转炉钢渣弱酸体系高效浸出工艺研究

本文以钢铁行业转炉产生的固体废弃物钢渣为试验原料，采用弱酸体系有效浸出Ca、Mg元素，以浸出液为固碳材料对钢铁行业产生的CO₂进行固定，显著减少行业碳排放量。从弱酸体系浸出试验的最佳工艺参数来看，原料粒度大于200目，反应温度为55℃，液固比为5∶1，反应时间为2 h，酸加入倍数为1.2。在该条件下，Ca、Mg、Fe的浸出率分别为85.24%、26.44%、5.83%，实现Ca、Mg元素有效浸出。     

锰矿中氯离子的去除工艺研究

本研究采用水洗和焙烧的方法处理国内某地区的高氯锰矿,直接除去锰矿中的氯离子,主要考察了水洗温度、焙烧温度、焙烧时间等因素对氯的去除效果。研究结果表明,提高水洗温度,可明显提高水洗除氯的效果。焙烧过程中,提高焙烧温度和时间,有利于氯的去除。经液固比为5:1、90℃洗涤后,除氯率可达86.31%。经700℃、4 h焙烧后,除氯率可达65.11%。     

超声波协同酶法提取银杏黄酮的工艺研究

研究了超声波协同酶法提取银杏黄酮的最佳工艺条件,以总黄酮得率为考察指标,研究了加酶量、pH值、液固比、超声波功率、酶解时间和温度等因素对银杏黄酮得率的影响,并在单因素的基础上通过正交试验对提取工艺条件进行了优化。结果表明:最佳提取工艺条件为加酶量1 mg/g,pH值4.5,液固比10∶1(mL/g),超声功率240 W,时间80 min和温度45℃,此时总黄酮的得率为2.78%。     

废铁屑的综合利用途径

在机械加工及制造行业，常产生大量的铁屑。利用这部分铁屑可生产许多化工原料或化学试剂，真正做到变废为宝，减少资源浪费。铁屑上一般含有油污，因此在使用前要除油，如将废铁屑加入到１０％纯碱（碳酸钠）溶液中并加热即可除油。本文仅介绍利用废铁屑生产以下产品。一...     

纤维在含砂压裂液中的悬砂性能评价

向压裂液中加入纤维可以提升压裂过程中压裂液的携砂能力。为研究纤维对压裂液性能的影响,通过室内实验研究纤维在基液中的分散性及其常规理化性能,利用显微镜研究纤维在冻胶型含砂压裂液中的微观结构,利用高温流变仪研究纤维对瓜胶压裂液在常温和高温下流变性的影响。实验结果表明：通过对6种纤维在瓜胶压裂液中的分散性和携砂能力、不同溶液中的溶蚀性筛选出一种固砂纤维;通过对携砂性能评价研究可得,固砂纤维的最佳加量为0.3%;通过电子显微镜观察,纤维的加入能在含砂压裂液中形成网状结构,并将陶粒包裹在结构中;流变仪测试结果表明,在常温25 ℃下,纤维的加入对压裂液的流变性能影响不大,高温100 ℃时,纤维的加入一定程度提高了压裂液在高温条件下的黏度。     

海绵铜常压-加压两段硫酸浸出工艺研究

研究了海绵铜常压-加压两段硫酸浸出工艺。结果表明,海绵铜在室温、液固比6∶1、浸出时间1h的条件下,铜常压浸出率约50%;常压浸出渣在120℃、液固比9.5∶1、浸出时间3 h、氧分压0.4 MPa的条件下,铜加压浸出率99.4%,常压-加压两段总浸出率高达99.7%。     

某硫化镍物料的加压浸出工艺研究

近年来,加压浸出工艺发展日趋成熟,在环境保护和强化金属提取方面展现出明显的优越性。因此,人们可以运用该工艺处理重有色金属硫化矿及难处理金矿。本文采用加压浸出工艺处理某硫化镍物料,考察了浸出液固比、浸出温度、酸度、压力等因素的影响,确定了优化浸出条件,并得到镍、钴的浸出率大于99%。浸出液经后续净化、萃取分离可制得相关硫酸镍产品。     

低品位氧化铜矿酸浸制取海绵铜

根据金堆地区某低品位氧化铜矿的性质,进行海绵铜的制备研究,确定了较佳的工艺参数：颗粒-4mm占85％、浸出剂浓度20％、液固比3：2、搅拌酸浸24h,铜的浸出率为90％以上;当铜浸出液浓度10．0g／L、置换时间16h,置换率大于99％。     

硫化氢脱除镍钴溶液中锌杂质研究

针对镍钴加压浸出液,通过硫化物沉淀溶度积的不同,采用硫化氢对镍钴溶液中的锌、铜进行沉淀,除锌铜率≥80%,镍损失率≤1%,达到选择性除锌的效果。     

钢渣煤矸石制取复合铁铝混凝剂及混凝效果研究

利用钢渣和煤矸石中的金属成分制取复合混凝剂,采用正交试验研究混凝剂的制取及混凝效果的影响因素,包括混酸的加入量,混凝剂的加入量以及pH值。实验处理印染废水,测定CODCr去除率和色度去除率。其正交试验显示：当混酸投加量为15 mL,混凝剂的投加量为15 mL/L-1,pH值为6时,CODCr的去除率可达85%以上,色度去除率可达90%以上。讨论了处理生活污水时pH值和混凝剂投加量对混凝效果的影响。     

Trading Prior to the Disclosure of Material Information: Evidence from Regulation Fair Disclosure Form 8‐Ks*

Regulation Fair Disclosure (Reg FD) Form 8‐K filings provide a venue where managers release information to the market as a whole that they designate as being material. Using this setting, we study trading patterns immediately prior to the public disclosure of material information. We offer three main results. First, using both intraday and daily trading data, we find abnormal trading volume of 21 percent (13 percent) in the hour (day) prior to the public disclosure, respectively. Second, we find that this pre‐disclosure abnormal trading volume is concentrated in firms that are smaller, have more growth opportunities, issue fewer voluntary disclosures, and have weaker external monitoring. Finally, we find that this pre‐disclosure volume is concentrated in subsamples in which the information relates to a firm's material contracts, a firm holds investor/analyst conferences, and there is insider trading activity in a firm's shares. Our results do not concentrate in a small number of firms or industries, and do not appear to be explained by the form through which managers first release the material information (e.g., Form 8‐K, press release, website posting, or social media). Our results are also robust to controlling for the firm's other filings and peer filings that occur around the disclosure. Overall, the trading patterns we document may show that, inconsistent with the spirit of Reg FD, a subset of investors trade on information managers deem material prior to its broad, public release.     

中国股票市场流动性价值研究——双重上市A、B股经验证据

本文首先利用流动性综合测度指标,将证券交易数量、证券流动性水平及证券市场流动性水平引入到证券价格函数中,构建了证券价格差异的流动性模型,从流动性角度探讨证券价格溢价问题,在理论上证明了证券流动性价值的存在性。随后,本文利用A、B股股票实证分析证券流动性价值,实证结果表明,股票流动性水平与股票市场流动性水平可以解释A、B股价格差异,中国股票市场存在流动性价值,流动性价值受股票流动性水平、股票市场流动性水平以及股票交易数量影响。     

活性炭-纳米铁复合材料处理含镍废水研究

为拓展活性炭的资源化利用,以过50目的活性炭作为载体,硫酸亚铁为铁源,采用液相还原法制备活性炭-纳米铁复合材料。用XRD对其进行结构表征,并就其对模拟的含镍废水进行还原去除研究。实验结果表明：m（活性炭）：m（硫酸亚铁）为1：2所制备的活性炭-纳米铁复合材料负载的粒子主要是α—Fe,具有较强的还原性,对含镍废水具有较好的去除作用,可在重金属废水处理中推广使用。     

The Determinants and Consequences of Information Acquisition via EDGAR

Using a novel data set that tracks all web traffic on the SEC's EDGAR servers from 2008 to 2011, we examine the determinants and capital market consequences of investor information acquisition of SEC filings. The average user employs the database very few times per quarter and most users target specific filing types such as periodic accounting reports; a small subset of users employ EDGAR almost daily and access many filings. EDGAR activity is positively related with corporate events (particularly restatements, earnings announcements, and acquisition announcements), poor stock performance, and the strength of a firm's information environment. EDGAR activity is related to, but distinct from, other proxies of investor interest such as trading volume, business press articles, and Google searches. Finally, information acquisition via EDGAR, both to obtain earnings news and to provide context for it, has a positive influence on market efficiency with respect to earnings news. Overall, our results are important because they provide a unique, user‐based perspective on investor access of mandatory disclosures and its impact on price formation.     

蛇纹石尾矿浸出液中金属的萃取分离

采用溶剂萃取法对蛇纹石尾矿酸性浸出液中的金属进行了萃取分离的研究。采用2-乙基己基膦酸单2-乙基己基酯(P507)萃取剂萃取浸出液中的Fe(Ⅲ)、Al(Ⅲ)和Ca(Ⅱ),使其与Ni(Ⅱ)、Mg(Ⅱ)分离,考察了P507浓度、皂化率、浸取液酸度及反萃剂浓度对各金属离子分离的影响,获得了最佳实验条件。之后用环烷酸提取Ni(Ⅱ),使其与Mg(Ⅱ)分离,考察了环烷酸萃取剂浓度、萃取级数、萃取时间及反萃剂浓度、相比和反萃级数对镍提取分离的影响。结果表明在适宜的萃取条件下可实现各金属之间的分离提纯,为蛇纹石尾矿的再利用提供了一条途径。     

Unexpected SEC Resource Constraints and Comment Letter Quality

We investigate whether reviews of transactional filings by the SEC unexpectedly constrain SEC resources, leading to lower quality comment letters for periodic reports. The Sarbanes-Oxley Act requires the SEC to review periodic reports (e.g., 10-Ks) at least once every three years. However, the SEC also reviews transactional filings (e.g., initial public offerings and acquisitions), which are unpredictable and often occur in waves. We find comment letters for periodic reports are of lower quality (in terms of outputs, inputs, and firm responses) during periods of abnormally high transactional filings. We also find that comment letters issued during periods of abnormally high versus low transactional filings are associated with increased information asymmetry and lower earnings response coefficients in the quarter after the resolution of the comment letter. Overall, our results suggest that unexpected resource constraints affect the quality of SEC oversight of periodic reports.     

硫脲法从电镀污泥中提金工艺研究

研究了酸性硫脲溶液从电镀污泥中浸提金的方法.通过考察多种因素对浸金效果的影响,确定了最佳浸提条件:在拟定的浸提条件下浸提4次,可以使电镀污泥中金的浸出率达91.0%.     

铁矾渣和锌精矿混合浸出试验研究

对铁矾渣、锌精矿的混合浸出进行了试验研究.试验结果表明,在180℃,铁矾渣和锌精矿配比为2∶1的条件下,加压浸出4h,锌的浸出率为91.04％,铁的沉淀率为81.33％.基本实现了锌精矿浸出、除铁和铁矾渣处理三重目标.     

WFGD系统对汞的影响分析

利用现有控制技术来协同控制汞污染是一项科学、合理、经济的技术措施。目前普遍认为脱硫系统对脱汞有着较大去除潜力，但脱硫系统对脱汞的影响大小及影响特性有着较大的不确定性，分析了脱硫系统各运行因素对汞的影响特性及汞的二次污染等问题，为科学合理的制定汞排放技术提供参考。     

The Spread of Antidumping Regimes and the Role of Retaliation in Filings

Over the past decade, the worldwide use of antidumping has become very widespread—41 WTO-member countries initiated antidumping cases over the 1995-2003 period. From another perspective, U.S. exporters were subjected to 139 antidumping cases during this period, by enforcement agencies representing 20 countries. In this context, it is natural to consider whether antidumping filings may be motivated as retaliation against similar measures imposed on a country's exporters. This is the focus of our study, though we also control for the bilateral export flows involved and nonretaliatory impacts of past cases, with other motivations—macroeconomic, industry-specific, and political considerations—dealt with through fixed effects. Applying probit analysis to a WTO database on reported filings, we find strong evidence that retaliation was a significant motive in explaining the rise of antidumping filings over the past decade, though interesting differences emerge in the reactions to traditional and new users of antidumping.