Sintering kinetics and alumina yield in lime-soda sinter process for alumina from coal wastes

An investigation of the application of the lime-soda sinter process to alumina extraction from coal wastes has been carried out. In the sintering stage, the optimal operating conditions have been obtained for the highest yield of alumina. The kinetics of sodium aluminate formation have also been studied in the sintering stage. The sinter mixes have been fired isothermally in air in the temperature range 1100 to 1350 °C. Alumina recovery of about 80 pct has been obtained by sintering coal-waste mixes having molar ratios of Na₂O/Al₂O₃ = 1.3 and CaO/SiO₂ = 1.8 at 1200 to 1250 °C for 20 to 30 minutes. Insoluble alumina compounds are responsible for the incomplete recovery. The major sinter components are identified as sodium aluminate and β-dicalcium silicate. The nucleation and growth kinetics equation is used to correlate the experimental data of sodium aluminate formation obtained under atmospheric pressure in the temperature range 1000 to 1200 °C. An activation energy of 286 kJ/mol has been calculated for fine coal-waste powder mixtures. Formerly Graduate Student in Metallurgy.     

强化烧结法氧化铝生产能耗及氧化铝制造成本

章在分析氧化铝生产蒸汽消耗的基础上，提出了以降低水耗为主要手段，通过节水，达到降低汽耗的目的；阐述了中州铝厂在提高节水管理、实施节水改造，提高溶液浓度等方面的实践与探讨，以及通过降低水耗、加强节汽管理，有效地降低强化烧结法氧化铝生产能耗，从而严格控制氧化铝制造成本，也大大地增强了企业的市场竞争能力。     

常压预脱硅技术在烧结法氧化铝生产中的应用探讨

本通过比较河南分公司和中州分公司的烧结法粗液脱硅流程的改进经验。提出了山西分公司烧结法粗液脱硅流程的改进方案，对粗液进行常压预脱硅，达到了降低脱硅机组压力，减少脱硅机组结垢，降低蒸汽消耗的目的。     

Recovering REEs from NdFeB wastes with high purity and efficiency by leaching and selective precipitation process with modified agents

A leaching and selective precipitation approach is proposed in this work to recover rare earth elements (REEs) from NdFeB magnet wastes collected from industry. Hydrochloric acid and oxalic acid were employed as the leaching and precipitation agents, respectively. Hexamethylenetetramine (HMTA) or tartaric acid was used as the chelating agent during leaching. Both leaching and precipitation processes were optimized individually. For leaching process, the effects of two different chelating agents, the concentrations of leaching agent, chelating agent, and temperature on the extraction and recovery yields were investigated. The optimized process based on the factorial experiment was determined to be the hydrochloric acid concentration of 6 mol/L, the tartaric acid concentration of 50 g/L, and the temperature of 313 K, by which the extraction yields of Fe and REEs up to 67.99% and 99.27%, respectively, are obtained. For the precipitation process, the optimized oxalic acid dosage and pH value were also determined. The produced RE oxide products have the purity and recovery yield up to 95.83% and 90.18%, respectively. These results indicate that the present method with low acid consumption and high product purity has advantages over many other approaches for REE recovery.     

氧化铝对铁矿石烧结质量和生产率的影响(英文)

烧结矿是现代高炉生产的主要含铁原料。合理控制入炉烧结矿的理化性能与冶金性能对高炉生产和稳定操作是很必要的。铁矿粉是烧结矿的主要原料,其化学成分和烧结料层内的热量条件在烧结过程中起着重要的作用。化学成分等参数也决定着烧结矿矿相结构和质量。由于含氧化铝原料的低反应性及其液相的高粘性,因此在人们的预料中高铝矿石对烧结矿结构组成的影响并不好。烧结混合料中的氧化铝在同化过程中需要消耗大量热量,延迟烧结过程。在确保高炉渣的流动性方面,氧化铝也需要消耗较大热量。不论是烧结还是高炉的生产实绩均表明,氧化铝是有害的。一般而言,高含铁量与低脉石的印度矿与其他矿石的不同特点就是氧化铝含量高。由于高品味铁矿石的消耗殆尽,使用可利用的烧结原料成为生产必需。因此,必须要掌握氧化铝的作用及其对烧结矿质量和生产过程的影响。实验室完成了不同氧化铝含量水平(2.00%～5.46%)的实验,可从中了解氧化铝在烧结矿矿物学、生产率、物理性能和冶金性能方面的影响。随着烧结矿中氧化铝含量的增加,残存赤铁矿、复合铁酸钙(SFCA)和孔隙率增加,而磁铁矿和硅酸盐比例下降。烧结生产率和烧结矿转鼓强度(TI)随着氧化铝含量上升而下降,反映烧结矿冶金性能的诸如低温还原粉化率(RDI)和还原率(RI)提高。     

低品位铝土矿的高效脱硫脱硅工艺研究

通过采用悬浮焙烧-碱浸脱硅的方式对铝土矿进行处理,并研究了焙烧温度、苛碱浓度、碱浸温度对焙烧矿碱浸脱硅的影响。结果表明,悬浮焙烧较优温度为930 ℃,在碱浸脱硅条件下液固比为8∶1,脱硅时间为30 min,苛碱浓度为110 g/L,脱硅温度为95 ℃时,可获得较高脱硅率,可达49.24%。Al₂O₃损失率为2.03%,精矿铝硅质量比可提至8.21,悬浮焙烧的脱硅精矿实际溶出率最高可达94.79%。采用石灰为脱硅剂,对碱浸脱硅后的碱液进行脱硅后,可对焙烧矿进行循环脱硅利用,脱硅后的精矿铝硅比均可达到7以上,从而使碱液实现了循环利用。      

NdFeB废料浸出工艺研究及浸出设备设计

由于中国目前对NdFeB废料回收稀土的自动化程度低,产品的纯度波动大,难以保证生产的安全性和运行的可靠性,导致稀土的回收率指标低。以盐酸优溶法对NdFeB废料回收为技术依托,首先对影响稀土流失较大的浸出除杂过程进行实验研究,并总结出提高浸出率的技术措施;然后对NdFeB废料浸出工艺过程进行研究;最后对浸出设备进行设计。稳定了稀土回收的纯度,提高了稀土的回收率指标,降低了生产成本,对NdFeB废料浸出工艺自动化和绿色生产的实现有积极的促进意义。     

烧结烟气氨水法脱硫技术研究

介绍了氨水法脱硫反应原理、工艺流程、技术特点和应用情况,分析了利用氨水法脱除烧结烟气中二氧化硫的优缺点,指出氨水法脱硫要采用焦化氨源,可大幅降低成本,同时要保证副产品硫酸铵的稳定化、品质和市场化,是氨法生命力的所在。     

浅析石墨焙烧法中的温度控制及影响

本文介绍了电解槽石墨焙烧法中的温度控制及对槽寿命的影响。     

软熔过程中烧结矿和块矿的交互作用

 为更好地明晰块矿的软熔行为并优化其在高炉内的使用,以烧结矿和澳大利亚纽曼混合块矿为研究对象,分别就两者在软熔过程中的物理和化学交互作用进行了试验研究。通过使用中子CT扫描软熔试验试样, 发现1 450 ℃时烧结矿与纽曼混合块矿的混合炉料孔隙度要高于两者单一炉料,即两者间存在着物理交互作用;通过采用扫描电镜和电子探针分析发现,1 200～1 300 ℃温度范围内烧结矿中钙和镁扩散到了块矿中,两者发生了明显的化学交互作用。在物理和化学交互共同作用下,配加约20%纽曼混合块矿的混合炉料软熔行为得到了明显改善,且其性能相似或略好于同碱度的单一烧结矿炉料,这表明块矿和烧结矿混合后能在高炉内形成温度区间更窄、位置更低、透气性更好的软熔带。     

安钢90m2烧结矿直供300m3高炉上料工艺的设计改造及应用

通过对安钢90m2烧结矿直供300m2高炉上料工艺的设计改造以及槽上筛分系统的科学布置设计,合理解决了高炉炉料结构的调整,缓解了炼铁厂原燃料上料系统的繁忙状况,有效保证了高炉原燃料的供应.     

铁矿粉烧结优化配矿及其模型研究进展

随着铁矿粉资源的不断消耗,各类铁矿粉呈劣化趋势,且大量新矿种出现,使烧结优化配矿需求愈发迫切.主要介绍了铁矿粉常温和高温等基础特性.其中,常温特性主要有化学成分、铁矿粉种类、粒度组成等,同时重点分析了与烧结生产息息相关的高温特征指标,主要有同化性、液相流动性、黏结性强度、铁酸钙生成特性、连晶特性、熔融特性、吸液性和烧结...     

含铅废渣料还原造锍熔炼回收铅和银工艺

针对铅锌冶炼企业产出大量含铅固体废弃物难以环保经济回收的难题,提出从多种含铅废料中回收二次铅的还原造锍熔炼新工艺.在热力学计算的基础上,进行以铅膏、铅渣、铅烟灰和黄铁矿烧渣的设计混合料为熔炼对象,以氧化铁为固硫剂,焦粉为还原剂,苏打和芒硝作为添加剂的工艺实验,研究熔炼过程中各影响因素对铅和银直收率的影响.得到优化的工艺条件:FeO/SiO₂质量比为1.10,CaO/SiO₂质量比为0.30,添加剂组成中Na₂CO₃/Na₂SO₄质量比为7∶3,焦粉用量为含铅物料质量的15%,熔炼时间为2 h,熔炼温度为1200℃.在此条件下综合实验中铅直收率为85.95%,银直收率为83.15%.新工艺具有固硫、综合利用和一步炼铅的优点.     

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In order to study effect of addition of semi- coke on sinter reduction behavior and confirm kinetic mechanism of reduction process, different proportions of semi- coke were added in the bulk layer to measure the reducibility of sinter and inspect the changes of reduction degree and rate. The reduction mechanisms of sinter at different stages were confirmed. By applying subsection attempting method to analyze kinetics of reduction process, different mechanism functions of the reaction process at earlier stage and later stage were determined.Furthermore, kinetic models were established and related kinetics parameters were figured out. The results of data- fitting show that the kinetic models at different stages are in good agreement with experimental data and the correlation coefficients are greater than 0. 99.With the increase of semi- coke proportion, the reaction rate constant krea of the reduction reaction at the earlier stage rises, and the effective diffusion coefficient DABP at the later stage rises.     

锌浸出渣火法处理工艺探讨

叙述了国内外锌浸出渣火法处理的主要工艺及装备,对技术、能耗及存在的问题进行了分析,探讨了锌浸出渣处理的新技术和应用前景.     

絮凝剂在烧结法赤泥沉降过程中的应用

在理论和生产实际相结合的基础上,总结了中州分公司多年的生产实际经验,详细阐述了絮凝剂在烧结法赤泥沉降过程中的配制与使用,对同行业推广应用和节能降耗有着普遍的借鉴意义。