Kinetics Analyzing of Direction Reduction on Manganese Ore Pellets Containing Carbon

Using high temperature carbon tube furnace, reduction of manganese ore pellets containing carbon was investigated. The reaction was divided into two stages at five minutes after reaction, and the kinetics model of reduction process was established. The experimental results showed that, the reaction rate in the earlier stage was controlled by the chemical reactions between FeO, MnO and carbon reductant, and the activation energy was 28.85 KJ/mol. In the later stage, as the carbon reductant replaced by CO, the reaction rate was controlled by CO-diffusing in solid products, and the cor- responding activation energy was 86.56 KJ/mol. Reaction rate of the later stage was less than the earlier one.

Combined effects of ultrasonic vibration and manganese on Fe-containing inter-metallic compounds and mechanical properties of Al-17Si alloy with 3wt.%Fe

The research studied the combined effects of ultrasonic vibration (USV) and manganese on the Fe-containing inter-metallic compounds and mechanical properties of Al-17Si-3Fe-2Cu-1Ni (wt.%) alloys. The results showed that, without USV, the alloys with 0.4wt.% Mn or 0.8wt.% Mn both contain a large amount of coarse plate-like δ-Al4(Fe,Mn)Si2 phase and long needle-like β-Al5(Fe,Mn)Si phase. When the Mn content changes from 0.4wt.% to 0.8wt.% in the alloys, the amount and the length of needle-like β-Al5(Fe,Mn)Si phase decrease and the plate-like δ-Al4(Fe,Mn)Si2 phase becomes much coarser. After USV treatment, the Fe-containing compounds in the alloys are refined and exist mainly as δ-Al4(Fe,Mn)Si2 particles with an average grain size of about 20 μm, and only a small amount of β-Al5(Fe,Mn)Si phase remains. With USV treatment, the ultimate tensile strengths (UTS) of the alloys containing 0.4wt.%Mn and 0.8wt.%Mn at room temperature are 253 MPa and 262 MPa, respectively, and the ultimate tensile strengths at 350 °C are 129 MPa and 135 MPa, respectively. It is considered that the modified morphology and uniform distribution of the Fe-containing inter-metallic compounds, which are caused by the USV process, are the main reasons for the increase in the tensile strength of these two alloys.

Strengthening pelletization of manganese ore fines containing high combined water by high pressure roll grinding and optimized temperature elevation system

Pelletization is one of useful processes for the agglomeration of iron ore or concentrates. However, manganese ore fines are mainly agglomerated by sintering due to its high combined water which adversely affects the roasting performance of pellets. In this work, high pressure roll grinding(HPRG) process and optimization of temperature elevation system were investigated to improve the strength of fired manganese ore pellets. It is shown that the manganese ore possesses good ballability after being pretreated by HPRG twice, and good green balls were produced under the conditions of blending 2.0% bentonite in the feed, balling for 7 min at 16.00% moisture. High quality roasted pellets with the compressive strength of 2711 N per pellet were manufactured through preheating at 1050 °C for 10 min and firing at 1335 °C for 15 min by controlling the cracks formation. The fired manganese pellets keep the strength by the solid interconnection of recrystallized pyrolusite grains and the binding of manganite liquid phase which filled the pores and clearance among minerals. The product pellets contain high Mn grade and low impurities, and can be used to smelt ferromanganese, which provides a possible way to use imported manganese ore fines containing high combined water to produce high value ferromanganese.

Selective catalytic oxidation of NO over iron and manganese oxides supported on mesoporous silica

The selective catalytic oxidation （SCO） of NO was studied on a catalyst consisting of iron-manganese oxide supported on mesoporous silica （MPS） with different Mn/Fe ratios. Effects of the amount of manganese and iron, oxygen, and calcination temperature on NO conversion were also investigated. It was found that the Mn-Fe/MPS catalyst with a Mn/Fe molar ratio of 1 showed the highest activity at the calcination temperature of 400 °C. The results showed that over this catalyst, NO conversion reached 70% under the condition of 280 °C and a space velocity of 5000 h-1. SO2 and H2O had no adverse impact on the reaction activity when the SCO reaction temperature was above 240 °C. In addition, the SCO activity was suppressed gradually in the presence of SO2 and H2O below 240 °C, and such an effect was reversible after heating treatment.

Location and size regulation of manganese oxides within mesoporous silica for enhanced antibiotic degradation

Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.

Synthesis of Mesoporous Silica and Ti-containing Molecular Sieves via A Novel Assembly

Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(IV) could be incorporated in the mesoporous struture.

Radio-frequency-heating capability of silica-coated manganese ferrite nanoparticles

MnFe204 nanoparticles （NPs） with various sizes and tight size-distribution were synthesized by a chemical solution- phase method. The as-synthesized NPs were coated with a silica shell of 4 nm-5 nm in thickness, enabling the water- solubility and biocompatibility of the NPs. The MnFe204 NPs with a size of less than 18 nm exhibit superparamagnetic behavior with high saturated magnetization. The capacity of the heat production was enhanced by increasing particle sizes and radio frequency （RF） field strengths. MnFe204/SiO2 NPs with 18-nm magnetic cores showed the highest heat- generation ability under an RF field. These MnFe204/SiO2 NPs have great potentiality to cancer treatments, controlled drug releases, and remote controls of single cell functions.

Studies on Synthesis of Stationary Phase Containing Nicotinamide Adenine Dinucleotide(NAD) Bonded to Phospholipid-Coated Aminated Silica for HPLC

Recently biospecific affinity chromatography has been widely used for the separation and purification of various enzymes and nucleic acids. In this paper, a series of synthetic reactions of solid-liquid phase were carried out on silica surface, using a macroporous(30 mu m), microspherical silica (8 mu m) as the matrix and gamma-aminopropyltriethoxysilane as the activating agent, the nicotinamide adenine dinucleotide(NAD) was bonded through its amino groups to the carboxylic groups of linked phospholipid which was bonded covalently on aminated support. The bonded stationary phase has high thermal stability, and could be used to separate of nucleotides with good resolution.

VKT多肽介导的固定化疏棉状嗜热丝孢菌脂肪酶催化制备生物柴油

生物柴油是一种环境友好的生物液体燃料,对于酶法生产生物柴油,迫切需要找到廉价和高效的固定化脂肪酶。本研究利用固体结合肽(SBPs)VKT,将其与疏棉状嗜热丝孢菌脂肪酶(Thermomyces lanuginosus lipase,TLL)融合构建融合脂肪酶,并将其固定化在硅基材料上,获得了一种新型的生物催化剂。在所测试的硅基材料(ZSM-5、Na-Y、SAR-100、MCM-41和SiO_(2)微粉)中,固定在ZSM-5沸石上的TLL-VKT(TLL-VKT@ZSM-5)表现出最佳的固定化效率和最大负载,且具有优异的pH、温度、储存和洗脱稳定性。以TLL-VKT@ZSM-5为生物催化剂,对麻疯树籽油进行转酯化反应,48h生物柴油得率即达到93.9%。此外,TLL-VKT@ZSM-5还表现出较高的重复使用性能,在7次重复使用后,生物柴油得率依然保持71.9%。本研究的酶固定化方法具有简单高效、稳定性高和重复使用性能高等优点。本研究显示VKT肽在酶蛋白固定化的应用方面具有较好前景。

蜂窝状ZSM-5沸石协同低温等离子体净化含硫恶臭气体

采用蜂窝状ZSM-5沸石协同低温等离子体净化5种典型含硫恶臭气体,通过沸石硅铝比、锰改性、放电电压参数的优化探究最佳工艺参数与处理效果。结果表明:降低硅铝比、锰改性利于提升蜂窝状ZSM-5沸石对含硫恶臭气体的整体吸附效率,增大硅铝比、适当增加锰负载量、提高放电电压则利于提升蜂窝状ZSM-5沸石协同低温等离子体对含硫恶臭气体的去除效率,其提升机制可能与沸石比表面积、外表面积和Mn^(3+)负载催化有关。在硅铝比为70(摩尔比)、锰负载量为10%(质量分数)、7.5 kV的条件下,锰改性蜂窝状ZSM-5沸石协同低温等离子体对含硫恶臭气体的去除效率均大于95%,比输入能量仅为2.3 J/L。

高硅氧化锰矿还原焙烧-酸浸工艺研究

依据锰矿的赋存形态,采用还原焙烧-酸浸法处理高硅复杂氧化锰矿,考察了焙烧温度、焙烧时间、煤与矿质量比、浸出温度、浸出时间、初始硫酸浓度、液固比等因素对锰浸出率的影响。结果表明,在焙烧温度880℃、焙烧时间1.5 h、煤与矿质量比18%、浸出温度55℃、浸出时间2 h、初始硫酸浓度1.80 mol/L、液固比5 mL/g条件下,锰浸出率达95.83%。

有限元分析在含锰金属蒙皮铆接结构疲劳断裂性能中的研究

随着计算机网络技术的迅速发展,有限元分析技术被广泛应用于铆接技术当中,在机械连接结构设计中起到了重要作用。为提高有限元分析法在求解含锰金属蒙皮铆接结构中断裂参数的精度,在有限元分析法中引入插值函数,推导出有限元分析模型,并对模型进行仿真验证。结果显示,受应力作用在x方向和y方向上分别产生0.02 mm和0.006 mm的位移,应力主要集中在铆钉与蒙皮的连接处,孔周会产生先下陷再上翘的内翘情况。上下壁板可承受最大应力SVM1和SVM2分别增加了63 MPa和61 MPa,在受到外加荷载的情况下裂纹会先出现在下壁板与铆钉结构的连接处。综合应力随着裂纹长度的增大而减小,起始应力值271 MPa为铆钉材料拉伸强度的83.4%,铆接结构疲劳断裂的扩展应力较小、铆钉材料综合起始应力较大。以上结果显示,基于有限元分析在含锰金属蒙皮铆接结构疲劳断裂性能中的研究,对铆接结构断裂研究领域具有一定的参考意义。

针对煤矿高铁锰矿井水处理工艺的研究与实践

为响应国家相关环保政策,解决矿区废水铁锰污染问题,针对含铁锰离子矿井水开展研究,以直滤技术作为核心单元改进传统除铁锰工艺,改进后的深度除铁锰工艺可稳定处理含铁锰矿井水,实现了矿井水处理站的自动化安全生产,节省了基建投资,缩短了工艺流程,降低了运行费用,为含铁锰离子矿井水处理提供了良好的技术支撑。

Microstructure of Solid Phase Reduction on Manganese Oxide Ore Fines Containing Coal by Microwave Heating

Microstructure of solid phase reduction on manganese oxide ore fines containing coal （MOOFCC） is one of important kinetics conditions of influencing microwave heating. On condition thai an atomic molar ratio of ro ： rc in MOOFCC is 1 ： 1.06 as well as a molecular molar ratio of rSiO2： rCaO is 1 ： 1.28, 1 kg of MOOFCC is heated by microwave to reach 1 000-1 300℃ and hold different time respectively. Experiments show that the metal phase takes the iron-based metal compounds containing manganese as the main content. The manganese content of metal phase increases with the xise of temperature. The particle size of the metal phase is within the range from 0. 01 to 0.05 mm. MO2 phase in the stuff is entirely changed into MnO phase and the slag phase is mainly composed of wollastonite and manganese olivine. The stuff reduced is loose and massive as a whole and its porosity is from 30% to 45%. The low softening-melting property and the low density of the stuff impact, to some degree, the solid phase reduction of powder by microwave heating.

Self-reduction of Manganese-rich Slag Briquette Containing Carbon

The self-reduction experiment of manganese-rich slag briquette containing carbon was carried out in a high- temperature carbon tube furnace. The main factors affecting the reduction rate were analyzed, and the kinetic model of reduction was established. The results show that the increase of basicity of briquette has an obvious effect on im- proving reduction rate. When the carbon ratio of briquettes is 1.2 and its basicity is 1.0, the reduction rate can reach 90 %. It can accelerate reduction process and decrease reduction time when the appropriate flux CaF2 is added to the briquette. The apparent activation energy of chemical reaction is 24.07 kJ/mol, and the apparent activation energy of internal diffusion is 107.55 kJ/mol by calculation. Therefore, the reduction rate of briquette is determined by the mass transfer of CO in the product layer.

单膜双室电沉积金属锰联产EMD的影响因素

针对传统膜电解法单独电解金属锰或电解二氧化锰(EMD)工艺存在资源利用率低、污染环境的问题,采用单膜双室电解法将金属锰与EMD进行同槽电解,且在阳极回收硫酸,并考察了阴极液硫酸铵浓度、电解液Mn^(2+)浓度、阳极液初始硫酸浓度、电流密度4个因素对电沉积效果的影响。结果表明:在阴极液硫酸铵浓度为120 g/L、电解液Mn^(2+)浓度为40 g/L、阳极液初始硫酸浓度为0.6 mol/L、阴阳两极的电流密度分别为400 A/m^(2)和800 A/m^(2)的条件下,进行6 h电解,得到阴极锰产率可达78.22%,酸回收率为62.41%,EMD产率为23.7%,电能消耗仅为5675 kW·h/t,槽电压为5.86 V。同时发现对锰产率影响最显著的因素是电流密度,对EMD产率及酸回收率影响最显著的因素是阳极液初始硫酸浓度和电流密度。在最佳实验条件下的阴极产品金属锰板表面光洁密实、具明显银白色金属光泽、晶粒分层聚集、颗粒粒度均一、并呈现蜂窝状组织,整体形态良好。

低中放射性废物处置用高整体容器密封材料的制备与性能研究

为开发具备大流动性、高强度和高耐久性能的高整体容器黏接填充密封材料,并使其能满足在低中放射性废物处置过程中多种严酷环境下服役300年的要求,本文以硅酸盐水泥、硅灰为胶凝材料,磨细石英砂为惰性填充材料,通过颗粒最紧密堆积原理获取初步配方,并以硅微粉替代部分水泥后,研究硅微粉对密封材料流变性能、孔隙结构、力学性能、耐久性能以及氮气渗透系数的影响。结果表明:硅微粉提高了密封材料的流动度及流变性能,降低了28和56 d的孔隙率,提高了劈裂抗拉强度、抗收缩性能、抗化学侵蚀性能、抗渗性能以及抗冻性能,但对其抗压强度及静弹性模量作用不明显。加入10%(质量分数)硅微粉的密封材料各项性能均优于国家标准要求,可以满足在严酷环境下安全服役300年要求。

磷肥工业副产含氟硅胶的综合利用

磷肥工业副产含氟硅胶的资源化利用是磷肥行业亟待解决的问题之一,若不对其回收利用,不仅是一种资源的浪费,还会对环境造成污染。介绍了磷肥工业副产含氟硅胶制备液体硅酸钠、五水偏硅酸钠、层状结晶二硅酸钠、4A分子筛、白炭黑、工业硅、碳化硅、氟硅酸铵和氟化氢铵等资源化利用技术,并就磷肥工业副产含氟硅胶的利用问题提出建议。

基于“双纳米”技术的含聚污水深度处理现场试验

为解决杏北油田高含聚污水深度处理水质达标难度大,三采区块采出污水无法深度处理回注至低渗透储层的问题,提出采用“纳米气混浮选+纳米硅基精细过滤”工艺的“双纳米”水处理技术,并在聚杏十一污水站开展了规模为2000 m^(3)/d工业化现场试验。现场试验结果表明,在来水含聚浓度为400 mg/L,油含量、悬浮物含量≤100 mg/L的水质条件下,出水的油含量、悬浮物含量均可稳定达到5 mg/L以下,可以实现含聚污水深度处理要求。且“双纳米”水处理技术具备较好的吸附及滤料再生效果,可以保障设备连续稳定运行;同时其工艺流程短、效率高,可大幅降低建设及运行成本,具备大规模工业化推广及应用价值。