铜泥的综合利用

在合成氨生产工艺中,广泛采用醋酸铜氨溶液(简称铜液)来洗脱净化原料气中的CO、CO2等有害成份.由于前工序脱硫不净常把少量H2S等无机硫和有机硫带入铜洗系统,导致铜液产生Cu2(OH)2CO3、油污和少量金属铜渣等杂质沉淀,这些下脚废料俗称铜泥.铜泥的产生是合成氨铜耗的主要原因,中、小氮肥厂的铜耗在0.3～0.8Kg(Cu)/t(NH3)之间,估计全国氮肥行业每年消耗的电解金属铜约6000吨至10000吨,产生的可回收铜泥在5千吨以上.我国是世界上铜资源不丰的国家,每年需大量进口金属铜及铜盐产品,随着国民经济的持续发展,社会对铜产品的需求量日趋增加.因此,开展铜泥的回收利用是有利可图的,不仅解决了铜泥资源的浪费和污染环境问题,而且为市场提供了急需的铜盐产品. 铜泥的回收利用技术中,具有适用性和显著经济效益的有下述两种方法.     

钙基固定剂对制氢和污染性气体减排的影响

在未来相当长的一段时间内,煤气化仍是大规模制取氢气的主要途径。目前,常规煤气化过程得到的是H2、CO和CO2为主的混合气,需要通过净化、变换和分离工艺才能得到洁净的氢气,工艺过程复杂。采用连续式超临界水反应装置,以质量分数为20%的水煤浆为反应原料,考察了Ca/C摩尔比和温度对褐煤制氢系统的影响。试验结果表明：Ca（OH）2不仅可以很好地固定气相中的CO2和硫化物,而且对煤气化过程也表现出较好的催化作用。反应温度600℃,压力为25MPa的条件下,与未加Ca（OH）2相比,Ca/C摩尔比为0.45时,气体中CO2的体积分数由50.7%降至1.0%,趋于完全固定;硫化物浓度由10 878mg/m3降至807mg/m3;H2的体积分数由32.4%增至73.3%。Ca（OH）2对煤气化的催化作用在高温下更加明显。     

高温烧结磷石膏钙渣制备轻质碳酸钙

以磷石膏钙渣为原料,通过高温煅烧,然后经消化、精制、碳化,制成轻质碳酸钙产品.研究结果表明:高温煅烧的最佳温度为 1 000 ℃,最佳煅烧时间为 1.0 h;沉淀反应的初始反应温度为 60 ℃,Ca(OH)2乳液质量浓度为 70 g/L,CO2流量为 1.8 L/h.制备的轻质碳酸钙产品各项指标均达到 HG/T2226...     

高Ca~(2+)浓度CO_2沉淀法由电石渣制备纳米CaCO_3

以NH4Cl溶液为浸取剂、CO2为碳化剂、多聚磷酸钠(STP)为添加剂,由电石渣制备纳米Ca CO3。实验结果表明:电石渣浸取液Ca2+浓度为1.0 mol/L、STP加入量为3.00%时,可制备出粒径为30~60 nm的纳米Ca CO3;STP可有效控制纳米Ca CO3的粒度和形貌;在最佳工艺条件下,由电石渣制备纳米Ca CO3的产率为80%,处理1 t电石渣产生的经济效益约为2 670元。     

氮掺杂活性炭催化湿式氧化—Ca(OH)_2沉淀工艺去除草甘膦废水中的磷

用30%(w)H_2O_2溶液氧化处理活性炭(AC),再以三聚氰胺为含氮前驱体经高温处理制得氮掺杂AC催化剂。采用催化湿式氧化(CWO)法去除草甘膦废水中的有机磷(OP),将其彻底氧化降解为PO_4~(3-),再利用Ca(OH)_2沉淀法去除总磷(TP)。表征结果显示:氮掺杂改性可在AC表面形成多种含氮碱性官能团,从而提高其对OP的催化氧化活性。实验结果表明:在温和的工艺条件下(130℃,1 MPa),该催化剂对不同来源废水的OP去除率均高于90%;当m(Ca(OH)_2)∶m(TP)为20时,Ca(OH)_2沉淀可有效去除CWO出水中的TP,最终出水TP质量浓度小于5 mg/L,可有效缓解后续生化系统除磷的压力。     

Ca(OH)2、高岭土与FeCl3组配处理含Pb2+废水

采用Ca（OH）2、高岭土与FeCl3组配处理含Pb^2＋废水。考察了Ca（OH）2加入量、高岭土加入量、FeCl3加入量、废水pH、搅拌转速、沉淀时间等因素对Pb^2＋去除率的影响。在Ca（OH）2加入量50mg／L、高岭土加入量90mg／L、FeCl3加入量13．2mg／L、废水pH7．0～8．0、搅拌转速170r／min、沉淀时间90min的条件下,该法可将废水中金属离子（包括Pb^2＋及少量的Zn^2＋,Cu^2＋,Cr^3＋,Ni^2＋）的质量浓度由42．4mg／L降至1．0mg／L以下,达到了GB18918--2002〈《城镇污水处理厂污染物排放标准》。     

氟化工废水处理技术

六氟丙烯高浓度氟盐废水,采用20%左右的Ca(OH)2乳液沉淀除F-、CO32-,回收KOH溶液,回用于生产中,达到废水零排放.生产中的浓缩装置废水、悬浮聚合物废水、PTFE净化R22废水和分散聚合4股含氟有机废水经混合后,采用石灰沉淀、铝盐絮凝除氟-生物接触氧化处理工艺,处理出水F-小于10 mg/L,COD小于l50 mg/L,BOD5小于30 mg/L,达到了规定的排放标准.     

磷酸铵镁沉淀法处理氨氮废水及沉淀剂的回用

用磷酸铵镁沉淀法处理氨氮废水,在pH为8．5、反应时间为20min、n（PO4^3-）：n（Mg^2＋）：n（NH4^＋）：1．2：1．1：1的最佳条件下,氨氮去除率为97．6％。采用加入足量饱和Ca（OH）2溶液的方法,可使上层清液中多余的Mg^2＋与PO4^3-形成Mg（OH）2和Ca3（PO4）2沉淀,离心后再用浓硫酸溶解,可达到回用的目的,而处理后上层清液中剩余磷酸盐质量浓度低于1mg／L,达到GB8978-1996《污水综合排放标准》中第二类污染物国家二级排放标准的要求。所得MgNH4PO4沉淀用加热碱溶方法回用,MgNH4PO4沉淀的回用次数小于6时,氨氮去除率在80％左右;所得MgNH4PO4沉淀用加酸溶解方法回用,氨氮去除率最高为35％。     

提高三甲氧基苯甲醛医药中间体废水可生化性的研究

分别采用混凝、化学氧化和加Ca(OH)_2曝气的方法对三甲氧基苯甲醛(TMBA)生产废水进行处理。实验结果表明:混凝和化学氧化的方法未能明显改善TMBA废水的可生化性,而加Ca(OH)_2曝气的方法能明显改善TMBA废水的可生化性;当TMBA废水中Ca(OH)_2的质量浓度为20 g/L、曝气时间为3.0 h时,废水的COD去除率为35%,色度去除率达到90%,BOD_5/COD提高到0.35。     

钙类化合物固硫作用动力学分析

通过钙类化合物对动力用煤固硫作用的模拟试验 ,对不同钙化合物固硫率 (J)与Ca/S及助剂关系的研究 ,得到了钙类化合物固硫率的次序 ,即 :JNaOH +CaO>JCaCO3>JCaO>JCa(OH) 2 ,结果说明固硫率与钙类化合物的存在形式有关 ,并解释了其固硫作用机理     

Determination of the Thermal Efficiency of Pre-boilover Burning of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed is calculated by a simple expression derived from a one-dimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in situ burning as a counter-measure to an oil-spill. The total heat release, as a function of the pool diameter, is obtained from an existing correlation. It is assumed that radiative heat is absorbed close to the fuel surface, that conduction is the dominant mode of heat transfer in the liquid phase and that the fuel boiling temperature remains constant. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). The effect of weathering on the burning rate decreases with the weathering period and that emulsification results in a linear decrease of the burning rate with water content.     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.     

富拉尔基发电总厂200MW机组除尘器改造

对富拉尔基发电总厂5号炉的设计条件进行了分析，针对燃用低硫煤，飞灰比电阻高，场地较小，除尘效率要求高的情况，在电除尘器的设计上采取有效措施，达到了排放要求。     

Review of the kinetics of alkaline degradation of cellulose in view of its relevance for safety assessment of radioactive waste repositories

The degradation of cellulose (a substantial component of low- and intermediate-level radioactive waste) under alkaline conditions occurs via two main processes: a peeling-off reaction and a basecatalyzed cleavage of glycosidic bonds (hydrolysis). Both processes show pseudo-first-order kinetics. At ambient temperature, the peeling-off process is the dominant degradation mechanism, resulting in the formation of mainly isosaccharinic acid. The degradation depends strongly on the degree of polymerization (DP) and on the number of reducing end groups present in cellulose. Beyond pH 12.5, the OH^- concentration has only a minor effect on the degradation rate. It was estimated that under repository conditions (alkaline environment, pH 13.3-12.5) about 10% of the cellulosic materials (average DP = 1000-2000) will degrade in the first stage (up to 10⁵ years) by the peeling-off reaction and will cause an ingrowth of isosaccharinic acid in the interstitial cement pore water. In the second stage (10⁵-10⁶ years), alkaline hydrolysis will control the further degradation of the cellulose. The potential role of microorganisms in the degradation of cellulose under alkaline conditions could not be evaluated. Proper assessment of the effect of cellulose degradation on the mobilization of radionuclides basically requires knowing the concentration of isosaccharinic acid in the pore water. This concentration, however, depends on several factors such as the stability of ISA under alkaline conditions, sorption of ISA on cement, formation of sparingly soluble ISA-salts, etc. A discussion of all the relevant processes involved, however, is far beyond the scope of the presented overview.     

Study of Aging Characteristics of Ternary Blends of Polyethylenes—II

Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.     

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated. The adsorbents that gave the highest metal removal efficiencies were peat A, a mixture of peat B and carbon-containing ash, and a mixture of peat A and blue. At an initial concentration of 5 mg/l for each metal, the removal of each species of metal ion from spiked water and spiked leachate solutions was very good (>90%) and good (>75%), respectively. When the initial concentration of each metal in the solutions was twenty times higher (100 mg/l), there was a noticeable decrease in the removal efficiency of Cu²⁺, Cd²⁺, and Ni²⁺, but not of Pb²⁺. Langmuir monolayer adsorption capacities, q_m, on peat A were found to be 0.57, 0.37, and 0.36 mmol/g for Pb²⁺, Cd²⁺, and Ni²⁺, respectively. The order of metal adsorption capacity on peat A was the same in the case of competitive multimetal adsorption conditions as it was for single-element adsorption, namely Pb²⁺ > Cd²⁺ ≥ Ni²⁺. The results show that peat alone (an inexpensive adsorbent) is a good adsorbent for heavy metal ions.     

袋式除尘器气流分布数值计算研究

采用结构化/非结构化混合网格技术、多孔介质模型及k-ε两方程湍流模型,对某袋式除尘器及进出口管道内的气体流场进行了数值计算.计算结果表明,合理布置导流板后,袋式除尘器两箱体流量偏差为1.8％;除尘器下游滤袋单元处理气量偏大,中游滤袋单元处理气量较小,最大流量与最小流量偏差为22.3％;靠近除尘器进口处灰斗内存在气流回流特性,易造成粉尘的二次附着现象.     

Kinetics of Hydrolytic Degradation of PLA

The chemical recycling of poly(lactic acid) (PLA) to its monomer is crucial to reduce both the consumption of renewable resources for the monomer synthesis and the environmental impact related to its production and disposal. In particular, the production of lactic acid from PLA wastes, rather than from virgin raw materials, it is also possible to achieve considerable primary energy savings. The focus of this work is to analyse deeply the PLA hydrolytic decomposition by means of a kinetic model based on two reactions mechanism. To this end, new experimental data have been gathered in order to investigate a wider temperature range (from 140 to 180 °C) and to extend the water/PLA ratio up to 50 % of PLA by weight. The reported results clearly highlight that more than 95 % of PLA is hydrolyzed to water-soluble lactic acid within 120 min, when it is hydrolyzed within 160–180 °C. Furthermore, the kinetic constant is highly influenced by reaction temperature. The proposed “two reactions” kinetic mechanism complies satisfactorily with the experimental data under analysis.     

Determination of the Burning Characteristics of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed is characterized by three distinct processes, ignition, flame spread and burning rate. Although all three processes are important, ignition and burning rate are critical. The former, because it defines the potential to burn and the latter because of the inherent possibility of boilover. Burning rate is calculated by a simple expression derived from a one-dimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in situ burning as a counter-measure to an oil spill. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). Ignition has been studied to provide a tool that will serve to assess a fuels ease to ignite under conditions that are representative of oil spills. Two different techniques are used, piloted ignition when the fuel is exposed to a radiant heat flux and flash point as measured by the ASTM D56 Tag Closed Cup Test. Two different crude oils were used for these experiments, ANS and Cook Inlet. Crude oils were tested in their natural state and at different levels of weathering, showing that piloted ignition and flash point are strong functions of weathering level.     

废旧冰箱塑料回收再生利用技术研究

目前我国的废旧冰箱已进入了一个报废高峰期,且大量废旧冰箱塑料的处理问题已成为当今地球环境保护的热点问题,而我国又是一个人均资源占有量很低的国家,因此,对废旧冰箱塑料进行回收与再生利用则具有极其重要的意义.介绍了废旧冰箱塑料的物理再生利用、化学再生利用、生物降解、能源回收利用的技术和方法.