处理我国中低品位高硫铝土矿脱硫工艺的讨论

到21世纪中期，我国高品位矿石资源将枯竭，氧化铝生产的主要矿石将是高硅低铝硅比矿石和相当部分没被利用的高硫中高铝硅比矿石。因此，开发研究高硫铝土矿的脱硫新工艺具有很大的现实意义，也符合国家的可持续发展的战略方针。拜耳法脱硫方法大多集中在溶出过程中及溶出后的处理，而在溶出前对铝土矿的预处理则研究较少，在高硫铝土矿的应用方面是我国氧化铝工业存在的一大空白。     

高硫铝土矿的选矿技术

本文叙述了我国的铝土矿资源及其部分地区的铝土矿硫含量高的特点,硫在氧化铝生产中的危害等。针对这一情况探讨性的提出了通过浮选的方法使铝土矿中硫的含量降低至使其能进行氧化铝的生产。对生产和研究有一定的先导性探索。     

煤液化残渣中硫的氧化规律

利用四氢呋喃溶解煤液化残渣,将煤液化残渣分离为油相和四氢呋喃不溶物固体,之后测定其中各形态硫的含量,发现煤液化残渣中98%(质量分数)的硫存在于四氢呋喃不溶物固体中,且主要以磁黄铁矿的形式存在。故此以四氢呋喃不溶物为原料进行空气氧化,研究其中硫的氧化转化规律。结果表明,干空气氧化四氢呋喃不溶物,四氢呋喃不溶物总含硫量减少,氧化过程中生成硫酸盐和单质硫,其中单质硫在氧化过程中进入气相而脱离四氢呋喃不溶物固体;湿空气氧化四氢呋喃不溶物,四氢呋喃不溶物总含硫量基本不变,反应过程中仅有硫酸盐生成。实验条件下,氧化过程由磁黄铁矿颗粒上覆盖的硫酸盐产物层中的氧扩散控制,扩散活化能为26.25 k J/mol。     

直接/间接接触模式下1株硅酸盐细菌铝土矿脱硅研究

为考察铝土矿生物浸出脱硅的机制,比较了硅酸盐细菌JY03在细菌-矿物接触/非接触模式下与铝土矿的作用,分析浸出过程中铝土矿表面形成的生物膜与钝化膜对溶硅的影响。结果表明,在细菌浸出的前期(0～6d),铝土矿表面生物膜与钝化膜还未形成,Al与Si的溶出主要受间接接触模式的影响;在6～12d内,铝土矿表面的生物膜逐渐显现,Si的溶出速率明显较非接触模式快,Si的溶出主要受接触模式的影响,12d后,浸出液中SiO2的浓度高于非接触模式17mg/L左右;在8～12d,Al2O3沉淀产生,接触模式下Al的溶出速率明显变缓,非接触模式下明显下降;浸矿12d后,Al2O3絮凝沉淀在铝土矿表面形成钝化膜,浸出液中Al2O3浓度显著下降,SiO2的浓度达到最大值并趋于稳定。因此可以认为,生物膜的形成有利于细菌浸矿溶硅,钝化膜则抑制Al与Si的溶出。     

拜耳法铝土矿杂质对溶出率影响的浅议

文章通过对拜耳法生产氧化铝的一水硬铝石成分分析及这些成分对氧化铝溶出率的影响，结合广西华银铝业有限公司目前使用的铝土矿成分进行对比分析，最终找到目前影响铝土矿相对溶出率偏低的主要原因。     

制备室温纳米ZnO脱硫剂方法的研究

为了提高ZnO脱硫剂的室温硫容及脱硫精度,对直接沉淀法进行了工艺改进,并利用动态实验以及XRD和XPS等表征手段对纳米ZnO脱硫剂进行了结构和效能分析.研究表明,通过在沉淀反应后添加Na2CO3溶液,解决了直接沉淀法阴离子难洗涤、颗粒易团聚、粒径分布不均等缺点,制备出粒径只有8.00 nm、颗粒均匀分散性好的纳米ZnO脱硫剂,其室温脱硫活性是同条件下其他方法制备纳米ZnO脱硫剂脱硫活性的5～10倍,且其脱硫产物中有不同于ZnS中的晶格硫的新硫物种产生.     

提高中低品位铝土矿拜耳法溶出率的试验研究

基于广西华银铝业有限公司目前所使用的铝土矿和已有的生产工艺流程,综述了在高压溶出铝土矿过程中,通过对铝土矿细度、石灰添加量、溶出温度以及溶出保温时间等因素的调整来进行溶出试验,最终能合理经济的指导实际生产。     

高硫石油焦的碱催化煅烧联合超声氧化深度脱硫（英文）

采用两段脱硫方法对高硫石油焦进行深度脱硫,并对碱催化煅烧和超声辅助化学氧化阶段的工艺条件进行优化。结果表明,在Na2CO3添加量25%、900℃恒温2 h、粒径80μm、升温速率1℃/min条件下,石油焦脱硫率达到最大值为67. 2%。在氧化温度80℃、HNO_3浓度65 wt%、反应12 h、粒径80μm、液固比20 mL/g的条件下,超声辅助氧化法的总脱硫率达到93. 5%。在碱催化煅烧过程中,噻吩硫和亚砜的去除率分别为73. 4%和59. 8%,经后续的超声波辅助氧化后,噻吩硫和亚砜的总去除率分别为93. 6%和93. 3%。同时,通过XPS分析了高硫石油焦在碱催化煅烧和超声辅助氧化工段中的脱硫机理。     

低温酸浸高铁铝土矿中铁和铝的溶出规律研究

采用低温酸浸法对广西高铁铝土矿中的铝和铁的溶出规律进行了研究,考察了硫酸浓度、浸出温度、浸出时间及液固比因素对铝土矿中铝和铁溶出率的影响.结果表明,最优浸出条件为浸出时间60min,浸出温度100℃,液固比5∶1,硫酸浓度20％.此条件下铁的浸出率为98.68％,铝的浸出率为3.02％,溶出比为32.68,可实现高铁铝土矿中铁和铝的分步溶出.对该浸出过程进行动力学分析研究表明,此条件下浸出过程属化学反应控制,其控制动力学方程为:lgk=3-1.83×10-31/T反应活化能Ea=35.11kJ/mol.     

辽宁某高硫钼矿选矿试验研究

针对辽宁某高硫钼矿进行了选矿试验研究。在磨矿细度为-200N占67％时,经两粗两扫获得钼粗精矿及浮钼尾矿,对钼粗精矿进行再磨再选后,获得钼品位49．43％,钼回收率91．11％的钼精矿。同时对浮钼尾矿中的硫进行浮选回收,采用一粗、一扫、两精的浮选流程,获得了品位为52％,回收率为72．04％的硫精矿。     

Treatment of high-sulfur coal using selective flocculation and microbial desulfurization in a draft-tube slurry bubble column

Experiments are performed to study a novel precombustion coal cleaning process for deashing and desulfurization of high-sulfur coals. The process is based on the integration of selective flocculation and microbial desulfurization in a draft-tube slurry bubble column bioreactor (DTSB). In the process, the unique features of the selective flocculation in ash reduction is preserved. Desulfurization of the pyrite particles is subsequently achieved through oxidation of pyrite by Thiobacillus ferrooxidans in a DTSB bioreactor. Samples of Pittsburgh No. 8 seam are used to test this multistage process. In this study, the effect of bacterial adaptation on the oxidation rate of pyrite is examined. Based on the kinetic data, a reactor model for the bio-oxidation rate of pyrite is developed. This model considers the bacterial adhesion and the kinetics of direct and indirect pyrite oxidation by T. ferrooxidans.     

Desulfurization of microwave pretreated fine coal by magnetic separation

The production of pyrite extraction by the conventional magnetic separation method was effectively improved by increasing the magnetic susceptibility of pyrite. The electromagnetic characteristics and the absorption response of fine high-sulfur coal were studied for their improving effect on the magnetic susceptibility of pyrite. In this study, the complex dielectric constant and the loss tangents of fine coal samples obtained from Weinan Co. were investigated in the frequency of 0.5?～?6.5?GHz. The complex dielectric constant of raw coal was small, indicating comparatively less loss of microwave energy during the magnetization process, essentially acting against the microwave energy absorption. The microwave energy absorption and electromagnetic parameters of coal samples depend on the thickness of the coal sample. When the microwave treatment time of the fine coal was 240?s, the sulfur content of the clean coal reached as low as 2.92%, and the optimum desulfurization degree and yield were 32.01% and 91.97%, respectively.     

硫化胶常温脱硫机理研究

利用甲苯－醋酸－氯化锌在常温睛脱除硫化胶中的橡胶结合硫，使之转化为H2S放出，判断此脱硫过程为Friedel-Crafts反应。     

Complete elimination of interferences in the organotin determination by oxidation with dimethyldioxirane combined with alumina cleanup

Most of the analytical procedures used in organotin (OT) speciation from sediment involves the Grignard derivatization reaction followed by a cleanup step and a desulfuration reaction since sulfur and/or sulfur species interfere with OT determination by GC/MS or GC-FPD. However, alkyl sulfides are generated from the coextracted elemental sulfur, and they are not removed by conventional desulfurization procedures. We propose here a method based on the oxidation of all the sulfur species with dimethyldioxirane (DMD) to sulfones or sulfur oxides. While sulfones are easily eliminated by alumina adsorption chromatography because they have higher polarity than OTs, the sulfur oxides are spontaneously evaporated. The DMD chemoselectivity favors the oxidation of sulfur compounds to sulfones in a few minutes, whereas OTs remain unreacted. In addition, the excess DMD is easily removed by evaporation under a nitrogen stream before the Al(2)O(3) cleanup step. The effectiveness of the desulfurization reaction combined with the cleanup step is demonstrated for a variety of sediment samples containing up to 3.1% of elemental sulfur, which is completely removed by adding 0.6 molar equiv of DMD. No statistical differences in the OT distribution pattern throughout the DMD intermediate oxidation steps were observed.     

Corrosion evaluation of one dry desulfurization equipment – Circulating fluidized bed boiler

As a clean fuel combustion technology, circulating fluidized bed (CFB) possesses various advantages. Among them, flexibility in fuels and superiority in desulfurization are the two prominent ones and can hereby facilitate sufficient utilization of high-sulfur fuels. But unfortunately, these low-grade fuels always introduce harsh service environment within the CFB boilers and consequently result in severe degradation extent on relevant equipments, especially the high-temperature sulfur corrosion. In this event, by nearly ten characterization methods, comprehensive investigation was carried out on a whole CFB boiler during downtime, and special emphasis was particularly laid on the failure components including one perforated nozzle along with its fractured inlet tube for primary air, and one perforated manhole door of refeed valve. Finally, countermeasure and suggestion was put forward, which can provide instructive significance in corrosion prevention for the CFB boilers, even other desulfurization equipments, running under similar aggressive conditions in engineering practice.     

Effects of type and dosages of organic depressants on pyrite floatability in microflotation system

Pyrite is considered as a disturbing sulfide mineral in the beneficiation of sulfide minerals and coal and in order to prevent floating of pyrite in the flotation, different inorganic, organic and biological depressants could be used. The most important organic pyrite depressants are starch, dextrin, guargum, carboxymethyl cellulose (CMC), ethylene diamine tetra acetic acid (EDTA), Diethylenetriamine (DETA). In this paper, flotation experiments were carried out by modified Halimond tube. At first, flotation experiments were performed to obtain optimal pyrite flotation condition (suitable collector and frother for maximum recovery). In optimal condition (collector: KAX?+?KIPX , 16?ppm; collector condition time: 4?min; frother: Poly Propylene Glycol (A65), 20?ppm; frother condition time: 30?s), pyrite recovery increased to 95.63%. Flotation kinetics experiments were performed and various kinetic models were evaluated on pyrite flotation. The results showed that flotation kinetics of pyrite is second-order. After obtaining optimal condition for flotation and kinetic studies, the effects of type and dosage of different organic depressants including starch, dextrin, guargum, carboxymethyl cellulose, EDTA and DETA at three concentrations (50, 100, 150?ppm) at neutral pH were comprehensively investigated. The results of the experiments showed that DETA can significantly reduce the recovery of pyrite at 150?ppm by 44%.     

Estimating the electrochemical reactivity of pyrite ores-their impact on pulp chemistry and chalcopyrite flotation behaviour

Prudent control of ore pulp chemistry via parameters such as redox potential (Eh), dissolved oxygen (DO) and pH, can markedly improve the flotation recovery, grade and selectivity of sulphide minerals. In this paper, the electrochemical reactivities of two pyrite minerals and their impact on chalcopyrite flotation are investigated using oxygen demand test and froth flotation. Changes in the surface chemistry/speciation are also investigated using X-ray photoelectron spectroscopy (XPS) and EDTA extraction technique. The oxygen demand test shows that the different pyrite ores display significantly different electrochemical reactivity. Furthermore, continuous aeration of the pulp reduces the reactivity of the pyrite ores. Solution and surface analysis results suggest the formation of hydroxide surface coatings on the pyrite surface as aeration progresses, preventing or minimising further oxidative reactions from taking place in the pulp. Flotation results showed that the flotation response of chalcopyrite is influenced by the pulp DO/Eh, and therefore the type and reactivity of the pyrite associated with it.     

The kinetics modeling of chalcopyrite and pyrite,and the contribution of particle size and sodium metabisulfite to the flotation of copper complex ores

In this study, a series of batch flotation experiments was conducted to evaluate both the role of particle size distribution and the presence of sodium metabisulfite Na₂S₂O₅ (SMBS) in chalcopyrite and pyrite flotation. Kinetic flotation tests were also carried out in order to evaluate the kinetics behavior of the above-mentioned minerals. Following this, different flotation kinetics models were compared to the data from the experiments. According to the obtained results, it can be stated that feed particle size distribution plays a greater role in chalcopyrite and pyrite grades rather than their recoveries. However, the contribution of SMBS is higher than that of particle size with respect to pyrite recovery. In this study, the maximum recoveries for chalcopyrite and pyrite were found to be 92.2% and 47.5%, respectively. The minimum pyrite recovery (13.47%) occurred in the presence of 40 g/t Xanthate-flomin (C-4132), 20 g/t methyl isobutyl carbonyl (MIBC), 20 g/t polypropylene glycol (F742), 200 g/t sodium metabisulfite (SMBS), and at a d ₇₀ of 70 µm. A comparison between several flotation kinetics models and the experimental data revealed that the perfect mixer and the Arbiter models showed completely similar results for both chalcopyrite and pyrite with respect to the use of different configuration of chemical reagents.     

Novel application of depressant sodium mercaptoacetate in flotation separation of chalcopyrite and pyrite

The development of flotation reagents with high selectivity and strong depression ability is of great significance in the efficient enrichment of copper sulfide ores. In this work, a new depressant, sodium mercaptoacetate (SMA) has been explored for the flotation separation of chalcopyrite and pyrite, and the depression mechanism of SMA was studied by Fourier Transform Infrared spectrometer (FTIR), adsorption tests, local electrochemical impedance spectroscopy test (LEIS), Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). Micro-flotation tests showed that SMA strongly depresses pyrite in the pH range of 6–10. When the dosage of SMA is 2.5 × 10⁻⁵ mol/L, the dosage of SBX is 1 × 10⁻⁵ mol/L, and pH = 6.5, the concentrate with a Cu grade of 31.93% and chalcopyrite recovery of 85.97% can be obtained, in which the pyrite recovery was only 4.18%, respectively. The strong chemical adsorption between SMA and Fe atomic sites exposed on the surface of pyrite reduces the hydrophobicity of pyrite and hinders the adsorption of SBX. In comparison, SMA has less adsorption on the surface of chalcopyrite and hardly affects the further adsorption of SBX. It was shown that SMA could be used as an effective depressant for pyrite in the flotation separation of chalcopyrite and pyrite.