硫脲法电镀污泥中提金研究

在电镀行业中金是常用的贵金属之一,提高含金污泥金的回收率一直是研究的热门。论文用酸性硫脲从电镀污泥处理后的树脂中回收金,并探讨了该方法的最佳工艺条件。结果显示,在40℃恒温搅拌条件下用FeCl3.6H2O(加入量2 g/L溶液)、硫脲(浓度1.0 g/L)的混合溶液(pH=1.5)浸取12 h,浸金率最高,可达85%。     

无砾石管式地下渗滤系统的改进研究

针对传统无砾石管式地下渗滤系统存在的处理性能差,渗滤通量低两个问题,通过去掉包裹织物,提高渗滤管开孔率、改变开孔方式,设计了无砾石微孔管地下渗滤系统。通过实验研究表明,无砾石微孔管地下渗滤系统对COD、氨氮的去除率比传统管式系统分别提高了10.8%、12.7%,总磷去除率并无显著差异,ORP值提高约85mV,渗滤通量提高26.8%。无砾石微孔管地下渗滤系统和传统管式地下渗滤系统对COD、氨氮在土壤中的降解趋势线存在明显的差异,而对磷的去除过程几乎完全相同。     

自动文摘系统中基于全信息词典的复杂语句分析方法及其实现

本文介绍了智能型自动文摘系统Ladies中汉语复杂语句的化简分析方法——义块组配及其实现.在使用全信息词典对词的语法、语义、语用信息进行全方位描述的基础上,义块组配对复杂句进行语义聚合,将被扩展的各个成分合并成能充分表达语法、语义信息的义块,从而大大简化了语法语义分析过程,为进一步的句子语义、语用分析和篇章理解打下了一个良好的基础.     

Melting characteristics during the vitrification of MSWI fly ash with a pilot-scale diesel oil furnace

Treatment of municipal solid waste incineration (MSWI) fly ash is becoming an important issue in China. A pilot-scale experiment was carried out to treat MSWI fly ash by using a diesel oil furnace (DOF) for more than 6 months. The effects of melting temperature on volume reduction, weight loss, compositional changes, and toxicity of leach water for molten slag have been investigated and reported. Results indicated that the volume reduction fraction of raw fly ash (RFA) and washed-fly ash (WFA) was 75–80% and the weight loss fraction was 23.8–30% at 1260–1350 °C. During the vitrification, CaO, A1₂O₃, and SiO₂ percentages in fly ash increased as the temperature increased, especially for SiO₂, which was caused by both the decomposition of carbonates or sulfates and the volatilization of metal chlorides because the main components in secondary fly ash collected from fabric filter bags were NaCl and KCl. The leaching concentrations of heavy metals in molten slag were lower than the standard values of TCLP. The releasing levels of dioxin and other pollutants (such as SO₂, HCl, CO, NO_x, etc.) in flue gas were all lower than the Chinese standard.     

Hydroceramics,a "new" cementitious waste form material for U.S. defense-type reprocessing waste

A "hydroceramic" (HC) is a concrete which possesses mineralogy similar to the zeolitized rock indigenous to the USA's current "basis" high level radioactive waste (HLW) repository site, Yucca Mountain (YM). It is made by curing a mixture of inorganic waste, calcined clay, vermiculite, Na₂S, NaOH, plus water under hydrothermal conditions. The product differs from conventional Portland cement and/or slag-based concretes ("grouts") in that it is primarily comprised of alkali aluminosilicate "cage minerals" (cancrinites, sodalites, and zeolites)rather than hydrated calcium silicates (C-S-H in cement-chemistry shorthand). Consequently it microencapsulates individual salt molecules thereby rendering them less leachable than they are from conventional grouts. A fundamental difference between the formulations of HCs and radwaste-type glasses is that the latter contain insufficient aluminum to form insoluble minerals with all of the alkali metals in them. This means that the imposition of worst-case "repository failure" (hydrothermal) conditions would cause a substantial fraction of such glasses to alter to water-soluble forms. Since the same conditions tend to reduce the solubility of HC concretes, they constitute a more rugged immobilization sub-system. This paper compares leach characteristics of HCs with those of radwaste-type glasses and points out why hydroceramic solidification makes more sense than vitrification for US defense-type reprocessing waste. Electronic Publication     

Towards proving type safety of .NET CIL

A crucial role in the Microsoft .NET Framework Common Language Runtime (CLR) security model is played by type safety of the Common Intermediate Language (CIL). In this paper, we formally prove type safety of a large subset of CIL. To do so, we begin by specifying the static and dynamic semantics of CIL by providing an abstract interpreter for CIL programs. We then formalize the bytecode verification algorithm, whose job it is to compute a well-typing for a given method. We then prove type safety of well-typed methods, i.e., the execution according to the semantics model of legal and well-typed methods does not lead to any run-time type violations. Finally, to prove CIL’s type safety, we show that the verification algorithm is sound, i.e., the typings it produces are well-typings, and complete, i.e., if a well-typing exists, then the algorithm computes one.     

Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching

The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. ＜38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.     

多金属硫化矿综合回收进展

介绍了近年来多金属硫化矿浮选的进展、浮选工艺和浮选药剂的现状及发展,总结了国内多金属硫化矿混合精矿化学法处理工艺的研究进展。对各种工艺进行了简单介绍和评论,并对其发展趋势进行了展望。     

攀枝花钛铁矿流态化盐酸浸出的动力学研究

本文探讨了攀枝花钛铁矿流态化盐酸漫出过程中金红石生成的机理和浸出动力学,揭示了表观选择浸出的本质,指出了产物层生成后的浸出速度仍然受未反应核界面化学反应控制。     

钛渣制备人造金红石的试验研究

对钛渣制备人造金红石进行了研究,通过在高温下NaOH与钛渣中含硅矿物的反应,破坏对杂质铁形成包裹的硅酸盐,焙砂水浸脱硅后,再经酸浸除铁等杂质,煅烧得到TiO2含量大于92%的高品质人造金红石。通过考察影响因素,确定钛渣制备人造金红石最佳工艺参数。按钛渣中铝、硅含量理论计算的4.5倍摩尔比加入氢氧化钠混匀,在900℃焙烧2 h。焙砂在液固比1∶1、常温下水浸出1 h脱硅;水洗样在液固比4∶1,盐酸浓度18%,浸出温度90℃,浸出时间4 h条件下进行了酸浸除杂;酸浸样在900℃下煅烧1 h制备人造金红石产品。