硫酸处理对伊利石和蒙脱石结构和形貌的影响

由于伊利石和蒙脱石结构四面体中Al³⁺代Si⁴⁺的数量不一样，所以层电荷数不同，酸处理过程结构的破坏程度也不同.本文以浙江安吉膨润土和吉林安图伊利石为原料，用硫酸和过氧化氢溶液对两种原料进行酸处理对比实验研究.我们对原料和酸处理样品的物相、结构、热学属性、谱学特性及微观形貌进行了表征分析.结果表明，蒙脱石样品在酸处理浓度2 mol/L时其结构被破坏，随着酸处理浓度的升高，片层表面由光滑平整变成边缘卷曲至层间坍塌；而伊利石样品在酸处理浓度6 mol/L时其结构和形貌基本完好；蒙脱石的耐酸蚀性能不如伊利石.本文的研究结果对伊利石和蒙脱石的应用开发具有一定的意义.     

包台型水稻不育系花药发育过程中的Ca2+分布

用焦锑酸钾沉淀法研究了包台型不育水稻及其保持系花药发育早期细胞中的Ca²⁺分布变化.从花粉母细胞时期开始,不育系与保持系花药中的Ca²⁺分布出现差异,不育系药壁外层和药室内壁及药隔中均有Ca²⁺出现,而保持系花药中基本没有Ca²⁺分布,在减数分裂时期表现更加明显,不育系药壁和药隔中的Ca²⁺相对于花粉母细胞时期明显地有所增加,特别是绒毡层细胞和药隔中木质部细胞的次生加厚壁上Ca²⁺增加尤其明显,而保持系花药中的Ca²⁺较少.笔者从花药发育的更早期去寻找水稻雄性不育的机理.     

无机盐作用下伊利石水化特性的分子模拟

伊蒙混层水化导致井壁失稳的现象相当突出，蒙脱石的水化研究较多。为研究伊利石在无机盐作用下的水化机理及膨胀特性，通过分子模拟技术建立了1M-tv和1M-cv两种在油气储层中较常见的伊利石晶体模型，并进一步通过分子动力学方法研究了伊利石层间粒子的微观分布和进入层间的无机盐阳离子的水化参数。结果表明，伊利石层间距随吸附水分子数的增大而增大，当水分子数为20时达到饱和状态； 1M-tv构型比1M-cv构型更容易发生水化膨胀； K⁺和Ca²⁺分别是一价阳离子和二价阳离子中水化数和水化半径最小的，且K⁺可以嵌入四面体片层的硅氧六元环中而难以发生离子交换，可有效阻止水分子进入伊利石晶体结构内部；实验结果很好地验证了KCl和CaCl₂对伊利石水化膨胀的抑制性。该结果对于页岩的防塌机理研究和钻井液水化抑制剂的研究具有一定的理论指导意义。     

山东枣庄陶枣煤田裂隙岩溶水水质评价研究

矿山闭坑后大量被污染的矿坑水对裂隙岩溶水具有潜在的影响.对陶枣煤田裂隙岩溶水水质评价发现区域内水质较差和极差级别分别占到总数的25.64%和41.03%,说明岩溶水总体水质较差.通过对岩溶水水化学特征分析得知,区内岩溶水阴离子类型有4种,分别为HCO^-₃型、HCO^-₃·SO₄^2-型、SO₄^2-·HCO^-₃型和SO₄^2-型,阳离子可划分为Ca²⁺、Ca²⁺·Na⁺和Ca²⁺·Mg²⁺或Mg²⁺·Ca²⁺3类型.通过对1991至2017年水化学动态特征分析发现区内地下裂隙岩溶水受煤矿开采影响较大,基于聚类分析法发现区内主要存在2种污染途径,分别为地表水渗透污染和矿坑水串层污染.     

某砂岩型铀矿床矿石酸法柱浸试验研究

为论证某砂岩铀矿铀浸出工艺,并获得浸铀试验工艺参数,设置了19组柱浸试验,选择其中4组作为试验研究主体,研究在0.2 g/L KMnO_4条件下,不同酸度条件铀浸出性能。试验结果表明,随着溶浸液硫酸浓度的增高,浸出液平均铀浓度及最高铀浓度明显增高,在加氧化剂(KMnO_4)条件下,浸铀速度快,铀浸出率可达90%以上,该矿床适合酸法浸出工艺。研究结果对确定该矿床酸法地浸工艺参数具有参考价值。     

某工业污染场地浅层地下水水化学特征与水质综合评价

为了表征某工业污染场地及周边地域内浅层地下水水化学特征和水质,选取15个采样点地下水水样,采用Piper三线图解法、舒卡列夫分类法、吉布斯模型、离子比值等分析水化学特征及成因,运用内梅罗综合指数法、模糊综合评价法评估地下水水质,并考察2种方法的相关性。结果表明：地下水水样分别呈弱酸、弱碱性,水化学类型以HCO^-₃·SO₄^2-·Cl^--Na⁺·Ca²⁺型为主,阴离子以Cl^-为主,阳离子以Ca²⁺为主;离子浓度受水岩相互作用、蒸发浓缩、阳离子交换作用和人为活动的影响,Ca²⁺、 Mg²⁺主要来源于石膏和碳酸盐的溶解,Na⁺、 Cl^-来源受岩石风化作用和人为活动共同影响;综合水质评价中Ⅴ类水占比最高,集中在工业污染场地周围;内梅罗综合指数法相较于模糊综合评价法评价结果过于悲观,易受极端值影响,两者的皮尔逊相关系...     

钙库操纵性钙内流对低氧性肺血管收缩作用的研究进展

低氧性肺动脉高压(HPH)是一种常见的高原病,发病原因主要是早期的肺血管持续收缩,以及后期的肺血管重构。低氧诱导的肺血管收缩与肺动脉平滑肌细胞(PASMC)内Ca²⁺浓度密切相关,而细胞膜上的电压依赖性钙通道(VDCC)、受体操纵性钙通道(ROCC)、钙库操纵性钙通道(SOCC)、Na⁺/Ca²⁺交换蛋白、Ca²⁺泵以及细胞内钙库的释放都是涉及细胞内Ca²⁺浓度的主要因素。其中SOCC的机制较为复杂且是影响Ca²⁺内流的关键。综述了低氧诱导SOCC介导的钙内流对肺血管收缩作用的研究进展。     

杭州龙井茶田土壤酸化过程分析

针对杭州龙井茶田土壤酸化趋势日益加重的现状,通过矿物表征、室内试验等技术方法,研究了茶田土壤酸性来源及产酸机制.在茶田现场采集6组20个土壤样品及对应岩样,茶田土壤pH稳定在4左右;通过XRD和XRF对土壤样品和岩石样品中的化学成分和矿物成分进行测定,结果显示茶田土壤中的常规阳离子含量远低于全国土壤元素丰度值;土壤和岩样动态淋滤试验结果表明,土壤酸性类型为HNO₃和H₂SO₄,基岩风化过程中产生的Ca²⁺含量较大,且易发生淋溶,土壤成土后K⁺、Ca²⁺、Na⁺、Mg²⁺等盐基阳离子淋失快且淋失量大,是造成酸化的主要原因.茶树在多年种植条件下,由于盐基阳离子淋失,使得土壤盐基饱和度降低,从而导致土壤缓冲能力降低,造成土壤酸化.     

浐河流域地表水水化学特征

为探究西安地区主要流域地表水水化学特征及其成因,以浐河流域为研究对象,利用Piper三角图、Gibbs图、相关性对其水化学离子组分特征及来源进行分析,以期对浐河流域的水资源利用与管理提供科学依据.结果表明：浐河流域地表水主控阳离子为Ca²⁺,均值在86.63 mg·L^-1,主控阴离子为HCO₃^-,占总阴离子含量的70%左右.浐河流域水化学类型为Ca²⁺-HCO₃^-型,水化学组分的形成主要受岩石风化的影响.离子组分中,Na⁺与Cl^-不完全来源于盐岩溶解,还有其他来源输入;Ca²⁺、Mg²⁺、HCO₃^-来源于碳酸盐的溶解.     

低含铟浸出渣中铟的氧压酸浸实验及动力学研究

采用氧压酸浸的方法浸出低含铟浸出渣中的铟,研究铟的氧压酸浸过程及动力学;研究搅拌速率、浸出温度、初始硫酸浓度、氧分压、物料粒度对铟浸出率的影响。研究结果表明:在浸出温度为220℃,物料粒度为75~80μm,硫酸浓度为1.53 mol/L,转速为650 r/min,氧分压为0.60 MPa时,铟、锌和铜的浸出率分别为99.5%,95.36%和95.94%;铟的浸出过程符合未反应收缩核模型,前期受化学反应控制,然后转为混合控制,后期受固体产物层扩散控制;化学反应控制和固体产物层扩散控制过程的表观活化能分别为46.09 k J/mol和11.62 k J/mol。     

具有Ruddlesden-Popper结构的Ca_(1+x)Mn_xO_(1+3x)(x=1,2,3)的合成及层间Ca~(2+)的抽出

采用溶胶凝胶法合成前驱体,然后在氧气气氛下加热合成了具有层状钙钛矿Ruddlesden-Popper结构的化合物Ca1+xMnxO1+3x(x=1,2,3),尝试采用酸溶液对其层间Ca2+离子进行抽出.实验发现HCl处理单层Ca2MnO4,层状结构遭到破坏;而用(NH4)2S2O8与HCl的混合溶液处理则能维持其层状结构,且Ca2+离子抽出率大于60%,其抽出机制为氧化还原和离子交换.用HCl能够抽出双层Ca3Mn2O7的层间Ca2+,并保持较好的结构.     

酸性环境中富水充填材料腐蚀及劣化机理

为了研究酸性环境对富水充填材料的影响,通过强度检测、扫描电镜、能谱分析及X射线衍射( XRD)等实验手段,分析富水充填材料在酸性环境中浸泡后的宏观性能及微观结构变化,并探讨其腐蚀及劣化机理.结果表明：富水充填材料在pH值为1和3的盐酸溶液中浸泡180 d后抗压强度比标养28 d的强度分别降低88.8%和58%,在pH值为3的硫酸溶液中浸泡后降低68%,pH值为1的硫酸溶液中浸泡后强度降为零;微观实验结果显示随着富水充填材料在硫酸溶液中浸泡时间的延长,试件内部有二水石膏生成,盐酸溶液中试件仅在pH值为1的溶液中浸泡180 d后产生二水石膏;盐酸溶液对富水充填材料的腐蚀主要为H+中和作用下硬化体结构的溶解腐蚀,硫酸溶液对材料的腐蚀为硬化体结构的溶解腐蚀和石膏的膨胀腐蚀;硫酸溶液对富水充填材料的腐蚀作用强于盐酸溶液.     

Sulfuric acid leaching of high iron-bearing zinc calcine

Sulfuric acid leaching of high iron-bearing zinc calcine was investigated to assess the effects of sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, and the stirring speed on the leaching rates of zinc and iron. The results showed that the sulfuric acid concentration, liquid-to-solid ratio, leaching time, and leaching temperature strongly influenced the leaching of zinc and iron, whereas stirring speed had little influence. Zinc was mainly leached and the leaching rate of iron was low when the sulfuric acid concentration was less than 100 g/L. At sulfuric acid concentrations higher than 100 g/L, the leaching rate of iron increased quickly with increasing sulfuric acid concentration. This behavior is attributed to iron-bearing minerals such as zinc ferrite in zinc calcine dissolving at high temperatures and high sulfuric acid concentrations but not at low temperatures and low sulfuric acid concentrations.     

酸浸法提钒新工艺的研究

研究了用稀硫酸直接浸出—萃取—反萃—氨水沉钒—煅烧的提钒工艺。结果表明,采用稀硫酸直接浸出,原矿渣中总钒的一次浸取率可达95%以上;用萃取-反萃方式净化和浓缩浸出液,同时使用萃取促进剂处理酸浸液,使萃取效率比传统方法有明显提高,萃取级数大大减少;沉钒步骤摒弃了传统的铵盐沉钒工艺,使用氨水直接沉钒,提高了产品的纯度。钒的总回收率达86%以上,比传统提钒工艺效率提高了20%以上,同时由于避免了焙烧从而解决了传统提钒过程中因焙烧等产生的HCl、Cl₂等污染问题。     

玉米秸秆还原浸出高铁低品位锰矿研究

采用"玉米秸秆硫酸预处理—浸出"工艺处理含Mn 9.63%(质量分数)的朝阳锰矿.通过试验考察用硫酸对玉米秸秆进行预处理的时间、秸秆用量、温度、硫酸浓度和浸出温度对锰浸出率的影响.试验表明,在秸秆用量2.5 g、时间10 min、硫酸浓度1.2 mol/L、温度80℃时预处理秸秆,浸出温度为90℃的条件下,锰的浸出率达92%,杂质铁溶出率仅为20%.玉米秸秆处理前后FTIR分析结果表明,对秸秆进行硫酸预处理能够破坏难降解的木质素结构,有利于提高锰的浸出效果.     

高温砂岩酸化微粒运移伤害物质来源与防治方法

塔里木油田大北-克深区块进行常规土酸酸化改造时使用盐酸作前置液防治钙、镁离子沉淀,却引发微粒运移,造成储层伤害。旨在剖析微粒运移伤害物质来源并提出相应的防治措施,分别从宏观和微观角度首次研究15%盐酸与黏土矿物在150℃下反应特征,包括溶蚀率测定、扫描电子显微镜(SEM)表征、电感耦合等离子体原子发射光谱(ICP-AES)分析及岩心驱替实验等。结果表明:(1)高温酸/岩反应过程中,氢离子置换了黏土矿物中的铝离子并生成水合二氧化硅;(2)结构受损的黏土矿物是发生微粒运移的物质来源;(3)自主研发螯合酸ZFJ-CA作前置液能够有效减轻对黏土矿物溶蚀,达到防治微粒运移目的。通过大量室内试验,首次揭示了盐酸与黏土矿物的高温反应特征,确定了微粒运移物质来源并对微粒运移实现有效防治,为矿场酸化改造提供了参考。     

Decomposition mechanism of chromite in sulfuric acid-dichromic acid solution

The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly understood. In this work, binary spinels of Mg-Al, Mg-Fe, and Mg-Cr in the powdered and lump states were synthesized and used as raw materials to investigate the decomposition mechanism of chromite in sulfuric acid-dichromic acid solution. The leaching yields of metallic elements and the changes in morphology of the spinel were studied. The experimental results showed that the three spinels were stable in sulfuric acid solution and that dichromic acid had little influence on the decomposition behavior of the Mg-Al spinel and Mg-Fe spinel because Mg2+, Al3+, and Fe3+ in spinels cannot be oxidized by Cr6+. However, in the case of the Mg-Cr spinel, dichromic acid substantially promoted the decomposition efficiency and functioned as a catalyst. The decomposition mechanism of chromite in sulfuric acid-dichromic acid solution was illustrated on the basis of the findings of this study.     

Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO₄·H₂O.     

Extraction of vanadium from vanadium slag by high pressure oxidative acid leaching

To extract vanadium in an environment friendly manner, this study focuses on the process of leaching vanadium from vanadium slag by high pressure oxidative acid leaching. Characterizations of the raw slag, mineralogy transformation, and the form of leach residues were made by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The result shows that the vanadium slag is composed of major phases of fayalite, titanomagnetite, and spinel. During the high pressure oxidative acid leaching process, the fayalite and spinel phases are gradually decomposed by sulfuric acid, causing the release of vanadium and iron in the solution. Meanwhile, unreacted silicon and titanium are enriched in the leach residues. With the initial concentration of sulfuric acid at 250 g·L-1, a leaching temperature of 140℃, a leaching time of 50 min, a liquid-solid ratio of 10:1 mL·g-1, and oxygen pressure at 0.2 MPa, the leaching rate of vanadium reaches 97.69%.