细粒金红石矿浮选工艺研究

对重选抛尾后的金红石粗精矿进行了浮选条件实验,并在此基础上进行了闭路实验,得到的精矿品位为TTiO2 22．49％,回收率为83．52％,达到了回收金红石的目的。     

江苏某榴辉岩型金红石矿综合利用研究

针对江苏某榴辉岩型金红石矿性质和特点,采用了“磁选—重选—磁选”联合工艺流程,在获得金红石精矿含TiO2品位为90.09％,金红石回收率为63.07％的基础上,还可获得纯度为90％的石榴石与纯度为86.59％的绿辉石精矿,回收率均大于76％.试验结果为该矿的开发利用提供了合理的工艺参数和工艺指标.     

常温浮选萤石研究

研究采用一种新型捕收剂XJD—01实现了在常温条件下的萤石浮选。浮选效果明显优于油酸加温浮选；采用粗磨浮选抛尾-粗精再磨精选-中矿单独精选的流程．获得了CaF2回收率为49．20％的二级萤石精矿和CaF2回收率为37．94％的四级萤石精矿两种精矿产品。在精选循环中还通过添加硫化钠有效地降低了精矿中的杂质含量。     

榴辉岩型金红石矿综合利用途径研究

以青海榴辉岩型金红石矿为对象,对可利用矿物金红石、石榴石、绿辉石等进行了详细的工艺矿物学研究和选矿试验研究,查明了矿石的矿物组成、工艺粒度以及各种矿石性质对于选矿的影响,最终采用重选—磁选—浮选的联合工艺流程,从TiO_2品位为1.67%的原矿中选得TiO_2品位为92.46%的金红石精矿,同时回收了品位分别为92.87%和85.0%的石榴石和绿辉石精矿,为矿区的开发利用提供了合理的选矿方法和技术指标。     

油酸钠与苯甲羟肟酸钠协同体系中金红石的浮选机理

采用单矿物浮选实验研究了油酸钠(SO)和苯甲羟肟酸钠(BHA)组合药剂体系中金红石的浮选行为,利用Zeta电位、接触角、表面张力、紫外漫反射光谱等手段分别从固?液、液?液界面化学角度研究了组合药剂之间、组合药剂与矿物之间的作用机制以及组合药剂对金红石浮选行为的影响机理。结果表明,药剂添加顺序对金红石浮选回收率有较大影响,不同pH值下组合药剂之间有明显的正协同效应,金红石回收率及协同效应指数的大小顺序为先苯甲羟肟酸钠后油酸钠>预先混合再添加>先油酸钠后苯甲羟肟酸钠;油酸根离子中富电子的双键与苯甲羟肟酸根离子中缺电子的苯环可能发生电子共轭效应并可生成多种离子间缔合物,缔合物在金红石表面吸附时最佳空间几何构象能否形成及形成数量的多寡对药剂之间的协同效应及金红石的浮选行为具有举足轻重的影响。金红石与组合药剂作用后的漫反射光谱显示组合药剂对金红石浮选回收率与其对金红石带隙宽度的影响顺序一致。     

某低品位金红石精矿的物性测试和可浮性研究

以陕南青山镇金红石矿重选后的低品位金红石精矿为研究对象,通过物性测试研究了其可浮性特征,考察了改性剂浓度、振荡温度、振荡时间、改性剂协同效应等因素对金红石精矿可浮性的影响。结果表明：该金红石精矿属高硅高铁型低品位精矿,主要物相为金红石、榍石、锐钛矿和绿泥石,平均粒度为38.29μm。油酸钠和煤油协同作用体系中,油酸钠浓度0.04 mol·L^-1、煤油用量0.05 mL、振荡温度40℃、振荡时间60 min、p H=7.8条件下,改性后的金红石精矿接触角增大了60.11°,金红石精矿的品位为90.12%,回收率较单纯使用油酸钠提高21.38个百分点;水杨羟肟酸和煤油协同作用体系中,水杨羟肟酸浓度0.08 mol·L^-1、煤油用量0.05 mL、振荡温度40℃、振荡时间90 min、pH=7.8条件下对金红石精矿进行改性,金红石精矿接触角为69.33°,品位为89.51%,回收率较单纯使用水杨羟肟酸提高了22.57%,改性效果良好。本研究结果可为该低品位金红石精矿的综合利用提供基础理论依据。     

亚油酸钠协同二元表面活性剂体系中金红石的浮选特性及机理

利用单矿物浮选试验分别研究了金红石在亚油酸钠与油酸钠或苯甲羟肟酸钠组成的二元表面活性剂体系中的浮选行为,采用Zeta电位、表面张力、接触角、紫外漫反射吸收光谱等手段从气/液、固/液界面探讨了组合药剂之间及组合药剂在金红石表面的作用机制。结果表明,药剂添加顺序对金红石浮选行为有较大影响,亚油酸钠与苯甲羟肟酸钠的协同效应指数要高于亚油酸钠和油酸钠组合体系;组合药剂在金红石表面的吸附可分为单层诱导共吸附和缔合物多层吸附两大类,分子间的缔合作用力及缔合产物的吸附状态是影响组合药剂协同作用及金红石浮选行为的关键因素;苯甲羟肟酸钠和亚油酸钠体系中不同药剂添加顺序下金红石浮选行为与其带隙宽度的变化有较好的一致性,而油酸钠和亚油酸钠体系中则未发现明确的对应关系。     

新型氯化钠浮选药剂的研制

采用自行开发的氯化钠浮选剂对旱要光卤石进行选别试验，闭路试验表明，精矿含KCl23.7%,NaCl4．13％，尾矿含KCl2.90%,NaCl84.03%,精矿KCl回收率可达96．79％，NaCl排除率达84．70％。     

攀枝花钛精矿制备高品质富钛料工艺分析

分析了攀枝花钛精矿晶型结构和元素分布特性,结合开发的攀枝花钛精矿制取人造金红石工艺和攀枝花钛精矿制取升级钛渣工艺路线,对2种工艺优劣进行了多方面分析评价,并参考国际钛原料发展方向,认为攀枝花钛精矿制备人造金红石工艺路线更易实现产业化。     

氨性催化氧化-氰化法处理含砷难浸金矿的研究(Ⅱ)

本文概述了氨性氧化-氰化法处理含砷难浸金矿的扩大实验结果．对于含有砷、锑、汞、碳的丹寨金精矿，其金品位为17．6g／t，金的氰化率可达84％与小型实验结果相符．     

Disinfection of spring water and secondary treated municipal wastewater by TiO2 photocatalysis

The photocatalytic disinfection of spring water and secondary treated municipal wastewater by means of UV-A irradiation over TiO₂ suspensions was investigated. Water samples were taken from a spring supplying water to the city of Chania, Western Crete, Greece, while wastewater samples were collected from the outlet of the secondary treatment of Chania municipal wastewater treatment plant. The effect of various operating parameters such as photocatalyst type (rutile, anatase, mixture of anatase and rutile) and concentration (0.5-1 g/L), contact time (up to 60 min) and sample pH (6-8) on the disinfection as assessed in terms of faecal indicator microorganisms (total coliforms and enterococci) inactivation was examined. A commercially available Degussa P25 TiO₂ powder, consisting of 75% anatase and 25% rutile, was found substantially more active than pure anatase or rutile for both groups of bacteria inactivation which increased with increasing contact time and catalyst concentration, whereas small pH changes had little effect on destruction. For both groups of bacteria tested, inactivation followed a first order kinetic expression with the gram positive Enterococcus sp. being considerably more resistant to photocatalytic disinfection than total coliforms.     

Effect of HCl concentration and reaction time on the change in the crystalline state of TiO2 prepared from aqueous TiCl4 solution by precipitation

TiO₂ powder with 50% by volume or more of brookite phase was obtained by heating aqueous TiCl₄ solution, whose final concentration of HCl after reaction was kept between 4.9 and 6.4 M, at 80 °C for 15 h. Rutile-type TiO₂ was obtained at 5 h of reaction time, a mixture of predominant brookite and rutile at 10–15 h while rutile phase was formed at 25 h. Brookite phase was transformed directly to rutile phase with increase of reaction time but to rutile via anatase phase through heat treatment.     

磷酸三丁酯萃取分离钛铁矿亚熔盐反应产物酸解液中Fe3+及金红石型TiO2的制备

在盐酸介质中以磷酸三丁酯(TBP)为萃取剂、磺化煤油为稀释剂,从钛铁矿与氢氧化钾亚熔盐反应产物的酸解液中萃取分离Fe3+,并利用萃取后的含钛液水解制备二氧化钛. 考察了萃取剂浓度、盐酸浓度、有机相和水相体积比(O/A)和萃取时间对铁萃取率的影响. 结果表明,钾系亚熔盐法分解钛铁矿的分解率在96%以上. 萃取率随着TBP浓度及盐酸浓度的增加和O/A值的减小而增大;通过调节萃取条件,萃取率可以达到99%以上. 用1.0 mol/L的NaCl溶液进行反萃,反萃率可达98%以上. 萃取后含钛液经水解可以制得纯度高于98%的金红石型TiO2球状颗粒.     

金红石相含量对混晶纳米TiO2光催化分解水制氢的影响

合成了不同金红石相含量的纳米TiO2,并研究了其光催化分解水制氢的活性.结果表明,未沉积Pt时,纯锐钛矿TiO2活性最高,金红石相含量的增加导致TiO2活性下降并在下降过程中出现波动.沉积Pt后,TiO2产氢速率随金红石相含量的增加先增后减,在金红石相质量分数为9.7%时达到最高,为40.35 mmol/(gcat·h).首次提出了金红石相含量时混晶纳米TiO2光催化分解水制氢活性的影响机理.     

Kinetics of Opacification of a TiO2-Opacified Cover Coat Enamel

Quantitative X-ray diffraction measurements were used to study the firing behavior of a typical TiO₂-opacified cover coat enamel. A model was developed for predicting the anatase and rutile concentrations as a function of time and temperature of firing. The model consists of three first order reactions: crystallization of anatase, crystallization of rutile, and inversion of anatase to rutile. It predicts successfully over a wide range of time-temperature conditions. Discrepancies are found, however, for short-time, low-temperature firings. The reflectance data do not correlate well with the crystalline concentration data. The correlation with color data is better, but is not perfect.     

TiO2, TiO2/Ag and TiO2/Au photocatalysts prepared by spray pyrolysis

TiO₂, TiO₂/Ag and TiO₂/Au photocatalysts exhibiting a hollow spherical morphology were prepared by spray pyrolysis of aqueous solutions of titanium citrate complex and titanium oxalate precursors in one-step. Effects of precursor concentration and spray pyrolysis temperature were investigated. By subsequent heat treatment, photocatalysts with phase compositions from 10 to 100% rutile and crystallite sizes from 12 to 120 nm were obtained. A correlation between precursor concentration and size of the hollow spherical agglomerates obtained during spray pyrolysis was established. The anatase to rutile transformation was enhanced with metal incorporations and increased precursor concentration. The photocatalytic activity was evaluated by oxidation of methylene blue under UV-irradiation. As-prepared TiO₂ particles with large amounts of amorphous phase and organic residuals showed similar photocatalytic activity as the commercial Degussa P25. The metal incorporated samples showed comparable photocatalytic activity to the pure TiO₂ photocatalysts.     

Flame synthesis of titania particles from titanium tetraisopropoxide in premixed flames

An experimental investigation of flame synthesis of titania particles was conducted in premixed flames. The titanium precursor and silicon dopant used in this study were titanium tetraisopropoxide (TTIP) and hexamethyldisiloxane (HMDS), respectively. The objective of this study was to investigate the influence of flame condition, TTIP concentration, and HMDS on the phase composition and particle morphology of titania synthesized in flames. It was found that the anatase content of titania particles made in flames was appreciably increased by the increase of oxygen concentration in the oxidizer. The increase of flame temperature results in the decrease of anatase content. A significant increase in rutile content of titania particles was observed by increasing the particle residence time at high temperatures. The doping of HMDS in flames inhibits the transformation of anatase to rutile phase and, therefore, reduces the rutile content of product particles. Under the flame doped with low concentrations of HMDS, titania particles with SiO₂ particle agglomerates attached were produced. Further increase of the HMDS concentration up to the Si to Ti molar ratio equal to 0.375 results in the formation of a large amount of SiO₂ agglomerates in the product.     

Photocatalysis of V-bearing rutile on degradation of halohydrocarbons

Natural rutile TiO₂ shows photocatalysis on degrading trichloroethylene and tetrachloroethylene. In natural rutile, V, Fe, Cu, etc. substitute for Ti, resulting in lattice distortions and defects. We found that rutile, after heating, quenching and electron irradiation, changes its surface characteristics and photoactivity. The quenched rutile has the highest concentrations of adsorbed water and V on its surface, resulting in high photoactivity. For example, quenching at 1273 and 1373 K significantly improved photoactivity of rutile. The heated rutile also increased the concentration of adsorption water on the surface, e.g., rutile heated to 1273 K improved degradation rate of halohydrocarbons. On the contrary, electron irradiation decreased the concentration of adsorbed water on the rutile’s surface, which results in lower degradation rate for trichloroethylene. Therefore, heating and quenching over 1237 K improve the photocatalytic efficiency of the natural V-bearing rutile on degrading halohydrocarbons. The XRD spectra of the rutile samples showed that heating, quenching and electron irradiation did not result in formation of new phases or phase transitions.     

电炉钛渣碱浸除硅、铝与碱浸渣的预氧化焙烧动力学

采用碱浸除杂-预氧化焙烧-活化改性-高压酸浸工艺处理云南地区电炉钛渣,制备高品位人造金红石. 研究了电炉钛渣碱浸除硅、铝的机理,考察了搅拌速率、粒度、温度、NaOH浓度、液固质量比、浸出碱试剂单因素对浸出率的影响,SiO2与Al2O3浸出率高达75%和50%;正交实验结果表明,NaOH浓度为1.5 mol/L、液固质量比为8、温度为沸腾温度(92.7℃)、浸出时间为1 h的条件下,浸出效果较理想;通过碱浸渣预氧化,有60%的TiO2以金红石形态析出,且在低于700℃下过程受界面化学反应控制,扩散较快,表观活化能为31 kJ/mol/, 850℃下过程受扩散控制,随空气流量增大氧化率提高.