利用粉煤灰制备高强矿物聚合材料的实验研究

以粉煤灰和内蒙古白云鄂博的富钾板岩提钾后的硅铝质滤渣为粉体原料,标准砂为骨料,采用振动成型方法,在90 ℃下养护24 h,制备了矿物聚合材料。实验结果显示：制品的7 d饱水抗压强度达78.5 MPa,28 d饱水抗压强度可达89.0 MPa;制品的含水率和吸水率分别为5.3%和15.0%;在20 ℃下,制品在浓度为1.0 mol/L的硫酸溶液中浸泡24 h,其质量损失率为2.1%。以制品的抗压强度为指标,研究了主要因素（提钾滤渣比例、固液质量比、硅酸钠含量和标准砂含量）对制品性能的影响。结果表明：干燥的提钾滤渣在粉体物料中的比例对制品的力学性能影响最大;硅酸钠水玻璃在液相中的比例约为70%,且标准砂占固相的比例为70%左右时,可制得力学性能良好的矿物聚合材料。矿物聚合材料的固结过程为：硅铝质原料在碱硅酸盐溶液中先分解为铝硅酸盐低聚体,低聚体再通过脱羟基聚合反应生成铝硅酸盐胶体相,进一步形成由[SiO₄]^4- 和[AlO₄]^5-四面体相互连接的具有三维网络结构的矿物聚合材料基体相,从而赋予制品良好的力学性能。     

高炉渣基矿物聚合材料的制备及其对铅离子的固定

以高炉渣和煅烧高岭土为粉体原料,KOH溶液为激活剂,采用振动成型方法,在20℃下养护24 h,制备矿物聚合材料。实验样品静置固化28 d,采用压力试验机可测得其抗压强度高达24~65 MPa。矿物聚合材料制品在1 d、3 d、7 d、28 d的X射线衍射(XRD)、红外光谱(IR)等测试分析表明,高炉渣中的玻璃相在强碱的作用下发生溶解,之后形成Si、Al低聚体,最后形成各种晶体。采用矿物聚合材料可以有效地固定Pb2+。用含Pb2+的溶液配制矿物聚合材料,静置固化28 d,测其抗压强度以及Pb2+溶出率。实验结果表明,Pb2+的存在降低了矿物聚合材料的1 d的抗压强度,但对7 d及28 d抗压强度没有影响,聚合材料对Pb2+固定率达到99.9%。     

西天山阿希金矿流体包裹体研究

西天山阿希金矿含金石英脉内流体包裹体粒度细小,形态多样,以单一液相为主.化学成分上属K⁺（Na⁺）-SO^2-₄（Cl^-）型,其中阳离子成分以K⁺为主,Na⁺次之;阴离子成分以SO^2-₄为主,Cl^-次之;气相成分以H₂O、CO₂为主,富含O₂、N₂等气体,还原性气体（H₂、CH₄、CO等）含量亦较高.成矿作用发生于浅成（300~900m）、低温（120~180℃）和较封闭的还原环境.成矿流体盐度低,主要为大气降水并混以少量火山成因的岩浆水.     

重金属污染土壤修复的Pb2+钝化产物稳定性

自然状态下土壤中重金属元素是否稳定存在是重金属污染固化修复技术中的核心问题。本文以常见重金属离子Pb²⁺为例,分析土壤中重金属离子与常见离子基团结合的稳定性。将第一性原理应用于Pb的存在形态和稳定性的分析,计算了PbCO₃、PbSO₄、PbCl₂、Pb₃（PO₄）₂、PbAl₂O₄和Pb₃Fe₂（PO₄）₄的自由能、能带和态密度。首先推断Pb²⁺和CO₃^2-、SO₄^2-、Cl^-、PO₄^3-等土壤中常见阴离子的结合稳定性,再判断加入金属阳离子Al³⁺和Fe³⁺对体系稳定性的影响。结果表明：铅化合物自由能从高到低趋势为PbCl₂、PbAl₂O₄、PbCO₃、PbSO₄、Pb₃（PO₄）₂、Pb₃Fe₂（PO₄）₄,其相应的结构稳定性顺序从大到小为Pb₃Fe₂（PO₄）₄、Pb₃（PO₄）₂、PbSO₄、PbCO₃、PbAl₂O₄、PbCl₂。通过对能带和态密度的分析,首先确定了SO₄^2-和PO₄^3-的引入能够增强含Pb体系的稳定性,进一步加入金属阳离子Fe³⁺会使体系更稳定。推测SO₄^2-、PO₄^3-为治理Pb²⁺污染合适的官能团,应选择容易释放SO₄^2-、PO₄^3-的物质作为合适的钝化剂。在实际应用中可选择磷酸二氢钠、无水硫酸钠、脱硫石膏等作为钝化剂。     

利用钾长石尾矿制备矿物聚合材料的实验研究

以福建沙县田口钾长石尾矿粉体为主要原料，以煅烧高岭石作配料，硅酸钠作结构模板剂，氢氧化钠作激活剂，进行了制备矿物聚合材料的实验研究，实验样品静置固化7－28d，其抗压强度高达19.4-24.9MPa。耐酸性，耐碱性指标均优于相似建材的国家标准。在配料组成中，控制高岭石用量为20％，适当提高硅酸钠的用量和固／液化，有利于提高制品的力学性能。实验表明，材料抗中度随固化时间的延长而叶抛物线式发展，矿物聚合材料的形成过程为：铝硅酸盐固体组分的溶解络合，分散迁移，浓缩聚合，脱水硬化。由铝硅酸盐凝胶相固化而在的基体相，其化学组成与沸石相近，微观结构极可能与蛋白质类似，物理形态上呈三维网状结构，将未溶解的晶质颗粒胶结为坚硬块体，是矿物聚合材料获得良好力学性能的结构基础。     

利用金矿尾砂制备矿物聚合材料的实验研究

利用北京平谷金矿尾砂、变高岭石、NaOH、KOH和水玻璃制备了矿物聚合材料 ,正交实验结果表明 35℃时的优化条件为尾砂含量 80 %～ 82 5 %、固 /液比 4 3～ 4 7、水 /碱比为4～ 5 (均为质量比 ) ,升高温度、延长固化时间及室温放置时间均会使矿物聚合材料的抗压强度显著提高。将金矿尾砂制备成矿物聚合材料 ,可使部分CN-转化成无害的CO2 -3 和H2 ,其他则以夹持 (物理 )方式固定下来 ;当存在Fe2 +或Fe3+离子时 ,CN-以氰化铁的化学方式固定下来。该矿物聚合材料在 1mol/L的HCl溶液中浸泡 30d ,质量损失 5 6 % ,结构完好 ,表现出良好的抗酸性。在 6 0℃下固化 2 4h ,室温放置 6d后抗压强度为 2 2MPa ;在 6 0℃下固化72h ,抗压强度为 36 6MPa。该研究为金矿尾砂的利用提供了一条新途径。     

南昌市大气NHx干沉降及其氮同位素昼夜变化特征

NH_x（NH₃和NH₄⁺）是大气中主要的碱性物质,NH_x干沉降是大气中NH_x移除的重要途径之一。本研究于2019年8月11日至31日在江西省南昌市东华理工大学分昼夜采集了大气NH_x干沉降样本(包括颗粒铵(NH⁺_4（p）)和气态氨(NH_3（g）)),测定了干沉降样本的NH₄⁺离子浓度、δ¹⁵N-NH₄⁺和pH,基于干沉降样品中NH_x浓度估算了大气中NH_x干沉降通量。结果显示,白天NH_x干沉降通量(0.2～25.9μg/（m²·h）,均值14.2±10.0μg/（m²·h）)低于夜晚(0.9～50.2μg/（m²·h）,均值23.1±1...     

有机污染物(菲)在弱透水层中的越流迁移特征

采用高渗透压渗流试验装置,模拟已被污染的浅层地下水越流通过弱透水层污染深层地下水的过程,研究不同矿化度、不同pH条件下有机污染物（菲）通过饱和黏性土弱透水层时的质量浓度变化特征。结果表明：矿化度的增加有利于弱透水层吸附截留渗滤液中的菲;高矿化度水中的Na+交替土层中的Ca²⁺、Mg²⁺,使水中的Ca²⁺、Mg²⁺质量浓度增加,与HCO^-₃、菲组合形成络合物;不同pH条件下,Ca²⁺、Mg²⁺、HCO^-₃对菲的迁移有阻滞作用,SO^2-₄参与还原反应并可与菲形成络合物,对菲迁移有促进作用。菲在弱透水层中的迁移能力很弱,衰减率达82％～96％,高渗透压下菲的污染锋面迁移速度为0.714 m/d,pH=8时菲通过弱透水层的迁移质量浓度最小。控制渗滤液的pH、组分可有效阻止菲在弱透水层中的迁移。     

泥河湾盆地东谷坨遗址地层易溶盐沉积及其环境意义

东谷坨遗址地处泥河湾盆地东部边缘,是该地区发掘次数和出土遗物最多的早更新世古人类活动 遗址之一。对遗址湖滨相沉积物易溶盐类的测试和分析表明,此剖面代表的泥河湾古湖易溶盐为Na+-CO2-3--SO2-4-HCO-3 型,属于淡水湖-半咸水湖,处于半干旱区湖泊演化早期的碳酸盐湖泊阶段。K+、Na+、Ca2+、Mg2+、Hco-3 和Cl -等 6类离子含量的变化曲线表现出较大的相似性,且它们与含盐量的变化大体一致。CaCO3含量及含盐量的变化与沉积物中细颗粒含量变化具有一致性,细颗粒含量较高时期对应 CaCO3 含量和含盐量相 对较高时期。根据含盐量和各主要离子比值并结合CaCO3 含量变化,将湖泊演化划分为 4个阶段,古人类在该 遗址活动时期对应于湖泊演化的前 3个阶段。该项研究对探讨东谷坨遗址利用者的生存行为与环境的关系具有重要意义。     

水化学及硫同位素对大冶矿区地下水硫酸盐污染的指示

铜铁矿区周边地下水硫酸盐污染是生态环境研究关注的热点问题,精确识别硫酸盐来源及迁移途径对于矿区周边地下水污染防控和供水安全至关重要.利用水化学与硫同位素耦合分析,结合矿区水文地质条件和潜在污染源分布,探讨了区内地下水硫酸盐污染特征、来源及迁移途径.区域内地下水包括松散岩类孔隙水、碳酸盐岩裂隙岩溶水及岩浆岩风化裂隙水,水化学类型主要为HCO₃·SO₄-Ca型,水化学组分主要来源于硅酸岩、碳酸盐岩和硫酸盐矿物的溶解以及硫化物氧化;地下水中SO₄^2-含量范围为44.4～2 089.0 mg/L,高值区主要分布在洪山溪尾矿库、矿渣堆存处及矿业生产区附近;地下水中δ³⁴S-SO₄^2-在2.6‰～31.5‰之间,反映其SO₄^2-具有多源性.地下水中SO₄^2-的主要来源包括含水层中石膏矿物的溶解和黄铁矿等含硫矿物氧化输入,高含量的SO₄     

Utilisation of fly ash in a geopolymeric material

Finding means of utilising waste products is a very important field of research at the moment. In this study, fly ash, a waste product of the electricity and petrochemical industries, was investigated as a basic ingredient of a new geopolymeric material. The similarity of fly ash to natural pozzolans has encouraged the use of this waste product in the synthesis of geopolymers, which, in turn, can best be viewed as consisting of a polymeric Si–O–Al framework. Manufacturing of the geopolymers was conducted by mixing fly ash, kaolinite, sodium silicate solution, NaOH and water. The samples were cured at 40, 50, 60 and 70 °C for different time intervals (6, 24, 48 and 72 h). The optimum condition was found to be at 60 °C for a period of 48 h. Compressive strength measurements show a maximum strength of almost 8 MPa after 28 days. Infrared spectroscopic measurements were obtained of the samples after 7 and 28 days. X-ray diffraction measurements show quartz as the main constituent with the largest part of the geopolymer structure being amorphous and glass-like.     

矿物聚合材料:研究现状与发展前景

矿物聚合材料是以铝硅酸盐矿物或工业固体废物为主要原料 ,以高岭石作配料 ,硅酸钠作结构模板剂 ,氢氧化钠作激活剂而制成的一类新型无机非金属材料。其形成过程为 :铝硅酸盐固体组分的溶解络合、分散迁移、浓缩聚合和脱水硬化。由铝硅酸盐凝胶相形成的基体相 ,其化学组成与沸石相近 ,微结构极可能与蛋白石类似 ,物理形态上呈三维网络结构 ,将未溶解的固体颗粒胶结为坚硬块体 ,是材料获得良好力学性能和化学稳定性的结构基础。矿物聚合材料的性能主要受配料组成和聚合反应的动力学过程所控制 ,其抗压强度随固化时间的延长而呈抛物线式发展。系统研究配料组成和固化条件对铝硅酸盐聚合反应的影响 ,建立表征矿物聚合材料组成结构性能的物理模型 ,是对其进行结构性能设计的理论基础 ,也是利用铝硅酸盐聚合反应实现工业固体废物资源化的技术关键。     

Compression Behavior of Mine Tailings Amended with Cementitious Binders

The objective of this study was to evaluate the effect of fly ash amendment on the compression behavior of mine tailings. Natural and synthetic (i.e., laboratory prepared) mine tailings were used to assess the effects of tailings composition and tailings solids content on compressibility. Three types of off-specification fly ashes and Type I–II Portland cement were used as cementitious binders. Tailings-fly ash mixtures were prepared at solids content of 60–75% (water content = 33–67%), water-to-binder ratios of 2.5 and 5, and were cured for 0.1 days (2 h), 7, and 28 days. Bi-linear compression curves on semi-log plots were observed in most of the binder-amended tailings specimens. The break in slope on the compression curve was identified as the breaking stress, whereupon cementitious bonds were broken. The breaking stress increased with an increase in fly ash content, which was attributed to a lower water-to-binder ratio and void volume-to-binder volume ratio that produced more effective particle bonding. Breaking stress also increased with an increase in CaO content and CaO-to-SiO₂ ratio of fly ash, which resulted in more effective bonding between particles. The effect of curing time on the breaking stress of fly ash amended specimens was characterized by (1) an increase in breaking stress via increase in curing time and cementitious bond formation or (2) a constant breaking stress with curing time due to competing mechanisms during loading. Specimens cured under a vertical stress showed an increase in breakings stress with applied load water removal prior to cementitious bond formation that reduced the water-to-binder ratio and led to more effective cementation.     

偏高岭土增强石灰-水泥固化淤泥的耐久性研究

淤泥富含有机质，分解后产生腐殖酸，进而影响淤泥固化效果。仅掺入12%水泥固化淤泥，当标准养护期超过60 d，其强度不增反减。联合掺入3%石灰和12%水泥，固化淤泥的pH值持续180 d处于10.5以上；无侧限抗压强度由750 kPa（养护期28 d）提升到1 500 kPa（120 d），说明借助石灰营造强碱性环境，可以提高水泥固化淤泥的强度；但养护到180 d后，其强度又降到1 250 kPa；钙离子浓度变化规律表明，这是由于腐殖酸溶蚀水泥和石灰的水化胶结物所致。借助偏高岭土卓越的火山灰反应能力，掺入3.0%偏高岭土，提升石灰（3%）?水泥（12%）固化淤泥的耐久性，发现180 d养护期内，其强度始终处于增长趋势，究其原因是偏高岭土富含无定形硅、铝氧化物，具有快速捕获氢氧化钙溶液中钙离子的能力，形成稳定的胶结物，而且不易受腐殖酸的侵蚀作用，证明偏高岭土能够有效提升石灰?水泥固化淤泥长期强度。     

Investigation of Cement–Bentonite Slurry Samples Containing PFA in the UCS and Triaxial Apparatus

Three mixtures of cement–bentonite slurry containing 28, 36 and 44 % PFA (as a proportion of cementitious materials) were tested using the unconfined compressive strength and triaxial apparatus to determine the stress–strain and shear strength relationships for samples cured for various periods. The samples were batched using 4 % bentonite and 20 % cementitious materials (by mass of water) and allowed to cure underwater once extruded from sealed moulds. Curing periods of 14, 28 and 90 days were selected to investigate the changes in behaviour at durations commonly specified (28 and 90 days) as well as providing insight into changing behaviour with curing (additional curing periods of 7 and 60 days were investigated on a smaller number of samples to increase understanding). Two rates of displacement were used (1.0 and 1.3 mm/min) and four confining pressures (0, 50, 100 and 200 kPa). Shear strength and strain at peak deviator stress of the samples do not appear to vary considerably with confining pressure. For samples containing 28 % PFA, the majority of physical properties exhibited by the cement–bentonite samples change with curing period up to 60 days, where after the properties become similar to those cured for 90 days.     

水玻璃-碱渣-矿渣固化高含水率淤泥的强度性质

利用工业固体废弃物碱渣和矿渣作为固化剂,水玻璃作为激发剂,对高含水率疏浚淤泥的强度性质进行试验研究,并通过X射线衍射测试探讨固化机理。研究表明,在对含水率为110%疏浚淤泥固化的正交试验中,碱渣、矿渣和水玻璃掺量越多固化土的无侧限抗压强度越大,影响3 d强度的因素主次关系为碱渣>水玻璃>矿渣,而7 d和28 d时变为水玻璃>碱渣>矿渣,水玻璃对28 d强度的影响显著。当水玻璃掺量一定而碱渣与矿渣总掺量相同时,碱渣对固化淤泥的作用强于矿渣。固化土中的水化产物包括钙矾石、水化氯铝酸钙、水钙沸石和水化硅酸钙等,其填充和胶结作用使淤泥强度得到提高。研究确定了满足一般填土工程要求的固化方案,为碱渣和矿渣作为高含水率淤泥固化剂的资源化利用提供理论依据和参数支持。     

The nature of olefins and carboxyl groups in an Australian brown coal resin

The chemical structure of the resin from an Australian soft brown coal (Yallourn) has been investigated by cross-polarization nuclear magnetic resonance spectroscopy with magic angle spinning (¹³C CP MAS NMR). Some additional solution ¹H and ¹³C data were also obtained. Solid-state experiments were performed with and without a delay period before data acquisition. The resulting free induction decays were Fourier transformed with respect to acquisition time and delay period to produce two-dimensional solid-state spectra. Assignments made from the spectra clearly demonstrate that the gross chemical structure of the Yallourn resin is best described as a polymerized diterpenoid with one axial carboxylic group and two double bonds. One double bond is trisubstituted, the other is monosubstituted. After consideration of various mechanisms for polymerization of diterpenoid units during biogenesis and coalification, it was concluded that polymerization occurs at the C₁₅ carbon atoms in the diterpenoids without cyclization of the methylene units at C₈.     

Natural zeolites enhance groundwater quality: evidences from Deccan basalts in India

The zeolite minerals characterized with hydrated aluminosilicates, negative ionic charge and 3D framework structure are well known for purifying the groundwater occurring in basaltic aquifer systems. However, the filtering mechanism at in situ field conditions is a complex process, which is rarely studied, and hence, it needs to be demonstrated. This paper explores the mechanism of hydrochemical processes and evolution of natural zeolites associated with basaltic rock to enhance groundwater quality. We present the hydrochemical findings and evolution processes derived from 46 groundwater samples (N_t = 46) belong to zeolitic (N_z = 25) and non-zeolitic (N_nz = 21) zones of a micro-watershed (4.4 km²) beset over basaltic terrain, Deccan Volcanic Province (DVP), India. The groundwater samples collected for one hydrological cycle (pre- and post-monsoons) are examined for major ion chemistry to determine the aqueous solution mechanism and ion-exchange process occurred in zeolitic and non-zeolitic zones. Further, the hydrochemical parameters are appraised by means of dominancy of ions, rock–water interactions, silicate weathering, chloro-alkaline indices, cation-exchange bivariate plots and the mechanism controlling groundwater chemistry. The results show that: 1) the purifying efficiency of zeolites for total ionic strength is observed as 63.85 and 68.58% during pre- and post-monsoons, respectively, 2) the significant reduction (36.51%) in total hardness attributed to the positive trend of chloro-alkaline indices depicting the ion-exchange phenomenon between Na⁺ and K⁺ (alkalies) and Ca²⁺ and Mg²⁺ (alkali-earth) elements in the zeolitic zone, 3) Gibbs plot shows the rock–water interaction as the predominant mechanism controlling groundwater chemistry in the zeolitic zone, and 4) the groundwater quality parameters from zeolitic zone are found within the permissible limit of WHO drinking water standards.     

Development of modified flyash as a permeable reactive barrier medium for a former manufactured gas plant site, Northern Ireland

A sequential biological permeable reactive barrier (PRB) was determined to be the best option for remediating groundwater that has become contaminated with a wide range of organic contaminants (i.e., benzene, toluene, ethylbenzene, xylene and polyaromatic hydrocarbons), heavy metals (i.e., lead and arsenic), and cyanide at a former manufactured gas plant after 150 years of operation in Portadown, Northern Ireland. The objective of this study was to develop a modified flyash that could be used in the initial cell within a sequential biological PRB to filter complex contaminated groundwater containing ammonium. Flyash modified with lime (CaOH) and alum was subjected to a series of batch tests which investigated the modified cation exchange capacity (CEC) and rate of removal of anions and cations from the solution. These tests showed that a high flyash composition medium (80%) could remove 8.65 mol of ammonium contaminant for every kilogram of medium. The modified CEC procedure ruled out the possibility of cation exchange as the major removal mechanism. The medium could also adsorb anions as well as cations (i.e., Pb and Cr), but not with the same capacity. The initial mechanism for Pb and Cr removal is probably precipitation. This is followed by sorption, which is possibly the only mechanism for the removal of dichromate anions. Scanning electron microscopic analysis revealed very small (<1 μm) cubic highly crystalline precipitates on the flyash, although this new crystalline zeolite growth did not occur rapidly enough to enable productive zeolite formation. Surface area measurements showed that biofilm growth on the medium could be a major factor in the comparative reduction of surface area between real and synthetic contaminant groundwaters. The modified flyash was found to be a highly sorptive granular material that did not inhibit microbiological activity, however, leaching tests revealed that the medium would fail as a long-term barrier material.