钛铁矿制备人造金红石半工业试验

以攀西地区钛铁矿为原料,在常压下采用低浓度盐酸进行多级浸出生产人造金红石的半工业试验。结果表明,采用该流程成功制备出了TiO2品位大于94%的人造金红石产品,同时解决了盐酸再生与再生酸循环利用衔接的技术难题。     

从低品位钛铁矿(河砂)中制取人造金红石

目前国内外生产人造金红石,大多采用高品位钛铁矿作原料。本文着重研究从低品位钛铁矿中直接制取人造金红石的可能性。在作了大量探索性试验的基础上,成功地从含低品位钛铁矿的河砂中制取人造金红石。工艺流程为:还原磁化焙烧-磁选-盐酸浸出。流程工序简单,原材料易,设备无特殊要求,有较好的技术经济指标。对处理其他低品位钛铁矿,也有参考价值。     

盐酸加盐浸出攀西钛铁矿的研究

使用含有氯化盐的盐酸和纯盐酸浸出钛铁矿,试验发现,在盐酸浓度为18%、液固比4.2,135℃的条件下,含有氯化盐的盐酸在30 min内浸出所得人造金红石品位与盐酸直接浸出得到的人造金红石品位相近,均在83.77%左右;且在含盐盐酸浸出1 h左右,反应基本达到终点,所得人造金红石品位约为93.19%以上。同时测试了盐酸中氯化盐的浓度对所得人造金红石品位和粉化率影响以及浸出前盐酸活度,发现含盐盐酸活度与氯化盐浓度以及种类有关,提高氯化盐阳离子价态或者氯化盐浓度对盐酸活度都有大幅度提升,但不同种类相同价态阳离子对盐酸活度影响相同;含盐盐酸浸出所得人造金红石品位比盐酸直接浸出所得高,但粉化率也更为严重。通过扫描电镜(SEM)分析可以发现,反应过程中氯化氧钛水解生成大量针状金红石并且发生聚结,形成球状颗粒,即化学因素是造成金红石粉化的主要原因。     

人造金红石母液预处理改性钛精矿研究

论述了人造金红石母液预处理改性钛精矿的基本原理和技术思路,并在实验室进行了人造金红石母液和盐酸两段浸出改性钛精矿试验,考察了液固比、浸出温度、浸出时间、盐酸浓度对制备人造金红石品位和钛回收率的影响,可得到钛品位92%以上的人造金红石产品。采用人造金红石母液预处理改性钛精矿,可节约盐酸用量及废酸处理成本约600元/t,经济效益显著。     

攀西钛精矿制备人造金红石研究

利用攀西地区储量丰富的高钙镁低品位钛铁矿制备符合沸腾氯化需要的高品质富钛料是推动钛行业发展的关键。通过对攀西钛铁矿矿物组成和结构等物相特性分析,提出了氧化还原改性-盐酸浸出制备人造金红石的方法。先在实验室进行工艺条件优化试验,确定了关键参数。在此基础上,进行了5 kt/a规模人造金红石的扩大试验。扩大试验实现了连续稳定运行,成功获得了满足沸腾氯化需要的优质人造金红石产品,其Ti O2≥90%,Ca O+Mg O≤1.0%。酸浸产生的废盐酸,采用喷雾焙烧技术得到了回收利用,实现了盐酸闭路循环,确保全流程无"三废"排放。最后,形成了"攀西钛铁矿流态化氧化—还原—常压浸出—废酸回收"制造人造金红石的成套工艺及操作制度。     

钛铁矿盐酸加压浸出制备人造金红石试验研究

对典型钛铁矿的化学成分、物相组成和表面结构进行表征,X射线衍射(XRD)分析其结果表明,钛铁矿中主要的物相成分为FeTiO_3。根据钛铁矿的成分特点,采用还原焙烧-盐酸加压浸出法对钛铁矿进行浸出制备人造金红石,研究了预焙烧处理对于铁元素价态及浸出效果的影响。结果表明,弱氧化焙烧和还原焙烧均能够改善钛铁矿的理化性能,强化其浸出效果。最佳的预处理方式为还原焙烧,还原剂用量为8%,焙烧温度900℃,焙烧时间60 min。对于还原焙烧后的钛铁矿进行盐酸加压浸出研究,考察了浸出温度、浸出时间、盐酸浓度、液固比等因素对浸出效果的影响。盐酸加压浸出的最优条件为:浸出温度140℃,浸出时间4 h,盐酸浓度20%,液固比9∶1。此条件下得到的浸出渣煅烧所得金红石TiO_2含量可达93.45%。该工艺流程比较简单,能够有效地实现钛铁矿中杂质的分离,获得高品位的人造金红石产品。     

盐酸浸出钛铁矿制人造金红石的技术研究

人造金红石的开发和利用已成为钛白粉生产的重要环节。通过研究提出"弱氧化-弱还原-加压浸出"制备人造金红石的方法。采用X射线衍射仪(XRD)对改性后钛铁矿进行了物相结构分析,采用X射线荧光光谱仪(XRF)对浸出的人造金红石进行了化学成分组成分析。实验结果表明:通过"弱氧化-弱还原-加压盐酸浸出"方法可以制备高品质可氯化人造金红石,当制备条件为:氧化温度为700℃、还原温度为580℃、浸出温度为155℃、浸出时间为6h、酸矿比为3∶1、盐酸浓度为22%时,可制备得到TiO_2为92.37%、TFe为1.55%,且浸出前后无明显粉化的人造金红石。该方法简单、低耗能,具有研究意义。     

熔盐氯化废渣回收氯化盐及其促进钛铁矿盐酸浸出研究

对熔盐氯化废渣进行氯化盐回收,并对回收氯化盐用于钛铁矿盐酸浸出体系作了初步研究。结果表明,水浸可以高效地将熔盐氯化废渣中的可溶氯化盐和不溶氧化物分离。水浸后剩余不溶残渣仅为11%,主要由Fe2O3、(Fe,Mg)2Ti O5和以及(Ca,Al,Mg)Si O3等性质稳定的物质组成,便于堆存,对环境无害。而KCl、Na Cl等废渣中主要氯化物在水浸母液蒸发结晶盐中富集,Cl元素回收率超过95%。回收得到的氯化盐添加到钛铁矿盐酸浸出体系中,可以提高钛铁矿的浸出反应活性。添加氯化盐比例越大,得到的人造金红石产品Ti O2品位越高。添加质量比为50%的氯化盐,可使人造金红石Ti O2品位由80.8%提升至84.5%。     

预氧化处理对云南钛精矿浸出过程粉化的影响

人造金红石作为天然金红石的优质代用品,大量用于生产氯化法钛白和海绵钛。针对云南钛精矿相关物化特性,采用预氧化钛精矿、盐酸浸取的方法制备人造金红石,研究预氧化处理对浸出率及粉化的影响。结果表明:预氧化处理改变了钛精矿结构,解决了盐酸浸出过程的粉化问题。在盐酸浓度为20%、酸矿比为5∶1时,加热到沸腾浸出在750℃时预氧化30 min后的钛精矿,得到的人造金红石粒度小于74μm的矿粒仅占3.29%,品位为77.1%。     

盐酸法制取人造金红石工艺研究

以攀枝花钛铁矿为原料,采用预氧化-前磁选-酸浸-过滤、洗涤-煅烧-后磁选工艺制取高品质人造金红石.在某钛黄粉厂1 000t/a生产装备上,针对酸浸工序,研究了浸出矿种类、浸出时间、浸出温度、酸浓度以及酸矿比对浸出效果的影响.通过条件优化试验和稳定试验,最终使产品细料率基本控制在15%以下,全流程钛总收率≥92%,人造金红石品位≥92%,并成功地将粗、细金红石分离.     

Soda ash roasting of titania slag product from Rosetta ilmenite

A soda ash roasting process for upgrading titania slag product of Rosetta ilmenite to a high grade titanium dioxide (TiO₂) is presented. The roasting process was carried out at moderate to high temperatures to yield a reaction product that would be easily decomposed by subsequent leaching procedures. Factors affecting the roasting process; namely the soda ash ratio to the slag material, the roasting time and temperature were studied. The optimised conditions used a Na₂CO₃ to slag ratio of 0.55:1 at a roasting temperature of 850 °C for 0.5 h duration period. The impurities associated with the roasted slag were subjected to leaching with water and dilute hydrochloric acid solution leaving synthetic rutile (TiO₂) as insoluble residue. To improve the quality of the synthetic rutile, an alkaline leaching step was added to remove the excess silica present in the treated titania slag. This method is capable of producing high purity synthetic rutile assaying about 97% TiO₂.     

Preparation of titania from llmenite by selective H2S sulfidization

Experiments on preferential sulfidization of ilmenite in a static bed by hydrogen sulfide gas with a flow rate of about 20 cu cm per min were conducted at 800°, 900°, 1000°, and 1100°C for different periods. Sulfidization (conversion of about 95 pct of the iron to its sulfide) at 1000°C for 5 hr or at 1100°C for 4 hr was considered quite suitable. The sulfidized samples were leached with boiling dilute hydrochloric acid and the influence of the concentration, amount of the acid, and the duration of leaching was studied. Leaching was most effective by employing 20 pct excess 2 N boiling hydrochloric acid for 1/2 hr. By this treatment, about 95 pct of the iron in ilmenite could be removed and a residue containing about 91 pct TiO₂ has been obtained. X-ray analysis revealed that TiO₂ in the residue has rutile structure. The merits of the process for commercial utilization have been mentioned briefly.     

氧化还原—机械活化对攀西钛铁矿浸出行为的影响

研究了"氧化还原—机械活化—盐酸浸出"的方法对钛铁矿中主要杂质离子铁离子浸出行为的影响,并采用XRD、SEM/EDS对处理前后的矿物结构进行分析。结果表明:经过氧化还原—活化处理,钛铁矿的物相明显发生改变,铁迁移至表面,形成了富铁的新表面,表面变得疏松、凹凸不平,出现了大量的微裂缝,铁浸出率有了显著的提高。     

Effects of Mechanical Activation on the HCl Leaching Behavior of Titanaugite,Ilmenite, and Their Mixtures

Structural changes of mechanically activated titanaugite were investigated systematically using X-ray diffraction, particle size analysis, and scanning electron microscopy. The hydrochloric acid leaching behavior of mechanically activated titanaugite and ilmenite single minerals and their mixtures also was studied. The results show that with increasing milling time, the crystallite size, lattice strain, and particle size changed continuously. Mechanical activation evidently improved the leaching reactivity of titanaugite and ilmenite with 20 wt pct HCl at 378 K (105 °C). The leaching behavior of ilmenite was promoted at the initial stage and then was inhibited when mixed with a mass ratio of titanaugite to ilmenite of 1:1. When the mass ratio of titanaugite to ilmenite decreased to 1:9, the leaching of titanaugite was promoted, whereas the leaching of ilmenite was inhibited throughout the whole process. The leaching inhibition of ilmenite is related to the formation of hydrous silicon dioxide from the dissolution of titanaugite.     

Preparation of synthetic rutile by hydrochloric acid leaching of mechanically activated Panzhihua ilmenite

Dissolution of mechanically activated Panzhihua ilmenite in hydrochloric acid for the preparation of synthetic rutile was investigated. Both the dissolution and its coupled titanium hydrolysis were greatly enhanced by the mechanical pretreatment. Increases in the lattice strain and surface area of ilmenite induced by energetic ball milling were responsible for the enhanced dissolution. The rapid hydrolysis led to formation of quantities of the nanosized primary particles, giving rise to a solid/liquid separation problem. The 15 min milled ilmenite, however, yielded an easy-to-filter hydrolysate due to formation of porous, micron-sized, secondary particles during the dissolution. The crystallization and aggregation behaviour of the primary particles were probably related to both the surface property of the un-reacted solid and the ferric ion concentration in solution. The technology for preparation of synthetic rutile was systematically investigated. The optimum milling and dissolution conditions were as follows: milling in air for 15 min, hydrochloric acid concentration 20%, initial reaction temperature 100 °C, ilmenite/20% acid mass ratio 1 g:5.5 g, reaction time ≥ 6 h. The synthetic rutile prepared under the optimum conditions contained 92% TiO₂ and 2.1% Fe₂O₃ as well as combined CaO and MgO of 0.28%. The results demonstrate that the mechanical pretreatment can take the place of the traditional high temperature pretreatment of ilmenite and avoid the dissolution being conducted under pressurized condition.     

预氧化在盐酸法制取人造金红石中的作用

论述了预氧化机理、酸浸反应机理和细化机理，并通过攀枝花钛铁矿与预氧化矿在1000t／a生产装备上的对比试验，考察了两种矿对酸浸后粗金红石品位及产品细料率的影响，阐明了预氧化有提高粗金红石品位、降低产品细料率的作用。     

钒钛铁精矿常压盐酸浸出分离铁钛试验研究

在常压条件下,采用盐酸浸出法对钒钛铁精矿进行选择性浸出试验,研究了液固比、浸出温度、浸出时间和盐酸浓度对铁和二氧化钛浸出率的影响,并对浸出渣结构、形貌、粒度及元素分布进行了研究。结果表明,盐酸浸出过程破坏了钒钛铁精矿中的磁铁矿物相,浸出渣表面出现了较为明显的粉化现象,铁元素进入浸出液;而钛铁矿未被破坏,仍以钛铁矿的形式存在酸浸渣中。最优浸出条件为:液固比为9∶1,浸出时间为60 min,盐酸浓度为18.6%,浸出温度为85℃。最优条件下铁的浸出率为85.41%,二氧化钛的浸出率为7.22%;酸浸渣的产率为27%,Ti O2品位约为34%。     

Feasibility study of the new rutile extraction process from natural ilmenite ore based on the oxidation reaction

Phase relations in the Fe₂O₃-FeTiO₃-TiO₂ system were investigated by equilibrating synthetic samples in evacuated sealed quartz tubes at a temperature of 1373 K. The equilibrium partial pressure of oxygen was measured by the electromotive force (EMF) method in the temperature range of 1273 to 1373 K. The phase diagram and oxygen partial pressure diagram in the titanium-iron-oxygen ternary system were then constructed at 1373 K. Rutile extraction from natural ilmenite ore was discussed from the thermodynamic viewpoint. It is found that rutile can be produced from common natural ilmenite ores not only by the reduction as the conventional titanium-rich slag process but also by an oxidation. Then, the oxidation experiment was conducted in air using Australian ilmenite ore to obtain rutile as one of the coexistent phases. Magnetic separation and leaching experiments for synthesized pseudobrookite and reagent rutile were conducted to confirm the possibility of separation of rutile from pseudobrookite. A new rutile extraction process was then proposed.