某褐铁矿磁化焙烧-磁选工艺的探讨

通过对某复杂褐铁矿进行磁化焙烧-磁选工艺条件的研究,在最佳焙烧温度750℃,焙烧时间50min,还原剂用量7％的磁化焙烧条件下,采用探索实验流程获得了铁精矿品位56．59％,铁回收率为74．60％的良好指标,对开发同类型矿石具有借鉴意义。     

安徽褐铁矿的磁化焙烧-磁选工艺

针对安徽某低品位褐铁矿石,采用磁化焙烧-磁选工艺进行了实验研究,对该矿的原矿进行了岩相分析,并对磁化焙烧-磁选工艺参数进行了优化.结果表明,该矿属低磷硫的低品位褐铁矿,褐铁矿与脉石矿物的镶嵌关系较为复杂,结晶水含量高,属难选矿石.对铁品位48.01%的原矿,在850℃、内配煤5%(质量分数)的条件下,磁化焙烧15min,焙烧矿磁化率达到最佳值,褐铁矿几乎全部转化为磁铁矿,这由X射线衍射结果证实.该褐铁矿通过磁化焙烧-磁选工艺可获得品位62.94%、回收率87.99%的铁精矿.     

块状铁矿石竖炉磁化焙烧的工艺优化

竖炉磁化焙烧是处理难选红铁矿较有效的方法。通过对弱磁块矿竖炉磁化焙烧的试验研究,提出了更加科学、高效的竖炉磁化焙烧理论,在现有鞍山式竖炉的基础上,通过高效控制铁矿石竖炉磁化焙烧还原气氛,对竖炉磁化焙烧工艺进行了优化。结果表明：还原气体H2体积分数提高到12%±1%,同时降低CO体积分数,提高块矿焙烧还原温度,可获得最佳的磁化焙烧效果;通过独立设置铁矿石磁化焙烧还原煤气系统与加热煤气系统,可实现还原煤气的成分、流量、压力灵活调节;通过减少还原煤气总量,将矿石还原煤气量降低至1400～1600m3/h,降低竖炉的生产成本;通过独立的还原煤气系统,提高还原煤气中焦炉煤气比例,将H2体积分数控制在12%±1%,矿石磁化率控制在2.33左右,降低了竖炉磁化焙烧煤气消耗,提高矿石磁化焙烧质量;为保证还原煤气降低用量后的压力和喷出的均匀性,将还原煤气喷出塔的出口面积缩小50%,使矿石能够充分、均匀地完成还原。     

隧道窑磁化焙烧工艺研究与探索

结合酒钢镜铁山粉矿资源利用现状,针对铁粉矿现有磁化焙烧工艺存在的问题,提出对隧道窑磁化焙烧工艺进行研究与探索。首先,利用马弗炉对0～15 mm镜铁山粉矿进行了磁化焙烧试验探索,根据探索性试验结果和焙烧特性,初步确定了隧道窑磁化焙烧试验流程和主要参数;其次,根据镜铁山粉矿在马弗炉探索性试验取得的还原焙烧规律,利用30 m平铺料式隧道窑开展了磁化焙烧扩大试验,在隧道窑焙烧温度1 050～1 100℃、高温焙烧时间60 min、还原剂配比3%的试验条件下,0～15 mm镜铁山粉矿整车综合焙烧产品磁选精矿品位达到56%、金属回收率达到86.63%,与目前的强磁选工艺比较,磁选后的精矿品位提高约9个百分点,金属回收率提高约19个百分点,说明镜铁山粉矿通过隧道窑进行磁化焙烧在技术上是可行的。     

含铁氰渣磁化焙烧回收铁精矿

以铁含量为35%的氰渣为研究对象,研究了焙烧温度、焙烧时间及碳氧比对煤基磁化焙烧过程的影响,并采用化学分析、XRD、SEM、热重分析等分析手段对含铁氧化物的转变过程进行表征。随着焙烧温度的提高,铁氧化物的物相转变过程为Fe₂O₃→Fe₃O₄→FeO。随着磁化焙烧焙烧时间的延长,尾渣中的Fe₂O₃首先被C还原为Fe₃O₄,还原得到的Fe₃O₄可被空气中的O₂重新氧化为Fe₂O₃。碳氧比较低时,磁化率接近2.33;当碳氧比超过3时,过量的煤与尾渣混合,Fe₂O₃还原反应不完全;在焙烧温度645℃、焙烧时间45 min、碳氧比3的优化焙烧条件下,得到焙烧矿的磁化率为2.34。     

酒钢镜铁矿尾矿再选试验

酒钢选烧厂排出尾矿中尚含有25%左右的铁,具有较高的回收价值。该尾矿中铁主要赋存于赤褐铁矿中,其次赋存于菱铁矿和磁铁矿中。为了回收尾矿中的铁,以兰炭作为还原剂,对该尾矿分别进行了磁化焙烧—弱磁选和强磁选—磁化焙烧—弱磁选研究,结果表明,未经强磁选预处理时,可得到铁品位54.50%,铁回收率86.26%的最优指标,该指标与目前现场指标接近;经强磁选处理后,可得到铁品位53.96%,铁回收率80.22%的最优指标,此流程在铁品位和回收率下降不多的前提下大大减少了焙烧和后磁选过程处理量,减少了能源的损失。     

磁化焙烧对高铁铝土矿中铁元素的分离回收影响

对铝土矿进行磁化焙烧—磁选处理,考察氢气通入量,焙烧温度及焙烧时间对铁回收率和品位的影响,并研究不同焙烧条件下矿石中铁元素的分离规律。结果表明,当氢气流量为40mL/min、400℃焙烧75min后,铝土矿中铁的回收率及回收品位最优,分别为69.58%和44.59%,能较好实现铁质元素的分离和回收。该条件下焙烧磁选后的铝精矿氧化铝的实际溶出率为86.2%,比未经过焙烧磁选的铝土矿提高了6.6个百分点。     

某菱铁矿的选矿试验研究

针对某菱铁矿(FeCO3)进行磁化焙烧处理,使FeCO3分解为氧化铁,再经碳还原为Fe3O4,焙砂再经过弱磁选选矿,使矿石中的铁得到了有效回收.     

酒钢尾矿制粒磁化焙烧试验研究

酒钢本部尾矿坝现堆存铁品位21%~24%的尾矿约7 000万t,为使尾矿中的铁资源得以回收利用,开展了酒钢尾矿制粒-磁化焙烧-干选抛废-磨矿磁选试验研究,结果表明,在煤粉与矿样的质量比为1.5%,焙烧温度为810℃,焙烧时间为30 min,焙烧产物磨矿细度为-0.074 mm占80%,弱磁选磁场强度为125 m T条件下,可获得铁品位为56.13%、铁回收率为72.87%的铁精矿。     

悬浮磁化焙烧金矿尾矿试验研究

对潼关金矿粒级为30～180 μm的尾矿进行了悬浮磁化焙烧试验研究.试验首先分析了尾矿不同粒级的铁含量;主要研究了焙烧气氛、焙烧时间和焙烧温度对焙烧产物物相组成的影响.试验结果发现:不同粒级的尾矿中铁分布基本相同;在焙烧时间和焙烧气氛相同时,焙烧温度越高,越易达到最佳焙烧效果;随焙烧时间延长,焙烧效果先好后差;随着焙烧...     

关于铁精粉中是否含有铁屑的检测

通过对铁精粉的外观、制样等情况判断几种铁精粉中含铁屑的检测方法.     

梅山铁矿尾矿浮选铁的试验研究

梅山铁矿尾矿组成复杂,脉石矿物的物理性质与铁矿物相近,分选困难。采用强磁选脱泥,脱泥精矿正浮选,以甲苯胂酸作铁矿物捕收剂,六偏磷酸钠作脉石矿物抑制剂,煤油为辅助捕收剂,通过一粗二精一扫流程,得到铁品位63.47%的合格铁精矿,回收率为24.04%。     

原料生铁与铸件组织遗传性研究

研究了４ 种不同产地的常用原料生铁的原始组织、相同过热温度下原料生铁与铸铁（ＨＴ２００）的组织和力学性能。结果表明,原料生铁中粗大石墨结及石墨片的大小和分布在低于１ ４５０ ℃的熔炼条件下,具有明显的遗传效应。由于原料组织的遗传效应造成铸件的抗拉强度相差近２０ ％ 。     

Iron supplementation

BACKGROUND: Besides decentration of the graft/host trephination and "horizontal torsion" "vertical tilt" is an important factor for reduced visual outcome after penetrating keratoplasty (PK). The purpose of this study was to evaluate the time course of vertical tilt in absolute value and direction and to correlate it with functional results after PK. PATIENTS AND METHODS: Fifty patients each (20 primary dystrophies, 30 keratoconus) underwent nonmechanical trephination (NMT) (excimer laser MEL60, Aesculap-Meditec, Heroldsberg, Germany) or mechanical motor trephination (MT) (Geuder, Heidelberg, Germany) in penetrating keratoplasty. All procedures (7.5 mm in dystrophies, 8.0 mm in keratoconus, 8 orientation teeth in NMT, double-running 10-0 nylon suture) were performed by one surgeon (GOHN). At a postoperative gate of 6 weeks, 6 months, before partial suture removal and after complete suture removal, corneal topography analysis (TMS-1, Tomey, Tennenlohe, Germany) was performed. After a Gram-Schmidt-orthogonalization corneal topography height data of 25 noncentric rings in 256 hemimeridians were decomposed into Zernike components of radial order n = 16 in the sense of minimizing the root mean square error. The tilt of the surface relative to the videokeratoscope axis was calculated from the Zernike components Z1(1) and Z1(-1). The meridional power at the cardinal meridians was derived from all parabolic Zernike terms. Tilt and the difference between both meridians of the Zernike representation (ZA) were correlated with the results of Zeiss keratometry (KA). Simulated Keratometry (SimK) of the TMS-1, subjective refraction (RZ) and best-corrected visual acuity. RESULTS: After NMT, vertical tilt of the graft was 3 degrees without significant change over time. Following MT, an equivalent time course could be observed before partial suture removal. However, after complete suture removal, a significant increase of the tilt was measured to 5 degrees (p = 0.02). No significant difference could be detected comparing keratoconus and Fuchs' dystrophy both in NMT and MT. The direction of the vertical tilt component piled up to the hemimeridian defined by the knot of the first running suture. At all postoperative follow-up examinations, the ZA of the Zernike decomposition showed a good correlation to the RZ, whereas the KA and the SimK did not. At the end of the follow-up, best-corrected visual acuity after NMT was 2 decimal lines better than after MT. CONCLUSIONS: The Zernike decomposition of topographic height data is a suitable tool for extraction and quantifying vertical tilt of the graft following penetrating keratoplasty. In contrast to conventional keratometry with its 4-point measurement, a decomposition of topographic height data into orthogonal polynomials enables a detection of both cardinal meridians even in corneas with a high degree of local irregularities.     

白云鄂博矿选铁尾矿中铁矿物的工艺矿物特征

白云鄂博矿矿区矿产资源丰富,氧化矿尾矿即将作为主要生产原料应用于白云鄂博矿综合利用示范基地生产线。文章以实验室氧化矿尾矿与磁铁矿尾矿为试验试样,根据粒度划分为5个不同粒级,旨在测定显微镜下上述尾矿的化学成分和粒度分布,同时深入研究其铁矿物的矿物组成和解离特性,从而为选铁工艺的优化提供必要的理论依据与技术支持。     

Recovery of Ultra-Fine Iron Ore from Iron Ore Tailings

Many attempts has been taken for further utilisation of the tailings and slimes through different routes i.e. beneficiation, agglomeration etc. Though the slimes and tailings contain huge ultra fines, conventional beneficiation methods many not be much effective for handling because of particle size limitations. Physicochemical method i.e. selective flocculation is a process for handling the ultrafine particles present in the tailings. Review shows that selective flocculation technique have very limited commercial application. Here the study focuses on the application of selective flocculation process for beneficiation of synthetic mixtures of iron ore and kaolinite as well as iron ore tailings. Results show that it is possible to achieve 65.78(%) of Fe, with 2.65% Al₂O₃, 3.66 SiO₂ (%) in the concentrate using synthetic mixture feed and more than 60% of Fe is obtained from natural iron ore tailings.     

高铁硫化矿选择性浸出铁的研究

将镍钴火法冶炼转炉渣进行还原硫化,制备成富含镍钴铜的高含铁硫化矿,并采用加压选择性浸出其中的铁。对铁的浸出行为进行了研究。结果表明,随着铜浸出率从98%降到-42%,铁浸出率从3%升到43%左右,选择性浸出后液含铁越来越高,而且以二价铁居多,这是造成高铁硫化矿难以进行加压选浸的主要原因。     

邯宝炼铁厂高块矿配比生产实践

对邯宝炼铁厂高块矿配比生产进行了总结,在炉役末期通过紧抓原料管理、高炉操作优化等措施,2019年块矿使用比例达到21.5％的较高水平,降低了生产成本.