ray diffraction （XRD）, and scanning electron microscopy （SEM）. Characterization studies revealed that the dolochar consists of quartz （free as well as locked）, free lime, Fe particles, and Ca or Mg and/or Ca＋Mg＋Fe oxide phases. The washability data of-300 ~m dolochar samples indicated that clean coal with 41wt% ash at 18% yield can be produced from dolochar with 78wt% ash. The studies further suggested that the liberation of the dolochar is hard to achieve for clear separation. The dolochar is observed to have high ash fusion temperature and the un- burned carbon can be best utilized for power generation.
文摘利用磁选和浸出技术从印度一水硬铝石样品中除铁,采用扫描电镜、电子探针显微分析仪和X射线衍射等定量矿物学评价技术进行深入的矿物学表征研究。结果表明,极细的赤铁矿颗粒与其他几种矿物相以复杂的方式结合在一起;即使粒度小于38μm,仍有约60%的赤铁矿未被解离出来;这个粒度也是物理分离过程去铁的极限。湿式强磁选研究表明,只有49%的铁可被除去。进一步的草酸浸出研究表明,在固液比0.05:1、温度90°C、时间120 min、酸浓度1 mol/L的条件下,可除去约76%的铁。铁在草酸中的溶解受化学反应控制,计算的活化能为35.15 k J/mol。
文摘The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO2 and A1203 levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO2, and 5.28wt% A1203 with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO2, and 6.80wt% A1203, when NazSiO3 with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.
文摘The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficiation plants. Under statistically determined optimum conditions, which include a temperature of 900°C, a reductant-to-feed mass ratio of 0.35, and a reduction time of 30–45 min, the roasted mass, after being subjected to low-intensity magnetic separation, yielded an iron ore concentrate of approximately 64 wt% Fe at a mass recovery of approximately 71% from the feed iron ore slime assaying 56.2 wt% Fe. X-ray diffraction analyses indicated that the magnetic products contain magnetite and hematite as the major phases, whereas the nonmagnetic fractions contain quartz and hematite.
