新型干法生产线热生料脱硫技术改造调试

我公司在生产过程中面临立磨停机以后窑尾废气SO2排放值较高的问题,给生产造成了很大的影响。为了解决这个问题,我公司引入热生料脱硫技术。通过不断优化调试方案,掌握了热生料脱硫技术的应用方法,并且解决了在应用过程中衍生的一系列问题。     

钙处理时机对LF-RH精炼过程Al2O3基夹杂物的影响

为研究LF-RH精炼工艺生产Q690钢时不同钙处理时机下夹杂物特征的变化,开展工业试验对RH精炼前后钙处理炉次取样进行定量分析对比。钙处理后夹杂物中CaO质量分数持续增加,CaS质量分数瞬态增加,夹杂物熔点降低。RH精炼前钙处理炉次中,RH精炼过程夹杂物的成分接近低熔点区,结束时夹杂物数量密度和面积分数分别为15个/mm2和0.01%。RH精炼后钙处理炉次中,RH精炼过程夹杂物依旧为高熔点Al₂O₃-MgO类型,结束时夹杂物数量密度和面积分数分别降至1个/mm2和0.002 5%。RH精炼前钙处理会使RH精炼过程夹杂物熔点以及夹杂物与钢液间的接触角降低,导致夹杂物去除驱动力降低,从而抑制夹杂物的去除。因此LF-RH精炼工艺生产铝脱氧钢时,为提高精炼过程钢中非金属夹杂物的去除效率,应在RH精炼后进行钙处理操作。     

含钼废渣冶炼钼铁的优化试验

利用含钼废料钼酸钙为原料,采用碳还原法冶炼钼铁,通过单因素分析试验及正交试验优化得出最佳的试验条件,钼酸钙加入量应低于10%,熔炼温度为1 525 ℃,保温时间为25 min,碱度为1.3。通过XRD、SEM、EDS分析得出用此方法生产得到的钼铁合金中,钼以Mo₂C、Fe₃Mo以及Fe₃Mo₃C的形式存在,渣系为二元玻璃渣系,具有与普通玻璃相似的成分系统。经测定合金中钼的回收率大于99%,钼资源回收效益可观。     

电弧炉短流程冶炼石油套管钢中夹杂物的演变规律

为研究石油套管钢(34Mn6)中夹杂物的演变规律,对钙处理效果进行精准化控制,进行全流程取样分析,通过采用SEM-EDS分析夹杂物形貌和成分,同时结合Aspex夹杂物自动分析仪统计夹杂物的数量、成分和尺寸分布。研究结果表明,LF精炼具有较好的脱硫与脱氧能力;钙处理前,由于渣钢反应的进行,夹杂物数量明显减少,夹杂物成分中SiO₂含量增加;经过钙处理后,夹杂物成分发生显著变化,由MgO-Al₂O₃系转变为MgO-Al₂O₃-CaO系和SiO₂-Al₂O₃-CaO系,夹杂物形貌由尖角夹杂向球状夹杂过渡。在铸坯中,夹杂物数量减少,其成分已偏离液相区,向富CaO区域移动。对钙处理进行优化,通过利用热力学软件FactSage进行计算,得出钢液中钙的质量分数稳定在0.001 3%时对夹杂物的改性效果最佳,钢液中的夹杂物控制较好。     

水氯镁石和高钙菱镁石制备氢氧化镁

氢氧化镁是一种应用广泛的新型绿色环保材料,如何低成本制备高品质氢氧化镁引起广泛关注。以水氯镁石和高钙菱镁石为原料,采用湿法冶金工艺制取氢氧化镁,探讨反应时间、反应温度、水氯镁石浓度、煅烧后物料的粒度等对氢氧化镁纯度的影响。结果表明,在80℃恒温水浴、反应时间6 h、水氯镁石浓度5%、煅后菱镁石粒度-45μm条件下得到的氢氧化镁沉淀纯度可达94.89%,主要物相为Mg(OH)₂和CaO。     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Li ALLOY WITH Ca ADDITION

Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The billets can be rolled to thin sheets at room temperature, from which it is obvious that the addition of Ca improves alloys ormalin. while it decreases with the excess addition of Ca. The results also show that the ultimate tensile strength （UTS） and yield strength （YS） of the alloy with lwt% Ca may rise by 28% and 25%, respectively, however, the elongation decreases. It is clarified that the adsorption of proper Ca on the grain boundaries refines α-Mg and improves the tensile properties, but the presence of excess Ca and stable Ca2Mg6Zn3phase worsens the elongation.     

环氧脂肪酸钙/锌的直接合成法及其热稳定作用

以一种简便的方法制备了环氧基保留完好的高纯度环氧脂肪酸钙/锌，并对其热稳定性进行了研究。研究表明，环氧脂肪酸钙/锌对聚氯乙烯（PVC）的热稳定作用类似于硬脂酸钙/锌，但其热稳定效能明显优于后者，环氧脂肪酸钙比硬脂酸钙具有较好的初期着色性，环氧脂肪酸锌较硬脂酸锌具有较长的“锌烧”时间。     

绿色溶剂碳酸二甲酯处理含酚废水研究

用绿色溶剂碳酸二甲酯 (DMC)对含酚废水进行了萃取处理 ,研究了时间、pH、溶剂组成、溶剂比等对萃取的影响。实验结果表明 ,DMC萃取苯酚的过程为物理溶解过程 ,因此萃取过程在几分钟之内就能达到平衡 ,而且萃取过程基本不受 pH值的影响。随着平衡水相浓度的增加 ,平衡有机相浓度增加 ,而且分配系数也增加。以 5 0 %DMC 正己烷为萃取剂 ,三级萃取 5g/L的苯酚废水 ,萃残液中的酚浓度降到了 4.82mg/L。     

关于生产精制元明粉的探讨

介绍了以山西运城南风自产芒硝为原料生产精制元明粉的几种工艺,以及国内外精制元明粉的市场及生产状况.精制工艺包括化学除杂法、原料优选法、重结晶法.结果表明,精制元明粉的生产过程实质是一个除杂、提纯过程：对于钙离子含量高的原料,可采用化学除杂法;对于氯离子含量高的原料,可采用氯离子富集法、冷冻法或洗涤法;镁离子较难去除,可采用水硝洗涤、冷冻法.     

The effect of increasing application rate of granular calcium ammonium nitrate on net nitrification in a laboratory study of grassland soils

Soil incubation studies were undertaken in controlled environment cabinets at 15°C to investigate the effect of increasing application rates of calcium ammonium nitrate (CAN) on net nitrification in two grassland soils. Granular CAN was applied to the surface of freshly collected, moist soil, at a rate equivalent to 0, 100, 200, 400, 800 and 1600µg NH ₄ ⁺ -N and NO ₃ ^- -N per gram of oven dry soil. In half the treatments finely ground CaCO₃ was incorporated into the moist soil to raise the starting pH. Changes in soil mineral N and pH were measured at weekly intervals up to six-weeks. The most probable number (MPN) technique was used to enumerate the NH ₄ ⁺ -N and NO ₂ ^- -N oxidizers at the beginning and end of the incubation.At low rates of CAN application there was considerable NH ₄ ⁺ -N oxidation to NO ₃ ^- -N during the incubation of both soils. Lime stimulated this N transformation. At high application rates (i.e. 800 and 1600 ppm) there was little change in NH ₄ ⁺ -N or NO ₃ ^- -N on either soil during the 6 week incubation, in the presence or absence of lime. The rate of NO ₃ ^- -N produced peaked at 5.6 and 3.8 mg NO ₃ ^- -N kg^–1 d^–1 on soil 1 and 2 respectively, in the presence of lime. Above a level of 400 ppm CAN (equivalent to 38 kg N ha^–1) the rate of NO ₃ ^- -N produced decreased. The higher rate of net nitrification in soil 1 compared with soil 2 was probably due to a higher number of nitrifying bacteria. Although high rates of CAN decreased the nitrifying activity of both soils there was little difference between treatments in the actual numbers of NH ₄ ⁺ -N and NO ₂ ^- -N oxidizers determined by the MPN technique.The results showed that the rate of granular CAN applied to the soil surface can influence the local activity of nitrifying bacteria and subsequent N transformations. At application rates of CAN generally used agriculturally for grass production, it is likely that net nitrification of the NH ₄ ⁺ -N in the fertilizer granule will be inhibited.