脲醛呋喃树脂中氮含量的测定

脲醛呋喃树脂中的含氮量,一般采用克氏定氮法,方法繁琐,费时较长,不利于快速分析的要求,本文利用气相色谱法对脲醛呋喃树脂中的氮含量进行分析测定,并建立了测定方法.方法简捷、快速、重现性好,加标回收率在100.8～109.0之间,准确度较高,可很好的满足工业生产中快速分析的要求.     

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。     

A farm level approach to define successful mitigation strategies for GHG emissions from ruminant livestock systems

Ruminant livestock systems are a significant source of greenhouse gases (GHGs). Thus far, mitigation options for GHG emissions mainly focused on a single gas, and are treated as isolated activities. The present paper proposes a framework for a farm level approach for the full accounting of GHG emissions. The methodology accounts for the relevant direct and indirect emissions of methane, nitrous oxide and carbon dioxide, including carbon sequestration. Furthermore, the potential trade-off with ammonia volatilisation and nitrate leaching are taken into account. A ruminant livestock farm is represented with a conceptual model consisting of five pools: animal, manure, soil, crop and feed. The carbon and nitrogen inputs, throughputs and outputs are described, and the direct emissions are related to the carbon and nitrogen flows. The indirect emissions included in the methodology are mainly carbon dioxide emissions from energy use and nitrous oxide emissions related to imported resources and nitrogen losses. The whole farm approach is illustrated with a case of two dairy farms with contrasting livestock density and grassland management. It is shown that the inclusion of carbon sequestration and all indirect emissions have a major impact on the GHG budget of the farm. For one farm, the effect of four mitigation options on the GHG emissions was quantified. It was concluded that a whole farm approach of full accounting contributes to a better insight in the interactions between the carbon and nitrogen flows and the resulting emissions, within and outside the farm boundaries. Consequently, the methodology can be used to develop efficient and effective mitigation strategies.     

Simulation of Fe-Al compounds developed during single superphosphate manufacture

In order to analyse iron phosphate complexes and gel-like phases encountered in the single superphosphate process, experiments were performed with a free-Al, Fe apatite crystal of Durango from Mexico phosphate rock and sulfuric acid. Reaction products were studied by X-ray diffraction and surface analysis methods namely X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that in a free Al, Fe-system, part of the Ca(H₂PO₄ )₂.H₂O (MCPM) forms before precipitation of any CaSO₄(CS) and gel-like phase such H₂SO₄.yH₃PO₄.xH₂O is formed. When iron is added, the precipitation rate of (CS) and (MCPM) increases and Fe₃(H₃O)H₈(PO₄)₆.6H₂O is formed. When Fe and Al are added, a gel-like phase is quickly formed with a molar ratio that changes with time and develops into crystalline compounds. The composition of this gel may be represented as a mixture of two phases: H₂SO₄.yH₃PO₄.xH₂O and a gel containing Al-Fe-Si.     

我国化肥催化剂工业现状

全国48家化肥催化剂制造厂总能力为57Kt/a,产量近30kt/a,设备利用率不到50%。平均万吨氨耗催化剂10.36t,高于国外5.60t水平。现生产31个品种203个型号的催化剂中有103种经部级鉴定,但经常使用的约50种。目前化肥催化剂工业水平与国外相比还存在四方面差距。     

Effect of catalysts in the quality of syngas and by-products obtained by co-gasification of coal and wastes. 1. Tars and nitrogen compounds abatement

The aim of this work is to analyse the possibility of using co-gasification technology to process coal mixed with wastes to take profit of its energy content and at the same time to minimize the environmental impact associated with the use of wastes and to diminish the costs of flue gas treatment. The addition to coal of different types of materials, like: pine based waste, petcoke and polyethylene (PE), was not found to give rise to any operational problems, regarding both the feeding system and gasification process and led to higher energy conversions, however, the gas presented higher tars and hydrocarbons content. Several catalysts were tested, such as, dolomite, olivine, nickel and magnesium oxides, zinc oxides and cobalt and molybdenum oxides. Catalyst action was analysed in tars release and also in ammonia compounds reduction. The presence of catalysts allowed increasing hydrogen release, whilst there was a decrease in hydrocarbons and tars contents. A nickel-magnesium oxide was the catalyst that led to the highest reduction in hydrocarbons and tars. This catalyst also led to the lowest NH₃ content in the fuel gas produced, due to the catalyst efficiency in NH₃ destruction.     

电除尘器出口烟气废热的利用

介绍了采用热管锅炉回收硫酸系统电除尘器出口烟气废热情况，可回收废热生产0．8MPa饱和蒸汽1．0t/h。通过严格控制饱和蒸汽压力、炉气的三氧化硫含量及入炉原料的水分含量，热管锅炉连续运行两年未发生泄漏。运行一年即可收回成本，经济效益显著。     

化肥企业质检机构的管理

针对我国化肥生产企业质检机构的现状 ,结合国家相关政策的要求 ,就如何搞好化肥企业质检机构的管理提出了诸多指导性意见     

Nitrogen fertilizer use in rainfed agriculture

Agronomic efficiency (AE) is defined as the increase in economic yield of a crop per unit fertilizer applied. Components of AE are physiological efficiency and apparent recovery fraction. The latter can be further separated into uptake efficiency and availability index. Ways to increase the nitrogen fertilizer use efficiency in rainfed agriculture through fertilizer management are discussed.     

表土复原的生态利用价值研究——关于巴彦淖尔市生产建设项目表土剥离、保护及利用的探索

表层腐殖层土壤是大自然赐予人类的难以再生的宝贵财富。表土具有较高的经济生产力,属于难以再生的资源,是生态建设的基础。从资源、生态方面考虑,生产建设项目进行表土剥离保护利用十分必要。本文分析了巴彦淖尔市表土剥离存在的主要问题,提出了表土剥离利用主要措施及有关技术要求。