Modification of FGD gypsum in hydrothermal mixed salt solution

A novel utilization way of the sludge from wet calcium-based flue gas desulfurization （FGD） processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus ,the modification of FGD gypsum was fulfilled.

Hydrothermal Synthesis and Characterization of Ce_(1-x)Mn_xO_(2-δ) Solid Solutions

Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11～15 nm.The incorporation of Mn ions in CeO2 resulted in a lattice volume reduction.Mn ions showed a mixed valence state of ＋2,＋3 and ＋4 in CeO2 lattice.An obvious red-shift of the absorption threshold edge was observed from the UV-visible spectrum.Compared with the bulk CeO2,Ce1-xMnxO2-δ nanocrystals exhibited a lower releasing oxygen temperature as indicated by TPR technique.

Synthesize of ZnO Nanorods on Quartz Substrates with Seed Layer via Hydrothermal Method: Influence of Solution Concentration

Vertically oriented ZnO nanorods have been synthesized by hydrothermal method on quartz substrates with a seed layer. The influence of solution concentration on the morphology, structural and optical properties was analyzed. Results indicated that with the increase of solution concentration, the diameter and uniformity of ZnO nanorods increased. And the preferred orientation is obviously which shows better crystal quality. Typically, when the solution concentration is 0.03 mol/L, the nanorods exhibit a stronger UV emission peak located around 380 nm. In the visible region, all synthesized samples demonstrate more than 80% of optical transparency.

Experimental Observation of the Ore-Forming Fluid NaCl-H_2O System in the Earth Interior

The NaCl-H_2O binary system is a major component of solutions coexisting with ores. Observation ofsaturated solutions of NaCl-H_2O by using the method of hydrothermal diamond anvil cell (HDAC) is a new approach tothe study of ore-forming fluids. The salinities of NaCl-H_2O solutions in experimental observation are in a range of 32-55%. The observed temperature range is 25℃-850℃, and the pressure range 1 atm-10 kb. In this temperature-pressure range, the supercritical single phase, two phases (L,V) close to the critical state and two-phased (L+V) immis-cible region were observed. And for the salinity of 35% the two phase L+V immiscible region of NaCl-H_2O solutionwas observed in a range of 253-720℃. Another temperature range, 400-817℃, was observed for the immiscible two-phased region of 50% salinity solution. In the high-temperature part of the two-phased immiscible region, the phase na-ture is very unstable. A "critical phenomenon" was observed when the heating path was very close to the critical state.It is possible to observe a 'critical phenomenon': an "explosion" occurred almost constantly at the interface between theliquid and vapour and the interface is rather obscure. A continuous transition between phases L and V could be foundin the immiscible L+V phase while heating continuously. Moreover, as the NaCl-H_2O solution was separated into liq-uid and vapour phases, static charges surrounding each vapour bubble could be seen, and these bubbles were attractedtogether by the static charges to form a special solution structure. Besides, critical states of different salinities of NaCl-H_2O were observed in order to study the properties of the fluids occurring in the rocks in the earth interior, the origin ofore-bearing fluids and the significance of supercritical fluid with respect to the ore formation. The comparison of the sa-linity data of the fluid inclusions in the minerals of ore deposits with observations of NaCl-H_2O under HDAC in theconditions of high temperatures and pressures, combined with further thermodynamic analysis of ore-formation condi-tions would explain in depth the factors determining the ore formation.

Hydrothermal synthesis of monodisperse Zn_(x)Cd_(1-x)S spheres and their photocatalytic properties

Monodisperse ZnxCd1-xS spheres were successfully fabricated with a high yield by a facile hydrothermal route.The as-prepared samples were characterized by X-ray diffractometry,scanning electron microscopy and UV-vis diffusion reflectance spectroscopy.The results indicate that all the prepared samples have the same hexagonal wurtzite phase and exhibit good size uniformity and regularity.Degradation of rhodamine-B（RhB） was used to evaluate the photocatalytic activities of ZnxCd1-xS samples.Zn0.4Cd0.6S possessed the best photocatalytic activity and exhibited high stability during the reaction.

Preparation of spherical cobalt carbonate from cobalt sulfate solution

A precursor of cobaltous dihydroxycarbonate was firstly prepared by precipitation reaction of cobalt sulfate solution and ammonium carbonate solution,and then a hydrothermal process for the precursor was conducted to obtain the spherical cobalt carbonate with low sulfur content.The experimental results show that the feeding method,final p H value of the precipitation reaction slurry and the concentration of the cobalt sulfate solution have obvious effects on the sulfur content,morphology and particle size distribution of the precursor.The sulfur content of the precursor is 0.0115 wt.%under the optimized conditions.The hydrothermal treatment with temperatures of 125-150℃can transform the precursor of cobaltous dihydroxycarbonate into spherical cobalt carbonate and decrease the sulfur content to 0.0030 wt.%in the obtained product.

Dissolubility of Hydroxyapatlte Powder under Hydrothermal Condition

The dissolubility of hydroxyapatite(HA) in the hydrothermal solution was investigated in Mo-rey-type autoclave over a temperature range of 150 to 350℃ and the pH value range of 5 to 9. It is shown that the dissolubility of HA is determined as a function of temperature and time under a constant filling ratio of autoclave , and the temperature coefficient for the solubility of HA is positive. The equilibrium time attained in the hydrothermal solution is shortened with the increase of hydroihermal temperature, and the effect of temperature on the solubility is obviously stronger than that of pH value. The solubility data suggest that HA has higher dissolubility in the HA-H2 O system under the hydrothermal condition than that under the normal temperature-pressure.

Ore-forming fluid characteristics and genesis of vein-type lead-zinc mineralization of Xiaohongshilazi deposit,Jilin Province, China

The Xiaohongshilazi mineral deposit in Jilin Province,China,is located in the accretion zone in the northern margin of the North China Block. The deposit contains two types of ore bodies: layered Pb-Zn ore bodies in volcanic rock and vein-hosted Pb-Zn ore bodies controlled by fractures. The vein Pb-Zn ore bodies are strictly controlled by tectonic fracture zones trending in S-N direction,which comprise sulfide veins or sulfidebearing quartz veins distributed along faults or structural fissures. The ores mainly appear mesh-vein and vein structures,and also show solid-solution separation and metasomatic textures. The metal minerals are mainly sphalerite,galena,and pyrite,etc. Wall-rock alteration includes mainly sericitization,chloritization,silicification and carbonatization,etc. Microscope observations and Raman spectroscopy analyses indicate that the oreforming fluid of the vein Pb-Zn ore bodies was mainly magmatic water with low temperature,low salinity,and a shallow depth of metallogenesis( ~ 1.5 km). Sulfur and lead isotope analyses indicate that the sulfide source is mainly formation sulfur or biogenic sulfur,which is similar to the sulfur source of hydrothermal deposit( negative( δ^(34) S values),while the main Pb source was the upper crust with some mantle input. This article argues that the vein Pb-Zn ore body of the Xiaohongshilazi deposit is a low-to medium-temperature hydrothermal vein type related to the formation of a shallow magma chamber.

Role of Microstructure and Spectrum Features on the Catalysis Effect of Ce1-x(Nd0.5Eu0.5)xO2-δSolid Solutions

Nanosized Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） solid solutions（x = 0.00-0.20） were synthesized by means of hydrothermal method.Then the solid solutions were ball milled with Mg2Ni and Ni powders for 20 h to get the Mg2Ni–Ni–5 mol% Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） composites.The structures and spectrum characteristics of the Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） solid solutions catalysts were analyzed systemically.XRD results showed that the doped samples exhibited single phase of CeO2 fluorite structure.The cell parameters and cell volumes were increased with increasing the doped content.Raman spectrum revealed that the peak position of F^2g mode shift to higher wavenumbers and the peak corresponding to oxygen vacancies were observed distinctly for the doped samples.UV-Vis technique indicated that the absorption peaks of Eu^3＋ and Nd^3＋ ions appeared; the bandgap energy was decreased linearly.The electrochemical and kinetic properties of the Mg2Ni–Ni–5 mol% Ce1-x（Nd0.5Eu0.5xO2-δ composites were measured.The maximum discharge capacity was increased from 722.3 mA h/g for x = 0.00 to 819.7 mA h/g for x = 0.16,and the cycle stability S20 increased from 25.0%（x = 0.00） to 42.2%（x = 0.20）.The kinetic measurement proved that the catalytic activity of composite surfaces and the hydrogen diffusion rate were improved for the composites with doped catalysts,especially for the composites with x = 0.16 and x = 0.20.The catalysis mechanism was analyzed from the point of microstructure and spectrum features of the Ce1-x（Nd0.5Eu0.5）xO2-δ solid solutions.

NaCl溶液浓度对磷石膏制备α-半水石膏转晶行为的影响

为提高湿法磷酸工艺排放的副产品磷石膏的利用率和附加值,采用常压水热合成法在NaCl溶液中制备α-半水石膏材料,研究了NaCl溶液浓度对α-半水石膏的结晶水含量、转晶行为、矿相组成和显微形貌的影响。研究结果表明,在温度为95℃质量分数为10.0%~20.0%的NaCl溶液中,磷石膏的结晶水含量均随着反应时间的延长逐渐降低,且降至约6%后将逐渐趋于平缓。结合XRD和SEM分析认为磷石膏在95℃质量分数为10.0%~20.0%的NaCl溶液中可脱水转晶形成稳定的六方柱状α-半水石膏。同时,磷石膏的脱水转晶速率呈现先缓慢上升而后快速升高,最后逐渐趋于平缓的变化趋势,属于典型的生长-成核动力学过程。随着NaCl溶液浓度的升高,α-半水石膏的诱导成核时间和晶体生长时间逐渐加快,总转晶时间逐渐缩短。其中,磷石膏在质量分数为20.0%的NaCl溶液中水热反应0.5 h后即可完全转变为α-半水石膏,与质量分数为15.0%的NaCl溶液相比缩短了1.38 h。因此认为,NaCl溶液浓度的提高有助于加快磷石膏的脱水转晶效率,这可为实际规模化生产α-半水石膏提供指导。

湖相热液白云岩成因机理——以准噶尔盆地玛湖凹陷二叠系风城组为例

[目的]湖相白云岩是一种重要的油气储层岩石类型,但成因机制研究较晚且相对薄弱。[方法]为研究湖相热液白云岩成因机理,以准噶尔盆地玛湖凹陷二叠系风城组白云岩为例,采用岩心观察描述,岩石薄片鉴定、扫描电镜、稀土元素、稳定同位素、流体包裹体等实验分析,系统研究了风城组白云岩的岩矿特征、地球化学特征。[结果]风城组白云岩主要发育在风城组二段和三段,以分散型、纹层型、条带—团块集合体型产出。白云岩形成于高盐度、强还原和受热液控制的典型碱湖环境。深部热液侵入为湖盆提供了丰富的Mg^(2+)、Fe^(2+)、HCO_(3)^(-)、CO_(3)^(2-)离子,为白云岩的形成提供了物质基础。湖相热液白云岩存在两种成因:一是热液—蒸发沉积成因,在热液侵入及干旱强蒸发作用下,高Mg/Ca、高pH值、高盐度湖盆水体提供了云化作用的介质,形成纹层状白云岩。二是埋藏—热液交代成因,深部热流沿断裂上升侵入地层,促进埋藏白云岩化,形成条带—团块状白云岩。[结论]研究结果对我国其他盆地湖相热液白云岩的研究具有重要借鉴意义。

湿法炼锌含铁溶液水热矿化沉铁行为研究

在常规湿法炼锌过程中,采用黄钾铁矾法、针铁矿法除铁工艺时存在铁渣中铁质量分数低而锌质量分数高、渣量大、无害化处理成本高等难题,为此,本文开展湿法炼锌含铁溶液水热矿化沉铁行为研究。研究结果表明:升高反应温度有利于Fe3+水解生成赤铁矿(Fe2O3),同时促进铁矾物相(MFe3(SO4)2(OH)6)向赤铁矿的转化,铁渣中铁质量分数显著升高;延长反应时间可提高Fe3+沉淀率,并使更多的黄钾铁矾(KFe3(SO4)2(OH)6)转化为赤铁矿;提高氧分压将加快Fe2+氧化成Fe3+的速率,促进赤铁矿物相的形成。在反应温度为180℃,氧分压为0.8 MPa、反应时间为3 h且控制碱金属离子浓度的优化条件下,溶液中94.29%的铁以赤铁矿(Fe2O3)形式沉淀入渣,沉铁渣中铁质量分数为57.75%、锌质量分数为0.82%。对比黄钾铁矾工艺,铁渣量减少约60%,铁渣中锌质量分数降低6.5%。采用水热矿化沉铁工艺,可在低酸条件下实现溶液中铁的矿化沉淀,得到铁质量分数满足氧化铁行业标准且可实现资源化利用的赤铁矿沉铁渣,可助力湿法炼锌行业向绿色低碳方向发展。

污泥焚烧灰中磷在超临界CO_(2)水热液中迁移转化

基于超临界CO_(2)水热液具有强酸性,且传质性能好,易于分离回收和可调控等优点,提出了超临界CO_(2)水热液浸出污泥焚烧灰(incinerated sewage sludge ash, ISSA)中磷的新方法.研究了ISSA中磷在超临界CO_(2)水热液中的迁移转化行为.考察了ISSA中磷形态及其矿物相,研究了压力、反应时间和液固比对ISSA中磷迁移转化的影响,并分析了超临界CO_(2)优秀的传质效果、反应中碳酸盐的生成以及ISSA表面反应位点的增加对ISSA中磷迁移转化速率的影响.结果表明:ISSA中磷含量高,且以非磷灰石无机磷(NAIP)为主;在压力为8.7 MPa、反应时间为60 min、液固比为20 mL/g的超临界CO_(2)水热液中,ISSA中磷的浸出率可达67.5%.该方法可替代目前酸碱顺序提取中的酸浸出工艺,在大幅缩短磷浸出时间的同时,提高了磷的浸出率,并彻底避免了重金属的浸出.该研究能够为绿色高效磷回收技术的开发提供理论依据和数据支持.

综合物探法在寻找隐伏半隐伏萤石矿中的应用

冀北地区萤石矿均为低温热液型,其与构造关系极为紧密。本次在冀北某萤石矿普查工作中,在隐伏半隐伏地区利用活性炭测氡法圈定断裂构造位置,利用激发极化法确定萤石矿化体蚀变带在地表的分布范围及其垂向分布特征。结果表明,萤石矿化体位于主断裂附近的次级断裂中,次级断裂因萤石填充堵塞氡气运移通道,氡浓度值相对较低,但活性炭测氡法对主断裂构造仍具有较好的指示作用,因此利用活性炭测氡法寻找主断裂构造位置,结合地质填图及槽探工程等手段在主断裂附近可以有效圈定萤石矿化范围;激电中梯剖面或面积测量可有效圈定矿化蚀变带在地表的分布范围,激电测深反演能够直接反映矿化体在深部的垂向分布特征。活性炭测氡法与激发极化法相组合的方法,辅以其它地质工程手段在冀北地区寻找隐伏、半隐伏低温热液型萤石矿床效果显著。

锌浸出液水热法制备纳米ZnO

纳米ZnO是一种新型的高功能精细纳米材料,用途广泛,采用水热法制备的纳米ZnO颗粒纯度高、晶形好且操作简便;含锌二次资源的锌浸出液中杂质元素较多,对后期产品纯素的影响较大,其中除铜、镉较为关键。本文以含锌二次资源的锌浸出液为原料,采用锌粉置换除铜、镉,然后以净化后的硫酸锌溶液为锌源,分别采用氨水、碳酸钠、氢氧化钠作为沉淀剂通过水热法制备纳米ZnO,并考察不同工艺参数对纳米ZnO物相和形貌的影响,结果表明:在合适条件下,锌粉置换后浸出液中铜、镉离子浓度分别为0.039 9 mg·L^(-1)、6.416 2 mg·L^(-1),可用于制备纳米ZnO;采用氨水和碳酸钠作为沉淀剂制得的产物均为ZnO和其他晶体的混合物,属于非纯相的不规则晶体;采用氢氧化钠作为沉淀剂可制得纯相纳米ZnO,最佳制备条件为锌碱摩尔比1∶2、反应时间1 h、反应温度120℃,制得的纳米ZnO呈现棱柱结构,粒径在50~100 nm之间,颗粒尺寸分布均匀。

Ge-rich hydrothermal solutions and abnormal enrichment of Ge in coal

AT present, the main source of germanium includes two types of ore deposits: some sulfide-rich Pb, Zn,Cu, Ag and An deposits and some coal deposits. Germanium occurs as an associated element in these oredeposits. The Lincang germanium deposit discovered recently in China occurs in a basin where there areexposed the Neogene coal-bearing clastic rocks with Indosinian Ge-rich (（1.9-5.0）×10-6) granitesas the basement in Lincang County, Yunnan Province. Germanium is mainly concentrated in the coalseams of the first coal-bearing horizon (Nth2) and in regard to its grade (normally n×100×10-6 with themaximum over 1000×10-6) and scale （the proven reserve about 800 t）, no such germanium mineralization has been reported so far in other parts of the world. What is the reason? The available studies have indicated that this germanium deposit is of epigenetic origin, whichdetermines that germanium must have been transferred into coal with the help of a kind of medium. It isnoticed that （i） organic germanium in natural waters is stable and it is never involved in its

Effects of ammonia concentration in hydrothermal treatment on structure and redox properties of cerium zirconium solid solution

Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts(TWCs).However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is still a challenge.In this paper,the cerium zirconium solid solution was prepared by a coprecipitation-hydrothermal method,and the effects of the ammonia concentration on their structures and redox properties were investigated.The results show that when the ammonia concentration is 0.8 mol/L,the aged sample(1100℃/10 h)of cerium zirconium solid solution has the highest specific surface area of 23.01 m^(2)/g.Additionally,the increase of ammonia concentration improves the uniformity of phase compositions and increases the oxygen vacancies.When the ammonia concentration reaches 0.4 mol/L,the cerium zirconium solid solution exhibits the best redox activity,with the lowest reduction temperature of 565℃.Therefore,increasing ammonia concentration in the hydrothermal treatment is beneficial to the thermal stability and redox performance of cerium zirconium solid solution.

Effects of Temperature Raising Speed on the Growth of BN Crystals in Hydrothermal Solutions

Cubic boron nitride (cBN) and orthorhombic boron nitride (oBN) crystals have been prepared in hydrothermal solutions by reacting H3BO3+NaN3+P and H3BO3+NaN3+N2H4 respectively. The experimental results indicated that, if the temperature was increased rapidly, both the yield and perfectness of BN crystals became poor. On the contrast, the yield and perfectness of BN crystals can be improved very much by slowly increasing the temperature of the reaction mixture. The results of X-ray powder diffraction (XRD), Fourier transform infrared spectrum (FTIR) and high resolution transmission electron microscopy (HRTEM) proved that the samples were composed of oBN and cBN.

Evidence of acid nature of ore-forming solutions

THE author thinks that the ore-forming solution is formed not by the near-neutral brine but by the strongacid solutions. Some evidence are the following: （i） The simulating experiments showed that, all near-neutral supergenic water as volcanic hotspring water of Tengchong, K-brine of Mengyejing, seawater of Qingdao, oil-gasses-bearing water of Chitianhua, rain water of Guiyang and CO2-bearing rain cannot form metal-bearing solutions by heating mixedabove-mentioned supergenic water with ore-source rocks as basalt, ore-bearing carbonate, sandstone andshale. The most content of Cu, Pb, Zn, Hg, Sb, As, Ag in solutions is only （0.3-0.5）×10-6.They cannot form any ore deposit. Oppositely, the acid solution of pH=1.0 is easy to form metal-bearingsolutions with every ore-source rocks. The most content of metal in solution is n×10-n×1000 × 10-6i.e. rose in 3-5 grades. The content of metals in humic acid-bearing solutions is variable, perhaps dueto the changes of humic components and content and due to easy-decomposition by oxidation or heating.So the best one in solutions to form ore-forming solution is only the acidic water.