电石渣循环制备超细碳酸钙的研究

将电石渣经预处理后溶解于氯化铵溶液中,用碳化法将其制备成超细碳酸钙.探讨了电石渣预处理等工艺对碳酸钙回收率的影响.探索循环式制备碳酸钙的工艺,对反应产生的氨水和氯化铵进行了回收.用扫描电镜和X射线衍射测试了所合成碳酸钙的晶形和性质.结果表明电石渣经干燥处理,溶解于质量分数为5%、过量30%的氯化铵溶液中,碳酸钙的回收率为99.64%.所合成的碳酸钙为针状文石型碳酸钙.     

一种由含铝矿物制备氧化铝的方法

该专利公开了一种由含铝矿物制备氧化铝的方法。该方法包括：细磨、磁选、酸处理、过滤分离、加热脱水分解和回收SO3等步骤。采用该法制得的高纯度氧化铝,经检测完全符合有色金属冶金行业YS／T274-1998《氧化铝》的标准,产品纯度达到99．5％。该方法的优点：物料全部循环利用、工艺流程简单、设备简便,没有固、液、气废弃物的排放,     

聚天冬氨酸的阻垢分散性能

以马来酸酐和铵盐为原料合成聚天冬氨酸,对聚天冬氨酸进行了红外光谱和差热-热重分析表征,并对其阻碳酸钙垢及分散氧化铁的性能做了较系统的研究。结果表明：所得产品的产率均在98．11％以上,并基本具备目标产物聚天冬氨酸的各种官能团;热分解温度为386．3℃;当加入量为4mg/L时,其阻垢率已接近100％;当加入量为30mg/L时,分散氧化铁性能最好,溶液透光率为48．7％。     

一种新型聚合物分散剂的制备及表征

以甲基丙烯酸和丙烯磺酸钠为单体、过硫酸铵溶液为引发剂合成聚合物分散剂（PMS）。最佳合成条件：单体总质量为60g,甲基丙烯酸和丙烯磺酸钠的摩尔比为3．0,过硫酸铵溶液加入量为12g,亚硫酸氢钠加入最为1g,反应温度为75℃。对最佳条件下制得的PMS进行应用实验,当100g陶瓷氧化铝粉末中PMS加入量为0．5g时,浆料的黏度较小,分散效果良好。PMS属于非品态聚合物,热稳定性良好,相对分子质量为2127。     

衣康酸/苯乙烯磺酸共聚物的合成及其阻垢性能研究

以衣康酸(IA)和苯乙烯磺酸(SSA)为原料,合成IA／SSA共聚物阻垢剂,确定的最佳合成条件：反应温度为103℃,反应时间为2h,引发剂用量为7％(占单体总质量),IA：SSA质量比为2．8：1。在此工艺条件下合成的IA／SSA共聚物阻垢剂,其阻碳酸钙垢的阻垢率可达99％。     

三烯丙基异氰脲酸酯合成废渣中氯化钠的回收

采用浸取—抽滤分离—减压蒸发—结晶的方法处理三烯丙基异氰脲酸酯(TAIC)合成废渣,回收其中的氯化钠。通过单因素实验和正交实验探讨了液固比、浸取温度、搅拌时间对氯化钠回收率的影响。实验结果表明,在浸取温度为30℃、搅拌时间为30 min、液固比为15的最佳工艺条件下,氯化钠回收率为81.53%。回收氯化钠产品符合GB/T 5462—2003《工业盐》精制工业盐一级标准。采用本工艺每处理1 t TAIC合成废渣可节约费用3 064元,经济效益显著。     

国内简讯

北京燕山石化公司合成ＹＳＳ - 96高效水稳剂　　马来酸酐及其聚合物因具有优异的热稳定性、阻碳酸钙垢等性能而受到广泛应用 ,但其抑制磷酸钙垢和分散氧化铁的性能较差。北京燕山石化公司研究院以水为溶剂 ,过硫酸铵为引发剂 ,丙烯酸 (ＡＡ)、2 -丙烯酰胺 - 2 -甲基丙磺酸 (ＡＭＰＳ)、马来酸酐 (ＭＡｎ)为原料 ,合成了ＡＡ/ＡＭＰＳ/ＭＡｎ三元共聚物 (ＹＳＳ - 96 )水稳剂。ＹＳＳ - 96水稳剂具有优异的抑制碳酸钙垢、磷酸钙垢、稳定锌盐和分散氧化铁的性能 ,而且具有较好的缓蚀性能。ＹＳＳ - 96与锌盐、有机磷酸盐复配使用 ,具有较好的…     

铝灰在耐火材料中的应用

铝灰是一次和二次铝工业的废弃物,研究利用铝灰提取氧化铝、棕刚玉、合成Sialon、镁铝尖晶石、TiN-AI_2O_3复合材料、莫来石、聚合氯化铝及硫酸铝等耐火材料的重要原材料和结合剂,并使其尽快投入生产,这样既节能环保,又能降低成本,提高经济效益。     

利用电石渣液相法制备纳米碳酸钙

以电石渣为原料、氯化铵溶液为浸取剂、碳酸铵溶液为碳酸化试剂、柠檬酸为晶形控制剂,采用液相法制备了高纯度的纳米级碳酸钙。考察了多种因素对反应的影响,通过X射线衍射仪和扫描电子显微镜对制得的碳酸钙进行表征。确定了最佳的工艺条件：碳酸化过程浸出液Ca^2＋浓度为0．6mol／L,柠檬酸与碳酸钙质量比为0．03,碳酸化反应温度为12℃。制得的碳酸钙粒径为40～60nm,为纯净的方解石型晶型。     

以煤矸石为原料合成Y型沸石

煤矸石中的煤系高岭岩，可用来生产氧化铝、氢氧化铝及硫酸铝、白炭黑等。而以煤矸石为原料制备沸石分子筛，则是一条更经济实用的应用途径，目前已合成A型、X型等沸石。作者以煤矸石为原料，采用导向剂法成功合成Y型沸石。     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Application of Cellulose Microfibrils in Polymer Nanocomposites

Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were added at low concentrations (2–10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young’s modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. Addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch–pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.     

四氮唑废水处理工艺设计

高浓度、高盐分的四氮唑生产废水通过三效蒸发浓缩,馏出液经铁炭氧微电解和混凝预处理,再采用水解酸化一接触氧化一反应二沉主体组合工艺进行处理。研究了该工艺所需构筑物和设备的设计与选型。该工艺在正常运行条件下,处理后出水pH6～9,COD 302mg／L,BOD5 108mg／L,SS30mg／L,色度36倍,水质达到GB8978--1996（污水综合排放标准》三级标准。     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

High Immobilization of NH4+ in Danish Heath Soil Related to Succession,Soil and Nutrients: Implications for Critical Loads of N

During recent decades heathlands havechanged into grasslands in regions with high atmosphericnitrogen deposition. In regions with intermediatedeposition level (e.g., Denmark) changes have been lesspronounced which may be due to delay or decrease inresponse of the ecosystem. The mor layer (O horizon) mayplay an important role for this delay due to high sinkstrength for N. In this study, the capacity for netNH₄ ⁺ immobilization and mineralization wasstudied during short- and long-term incubations (2–36 days)of mor samples from Danish dry inland heaths. High short-term capacity for net NH₄ ⁺ immobilization wasfound to be a general characteristic of Danish heath morlayers both under heather (Calluna vulgaris) andcrowberry (Empetrum nigrum ssp nigrum), the latterdominating late stages in heathland succession. The netNH₄ ⁺ immobilization was higher under youngcompared to old or dead vegetation, and higher on lessnutrient poor soils than on extremely nutrient poor soils.The addition of N, P and C stimulated CO₂ productionand net NH₄ ⁺ immobilization, but not net Nmineralization. The immobilization of ¹⁵NH₄ ⁺caused release of dissolved organic N, increased N anddecreased C/N ratio in the microbial biomass, and indicatedgrowth of microorganisms with other metabolic abilitiesthan the indigenous population. No evidence was obtained ofstabilization of immobilized ¹⁵NH₄ ⁺ intosoil organic matter during the experiment. On background ofthe results and current knowledge it was concluded that therecognition of the high capacity for net NH₄ ⁺immobilization in mor layers does not allow for a raiseof critical loads for N for northern dry inland heaths.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.