酸雨环境下老旧砖砌体的抗压性能

为研究酸雨环境下老旧砌体抗压力学性能退化规律,实验室配置了PH值分别为1.5、2.5和3.5的3种硫酸和硝酸混合溶液来模拟酸雨环境,采用完全浸泡加速腐蚀的试验方法对砖、砂浆和砖柱进行不同程度的腐蚀,并测定其抗压强度。试验表明,随着腐蚀时间的增加,砂浆试块抗压强度先增大后降低;砖试块抗压强度随腐蚀时间的增加而降低;模拟酸雨溶液PH值越小,砂浆和砖试块抗压强度降低程度也愈大;砖柱极限承载力和弹性模量均随腐蚀时间的增加而降低,且模拟酸雨溶液PH值越小,降低程度愈大;随着腐蚀时间的增加,砖柱初始刚度逐渐减小,极限破坏位移增大;模拟酸雨溶液PH值越小,砖柱在达到峰值荷载时的变形值越小,脆性愈大;基于试验结果,建立了酸雨环境下砖柱应力应变曲线上升段统一数学表达式及酸雨侵蚀后普通烧结粘土砖砌体剩余抗压强度回归公式。     

Effect of matrix modification on durability of cementitious composites in an acid rain environment

The durability of silane-modified mortar, a cementitious composite, in acid rain environment was investigated given its extensive usage as a structural material. The results indicated that the addition of silane decreased the compressive strength of the cementitious composite. Wetting angle was increased by incorporating silane into the matrix. Decrease in both water absorption ability and coefficient of capillary suction confirmed hydrophobicity as induced by silane addition. Results of mechanical testing, scanning electron microscopy and X-ray diffraction showed that the sulfuric acid resistance of mortar was enhanced by silane. Based on these results, it is revealed that silane addition inhibits the diffusion of water, and consequently, sulfate ion diffusion rate decreases, thereby resulting in reduction in the rate of corrosion of cementitious composites by sulfuric acid.     

石家庄市酸雨污染特征及其成因分析

根据2008-2012年的酸雨监测数据,研究了石家庄市5年来大气降水量、pH值、电导率及降水化学组成的变化规律和趋势.结果表明：石家庄市5年来年均降水量为557.4 mm,降水集中在6-9月份.降水pH值最大为7.98,最小为4.41,年均值为5.88.电导率为12.37～18.03ms/m,年均值为14.96ms/m,且与pH值呈一定的负相关性.酸雨频率年均值为4.35％,近2年没有酸雨发生.降水中阴离子浓度由高至低依次为SO42-,NO3-,Cl-,F-,阳离子浓度由高至低依次为Ca2＋,NH＋,Mg2＋,K＋,Na＋.石家庄市的酸雨类型由硫酸型向硫酸和硝酸混合型过渡.     

AT90S8535单片机控制系统在洗衣粉磺化中的应用

洗衣粉生产过程中磺化环节(即原料苯和硫酸反应生成苯磺酸)非常重要,其生成物pH值的精度直接影响洗衣粉的质量.本文介绍了采用AT90S8535单片机控制系统对洗衣粉生产的磺化环节pH值进行控制的控制思想、系统硬件组成及系统软件的实现方法.     

微波条件下提取果胶的研究

以橘皮为原料,在微波条件下,用盐酸溶液萃取、硫酸铝沉淀提取果胶。探讨了微波辐射时间、微波辐射温度、ｐＨ值、液料比及硫酸铝用量对果胶产率的影响。通过正交实验确定最佳工艺参数     

油页岩灰渣制备聚合硅酸铝铁絮凝剂的研究

以油页岩灰渣为原料制备了高效无机高分子絮凝剂聚合硅酸铝铁（PFAS）,研究了聚硅酸（PS）稳定性及PFAS的混凝效果。研究结果表明,当pH小于5．6时,随pH值增大,PS形成速度加快,稳定性降低,pH大于5．6时,溶液在几秒内即出现凝胶。随着温度升高或硫酸浓度增大,PS形成速度加快,稳定性降低。PFAS投加量增加,对炼油废水浊度的去除率不断增加。在PFAS投加量相同时,随着PFAS中（Al＋Fe）／Si摩尔比增大,PFAS对炼油废水浊度去除率增大,当n（Al＋Fe）/nSi=10／1时,样品性能最优,继续增加（Al＋Fe）／Si摩尔比,PFAS絮凝性能降低。     

硫酸和氧化亚铁硫杆菌浸出低品位磷矿

研究了硫酸和氧化亚铁硫杆菌（Af．f．）浸出低品位磷矿过程中初始pH值和底物成分对磷的浸出率的影响．实验结果表明：在初始pH值为1．50～3．50时，硫酸和Af．f．都能有效提高细菌培养液中磷的浸出率，且当pH值为2．00、培养底物为混合矿时，Af．f．浸出磷矿中磷的浸出率最大，达到9．50％．     

Removal of phosphorus from iron ores by chemical leaching

1 INTRODUCTION With the rise of the price of iron ores in the global market, the iron and steel companies in China have to increase the proportion of domestic iron ores in iron-making production. However, iron ores produced in China commonly contain many impurities, such as phosphorus, sulphur, silica, etc[1]. Phosphorus is one of the main harmful elements to ferrous metallurgy, and it will affect the quality of iron and steel products[2]. At present, China has explored some large mines,…     

Effect of Flotation Reagents on the Cake Moisture of Copper Concentrate

The effect of reagents used in separating chalcopyrite from pyrite on the cake moisture of the copper concentrate at Daye Iron Mine Mineral Processing Plant was investigated. The results showed that the dosage of lime used for depressing pyrite was the main factor that increased the filter cake moisture of copper concentrate. With increasing the dosage of lime, the cake moisture of copper concentrate increased sharply. The cause was concluded to be the addition of lime to the pulp, which resulted in the formation of floc and a high pH value. The collector Z-200#, used for collecting chalcopyrite, had, as well, an adverse effect on the cake moisture of copper concentrate, but its effect was inferior in respect to that of lime. The cake moisture of copper concentrate can be decreased by changing the method with which lime is added and the pH value of pulp is regulated. The experiment results showed that the sulfuric acid was the best regulator. When the clarified liquor of lime was used as a depressant and the pH value of the pulp was regulated to 6.5?7.0 by adding sulfuric acid, the cake moisture of copper concentrate was reduced from 15.49% to 13.13%. The examination of chalcopyrite surface by using ESCA (Electron Spectroscopy for Chemical Analysis) showed that calcium sulfate and iron hydroxide had formed on the surface of chalcopyrite when lime was added to the pulp. The formation of calcium sulfate and iron hydroxide on its surface increased the hydrophilicity of chalcopyrite so that its cake moisture increased. The addition of sulfuric acid to the pulp not only removed the calcium sulfate, but also reduced the concentration of iron hydroxide on the surface of chalcopyrite so that the cake moisture of copper concentrate was decreased.     

酸性水环境下桥梁桩基混凝土的配制与耐久性研究

针对酸性水环境下桥梁桩基混凝土的配制,研究了矿物掺合料、水胶比以及侵蚀溶液pH值对混凝土抗酸侵蚀性能的影响。混凝土的粉煤灰掺量从20%～50%变化,矿粉掺量从35%～65%变化,水胶比分别取0.35、0.39、0.43,酸性水侵蚀环境通过pH值分别为1、2、4的硫酸溶液模拟,抗酸性能通过测定1年龄期的混凝土抗压强度变化率表征。结果表明,降低水胶比有利于提高混凝土的抗酸侵蚀性能;矿物掺合料对混凝土耐酸性能的改善作用与其品种、掺量及模拟侵蚀溶液的pH值大小有关。大掺量粉煤灰混凝土比大掺量矿渣粉混凝土具有更好的耐酸性能。     

酸处理对云杉硫酸盐浆脱木素的影响

云杉硫酸盐在试验条件下，使用控制ｐＨ的稀硫酸处理能成功地脱木素，酸处理后紧接着进行碱抽提所获得的效果比单独进行酸处理或碱抽提要好些，当硫酸处理时加入含氮化合物（ＮａＮＯ３和ＮｄＮＯ２），能提高脱木素的选择性。氧脱木素和酸处理的组合试验表明，在适合条件下氧脱木素前进行硫酸予处理是可行的。     

Solvent extraction of copper and zinc from bioleaching solutions with LIX984 and D2EHPA

The solvent extraction of copper and zinc from the bioleaching solutions of low-grade sulfide ores with LIX984 and D2EHPA was investigated. The influences of extractant content, aqueous pH value, phase ratio and equilibration time on metals extraction were studied. The results show that LIX984 has a higher selectivity for copper than for iron, zinc and other metals, and has the copper extraction rate above 97%, while the zinc and iron extraction rate is less than 1.6% respectively. Zinc extraction is carried out following the copper extraction from the raffinate. The zinc extraction with di(2-ethylhexyl) phosphoric acid(D2EHPA) is low due to its poor cation exchange. A sodium salt of D2EHPA is used and the zinc extraction rate is enhanced to above 98%. Though iron (Ⅲ) is strongly extracted before the extraction of zinc by D2EHPA, it is difficult to strip iron from the organic phase by sulfuric acid. The zinc stripping rate is above 99% with 100 g/L sulfuric acid, while that of iron is 0.16%. Hence,the separation of zinc from iron can be achieved by the selective stripping.     

苯酚-硫酸导数光谱法快速测定中药中多糖的研究

研究发现多糖－苯酚－硫酸显色的反应体系的一阶导数光谱值与多糖含量成正比，据此建立了苯酚－硫酸显色导数光谱分析多糖的方法，它具有选择性好、不受样品颜色的干扰、所需样品量少、简便、快速、准确的优点。直接应用于甘草、黄芪、当归、女贞子、红参、枸杞、茯苓等单味药水提液及癌症化疗的减毒增效复方中药口服液中多糖含量的测定，取得了满意的结果。     

Prediction of the residual strength for durability failure of concrete structure in acidic environments

According to the results of accelerated tests of acidification corrosion depth and compressive strength of concretes subjected to sulfuric acid environments, the acidification depth laws of concretes were predicted based on the grey system theory. Thus, the remaining compressive strength was calculated when the acidification depth reached the protection layer thickness of concrete structures, which indicates that the limit state of durability failure can be defined based on strength degradation, and the calculation process was illustrated by an example. The calculated results show that the remaining compressive strength values in the durability failure limit state for the concrete structures exposed to pH=2 and 3 sulfuric acid water environments and wet-dry cyclic sulfuric acid environment with pH=2 are 74%, 72%, and 80% of initial strength, respectively. The method provides references for the durability evaluation of concrete structure design under the acidic environments.     

还原-偶氮光度法测定硝基苯的改进研究

提出了国标中分光光度法测定硝基苯的三种改进方案：将盐酸介质改为硫酸介质;由室温改为在水浴中加热排汽泡;将两次用酸碱调节pH改为邻苯二甲酸氢钾—盐酸的缓冲溶液控制pH.均可得到满意的结果.     

三轴应力作用下化学侵蚀对砂浆力学性能的影响

开展了不同水化学腐蚀下砂浆试样的常规三轴压缩试验,分析了溶液pH值、浓度及水化学成分对试样的腐蚀程度及微细观结构的影响效应,探讨了砂浆试样的水化学腐蚀机理,并进一步对比分析了不同水化学作用对砂浆物理力学参数的影响规律。基于化学腐蚀后试样产生的次生孔隙率,建立了新的损伤参量来定量描述试样物理力学性质随水化学损伤的演化过程。     

稀硫酸和高温热水预提取桉木半纤维素

对桉木半纤维素稀硫酸和高温热水预提取的条件进行了研究。结果表明,酸浓度、预提取温度和时间影响水解液中木糖的浓度。3%稀硫酸预提取4 h后木糖浓度达到最大值19.224 g/L;170℃预提取4小时,木糖浓度达到14.329 g/L。并利用水解液制备了球形碳材料,对半纤维预提取机理进行了分析。     

Bacterial oxidation activity in heap leaching

Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans (T. f. ) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The surveys of production process and the bacterial oxidation activity in the heap bioleaching were investigated. The results show that pH value is high, bacteria biomass and ferric concentration are low, generation time (above 7.13 h)is long in leachate, and less bacteria are adsorbed on the ores. The bacteria in the leachate exposing on the surface and connecting with mineral, have much faster oxidation rate of Fe(Ⅱ) and shorter generation time, compared with those which are in the reservoir for a long time. There is diversity for oxidation activity of Fe(Ⅱ), while there is no diversity for oxidation of sulfur. So it is advisable to add sulfuric acid to degrade pH value to 2.0, add nutrients and shorten recycling time of leachate, so as to enhance bacteria concentration of leachate and the leaching efficiency.     

降低异戊烷的碘值和酸值方法的研究

利用酸值和碘值测定的标准方法对大庆油田化工有限公司轻烃分公司提供的6个异戊烷样品的酸值和碘值进行分析,并与合格产品对比,研究了异戊烷样品的酸值和碘值。依据异戊烷样品酸值和碘值偏高的原因．设计了多层KOH填充柱法和浓硫酸处理法,利用该方法对异戊烷样品进行处理。处理后试样品的酸值和碘值均优于合格品。     

Meso—四（对磺酸基苯基）卟啉的合成及吸收光谱行为

在体积比为５：１的丙酸和异丙酸介质中,以苯甲醛和吡咯合成了四苯基卟啉。经磺化得到ｍｅｓｏ－四（对磺酸基苯基）卟啉,产率１３％。研究了该卟啉在水溶液中的可见吸收光谱行为。实验表明该卟啉可以不同的离子形式（Ｈ２ＴＰＰＳ２＋、ＨＴＰＰＳ＋和ＴＰＰＳ）及二聚体形式存在。同时水溶液的离子强度、酸度和温度都对其可见吸收光谱行为及存在形式有重要影响。