内螺纹变截面铜管拉伸工艺的研究

此文提出了内螺纹变截面铜管分段拉仲一次成形新工艺,并就工艺因素对该管拉伸成形的影响进行了试验研究,从而为合理制订成形工艺提供了依据。     

火焰原子吸收分光光度法测定鱼内脏及河流底泥中的铜

采用火焰原子吸收分光光度法测定鱼内脏及河流底泥中的铜。鱼内脏经组织捣碎机捣成匀浆后，加硝酸消解；底泥则经氢氟酸和高氯酸消化。该方法具有灵敏度高，精密度和回收率较好等特点。     

地下水中铜的形成及其与人群健康的关系

利用国家科技攻的成果，并根据国内外的研究现状，论证了地下水中铜元素的形成及其与人群健康的关系。     

铜的快速电解法测定

为适应用废铜制取电解铜时快速测定铜的需要，试验用快速电解法测定电解铜中的铜的方法，采用水浴控制溶样温度，电炉加热驱氮，加大电解电流，缩短电解时间，对不同电解酸度进行了探讨，样品测定结果重现性好，准确性较好。     

交联氨基淀粉的制备及对铜离子的吸附性能

以玉米淀粉为原料，经环氧氯丙烷交联、醚化．合成醚化淀粉3-氯-2-羟基丙烯基交联淀粉。在碱性条件下．醚化淀粉进一步通过胺化反应．制备出对重金属具有较强吸附性能的氨基淀粉。对氨基淀粉的合成工艺及其对铜离子的吸附性能的实验结果表明：随着pH的增加．吸附量增加：在相同pH时，随着溶液中铜离子初始浓度的增加，吸附量增加，但吸附速率降低：铜在固液相中的分配比降低。     

水中微量铝的间接原子吸收法测定

在ＨＡｃ－ＮａＡｃ缓冲溶液（ｐＨ４．５）体系中，利用（１－（２－萘酚（ＰＡＮ），Ａｌ＾３＾＋与Ｃｕ＾２＾＋－ＥＤＴＡ发生定量交换反应，用氯仿萃取出Ｃｕ＾２＾＋－ＰＡＮ，用原子吸收法测定水中的Ｃｕ＾２＾＋，以间接测定ＡＬ＾３＾＋。方法的最佳线性范围为０．１－１．０ｍｇ／Ｌ，最低检出浓度为０．１ｍｇ／Ｌ；测定河水，饮用水，地下水中的Ａｌ＾３＾＋，其回收率在８５．０％－１０９％之间，变异系数为１．５％－     

Production of hydrogen by steam gasification of dehydrochlorinated poly(vinyl chloride) or activated carbon in the presence of various alkali compounds

Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of various alkali compounds at 3.0 MPa and 560°C–660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen and steam. Hydrogen and sodium carbonate were the main products, and methane and carbon dioxide were the minor products. Yields of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds on the gasification reaction was as follows: KOH > NaOH > Ca(OH)₂ > Na₂CO₃. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However, the rate became saturated at a molar ratio of NaOH/C greater than 2.0.     

The composition and environmental hazard of copper slags in the context of the Basel Convention

A recent comprehensive review of the characteristics and utilization of copper slags encourages (properly) several applications for this important pyrometallurgical byproduct. However, the review does not include possible environmental effects from these slags. The United Nations Basel Convention on the Transboundary Movement of Hazardous Wastes and Their Disposal characterizes copper compounds that exhibit specified hazard characteristics as hazardous wastes. In 1996, the Convention considered further characterization of these and other compounds and substances. The final characterization of copper slags is as non-hazardous, i.e., exempt from control. This decision was based in part (if not largely) on the data that are presented here. Literature reports were used to accumulate data describing the chemical composition and acid leaching of commercial copper slags from three countries. From these data, average values of chemical composition and their statistical confidence limits (95%) were calculated. The variability of the chemical analyses of three commercial slags produced over 19 or 20 months were statistically analyzed and shown to be small. The concentrations of toxic heavy metals in the slags are low and the frequency distributions of the values are narrow. Most of the data are normally distributed, validating the use of the statistics used and permitting predictions of likely values. The amounts of heavy metals extracted by an aggressive standard acid leach procedure are low and well below the United States. regulatory levels derived from drinking water standards. The results for total composition and leaching illustrate why the U.S. Environmental Protection Agency made a regulatory determination that such slags are not hazardous wastes. Later, in 1996, the Basel Convention Technical Working Group concurred and the Parties to the Convention adopted their recommendation.     

Simultaneous removal of Cu(II) and Cr(VI) by Mg–Al–Cl layered double hydroxide and mechanism insight

Mg–Al–Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20 mg/L) and Cr(VI) (40 mg/L) were completely removed within 30 min by Cl-LDH in a dosage of 2.0 g/L; the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200 mg/L) and Cr(VI) (400 mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg²⁺ and Al³⁺ in relevant solutions were monitored. To get the underlying mechanism, the Cl-LDH samples before and after adsorption were thoroughly characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On the basis of these analyses, a possible mechanism was proposed. The coadsorption process involves anion exchange of Cr(VI) with Cl⁻ in Cl-LDH interlayer, isomorphic substitution of Mg²⁺ with Cu²⁺, formation of Cu₂Cl(OH)₃ precipitation, and the adsorption of Cr(VI) by Cu₂Cl(OH)₃. This work provides a new insight into simultaneous removal of heavy metal cations and anions from wastewater by Cl-LDH.     

Supercritical water oxidation of polyvinyl alcohol and desizing wastewater：Influence of NaOH on the organic decomposition

Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate (98.25%) based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously.