氧化酸性铬兰K褪色光度法测定痕量锰

MnO_4~-对酸性铬兰K有褪色作用,本文借此进行吸光光度法测定锰的研究。实验表明,在0.72—1.15mol·L~(-1)H_2SO_4介质中,有色溶液的最大吸收波长为524nm,锰量在0—40ug/25ml范围同有色溶液吸光度的减少值成线性关系。方法简单,快速,选择性好,灵敏度比高锰酸盐法高近10倍,用于测定地质矿样中的痕量锰时,结果满意。     

Scouring erosion resistance of metallic materials used in slurry pump service

Low impact angle erosion resistance is a critical requirement of materials used in pumps, piping, valves, nozzles, cyclones and other components which transport and process most mineral slurries.The Coriolis method offers a suitable technique for assessing behavior under such scouring attack conditions. It is being used increasingly in support of the mining/mineral processing industry, to compare and discriminate between candidate materials and also assist in the development of new products and protection systems. The specific method used in the current study involves high velocity erosion with aqueous slurry containing 10 wt.% of AFS 50-70 silica test sand. This compares reasonably with the main, extremely abrasive solids constituent encountered in mining and processing oil sands deposits in northern Alberta, Canada. These are becoming a rapidly growing and critically important source of oil in North America.Abrasion resistant chrome white iron castings typically covered by the ASTM A532 standard, are used widely in slurry pump components particularly in oil sand operations. However, the development of proprietary cast hypereutectic chromium white irons with microstructures containing primary M₇C₃-type carbides, is providing the capability to significantly improve the wear performance of such parts. In certain applications where corrosion contributes significantly to overall attack, lower carbon and higher chromium-bearing variants are employed.A comparison of the Coriolis erosion behavior of a wide range of commercially available cast wear and corrosion resistant and high toughness alloys used in pump manufacture, has confirmed anticipated performance ranking and the superiority of the latest generation of hypereutectic chrome white irons. The ameliorative influence on scouring erosion behavior of high carbon content, hardness and carbide volume fraction and particularly of fine carbide size has been demonstrated. A correlation is drawn between test data and service performance.     

狭缝式铬刚玉透气砖的研制及应用

把以电熔刚玉、氧化铬为主要原料制成的低水泥振动成型座砖,经机压成型的铬刚玉套砖、铬刚玉造气板,和以电熔刚玉为主要原料制成的弥散型刚玉透气塞、钢套等组合在一起,制成狭缝式铬刚玉透气砖。经使用该砖达到进口透气砖的水平。     

煤灰渣在Cr2O3-Al2O3-ZrO2砖表面润湿与渗入行为的研究

将灰分(w)为6.81%,挥发分(w)为32.68%的煤制成煤灰后,压成圆柱形的煤灰柱放在Cr2O3(w)含量约为90%的Cr2O3-Al2O3-ZrO2砖上,再推入管式加热炉中,在Ar气氛下,通过升温试验(升温至1200℃)和保温试验(升温至1165℃保温20min),考察了煤灰渣在Cr2O3-Al2O3-ZrO2砖表面的润湿与渗入行为。结果表明无论是升温试验还是保温试验,煤灰柱的变化过程完全一致,都经历了变形、熔融和润湿等一系列的变化。对升温试验过程中煤灰柱变化的观察和照片的处理结果均表明煤灰柱在1100℃时局部凹进去形成不规则形状;在1165℃时煤灰完全熔化,煤灰柱变成半球形;在1180℃时接触角<90°,煤灰渣开始在Cr2O3-Al2O3-ZrO2砖表面发生润湿。对升温试验后的Cr2O3-Al2O3-ZrO2砖表面和渣表面的化学组成分析表明有大量Fe堆积在煤灰渣与Cr2O3-Al2O3-ZrO2砖表面接触处,而邻近处几乎没有发现Fe,可能是由于Fe与Cr2O3-Al2O3-ZrO2砖中的一些组分形成了某种晶相,使得Fe很难进入Cr2O3-Al2O3-ZrO2砖;接近煤灰渣的Cr2O3-Al2O3-ZrO2砖表面组成中出现了Ca,说明熔融灰渣中的Ca渗入Cr2O3-Al2O3-ZrO2砖;同时,煤灰渣中出现了Cr,表明在熔融灰渣渗入Cr2O3-Al2O3-ZrO2砖的同时,砖中的Cr也熔入了熔渣中。     

30CrMnSi镀铬后激光表面合金化

为研究激光表面合金化工艺对镀铬后30CrMnSi组织与硬度的影响,以CO2激光器为热源,采用正交试验法,对其表面进行单道扫描,获得了金相组织和显微硬度均优于基体的合金化层.研究结果表明:激光合金化层晶粒显著细化,平均硬度明显高于基体硬度.激光功率500W,扫描速度10mm/s,保护气体流量10L/min时,合金化层组织细小均匀致密,最高硬度达829HV,约是基体硬度的2.6倍.     

Problems in laser repair-welding a surface-treated tool steel

A research work is described on the development of defects in laser repair welding of a surface-treated tool steel. Repair welding tests were carried out on plasma-nitrided and on chrome-plated type 1.2738 steel plates. Welding defects in the chrome-plated samples were mainly due to chrome and oxygen overalloying of the weld metal, leading to extensive hot cracking. Cracks of the surface chrome deposit in the HAZ due to welding stresses were also detected. In the nitrided samples, welding resulted in the copious formation of gas pores due to nitrogen release during weld metal solidification. A procedure for combined laser pre-treating and laser welding of the nitrided samples was thus presented. The procedure is aimed at minimising the negative effect of the laser beam on the structural integrity of the base and welded material. The results of the microstructural analyses revealed that a significant reduction in defects could be achieved by the proposed method in the nitrided samples.     

铬天青-S分光光度法测定钛合金中铝的分析

以甘露醇作为钛掩蔽剂,用铬天青-S作为显色剂测定钛合金中铝的方法,成功解决了传统分析中须沉淀分离来消除干扰的问题,简化分析手续,缩短分析时间,测定结果准确。     

浏览器的争夺战

有这么一句话很多人都知道:未来的一切都是WEB的。对操作系统的作用越来越被测览器所淡化,以后的趋势就是人们只要一个测览器能上网就可以了,所有一切都是在网上进行。所以这Web之争实际上就是浏览器之争,谁能夺得浏览器市场谁就能在未来的Web世界占绝对的优势。     

铬天青S分光光度法测定钼精矿中的铝

在乙酸缓冲溶液中，铝与铬天青Ｓ生成稳定的紫红色络合物，在５４５ｎｍ处，铝在０￣５０μｍＬ符合比耳定律，回收纺在９８％￣１０４％之间，本法对钼精矿中铝的测定达到了满意的结果。     

铬渣和含铬废水的处理综述

叙述了铬渣和含铬废水对人类健康和环境的各种危害性 ,列举了铬渣和含铬废水的各种治理方法 ,并为工程设计和生产工艺提出了一些有益的建议。