Water Self-Softening Processes at Waterfall Sites

Many rivers in tropical and subtropical karst regions are supersaturated with respect to CaCO3 and have high water hardness. After flowing through waterfall sites, river water is usually softened, accompanied by tufa formation, which is simply described as a result of water turbulence in fast-flowing water. In this paper, a series of laboratory experiments are designed to simulate the hydrological conditions at waterfall sites. The influences of air-water interface, water flow velocity, aeration and solid-water interface on water softening are compared and evaluated on a quantitative basis. The results show that the enhanced inorganic CO2 outgassing due to sudden hydrological changes occurring at waterfall sites is the principal cause of water softening at waterfall sites. Both air-water interface area and water flow velocity increase as a result of the 'aeration effect', 'low pressure effect' and 'jet-flow effect' at waterfall sites, which greatly accelerates CO2 outgassing and therefore makes natural waters become highly supersaturated with respect to CaCO3, consequently resulting in much CaCO3 deposition and reduction of water hardness. Aeration, rapidly increasing air-water interface area and water flow velocity, proves to be effective in reducing water hardness. This study may provide a cheap, safe and effective way to soften water.

Ion Exchange Softening and Alkalization Treatment for Zerodischarge of Circulating Cooling Water

In order to solve the problems including pipe corrosion, scaling and microbial growth, which severely threat safe op-eration of circulating cooling water system, this paper proposes ion exchange softening and alkalization process to solve these problems and carries out a series of studies to study the feasibility of ion exchange softening and alkaliza-tion process in the simulation process of circulating cooling water system. The studies include product water quality of ion exchange softening and alkalization process, effect on the performance of carbon steel and brass, and the inhibition that suppresses microbial growth. The results indicate that ion exchange softening and alkalization process is feasible to prevent the circulating cooling water system from scaling, pipe corrosion, and microbial growth without any other chemicals. Thus circulating cooling water system can achieve zerodischarge of wastewater.

Study on Influencing Factors of Bio-electrochemical System for Water Softening

Bio-electrochemical system( BES) was used to soften hard water,and effects of ion species,electrode area and influent concentration on the performance of BES to soften hard water were analyzed. The results showed that it was more easy to remove Mg^(2+) from the hard water than Ca^(2+). Increasing electrode area could enhance the performance of BES to soften hard water. When the amount of added graphite at the anode was 150 g,the removal efficiency of Ca^(2+) increased by 18. 1%. The increase of influent concentration at the anode and the cathode could improve the softening efficiency of hard water by BES. As COD concentration at the anode and NO_3^--N concentration at the cathode increased to 2000 and 300 mg/L,the removal efficiency of Ca^(2+) rose by 36. 1% and 9. 4% respectively.

Effects of water hardness on selective flocculation of diasporic bauxite

The effect of electrolyte on settling behavior of kaolinite was studied. Effects of hard water on selective flocculation of diasporic bauxite was tested and the measures were taken to eliminate the effects of Ca2＋ and Mg2＋ in hard water. The results indicated that, not only the concentration of electrolyte ions but also the ionic valence of the electrolyte ions affects the settling behavior of kaolinite; hard water significantly affects its selective flocculation owing to Ca2＋ and Mg2＋; general dispersants could not eliminate the effects of Ca2＋ and Mg2＋. Self-made softening agent in our lab could weaken or eliminate the effects of hard water on flocculation processes. The results of molecular dynamics simulation show that softening agent molecules could restrict Ca2＋ and prevent them from playing their roles, so as to eliminate the effects. The continuous pilot experiment results of bauxite flocculation were even better than those obtained in laboratory.

Hydrophilic and strength-softening characteristics of calcareous shale in deep mines

To better understand the mechanism of the strength weakening process of soft rocks in deep mines after interacting with water, a self-developed experimental system, Intelligent Testing System for Water Absorption in Deep Soft Rocks （ITSWADSR）, is employed to analyze the hydrophilic behavior of deep calcareous shale sampled from Daqiang coal mine. Experimental results demonstrate that the relation between water absorption and time can be expressed by power functions, and the soakage rate decreases while the soakage increases with time. In order to quantitatively calculate the weight coefficients of the influential factors for water absorbing capacity of rocks, a series of testing methods are adopted, including scanning electron microscope （SEM）, X-ray diffraction and mercury injection test. It is demonstrated that the effective porosity has a positive correlation with the water absorbing capacity of rocks and the contents of illite and illite/smectite. The initial water content presents a negative correlation with the water absorption capacity of rocks. According to the absolute value of weight coefficients of various influential factors, the order of magnitude from high to low is captured： initial water content, illite, illite/smectite formation （S=5%）, and the effective porosity. After water absorption tests, uniaxial compressive strength （UCS） tests were performed on rock specimens allowing a linear relationship between the UCS and the water content of rock to be established, indicating that the strength of calcareous shale decreases linearly with the increasing water content.

Development of high quality Fe_3O_4/rGO composited electrode for low energy water treatment

Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.

磷建筑石膏矿渣水泥的水化过程与耐水性能

通过凝结时间、流动度、孔溶液pH值、抗折强度、抗压强度、吸水率、软化系数、水化热和水化产物分析测试,探究了磷建筑石膏(CPG)掺量对石膏矿渣水泥水化过程与耐水性能的影响.结果表明:随着CPG掺量的增加,石膏矿渣水泥的凝结时间缩短,流动度减小,吸水率与3 d水化累计放热量均增大;水泥净浆孔溶液的pH值在水化早期快速下降,56 d时保持不变;当CPG掺量从40%增加到70%时,56 d水泥净浆孔溶液的pH值从11.02减小到10.62,水泥胶砂的软化系数从0.98减小到0.91,主要水化产物均为二水石膏和钙矾石,并且钙矾石的含量随着CPG掺量的增加而减少.

硅酸钠改性磷石膏道路稳定材料性能及固化机理

以磷石膏资源化利用为目的,探索了硅灰和水泥固化高浓度原状磷石膏制备道路稳定材料的最优配比设计,并以此为基础研究了硅酸钠增强道路稳定材料的性能,分析了固化机理。结果表明,当水泥、硅灰、消石灰的质量比为5∶3∶2,并加入1.5%(质量分数)的硅酸钠时,磷石膏道路稳定材料的力学性能和耐水性能显著提高,28 d无侧限抗压强度可达9.77 MPa,软化系数可达0.81,水稳系数可达1.0,同时浸出液中氟离子和可溶磷浓度满足《污水综合排放标准》(GB 8978—1996)一级限值。微观测试表明,水化反应产生的大量水化硅酸钙凝胶可将二水硫酸钙包裹,同时硅灰和硫酸钠的填充作用使整体结构更加密实,形成性能良好的磷石膏道路稳定材料。

内水渗漏软化基底对盾构隧洞衬砌管片受力性能的影响分析

水工盾构隧洞在运行过程中存在内水渗漏导致基底软化的风险,基底软化将对隧洞管片受力变形产生影响。依托实际水工盾构隧洞工程,构建了由管片、灌浆体和围岩组成的三维有限元数值模型,针对Ⅴ类围岩条件下因渗漏导致基底均匀和不均匀软化的状况,研究了管片的受力性能变化规律。结果表明:在内外荷载作用下,管片的环向应力、竖向位移和定位销应力均随基底软化深度的增加而增大,均匀软化条件下仰拱管片出现峰值为1.88 MPa的拉应力,存在管片开裂风险;基底软化导致定位销应力增大,而管片竖向位移的变化幅度较小。研究成果可为水工盾构隧洞的安全运行监测提供科学依据。

三轴加载条件下含水率对煤体力学特性影响的试验研究

含水率对煤体力学特性具有重要影响,为深入探讨三轴加载条件下含水率在煤体力学中的作用机制,选择平顶山矿区代表性煤样并设置不同含水率水平的试验组,开展了不同含水煤样的单轴压缩试验和不同围压条件下的含水煤样三轴压缩试验,并对不同含水煤样进行应力-应变关系、抗压强度等方面的综合性能测试。结果表明:不同围压条件下,含水煤体的应力-应变曲线呈现相同趋势。三轴加载条件下,含水煤体轴向方向的应力-应变曲线与单轴加载时的煤体轴向方向的应力-应变曲线形式相同。相同含水率条件下,不同围压的试验煤样出现应力峰值时的轴向应变略有不同,整体呈现围压越大,其出现应力峰值对应的轴向应变越小。整个加载过程中,试验煤样轴向应变始终为正值,即煤体轴向方向发生轴向压缩变形,与此同时,试验煤样径向产生膨胀变形。单轴/三轴加载条件下,随着含水率增加,峰值强度整体呈降低,含水率与峰值强度呈一元二次函数关系。随着围压增加,峰值强度整体呈下降趋势。随着含水率增加,岩石软化系数整体呈现降低趋势。含水率与软化系数呈一元二次函数关系。研究结果为平顶山矿区煤炭资源的合理开发和利用提供了科学依据。

水软化作用下页岩微观结构和力学性质演化特性

在雨水或者地下水的浸泡下,页岩力学性质会大幅度降低,容易导致泥石流、隧洞塌陷、滑坡等灾害。以页岩为研究对象,通过微观岩石力学试验研究了水软化作用下页岩的微观结构和力学特性演变规律。研究结果表明:在浸水10 d后,页岩表面粗糙度平均值和最大值分别增至259.1 nm和561.9 nm。页岩主要由石英、绿泥石、伊利石和钠长石组成,其中绿泥石为层状硅酸盐。在水软化作用下绿泥石发生崩解并且释放晶层间膨胀力,导致页岩样品粗糙度增加。随着浸水时间的增加,高、中、低3类强度矿物的弹性模量逐渐减小;低强度矿物的黏聚力呈现下降趋势,从16.7 MPa降低到6.0 MPa,而内摩擦角随浸泡时间轻微波动,其平均值为42.5°。

再生砂混凝土的吸水与抗氯离子渗透性能影响因素研究

为了探明再生砂混凝土的吸水性能和抗氯离子渗透性能特性,研究了水胶比(0.37、0.45、0.58)、再生砂掺量(0、30%、50%、70%、100%)、再生砂中微粉含量(3%、7%、10%)、矿物掺合料品种和掺量、再生砂预湿程度(0、50%、100%)等因素对再生砂混凝土体积吸水率、软化系数和电通量的影响,对比了不同影响因素对再生砂混凝土吸水性能和抗氯离子渗透性能的影响程度。结果表明:随着再生砂掺量和微粉含量的增加,混凝土的吸水性能增强、耐水性降低、抗氯离子渗透性能下降;而通过掺入多元复合矿物掺合料(15%粉煤灰+15%矿粉+8%硅灰)、降低水胶比和提高再生砂的预湿程度,均能不同程度改善再生砂混凝土的吸水性能和抗氯离子渗透性能。

湿陷性黄土地区碎石排水系统砂岩碎石遇水软化试验研究

为研究延安湿陷性黄土地区进行的平山造地工程碎石排水系统中砂岩的遇水软化特性及其对工程施工稳定性的影响,采用WDW-600微机控制电子万能机对现场所取砂岩岩样开展了岩石单轴压缩试验和圆盘劈裂试验,测定烘干状态、天然状态、浸水饱和状态三种不同含水量的砂岩的强度及软化特性,结果表明:该地区砂岩遇水后会发生较为明显的强度软化,其中岩石抗压强度软化程度稍大,烘干样、天然样和饱和样平均抗压强度分别为14.54MPa、10.58MPa和7.70MPa,软化系数为0.53;烘干样、天然样和饱和样平均抗拉强度分别为1.43MPa、1.30MPa和0.83MPa。试验增强了对延安湿陷性黄土地区砂岩遇水软化力学性能的认识,对岩石遇水软化后排水系统承载性能计算和稳定性分析具有参考价值。

基于超声波技术的矿井水井下预处理试验研究

混凝、沉淀(浮升)和过滤是矿井水的预处理方法,但设备占地面积大、耗费时间长、混凝剂与絮凝剂污染等问题一直制约着矿井水井下处理技术的进一步发展。为此,以现场采空区水样与岩样为研究对象,设计了一套基于超声波雾化技术的矿井水井下预处理装置,采用超声波雾化技术进行矿井水澄清与预软化处理,满足井下生产、消防及降尘用水需要。结果表明:(1)该方法可将黑灰色且有大量固体杂质悬浮物的浑浊矿井水澄清,有效去除水中难溶的固体杂质;(2)超声波雾化技术对水的总硬度降低72.24%,Ca^(2+)的质量浓度由试验前的5.33 mg/L降低到0.81 mg/L,Mg^(2+)的质量浓度由5.23 mg/L降低到2.13 mg/L,对pH值的影响较小;(3)经超声波雾化后的采空区水可满足井下消防洒水、喷淋降尘、采煤设备开采过程及冷却水的使用要求。

基于PSO‑BPNN模型的氯氧镁水泥混凝土耐水性预测

为快速准确地获得具有优异耐水性氯氧镁水泥混凝土(MOCC)的配合比,设计了拓扑结构为4‑10‑2的粒子群优化(PSO)算法-反向传播(BP)神经网络(PSO‑BPNN)模型.该模型的输入层参数为n(MgO)/n(MgCl_(2))、粉煤灰掺量、磷酸掺量和磷肥掺量,输出层参数为MOCC的抗压强度和软化系数;模型数据集为144组,其中训练集数据为100组,验证集数据为22组,测试集数据为22组.结果表明:PSO‑BPNN模型在MOCC抗压强度预测中的评价参数——决定系数R^(2)=0.99、平均绝对误差S_(MAE)=0.52、平均绝对误差百分比S_(MAPE)=1.11、均方根误差S_(RMSE)=0.73;其在软化系数预测中的评价参数——R^(2)=0.99、S_(MAE)=0.44、S_(MAPE)=1.29、S_(RMSE)=0.62;与BP神经网络(BPNN)模型相比,PSO‑BPNN模型具有更强的双参数预测能力,可用于MOCC配合比的正向设计和反向指导.

锦屏大理岩原位应力环境水软化特性分析

中国水电资源主要集中在西部高山峡谷地区,将水电站建筑物布置在极深洞室群常常是经济且较优的选择。受典型河谷地貌特征和区域强烈高地应力、高渗透压环境影响,极深洞室围岩力学特性演化规律和长期稳定性是亟需解决的关键科学问题。不同赋存深度应力环境下,水岩耦合作用对岩石力学性质的影响尚不明确,导致深部岩体工程面临一定的风险性和低效性。基于自主设计并研制的深部原位应力环境岩石饱水试验系统,开展锦屏大理岩原位应力环境与无压环境下饱水时长为1、23、60和100 d的水软化试验,并进行5组不同围压下的三轴压缩试验。研究发现:深部原位应力环境下锦屏大理岩饱水100 d后峰值强度劣化程度约为无压饱水100 d的3倍,其余力学参数(如内聚力、内摩擦角等)劣化度也远大于无压饱水条件;锦屏大理岩峰值强度劣化度随水岩耦合环境深度的增加(100、1000、1400、1800和2400 m)均呈现先减小后增大的非线性变化特征;通过探索锦屏大理岩水软化机理,发现摩擦弱化效应与孔隙水压力作用共同造就了锦屏大理岩峰值强度非线性变化规律。结果表明,原位应力环境下的水软化效应及其对围岩力学性质的影响更加突出,在对深部地下工程进行稳定性分析时必须考虑围岩水软化特性,该结论对锦屏地下工程的建设和维护具有重要的指导意义。

不同掺合料提升磷石膏基材料耐水性方法研究综述

磷石膏作为湿法磷酸的工业废弃物,主要应用于建筑材料、化学工业、农业等领域。因磷石膏内部含有未完全分解的磷矿、残余的磷酸、氟化物、酸不溶物、有机质等杂质,使其在建筑材料领域利用率较低,通常掺入其他水硬性材料对磷石膏进行改性,而改性后的磷石膏基复合胶凝材料的耐水性较差。针对磷石膏基复合胶凝材料耐水性较差的问题,本文综合前人已有的研究,论述了掺加不同掺合料对磷石膏基材料耐水性的影响,包括掺加水泥、粉煤灰、硅灰、矿渣、减水剂、含氢硅油、石蜡、有机硅、聚乙烯醇、三乙醇胺、碱性激发剂等,以及改善水胶比、粒径和养护方式、合理安排组分设计等辅助方法,总结分析了不同掺合料对磷石膏基复合胶凝材料耐水性的影响机理,阐述了掺合料对磷石膏基材料的的作用机理,确定了合理的掺合料掺加范围。

焦炭与不锈钢耦合阴极的电化学水软化性能研究

以304不锈钢网作为外层支撑床,锯齿不锈钢网作为内部支撑结构,在复合锯齿网的锯齿空隙中填充焦炭,制备了一种由焦炭与不锈钢两种材料耦合的填充床电极,用于解决电化学水软化阴极无法长期高效运行的问题。探究了最优的电极结构参数,结果表明,在阴阳极间距、外层平网孔径和表观电流密度分别为1.5 cm、20目、80 A/m^(2)时,电极对总硬度为700 mg/L的模拟循环冷却水的软化速率达到最佳,为46.873 g(/m^(2)·h)。当电极表面被垢层覆盖导致软化速率大幅下降时,通过振动方式对电极进行再生,研究了电极的使用寿命,结果表明,维持电极连续工作37 d,电极对循环冷却水仍保持较高的软化速率,可维持电化学水软化系统的长期高效运行。本研究可为解决电化学水软化阴极因无法有效再生导致的电化学水软化系统性能下降问题提供参考。

《伤寒杂病论》中芍药-附子药对配伍治疗探析

《伤寒杂病论》中以芍药-附子药对配伍的方剂有5首,分别治疗痹病及水液代谢障碍疾病,通过对痹病及水液代谢障碍疾病的病因病机、治法、用药特点进行分析,认为芍药-附子药对配伍在治痹三方中主要发挥温阳散寒止痛、调和阴阳的功效,在治水两方中起到温阳利水、敛阴生津的作用。

促进CaCO_(3)在溶液中成核的高效电化学水软化器

为解决电化学法除垢存在的电极频繁清理及效率低下的问题,开发了电极水平排列的新型电化学水软化反应器,设置从阴极区进水,从阳极区出水,利用水流和气泡运动推动OH-扩散,强化CaCO_(3)在溶液中成核。通过优化电流密度、流速和进水硬度强化电化学水软化反应器内CaCO_(3)在溶液中的成核,在流速为2.7 L/h、电流密度为80 A/m^(2)、进水硬度(以CaCO_(3)计)为400 mg/L时,软化效率可达到155 g/(h·m^(2)),硬度去除量可达到150 mg/L,电流效率可达到50%,去除单位质量CaCO_(3)能耗为15 kW·h/g,有效地降低了阴极清理频率。