化学沉淀法处理酸性含氟废水研究

针对某磷肥厂除氟工序中废水含氟量过高的问题,设计了"熟石灰沉淀-水循环利用"的工艺改进方案;如遇紧急情况需要对含氟废水进行外排时,则以聚合氯化铝(PAC)进行混凝深度处理;并进行了除氟实验。结果表明,含氟废水当加入理论质量1.3倍的熟石灰、反应30 min时,即可使废水中F-含量达到工厂废水循环利用要求的质量浓度30 mg/L以下;熟石灰处理后的循环水达到GB 8979-1996一级排放标准的混凝PAC最大投加量为0.6 g/L。对反应生成的沉淀物进行X射线衍射表征表明,废水中的氟是以氟化钙的沉淀形式析出。该法流程简单、处理效率高、反应时间短,系统封闭运行,几乎无废水排放。     

超高石灰铝法去除水中氯离子实验研究

采用超高石灰铝法向含氯废水中添加氧化钙和偏铝酸钠,使钙离子、铝离子与氯离子形成不溶性的沉淀,达到去除氯离子的目的。考察了时间、温度、氧化钙添加量、偏铝酸钠添加量对溶液中氯离子去除的影响,结果表明:超高石灰铝法可以有效去除氯离子,当温度为40℃,搅拌时间为40 min,n(Ca)∶n(Al)∶n(Cl)为5∶3∶1时,氯离子去除率达到80.05%,石化废水处理后的氯离子质量浓度为193 mg/L,达到回用水要求氯离子低于200 mg/L的标准。     

石灰纯碱法耦合聚合氯化铝预处理高矿化度矿井水的实验研究

高矿化度矿井水回用常采用膜技术进行脱盐,但运行过程中水中硬度和悬浮物会造成膜污染极大影响了膜性能,开展预处理降低矿井水硬度及浊度,对减轻膜污染、提高出水水质、降低运行费用有重要的作用。本文采用石灰纯碱法耦合PAC去除矿井水的硬度及浊度,采用单因素试验考察了药剂投加量、反应时间、沉淀时间对去除效果的影响。试验结果表明,氢氧化钙投加量为100 mg/L、碳酸钠投加量为10 mg/L、PAC投加量为20 mg/L,反应30 min,沉淀15 min,此时水样的总硬度为51.54 mg/L,总硬度去除率为48.11%,浊度去除率为98.13%。吨水药剂费用3.07元。     

高含盐高硬度废水化学软化的预处理工程

针对某工业园区排放的经过超滤+反渗透工艺系统处理过的工业高含盐高硬度废水(总硬度为1 900~3 200 mg/L),采用高密池、液碱-纯碱法及V型滤池处理工艺进行化学软化的预处理。本文首先加入液碱调节废水的pH值至11.2,投加纯碱量为理论计算量的1.2倍;之后投加絮凝剂和助凝剂进行沉淀;沉淀后的出水加入硫酸调节pH值为8左右,然后经V型滤池过滤后出水总硬度可降至100 mg/L以下,浊度降至1.0以下,总硬度去除率达99%以上。     

铜冶炼污酸除砷工艺比较研究

硫化法与石灰-铁盐法均为工业处理含砷污酸的重要方法,2种方法对于环境保护和水的回收利用具有重大意义。比较研究了硫化法与石灰-铁盐法对铜冶炼污酸的处理效果。实验表明硫化法因子影响顺序为S/As摩尔比>温度>时间,当S/As摩尔比为4.5,温度45℃,时间30 min时,污酸处理后砷质量分数低于0.1 mg/L,小于国标0.5 mg/L;通过2段石灰-铁盐法处理污酸,采用分段处理-一段渣洗涤的方法可使渣量减少26.7%,处理后的水中砷质量浓度为36 mg/L,将沉降后的废水采用铁盐+絮凝剂的方式处理后,废水中砷质量浓度为0.18 mg/L,可以达标排放。     

催化转化-生物降解法处理高浓度甲醛废水

提出了催化转化-生物降解法处理高浓度甲醛废水的新方法。研究发现,在温度为70℃,催化转化剂与甲醛摩尔比为1∶5,反应30 min,废水中甲醛去除率可达99.96%。预处理后的甲醛废水BOD5/CODcr值由0.12升至0.50,甲醛浓度<3 mg/L,大大提高了废水的可生化性。实验结果还表明,在采用生物降解法处理预处理后的甲醛废水过程中,当温度为35~40℃,pH值为7.0~7.5,水力停留时间(HRT)为9~12 h时,厌氧反应器有机负荷(OLR)为8.0~10.0 kg/(m3.d),好氧反应器OLR为1.0~2.0 kg/(m3.d),CODcr总去除率达到98.81%,出水COD<100 mg/L。该方法具有工艺简单、处理效率高和成本低等特点,有极高的实际应用价值。     

无定形氢氧化铝除氟实验研究

本文针对某企业酸性浸出废水中氟的脱除,采用无定形氢氧化铝进行除氟实验研究;设定反应条件:氢氧化铝加入量45 g/L,反应温度70℃,反应时间60分钟,实验结果表明在该条件下除氟率能达到98%,废水中氟含量能由600 mg/L降至12 mg/L。     

石灰法处理铜、锌废水研究

本研究通过对模拟废水分析测定,主要研究了石灰沉淀法处理方法的去除效果和药剂投加量,投药比例,运行时间,pH值的最优条件综合分析。根据实验目的和实际情况,使用硫酸铜、硫酸锌、硫酸铅、硫酸镉、配置成的含Cu~(2+)、Zn~(2+)的浓度分别为0.4 g/L、0.2 g/L。石灰沉淀法处理重金属废水有较好的效果,其中沉淀剂为石灰,混凝剂为聚丙烯酰胺。其最优的操作条件为:反应pH为9;PAM的投加量分别为50 mg/L;快速搅拌过程的搅拌速度为220 rpm,搅拌时间为6 min;慢速搅拌速度为50 rpm,搅拌时间为10 min时。处理后,Cu~(2+)的浓度达到0.001mg/L,Zn~(2+)的浓度达到0.040 mg/L。     

碱解缩聚-臭氧氧化-生化处理酚醛树脂废水

对于挥发酚1156 mg/L,甲醛2814 mg/L的酚醛树脂废水的试验研究表明,试验采用碱解缩聚-臭氧催化氧化-生化法处理工艺是可行的。65℃条件下石灰法反应45 min,甲醛的去除率达到99. 87%;常温常压下,p H值为9,双氧水投加量为1 g/L的条件下,臭氧投加量为2000 mg/L,挥发酚的去除率为96%;中和稀释后经生化工艺处理可达标排放。     

煤气化含氟废水深度处理的研究及应用

以豫东某煤化工园区煤气化含氟废水为研究对象,采用石灰-硫酸铝化学沉降两级反应和活性氧化铝深度吸附组合工艺进行除氟研究;结果表明,在一级反应池内,石灰浓度为1 000mg/L、PAM浓度为2mg/L、pH11,二级反应池内硫酸铝浓度为1 200mg/L、PAM浓度为1.5mg/L的情况下,氟脱除率可达到90%以上,最后通过活性氧化铝吸附,处理后废水氟含量可控制在1.5mg/L以下,并实现了现场应用,满足当地环保排放要求。     

Hardness testing of plastics

The effect of time of indentation and time of recovery on the Rockwell hardness, of a series of glassy and crystalline polymers has been determined. An analytical technique, based on conventional viscoelastic approaches, has been developed. This technique permits the resolution of the hardness number into its components of permanent deformation, retarded elastic compression, and retarded elastic recovery. Subtraction of components due to retarded elastic response results in hardness numbers dependent only the time-dependent permanent deformation. Extrapolation of this data to zero time results in an absolute or time-independent value of Rockwell hardness, designated R_o.     

Hardness of carbon materials

Data on the hardness of carbon materials obtained via conventional technologies are summarized. The data are compared with the structure characteristics and the properties of the carbon materials. Correlations of the structural characteristics and the properties of the carbon materials with their hardness have been revealed.     

镀层硬度的测定

硬度是材料的一种机械性能.在表面处理行业中,硬度是检验镀层或其它涂层质量的重要指标之一.介绍了硬度的定义、测定方法、特点及表示方法等.其中测试方法按施加试验力的方式分类介绍,在八种测试方法中侧重适用于镀层及涂层表面维氏硬度、努氏硬度和洛氏硬度的测定.     

超软弹性体硬度的测定

该文叙述了一种用于测量极软硅橡胶硫化胶硬度的新方法，并比较了这种方法与现用邵尔A和邵尔00方法的区别，论述了试验条件对测量精度的影响。     

水硬度的测定方法

概述了水硬度的分析测定方法,主要介绍了EDTA络合滴定法,分光光度法,原子吸收法,ICP-AES法,离子色谱法,自动电位滴定法,离子选择性电极-流动技术法几种测定方法,对比了各种方法的优劣,并指出测定方法的发展方向。     

陶瓷材料硬度表示方法的探讨

本文详细论述了陶瓷材料硬度的不同测试方法以及各种方法的优缺点,并对影响耐磨陶瓷材料硬度的因素进行了分析。以95氧化铝瓷为例,对其洛氏硬度进行了对比试验,发现A、C不同标尺之间的换算在一个特定范围存在相应误差。     

Hardness and fracture toughness of moissanite

Disparities prevail among the reported hardness and fracture toughness values for hard and brittle materials. A better understanding of the physical nature of hardness and fracture toughness and a standardized technique for reliable measurements of these quantities is urgently needed. We strongly recommend the use of the measured hardness after the bend in the hardness versus load (H−F_Load) curve, when the hardness approaches its asymptotic value. The present work reports a systematic study of hardness and fracture toughness on moissanite (single crystal hexagonal silicon carbide, 6H-SiC) samples. The measurements were performed over a broad load range from 0.49 to 294 N with the direct indentation method. Asymptotic values of Knoop hardness of H_K = 19 GPa and Vickers hardness of H_V = 22 GPa were reached at a high load between 50 N and 100 N. A consistent fracture toughness of K_IC = 1.8 MPa·m^1/2 was obtained across the entire load range. Our study presents experimental results for the hardness and fracture toughness of moissanite in the asymptotic-hardness region, and it raises concern regarding the application of moissanite single crystals as anvil material under shear/fracture conditions.     

Toward Demystifying the Mohs Hardness Scale

Today, the Mohs scale is used profusely throughout educational systems without any persuasive understanding of the fundamental principles. Why one mineral has a scratch hardness over the next culminating in a scale of 1 (chalk) to 10 (diamond) has no atomistic or structure‐sensitive basis that explains this outcome. With modern computationally based atomistic and multiscale models, there is increasing promise of defining the pressure and rate‐dependent parameters that will allow a fundamental understanding of the Mohs scale. This study principally addresses the combined fracture and plasticity parameters that qualitatively affect fracture at the nanoscale. A physical model wherein the crack tip under a scratch is shielded by dislocations is supported by molecular dynamics (MD) simulations in both ductile aluminum and brittle silicon carbide. Next, this model is applied to nanoindentation data from the literature to produce a ranking of Mohs minerals based on their fundamental properties. As such, what is presented here is a first step to address the flow and fracture parameters ultimately required to provide a figure of merit for scratch hardness and thus the Mohs scale.     

水性木器涂料的硬度问题

讨论了硬度的定义、水性木器涂料涂膜硬度的影响因素、硬度与抗划伤性和耐磨性的关系、水性木器涂料硬度的常用测量方法。强调了测量方法本身侧重点的不同造成测试结果的不可比性。对水性木器涂料硬度的要求应该根据涂料的实际用途而定,不必过分追求高硬度。     

Hardness of polycrystalline SiO2 coesite

We measured elastic moduli and hardness of polycrystalline SiO₂ coesite. Translucent polycrystalline bulk coesite with a grain size of about 10 micrometers was fabricated at 8 GPa and 1600°C using a Kawai-type multianvil apparatus. The obtained bulk and shear moduli are 94(1) and 60.2(3) GPa, respectively. The resulting Vickers and Knoop hardness values are 10.9(7) and 9.6(4) GPa, respectively, at an indentation load of 4.9 N. Coesite is as hard as other fourfold coordinated silica materials such as quartz and densified silica glasses. The hardness values of coesite and the fourfold coordinated silica materials are about one-third of those of sixfold coordinated silica materials, stishovite, and seifertite, which are the hardest known oxides.