“提铁降杂”选矿工艺技术研究与生产实践

介绍了鞍钢矿业推动"提铁降杂"新的学术思想,以及鞍山贫赤(磁)铁矿选矿新工艺、新药剂与新设备研究及工业应用,使鞍山式铁矿石的选矿技术取得重大突破,选矿装备、技术指标达到国际领先水平,为我国贫铁矿产资源高效开发利用和提升国产铁精矿的国际竞争力,提供了技术支撑和成功范例。     

某高铝高硅难选铁矿选矿试验研究

某铁矿具有矿物种类多、铝硅双高等特点。原矿中TFe为24.94%,MFe为3.99%,SiO₂为33.81%,Al₂O₃为13.75%。铁的化学物相分析结果显示,磁铁矿中铁的占有率为16.00%,赤铁矿中铁占有率为36.49%,硅酸铁中铁的占有率为41.34%。为了高效充分利用该矿石资源,采用"弱磁选—强磁选—反浮选"工艺流程及新型捕收剂BK448进行选矿试验,获得最终指标为:铁精矿1铁品位为65.45%,铁回收率为15.43%;铁精矿2铁品位为60.86%,铁回收率为31.42%。总之,该铁矿在磁铁矿和赤铁矿中铁总占有率为42.49%情况下,获得全铁回收率为46.85%的较好指标。     

碱度和内配燃料对赤铁矿球团强度的影响

针对赤铁矿球团强度低的问题,以巴西某赤铁矿精矿为对象,研究了碱度、内配燃料以及它们的相互作用对赤铁矿球团强度的影响。结果表明：制备含镁熔剂性赤铁矿球团时,将碱度控制在0.3~1.2可显著提高预热球团和焙烧球团的抗压强度;制备内配燃料酸性含镁赤铁矿球团时,焦粉配比不超过1.0%可改善预热球团强度而基本不影响焙烧球团强度;制备内配燃料熔剂性含镁赤铁矿球团时,将焦粉配比控制1.5%以内,球团碱度控制在0.9,可显著提高焙烧球团强度。由此可见,制备内配燃料熔剂性含镁球团是改善赤铁矿球团强度的有效途径。     

平行和垂直交叉排列组合棒介质高梯度磁选对比研究

为研究棒介质排列组合对高梯度磁选效果的影响,应用"单元介质分析法",选择铁品位38.10%的细粒赤铁矿,进行棒介质丝平行与垂直交叉排列组合对比研究。结果表明,与单一丝径棒介质比较,不同丝径组合式棒介质可以兼顾对不同粒级磁性矿粒的选择性捕获,有利于提高分选指标,且组合程度越高,提升分选指标越明显;介质丝平行与垂直交叉排列组合各有特点,后者捕获概率大些,但夹杂现象多些,因此精矿产率和铁回收率更高,但精矿品位更低。     

Photoelectrochemical water splitting at nanostructured α-Fe2O3 electrodes

In this study, nanostructured α-Fe₂O₃ thin films were deposited by simple electrodeposition for photoelectrochemical water splitting. Post-annealing temperature was found to have drastic effect on photoactivity of these films. SEM analysis illustrated that size of nanoparticles increases with annealing temperature. The current–potential characteristics showed that the water-splitting photocurrent strongly depends on post-annealing temperature. A maximum photocurrent density of 0.67 mA/cm² was observed at 1.23 V versus reversible hydrogen electrode (RHE) under standard illumination conditions (AM 1.5 G 100 mW/cm²), and the water-splitting current was over 1.0 mA/cm² before the dark current flow starts (at 1.55 V versus RHE). The electrode shows an onset potential as low as 0.8 V (versus RHE) for water photooxidation, which is one of the best results reported for hematite photoanodes. This high photoactivity of electrodes is attributed to the preferential growth of hematite nanostructures along the most conductive plane (001) and incorporation of Sn in film from the substrate at high annealing temperature. The best-performing electrode shows an incident photon conversion efficiency (IPCE) of 12% at 400 nm (in 1 M NaOH at 1.23 V versus RHE), which indicate the improved light-harvesting properties of these nanostructures.     

Hematite crystal growth in high-temperature lead-free multicomponent alkali borosilicate glass frit for red overglaze enamels

To elucidate the crystal growth process of hematite in high-temperature lead-free multicomponent alkali borosilicate glass, which is essentially important to control the color of red overglaze enamels, frit and hematite mixture is heat-treated and subjected to microscopic observations. Hematite particles slightly grew due to sintering at low temperature. Once the glass matrix formed near the softening point of frit, hematite dissolved into glass fluid. Hematite crystal growth concomitantly ensued with decrease in the number of hematite particles via Ostwald ripening as the temperature increased. The grown particles exhibited an anisotropic morphology with straight outlines reflecting crystal planes, the morphology of which is completely different from those grown by sintering and particles prior to heating. These results suggest that comprehensive understanding of frit and hematite from the perspectives of glass science and chemistry as well as powder technology are important to truly control the color of red overglaze enamels.     

Deep surface reconstruction of Co-based cocatalyst on Ti-doped α-Fe2O3 photoanode for highly efficient water oxidation

Transition metal-based cocatalysts play important roles in promoting the surface kinetics of hematite (α-Fe₂O₃) photoanode. However, their performances are restricted by the shallow reconstruction process for generating highly efficient metal oxyhydroxides, where the oxygen evolution reaction (OER) occurs. Therefore, a Brnsted base-regulated strategy is developed to promote the in situ surface reconstruction of cocatalysts on Ti-doped α-Fe₂O₃ (Ti–Fe₂O₃) under photoelectrochemical conditions. After deep surface reconstruction by electrochemical activation, the CoWO₄ cocatalyst decorated Ti–Fe₂O₃ photoanode (a-CoWO₄/Ti–Fe₂O₃) delivers a photocurrent density of 0.88 mA cm^?2 at 1.23 V_RHE, which is about 3.0 times of activated Ti–Fe₂O₃ (a-Ti-Fe₂O₃) and 1.5 times of activated CoO_x/Ti–Fe₂O₃. Tungstate promotes the surface reconstruction of cobalt-based cocatalyst, resulting in a significant increase in bulk charge separation efficiency (η_sep) and surface charge injection efficiency (η_inj). Moreover, the type-II heterojunction between CoWO₄-derived CoOOH and a-Ti-Fe₂O₃ drives the rapid separation and transfer of photogenerated electron-hole pairs, and enhances the performance of Ti–Fe₂O₃ photoanode.     

Slon－2000立环脉动高梯度磁选机分选弓长岭贫赤铁矿的工业试验

Ｓｌｏｎ－２０００立环脉动高梯度磁选机属我国自行研制的新型高效大型强磁选设备．该机在弓长岭选矿厂完成了六个月分选贫赤铁矿的工业试验，与Ｓｈｐ－２０００平环强磁选机比较，在给矿性质相同条件下，该机精矿品位提高７．２１个百分点，尾矿品位降低５．４１个百分点，作业回收率提高７．３６％，该机磁介质不堵塞，设备作业率达９８．８％，克服了平环强磁选机磁介质易堵塞和长期难以解决的设备作业率较低的问题．     

Statistical analysis and concentration of iron ore using Longi LGS 500 WHIMS

A Longi LGS 500 wet high intensity magnetic separator(WHIMS) was used to concentrate a fine, low grade South African hematite ore. The ore was prepared into different size fractions and was subjected to changes in pulp density, magnetic field intensity and pulsation frequency which followed a 33 full factorial matrix. The concentrate mass yield and Fe grade were selected as the dependent responses to the changes. The analysis of variance(ANOVA) shows that the variables investigated are significant to the material's response to magnetic separation. This significance was in the order of magnetic field intensity followed by pulsation frequency and then pulp density. It was also noted that a single stage magnetic separation has a potential to upgrade a feed( 75 lm and 40% Fe) to a 55% Fe grade, as the pulsation frequency increases. In addition, the model predictions and actual data were in good agreement, reporting regression coefficients within acceptable ranges.