This paper summarizes and sorts the operational data of titanium dioxide industry in China in 2022, such as production capacity, yield, apparent market demand, production capacity distribution, etc., and focuses on analyzing the recent growth trend of titanium dioxide production capacity and the corresponding changes in the supply and demand relationship of titanium ore raw materials. It is pointed out that the yield and production capacity of titanium dioxide in 2022 will continue to maintain an increasing trend, and the concentration of production capacity will be further improved. At the same time, the further expansion of the scale of existing producers and the increase of joining projects outside the industry will lead to the shortage of titanium ore supply. In addition, with the rise of the green new energy battery material industry, a large number of iron phosphate or lithium iron phosphate project construction or preparation, will lead to the surge of titanium dioxide production capacity, aggravate the contradiction between titanium ore supply and demand; then the market prospects and industry outlook is worrying, all parties should pay close attention to and timely adjust.
Vanadium pentoxide (V2O5) has attracted extensive attention due to its layered structure, abundant resources, high capacity, low cost, high Na+ ionic conductivity, small volume change during Na-ion insertion/extraction, and mesopotential platform. V2O5/graphene nanocomposites were successfully prepared by hydrothermal method, using oxalic acid and V2O5 as raw materials. The results show that the V2O5 nanowires and graphene are closely intertwined with each other, forming a V2O5-graphene nanocomposite with a tightly network structure. The structure can provide fast electron transfer kinetics, expand the effective contact area between the electrolyte and the electrode material, improve the conductivity of the material and buffer volume changes during Na-ion insertion/extraction. Thus, the electrochemistry properties of V2O5/rGO nanocomposites are effectively improved (Over 100 cycles, 154 mAh/g at 100 mA/g).
In this paper, the direct reduction-magnetic separation method was used to recover Fe from vanadium titano-magnetite (VTM) tailings. Under the conditions of reduction temperature 1250 ℃, reduction time 2 h and reducing agent dosage 20% of the mass of the tailings, the metallization rate of pellets was 92.71%. After adding 5% CaCO3 and prolonging the holding time to 6 h, the average diameter of Fe grains increased from 14.53 μm to 25.39 μm. By fitting the growth rate of Fe grains, it was found that the grains growth rate constant increased from 0.26 μm2/min to 1.45 μm2/min after adding CaCO3. After magnetic separation, the direct reduced iron with TFe content of 90.72% and the titanium slag with TiO2 content of 41.75% could be obtained. The recovery rate of Fe reached 91.05%, which greatly improved the resource utilization of VTM.
To accurately explore the dynamics of carbon reduction reaction of vanadium-titanium magnetite powder, the test was conducted by hydrothermal method without adding any modifier. Carbon-coated vanadium-titanium magnetite powder was prepared with glucose as carbon source. The heating curves of weightlessness of carbon-coated vanadium-titanium magnetite powder obtained under different heating rate of 5, 7.5, 10, 15, 12.5, 1 5 K/min were measured by high temperature comprehensive thermal analyzer . Combined with the FWO formula and CR formula, the experimental data were calculated,as well as the kinetic parameters of carbon-coated vanadium-titanium magnetite powder. The results show that the weight loss rate of carbon-coated vanadium-titanium magnetite powder in a certain temperature range is proportional to the amount of carbon coating and the heating rate. The activation energy in this reaction is about 73.533 kJ/mol with a reaction mechanism of tertiary chemical reaction model.
总结回顾了中国钛白粉工业2019、2020年的各项行业数据和表现,分析了当前面临的形势及发展趋势,认为高质量发展成为钛白粉行业未来发展的主旋律,钛白粉产能集中度虽有提高,但洗牌效应短期内难以呈现,这也是行业发展的一个难题,另外行业监管、氯化法钛原料问题、环保及清洁生产问题仍不容忽视。
从2020年我国钛工业钛精矿、海绵钛、钛锭、钛材等品种的产能、产量、应用和进出口等数据分析了我国钛工业的整体情况,并对目前行业存在的问题提出了建议。
某低品位钒钛磁铁矿,TiO2品位为6.15%,矿物组成复杂,为充分回收其中的钛铁矿,针对钛的赋存状态及粒级分布特点,制定了强磁磁选预抛尾、重选提质、细磨弱磁选除铁、反浮选脱硫与一粗一扫两精浮钛组合工艺流程,研究了磁感应强度、磁介质大小、脉动冲程、磨矿浓度、磨矿时间、浮选调整剂及捕收剂用量等的影响,在获得最优工艺条件的基础上,按“一段强磁抛尾—两段重选抛尾—磨矿—除铁—浮选”的工艺流程进行了闭路试验。试验获得了TiO2品位48.22%,回收率为35.19%的钛精矿。矿石中主要有用的矿物钛铁矿得到了有效的回收。
为了探究Mg处理对易切削钢中夹杂物的影响,以1144高硫易切削钢为试验钢种,采用金相和能谱仪等手段研究了Mg处理对1144易切削钢中夹杂物的形态、尺寸分布和夹杂物成分的影响。结果表明:在易切削钢铸坯中,Mg处理使得易切削钢铸坯硫化物夹杂由Ⅱ类向Ⅲ类、Ⅰ类转变,分布更为均匀,同时使得复合硫化锰夹杂物比例提升。在轧材中,使得钢中夹杂物球化,并且钢中硫化锰夹杂物的尺寸和分布也得到了较好的改善,同时,Mg处理能够有效提高易切削钢的切削加工性能。
在弹簧钢55SiCr成分基础上进行钒微合金化处理,获得了55SiCrV,通过淬火+回火正交试验、显微组织观察、力学性能测试和X射线衍射等手段,研究并分析了淬火+回火工艺对弹簧钢55SiCrV微观组织和力学性能的影响,结果表明:0.20%V的添加可使55SiCrV组织中存在大量弥散均匀分布的10~35 nm含钒析出相,强化效果最佳。淬火+回火处理可以改变55SiCrV的显微组织比例,其中的残余奥氏体可以降低强度和增加塑性,55SiCrV获得最佳力学性能匹配(Rm=1 815 MPa、Z=28%)的热处理工艺为900 ℃淬火+430 ℃回火,对应其残余奥氏体含量为2.3%。
分别采用NaOH、HCl浸出废SCR催化剂,碳酸钠焙烧-水浸废SCR催化剂选择性分离钛。试验表明:碳酸钠焙烧-水浸废催化剂可实现钛与钒、钨高效分离。较优工艺条件:焙烧温度850 ℃,焙烧时间3 h,碳酸钠与废催化剂质量比为1.3,浸出温度95 ℃,浸出时间1 h,搅拌速度500 r/min。V、As、W的浸出率分别为52.26%,98.24%和99.9%。采用硫酸浸出废SCR催化剂钠化焙烧渣实现高效提取钛。工艺条件:上述较优条件焙烧渣,40%硫酸,液固比4∶1,浸出温度90 ℃,浸出时间3 h,搅拌速度500 r/min。钛的浸出率为93.4%。采用自生晶种水解法制备偏钛酸,钛水解率为94.05%,偏钛酸纯度为94.07%。
电渣重熔对于提高钢的纯净度有明显的效果,但对于低氧含量钢种存在增氧现象。通过采用GCr15轴承钢作为自耗电极,研究在大气环境下和Ar保护下使用不同渣系对轴承钢中氧含量及夹杂物的变化规律。研究发现,采用CaF2-Al2O3-CaO三元渣系在氩气保护下电渣重熔GCr15轴承钢时,电渣锭中的氧含量随渣系中的Al2O3含量下降而降低,而使用不含Al2O3渣系重熔的电渣锭中氧含量最低;氩气保护下重熔的电渣锭中的夹杂物直径均比使用同种渣系在空气中重熔的电渣锭要小。氧含量增加主要是因为电渣重熔过程渣池温度过高,导致渣中Al2O3稳定性变差所致。
利用透射电镜(TEM)对纳米二氧化钛的形貌和粒度进行分析后,将纳米二氧化钛制成乳胶漆、汽车漆、家具漆和防腐漆,对其进行耐候性、随角异色等性能分析。结果表明,金红石纳米二氧化钛可大幅度提高乳胶漆的耐候性、耐水性、耐碱性和耐洗刷性能,可提高家具漆和防腐漆的耐候性;纳米二氧化钛和铝粉配合制成的汽车漆具有随角异色效果,二氧化钛的粒度对其随角异色性能有很大影响,平均粒径为280 nm的普通颜料钛白改性铝粉漆无随角异色效果,平均粒径为35 nm的纳米二氧化钛改性铝粉漆有显著的随角异色效果,并且随纳米二氧化钛加量的增加,其不同角度的颜色差异增大。
将钒微合金化试验钢分别加热至780、800、820 ℃和840 ℃保温一段时间后,依次经过缓慢冷却、快速冷却、模拟镀锌后,空冷至室温。研究结果表明,780 ℃退火时微观组织均匀性较差且发现未溶解的碳化物,导致强度和塑性均不佳。随着退火温度的升高,铁素体尺寸及分数逐渐降低,中低温转变产物含量逐步增加且其尺寸有所粗化。当退火温度为800 ℃时,马氏体含量达到最大,当退火温度进一步升高时,马氏体含量有所降低,而贝氏体含量则有所增加,导致抗拉强度在800~840 ℃范围内变化不大,而延伸率先升高后降低。当退火温度为820 ℃ 时,带钢获得较佳的力学性能,屈服强度、抗拉强度、屈强比、断后伸长率A80和扩孔率分别为486 MPa、835 MPa、0.58、16.0%和27%。
钛白废酸中含有可观的资源,废酸的再加工与增值正逐渐成为钛颜料工业的焦点。针对硫酸法钛白副产废酸的回收与利用现状展开综述,主要介绍了废酸在提取金属元素、浸出金属元素、回收硫酸以及工业生产方面的应用,并在此基础上,对今后钛白废酸资源化利用的发展做了相关展望,以期为相关行业的从业者带来废酸利用方面的参考。