Hydrogeochemical Characteristics of Groundwater at the Xikuangshan Antimony Mine in South China

The hydrogeochemical influence of the Xikuangshan antimony mine on groundwater quality was investigated by analyzing groundwater from 24 springs in the area for major and trace elements. The samples had a pH of 7.6–8.5; total dissolved solids ranged from 125 to 607 mg/L. The groundwater was dominated by alkaline earths (Ca²⁺ + Mg²⁺) over the alkalies (Na⁺ + K⁺), and weak acids \(\left( {{\text{HCO}}_{ 3}^{ - } } \right)\) over strong acids \(\left( {{\text{SO}}_{4}^{2 - } + {\text{Cl}}^{ - } } \right)\). Calcite was generally supersaturated and gypsum was always undersaturated, while dolomite was undersaturated in 34 % of the samples. Iron was negatively correlated with Ca²⁺, Mg²⁺, and \({\text{SO}}_{ 4}^{ 2- }\), which is consistent with Fe removal during acid buffering. Scatter diagrams and correlation coefficients between the major ions indicate dissolution of carbonates and gypsum as major processes, which could promote calcite precipitation.     

高纯钽板的轧制与退火织构

选用经过电子束熔炼后的高纯钽锭进行开坯轧制, 研究该钽板织构随压下量与退火温度的变化, 研究结果表明: 在850 ℃退火的板材, 延续轧制板材的织构特征, 存在由{100}<110>组分和γ织构及其强弱变化所构成的织构梯度。在1 000 ℃退火的板材, 织构组分({100}<110>组分和γ织构)没有明显变化, 仅仅强度提高。在1 150 ℃退火的板材, 表面{100}<110>织构衍生出新的{112}<110>组分。在1 300 ℃退火的板材, γ纤维织构出现{111}<112>取向的择优生长。     

Pyromorphite : Bunker Hill Mine,Coeur d'Alene District,Shoshone County,Idaho

Nikischerite, ideally NaFe²⁺ ₆Al₃(SO₄)₂(OH)₁₈(H₂O)₁₂, occurs as dark yellow-green micaceous plates to 4 mm, forming radiating balls and aggregates (Huminicki et al. 2003). The mineral has a dull to greasy luster, a pale grayish streak, and a Mohs hardness of 2. It has a perfect cleavage parallel to {001}, which is also the dominant form displayed by the platy crystals. The type locality is the Huanuni tin mine, Dalence Province, Oruro Department, Bolivia, where nikischerite occurs in and on a clay matrix, associated with minor pyrite, pyrrhotite, siderite, and cronstedtite.     

The Hydrogeochemistry of Arsenic in the Clara Mine,Germany

Abstract.   The oxidative dissolution of primary arsenic-bearing sulfide minerals in barite-fluorite veins is a potential source of arsenic in the Clara Mine. Geological structures, especially the mineral veins, provide potential pathways for the water. The highest arsenic concentrations are found in ground water within the eastern part of the mine. Arsenic and major ions are positively correlated and provide evidence that arsenic is likely derived locally from the water-vein/water-rock interaction. Geochemical modeling with PHREEQC shows all the arsenate mineral phases to be significantly undersaturated, although secondary arsenate minerals are common in the oxidized part of the deposit. The mine waters plot near the boundary of Fe(OH)₃ and Fe²⁺ in the pH-Eh diagram for the As-Fe-S-H₂O-system. Arsenic occurs as the 5-valent species and . Statistical analysis illustrates a strong association between As, Fe, pH, and HCO₃. Oxidation of the primary As-bearing minerals, such as pyrite and arsenopyrite, and the subsequent behavior of the oxyanion, arsenate, generally controls the distribution and speciation of arsenic. The low concentrations of dissolved As is due to co-precipitation and adsorption of arsenate by Fe, Al, and Mn (oxy)hydroxides.     

Recovery of boron from borax sludge of boron industry

A two-step process for boron recovery from borax sludge is proposed in the present work. The borax sludge was leached with sulphuric acid solution. Then, for the removal of alkaline species from the leachate, calcium and magnesium were precipitated by adjusting the pH of leachate using 1.5 M NaOH and 1.5 M HCl solutions. The effects of pH, temperature, concentration and time on the precipitation process were investigated. It was determined that the calcium and magnesium concentrations in the leachate were reduced from 121 mg/L to 2.6 mg/L and from 145 mg/L to 4.0 mg/L, respectively, at a pH value of 12, a temperature of 70 °C, an initial boron concentration of 500 mg/L and a precipitation time of 3 h. Under these optimum conditions, it was observed that the boron concentration in the solution decreased very slightly. In this process, the alkaline species were successfully separated from the boron.Finally, borax pentahydrate (Na₂B₄O₇·5H₂O) was produced by the evaporation of the final solution obtained after precipitation process.     

Geomechanical conditions for quasi-resonances in geomaterials and block media

Conclusions  Based on voluminous information about relations between the dimensions of the central zones of crustal earthquakes and various energy classes of underground explosions, as well as mine shocks and man-induced tremors, therefore, the hypothesis that we had previously advanced relative to the quasi-resonant mechanism of their manifestation is confirmed. Here, the geomechanical conditions for the development of quasi-resonances associated with the inducement of pendulum waves are characterized by the dimensionless energy criterion k:

Behavior and effect of calcium during hydrothermal sulfidation and flotation of zinc-calcium-based neutralization sludge

Neutralization sludge (NS), a calcium-based heavy metal waste, was produced in large quantities during wastewater treatment using lime milk neutralization in the nonferrous metal industry. During hydrothermal sulfidation and flotation of NS, the phase transition of calcium compounds might play a crucial role in the subsequent flotation for low metal recovery. During hydrothermal sulfidation, calcium minerals in NS were converted and further developed into bulk CaSO₄ crystals with many nano-ZnS crystals adhering on its surface. Specifically, the conversion of CaCO₃ into CaSO₄ could accelerate the sulfidation of NS. However, the presence of CaSO₄ could slow the growth rate of ZnS crystals, which imposes a negative effect on subsequent flotation. CaSO₄ crystals with irregular shapes and incomplete crystallization combined with nano-ZnS crystals were frequently observed in concentrates after flotation, whereas CaSO₄ crystals of regular shape and high crystallinity were mainly discovered in tailings, indicating that modifying the crystalline nature and texture of CaSO₄ crystals is a feasible method for separating ZnS and CaSO₄ and for increasing metal recovery. Furthermore, the adsorption of collectors on CaSO₄ was hardly detected, indicating that CaSO₄ barely competed with ZnS for collectors during flotation.     

室温动态等径角挤压CP-Ti的变形孪晶研究

室温下运用动态等径角挤压(D-ECAP)技术实现了工业纯钛(CP-Ti)在L型模具内的高应变率剪切变形,结合电子背散射衍射(EBSD)技术研究了CP-Ti动态剧烈塑性变形过程中的孪生行为。结果表明,D-ECAP变形在CP-Ti中激发了大量的一次■孪晶,同时生成了少量的一次■孪晶。在单个晶粒内部,一次■压缩孪晶和一次■拉伸孪晶分别存在四种和两种孪晶变体,以一次■压缩孪晶和一次■拉伸孪晶为基体可进一步激发二次■孪晶以及三次■孪晶,其中二次■孪晶均存在两种孪晶变体。     

Al-Sc-Zr-Er-Ti铝合金累积叠轧组织性能及织构研究

采用背散射电子衍射、X射线衍射、拉伸试验等手段研究了Al?Sc?Zr?Er?Ti铝合金室温累积叠轧过程中组织、性能与织构的变化.结果表明,累积叠轧使合金的大角度晶界比例提升,从而有效细化晶粒,4道次后合金超细晶粒平均晶粒尺寸达到0.83μm,晶粒组织也更加均匀.随着叠轧次数增加,整体织构强度增加,沿α取向线的Brass...     

Collecting in Europe

Artsmithite, Hg¹⁺ ₄Al(PO₄)_2-x(OH)_1+3x (where x = 0.26), occurs as a colorless-to-white matted nest (measuring 1 × 3 mm on the holotype specimen) of randomly scattered fibrous to acicular crystals at the Funderburk prospect, Pike County, Arkansas. The mineral is monoclinic, and individual crystals average 0.5 mm in length with a length-to-width ratio in excess of 100:1. Individual fibers are flexible and elongated along [001] and are colorless and transparent. Artsmithite is vitreous, has an off-white to cream-colored streak, shows no obvious cleavage, and displays an irregular fracture. It does not fluoresce, and its calculated density is 6.40g/cc. Optically, the mineral is biaxial positive with a 2V measured at 60 degrees and all indices of refraction exceeding 1.80; r < v, distinct; and the fibers are length slow with Z approximately equal to c. Associated minerals on the holotype specimen are quartz, goethite, dickite, and cinnabar; other species reported from the locality include barite, calcite, calomel, eglestonite, fluorapatite, galena, livingstonite, mercury, metacinnabar, montroydite, perhamite, pyrite, siderite, stibiconite, stibnite, and terlinguaite. Artsmithite is a secondary phase, probably produced during the weathering and chemical breakdown of cinnabar and fluorapatite (Roberts et al. 2003).     

退火温度及冷轧压下量对低碳铝镇静钢退火织构的影响

研究了退火温度及冷轧压下量对低碳铝镇静钢退火织构的影响.结果表明,在退火温度700℃、压下量70％时,γ织构明显增强;但压下率进一步增加,γ纤维织构反而减弱,并出现了较强的旋转立方织构.压下量70％和75％时,有利于深冲性能的{111}<110>织构和{112}<110>织构较强,而对冲压性能不利的旋转立方织构{100...     

Biotic and Abiotic Sequestration of Selenium in Anoxic Coal Waste Rock

Mobile selenium oxyanions (\({\text{S}}{{\text{e}}^{{\text{VI}}}}{\text{O}}_{4}^{{2 - }}\) and \({\text{S}}{{\text{e}}^{{\text{IV}}}}{\text{O}}_{3}^{{2 - }}\)) can be sequestered by biotic or abiotic reduction to non-mobile species or by adsorption to mineral surfaces. Microbial analyses and geochemical batch testing with samples collected from a coal waste rock dump in the Elk Valley, British Columbia, Canada were conducted to assess whether Se can be sequestered in anoxic, waste rock by these mechanisms. Bacteria that reduce Se(IV) and Se(VI) to Se(0) were isolated from the waste rock. Isolates that reduce Se(IV) to Se(0) were present in a water sample collected from an underlying rock drain. Three isolates were affiliated with Pseudomonas and Arthrobacter. One isolate was a putatively novel species. The production of Se(0) was confirmed by X-ray absorption near edge spectroscopy of a red precipitate isolated from a broth media containing rock-drain water. No adsorption or reduction of Se(VI) was observed in anoxic, abiotic (sterile) batch tests conducted with waste rock and a 1.0 mg/L Se(VI) solution, whereas Se(IV) was adsorbed by the waste rock and subsequently reduced to Se(0) in abiotic batch tests with a 0.7 mg/L Se(IV) solution. In non-sterile batch tests using waste rock and rock-drain water (0.39 mg/L Se(VI)), Se(VI) was biologically reduced to Se(IV), which was subsequently removed from solution by a combination of bioreduction, adsorption, and possibly abiotic reduction. This study suggests that, under anoxic conditions, Se sequestration in waste rock may occur via biotic reduction of Se(VI) to Se(IV) followed by adsorption of Se(IV) and abiotic and biotic reduction of Se(IV) to Se(0).     

Influence of Drainage with High Levels of Water-Soluble Salts on the Environment in the Verhnekamskoe Potash Deposit,Russia

Saline drainage from slurry storage facilities can deteriorate the properties of clay barriers in the beds of embankment dams and slurry ponds and cause saline drainage to infiltrate into groundwater. The chemistry of slurry material, drainage, springs, surface water, and soils was studied near the slurry storage facility of the Verhnekamskoe potash mine (Russia). Our study showed that the Na–Cl type mine drainage water, with high amounts of nitrogen compounds, increased the salinity of the groundwater and surface water, and the river valley ecosystems. As a result of ion exchange and leaching, the soil, groundwater, and surface water have elevated levels of \({\text{C}}{{\text{a}}^{2+}}\), \({\text{M}}{{\text{g}}^{2+}}\), \({\text{SO}}_{4}^{{2 - }},\) and \({\text{F}}{{\text{e}}_{{\text{total}}}}\), and extremely high \({\text{~N}}{{\text{a}}^+}\) and \({\text{C}}{{\text{l}}^ - }{\text{~}}\) values. Iron-rich precipitates and hydrogen sulfide tend to form down-gradient in the saline, water-logged seepage areas.     

Specifics of the sulfuric-acid processing of galena concentrates in the presence of nitrous acid

Conclusions  

高纯Al-0.5％Cu合金的轧制织构

采用取向分布函数(ODF)研究轧制形变量对高纯Al-0.5％ Cu合金织构的影响.结果表明,30％轧制变形量主要有{112} ＜351＞,50％时{114} ＜110＞织构,70％时出现了较强的铜式织构｛ 211｝ ＜111＞和{111｝纤维织构,在形变量达到90％后,由于出现了剪切力,织构为非常强烈的旋转立方{001｝ ＜110＞.分析Al-0.5％Cu合金的α和β线,发现随着变形量的增大,织构向C取向聚集.     

锡石表面电子结构及羟基化第一性原理计算

基于密度泛函理论,采用Materials Studio 7.0软件进行了锡石{100}、{110}、{101}解理面的电子结构及表面能的第一性原理计算,并以此为基础进一步研究了氢氧根离子在锡石{100}表面上吸附的羟基化影响。计算结果表明:与{101}面相比,{100}面和{110}面具有更低的表面能,是锡石最常见的解理面;氢氧根离子主要通过带负电的氧原子与表面上五配位的锡原子发生键合形成吸附,这种具有悬挂键的锡原子是锡石表面的活性位点。理论模拟计算能为新型锡石捕收剂的开发提供指导。     

Hydrothermal modification to improve the floatability of ZnS crystals

Crystalline structure and surface properties significantly affect the floatability of metal sulphides. In this study, a novel methodology to modify zinc sulphide (ZnS) crystals was proposed to improve the floatability of the crystals. Initially, ZnS crystals, synthesised from zinc hydroxide (Zn(OH)₂) and sulphur (S) under hydrothermal conditions, were used to assess the floatability. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to analyse the crystalline structure and surface properties of the sulphides. Conventional flotation tests were performed to evaluate the floatability. The effects of mineraliser (KOH) concentration, precursor (Zn(OH)₂) concentration, hydrothermal temperature and holding time on the floatability of the ZnS crystals were investigated. The optimal flotation recovery of ZnS (82.53%) was obtained with a KOH concentration of 5 mol/L, a Zn(OH)₂ concentration of 10%, a holding time of 4 h and a hydrothermal temperature of 260 °C. Then, sludge containing fine and amorphous zinc compounds, which was generated during the disposal of metallurgical waste water, was employed to test the recovery of valuable metals using modified hydrothermal sulphidation. The results show that the recovery of Zn in the sludge can reach 66.3% under the optimal conditions.     

分子动力学研究Cu析出相对BCC-Fe∑3{111}晶界拉伸性能的影响

采用分子动力学方法模拟计算了BCC-Fe∑3{111}晶界处Cu析出相尺寸(直径:1.0、1.5和2.0 nm)及体系温度变化(1~600 K)对晶体拉伸性能的影响。利用OVITO可视化软件进行数据可视化处理,并采用Wigner-seitz Defect Analysis方法对拉伸过程晶体点缺陷演化规律进行分析。结果表明,∑3{111}晶界处存在Cu析出相时,拉伸过程中Cu析出相内部会首先产生空位缺陷导致晶体断裂强度降低,且Cu析出相尺寸越大,晶体断裂强度越低。当晶界处Cu析出相尺寸不变时,随着体系温度升高,晶体的断裂强度随之降低,并且晶界处Cu析出相尺寸越小时温度升高对晶体断裂强度的降低作用越大。     

Who's Who in Mineral Names: Nevada Mineral Names

Kampfite, ideally Ba₆Si₈O₁₆(CO₃)₄Cl₂, forms pale blue-gray irregular masses to 10 mm enclosed in quartz-rich portions of sanbornite-bearing rock in the barium-silicate-rich deposits at Big Creek and Rush Creek, Fresno County, California (Basciano et al. 2001). The mineral is translucent and has a vitreous luster, white streak, hardness of 3, and density of 3.5 g/cm³. It is brittle with uneven fracture and one perfect cleavage on {001}. Associated minerals include celsian, fresnoite, macdonaldite, pyrrhotite, titantaramellite, traskite, witherite, and two other new minerals. The deposit probably began as sediments of Paleozoic age that were metamorphosed prior to being uplifted to their present position.     

Magnesium chloride as a leaching and aragonite-promoting self-regenerative additive for the mineral carbonation of calcium-rich materials

Two approaches for the intensification of the mineral carbonation reaction are combined and studied in this work, namely: (i) the calcium leaching and aragonite promoting effects of magnesium chloride (MgCl₂), and (ii) the passivating layer abrasion effect of sonication. The alkaline materials subjected to leaching and carbonation tests included lime, wollastonite, steel slags, and air pollution control (APC) residue. Batch leaching tests were conducted with varying concentrations of additives to determine extraction efficiency, and with varying solids-to-liquid ratios to determine solubility limitations. Aqueous mineral carbonation tests, with and without the use of ultrasound, were conducted applying varying concentrations of magnesium chloride and varying durations to assess CO₂ uptake improvement and characterize the formed carbonate phases. The leaching of calcium from lime with the use of MgCl₂ was found to be atom-efficient (1 mol Ca extracted for every mole Mg added), but the extraction efficiency from slags and APC residue was limited to 26–35% due to mineralogical and microstructural constraints. The addition of MgCl₂ notably improved argon oxygen decarburization (AOD) slag carbonation extent under sonication, where higher additive dosage resulted in higher CO₂ uptake. Without ultrasound, however, carbonation extent was reduced with MgCl₂ addition. The benefit of MgCl₂ under sonication can be linked to the preferential formation of aragonite (85 wt% of formed carbonates), which precipitates on the slag particles in the form of acicular crystals with low packing density, thus becoming more susceptible to the surface erosion effect of sonication, as evidenced by the significantly reduced carbonated slag particle size.