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长治地区煤炭灰分含量与煤灰成分关系研究 预览
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作者 郭亮 《山西化工》 2019年第3期93-94,99共3页
煤炭灰成分中的硅铝比是煤气化技术评价煤质的一项重要参数。通过对长治地区原煤和精煤的跟踪分析,发现了灰分和硅铝比成一定的线性关系,依据灰分对煤质的硅铝比有一定的预判,减少了测定硅铝比的频次,降低了分析成本,对于实际工作具有... 煤炭灰成分中的硅铝比是煤气化技术评价煤质的一项重要参数。通过对长治地区原煤和精煤的跟踪分析,发现了灰分和硅铝比成一定的线性关系,依据灰分对煤质的硅铝比有一定的预判,减少了测定硅铝比的频次,降低了分析成本,对于实际工作具有指导意义。 展开更多
关键词 灰分 煤灰成分 硅铝比 煤质
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粉煤灰易溶盐浸出液制取条件的分析和确定 预览
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作者 白新春 曾平 +2 位作者 杨雪玲 王继华 朱小丹 《电力勘测设计》 2019年第3期7-9,15共4页
在采集全国火力发电厂灰场中的粉煤灰试样的基础上,分析了粉煤灰易溶盐析出离子中的主要离子占比,以及对建筑材料存在腐蚀性的主要腐蚀介质,对主要离子先后两次开展易溶盐试验,确定了易溶盐浸出液制取条件中的最佳灰水比和震荡时间,为... 在采集全国火力发电厂灰场中的粉煤灰试样的基础上,分析了粉煤灰易溶盐析出离子中的主要离子占比,以及对建筑材料存在腐蚀性的主要腐蚀介质,对主要离子先后两次开展易溶盐试验,确定了易溶盐浸出液制取条件中的最佳灰水比和震荡时间,为测定对建筑材料存在腐蚀性的主要易溶盐指标含量提供了重要的试验依据。 展开更多
关键词 粉煤灰 易溶盐 灰水比 震荡时间
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Linking tree growth rate,damage repair,and susceptibility to a genus-specific pest infestation 预览
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作者 Kayla N.Boyes Kathryn G.Hietala-Henschell +2 位作者 Alexander P.Barton Andrew J.Storer Jordan M.Marshall 《林业研究:英文版》 CAS CSCD 2019年第5期1935-1941,共7页
Pest preference and subsequent susceptibility of a host individual is likely related to previous growth patterns in that host.Emerald ash borer(Agrilus planipennis Fairmaire)is a pestiferous beetle introduced to North... Pest preference and subsequent susceptibility of a host individual is likely related to previous growth patterns in that host.Emerald ash borer(Agrilus planipennis Fairmaire)is a pestiferous beetle introduced to North America from Asia.While all species of ash are susceptible to attack,some individual trees appear to survive infestation.We selected ash trees in southeastern Michigan,collected cores and categorized trees as high tolerance to emerald ash borer attack(high overall health,low crown dieback),low tolerance(low overall health,high crown dieback)and intermediate tolerance(in-between the other categories).We artificially wounded trees and measured wound closure after 3 years.Ring width indices were not correlated between high and low tolerance trees.Regression slopes comparing growth and years were significantly different between the three tolerance categories,with high tolerance trees having the steepest slope.Wound closure was greatest in high tolerance trees.High tolerance trees demonstrating more rapid(steeper regression slope),consistent(lower variance),and effective(greater wound closure)growth.Those vigorously growing trees likely had more capacity to repair damage caused by emerald ash borer,leading to healthier trees in our categorization.Linking previous host growth patterns to health may have implications related to identifying individual trees potentially tolerant to attack. 展开更多
关键词 AGRILUS ASH Dendrochronology EMERALD ASH BORER FRAXINUS Invasive species
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铜冶炼烟灰综合利用技术研究 预览
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作者 易超 《世界有色金属》 2019年第15期7-8,共2页
循环经济是我国21世纪经济发展必然趋势,回收利用生产、生活中产生可再生资源。近年来,金属铜应用领域不断扩大,铜烟灰为目前铜冶炼行业中主要废弃物之一,其中含有铜、铅、锌、铋等多种有价金属,可从烟灰中回收铜、锌、铅、镉、铋,符合... 循环经济是我国21世纪经济发展必然趋势,回收利用生产、生活中产生可再生资源。近年来,金属铜应用领域不断扩大,铜烟灰为目前铜冶炼行业中主要废弃物之一,其中含有铜、铅、锌、铋等多种有价金属,可从烟灰中回收铜、锌、铅、镉、铋,符合我国目前大力推行可用废弃物资源化产业政策,对促进循环经济发展,实现可持续发展具有重要意义。 展开更多
关键词 铜冶炼 烟灰 综合利用 意义 技术
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废线路板冶炼烟灰脱铅渣中金的回收试验研究 预览
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作者 周立杰 刘风华 +3 位作者 邹结富 赵海 贾宁 施建龙 《中国资源综合利用》 2019年第8期1-4,共4页
废线路板熔池熔炼过程中会产生富含贵重金属的烟灰,本文针对经过脱除重金属的脱铅渣,进行了金的回收试验研究。通过优化NaClO3浓度、NaCl浓度、浸出时间、浸出温度和搅拌转速等参数,本研究确定了烟灰脱铅渣中金回收的最佳工艺条件,为废... 废线路板熔池熔炼过程中会产生富含贵重金属的烟灰,本文针对经过脱除重金属的脱铅渣,进行了金的回收试验研究。通过优化NaClO3浓度、NaCl浓度、浸出时间、浸出温度和搅拌转速等参数,本研究确定了烟灰脱铅渣中金回收的最佳工艺条件,为废线路板冶炼烟灰中金的资源再生提供了新的路径。 展开更多
关键词 废线路板 烟灰 氯化法
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基于质量综合评价的积雪草干燥方法筛选研究
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作者 陈翠莎 杨丽飞 +5 位作者 刘莎 李尧尧 任振丽 张福强 聂绪强 吴发明 《中草药》 CAS CSCD 北大核心 2019年第20期4911-4919,共9页
目的探讨不同干燥方式对药材质量的影响,筛选积雪草适宜干燥方法。方法分别采用热风干燥、晒干、晒半干后热风干燥、阴干、微波以及真空干燥对积雪草全草鲜品进行干燥加工,并测定干燥时间和折干率;参考药典方法对积雪草药材性状特征、... 目的探讨不同干燥方式对药材质量的影响,筛选积雪草适宜干燥方法。方法分别采用热风干燥、晒干、晒半干后热风干燥、阴干、微波以及真空干燥对积雪草全草鲜品进行干燥加工,并测定干燥时间和折干率;参考药典方法对积雪草药材性状特征、鉴别、检查、浸出物含量进行分析;采用HPLC法测定样品中积雪草苷、羟基积雪草苷、积雪草酸、羟基积雪草酸、山柰酚-3-O-芸香糖苷、山柰酚和槲皮素的含量;并采用加权评分法进行多指标综合评价排序。结果不同干燥方法耗时差异大,其中晒干、阴干和50℃真空干燥超过100 h,微波干燥低至1.5 h;折干率均值为24.83%;不同干燥方法对药材性状影响主要反映在色泽和气味,其中50~70℃热风干燥色泽较佳,为浅绿色,80、85℃热风干燥和微波干燥气味也发生了显著变化;水分和灰分含量虽有一定差异,但均符合药典标准;干燥方法对浸出物也有一定影响,晒干方式的浸出物含量达到最大,为45.70%,阴干方式的浸出物含量最小,为29.67%;HPLC法测定的7个有效成分含量总和最高的是较为温和的干燥方式阴干,为83.032 mg/g,最低的为75℃热风干燥,为40.982 mg/g;羟基积雪草苷和积雪草苷总和含量最高的为80℃热风干燥,最低的为75℃热风干燥;加权评分排在前3位的分别为70℃热风干燥、晒半干后50℃热风干燥、50℃热风干燥,85℃热风干燥排在末位。结论积雪草产地的适宜干燥方法为70℃热风干燥。 展开更多
关键词 积雪草 干燥方法 积雪草苷 羟基积雪草苷 加权评分 质量综合评价 折干率 HPLC 积雪草酸 羟基积雪草酸 山柰酚-3-O-芸香糖苷 山柰酚 槲皮素 色泽 气味 水分 灰分 晒干 阴干 真空干燥 微波干燥 热风干燥
JR-SA06高效油浆脱灰剂的工业应用 预览
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作者 黄辉明 杨成武 +1 位作者 马庆功 李辉 《石油炼制与化工》 CSCD 北大核心 2019年第11期21-25,共5页
催化裂化油浆中固体催化剂粉末的脱除是当前油浆深加工过程中普遍面临的一个技术难题。为了实现油浆的深度净化,提高油浆的综合利用价值,某公司2.30Mt/a催化裂化装置首次工业应用JR-SA06高效油浆脱灰剂。应用结果表明:在脱灰剂相对外甩... 催化裂化油浆中固体催化剂粉末的脱除是当前油浆深加工过程中普遍面临的一个技术难题。为了实现油浆的深度净化,提高油浆的综合利用价值,某公司2.30Mt/a催化裂化装置首次工业应用JR-SA06高效油浆脱灰剂。应用结果表明:在脱灰剂相对外甩油浆添加量(w)为500μg/g、沉降温度为90~95℃的试验条件下,经过72h沉降后,油浆灰分由0.28%降至0.019%,平均脱灰率达到了93.16%,优于一般脱灰剂,为油浆的后续加工利用创造了良好的条件。 展开更多
关键词 催化裂化 油浆 脱灰剂 灰分 脱除率
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干煤粉气化炉灰渣特性分析及脱水优化改造 预览
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作者 李小超 袁超 《云南化工》 CAS 2019年第5期73-74,共2页
国家能源集团宁夏煤业400万吨/年煤制油项目采用神宁炉干煤粉加压气化技术,全装置共有28台气化炉,装置产生的粗渣、滤饼处理量大且成本较高。通过对气化装置炉渣水分、堆密度、细度进行分析研究,对灰渣脱水进行优化改造,并对其改造效果... 国家能源集团宁夏煤业400万吨/年煤制油项目采用神宁炉干煤粉加压气化技术,全装置共有28台气化炉,装置产生的粗渣、滤饼处理量大且成本较高。通过对气化装置炉渣水分、堆密度、细度进行分析研究,对灰渣脱水进行优化改造,并对其改造效果进行评价,对减少环境污染,提高水资源回用,以及为后续其他装置渣脱水提供技术支持和经验。 展开更多
关键词 干煤粉气化 灰渣 脱水 改造优化
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芊玖舒胶囊的吸湿稳定性研究
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作者 吴琼 梁茜 +2 位作者 江帆 骆衡 安崇惠 《华西药学杂志》 CAS CSCD 2019年第2期203-206,共4页
目的为提高芊玖舒胶囊在大生产中的吸湿稳定性,优化浸膏干燥技术及颗粒制备参数。方法采用浸膏预混辅料新技术,以95%乙醇作为润湿剂制粒,以水分、葛根素、总黄酮、灰分、崩解时限、性状等为主要考察指标,考察产品的影响因素、加速稳定... 目的为提高芊玖舒胶囊在大生产中的吸湿稳定性,优化浸膏干燥技术及颗粒制备参数。方法采用浸膏预混辅料新技术,以95%乙醇作为润湿剂制粒,以水分、葛根素、总黄酮、灰分、崩解时限、性状等为主要考察指标,考察产品的影响因素、加速稳定性及长期稳定性。结果颗粒剂流动性改善良好,休止角达到33.3度,相对临界湿度为80.2%,高湿环境是影响稳定性的重要因素;3批产品加速、长期稳定性符合规定。结论大生产工艺中采用浸膏预混淀粉干燥分散新技术及95%乙醇制粒工艺能有效提高产品吸湿的稳定性,可为药物制剂工艺在保健食品大生产中的应用提供参考。 展开更多
关键词 芊玖舒胶囊 制粒方法 吸湿性 稳定性 葛根素 总黄酮 水分 灰分
Determination of Moisture, Ash, Extract Content and TLC identification of Tibetan Medicinal Material Dracocephalum tanguticum Maxim. 预览
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作者 Pei QUN Risha WEIZE +3 位作者 Zhe LIU Haiyan XIANG Yunzhang XU Yuan LIU 《药用植物研究(英文版)》 2019年第4期51-53,59共4页
[Objectives] The moisture, ash and extract content of Dracocephalum tanguticum Maxim. were measured.[Methods] The moisture, total ash, acid-insoluble ash and extract content of D. tanguticum Maxim collected from 16 pr... [Objectives] The moisture, ash and extract content of Dracocephalum tanguticum Maxim. were measured.[Methods] The moisture, total ash, acid-insoluble ash and extract content of D. tanguticum Maxim collected from 16 producing areas were detected by using the methods in Chinese Pharmacopoeia (2015 edition, volume I), and D. tanguticum Maxim. was identified by thin layer chromatography in Chinese Pharmacopoeia (2015 edition, volume I).[Results] The moisture content of D. tanguticum Maxim collected from 16 producing areas ranged from 8.68% to 10.36%, averaging 9.28%. The content of total ash was between 7.21% and 11.60%, averaging 9.89%. The content of acid-insoluble ash was 0.21%-2.71%, averaging 1.51%. The extract content (water-soluble) was 26.67%-42.91%, averaging 32.65%. According to the results of TLC identification, the 16 samples and reference substance had the same characteristic spots at the corresponding positions.[Conclusions] It was recommended that the moisture, total ash and acid-insolue ash content of D. tanguticum Maxim were not be more than 11%, 12%, and 3% respectively, while the extract content was not less than 26%. It provides reference for filling the gaps in the quality standards of D. tanguticum Maxim. 展开更多
关键词 TIBETAN MEDICINAL MATERIAL Dracocephalum tanguticum MAXIM MOISTURE ASH Extract content TLC
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Physical and mechanical properties of municipal solid waste incineration residues with cement and coal fly ash using X-ray Computed Tomography scanners
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作者 Toshifumi MUKUNOKI Ta Thi HOAI +2 位作者 Daisuke FUKUSHIMA Teppei KOMIYA Takayuki SHIMAOKA 《结构与土木工程前沿:英文版》 EI CSCD 2019年第3期640-652,共13页
A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e.,incineration residues) are commonly disposed as landfill.Meanwhile,reclamation of landfill sites to create a new land space after... A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e.,incineration residues) are commonly disposed as landfill.Meanwhile,reclamation of landfill sites to create a new land space after their closure becomes an important goal in the current fewer and fewer land availability scenario in many narrow countries.The objective of this study is to reclaim incineration residue materials in the landfill site by using cement and coal fly ash as stabilizers aiming at performing quality check as new developed materials before future construction.Indeed,physical and mechanical properties of these new materials should be initially examined at the micro scale,which is the primary fundamental for construction at larger scale.This research examines quantitative influences of using the combination of cement and coal fly ash at different ratio on the internal structure and ability of strength enhancement of incineration residues when suffering from loading.Couple of industrial and micro-focus X-ray computed tomography (CT) scanners combined with an image analysis technique were utilized to characterize and visualize the behavior and internal structure of the incineration residues-cement-coal fly ash mixture under the series of unconfined compression test and curing period effect.Nine types of cement solidified incineration residues in term of different curing period (i.e.,7,14,28 days) and coal fly ash addition content (i.e.,0%,9%,18%) were scanned before and after unconfined compression tests.It was shown that incineration residues solidified by cement and coal fly ash showed an increase in compression strength and deformation modulus with curing time and coal fly ash content.Three-dimension computed tomography images observation and analysis confirmed that solidified incineration residues including incineration bottom and fly ash as well as cement and coal fly ash have the deliquescent materials.Then,it was studied that stabilized parts play a more important role than spatial void distribution in i 展开更多
关键词 mechanical property MUNICIPAL solid waste INCINERATION RESIDUES coal FLY ash unconfined compression test image analysis X-Ray COMPUTED Tomography scanners
燃煤电厂烟气飞灰吸附氨变化规律 预览
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作者 石磊 牛国平 +5 位作者 马强 杨世极 李淑宏 常磊 袁壮 舒凯 《热力发电》 CAS 北大核心 2019年第6期53-57,共5页
氨逃逸分析是火电厂脱硝系统常规试验项目之一,烟气经过选择性催化还原(SCR)脱硝系统后,其中的飞灰会吸附一定量的逃逸氨,导致飞灰表面物理性质改变,进而引起燃煤锅炉尾部受热面腐蚀、堵塞,影响火电机组安全稳定运行。本文对某300 MW燃... 氨逃逸分析是火电厂脱硝系统常规试验项目之一,烟气经过选择性催化还原(SCR)脱硝系统后,其中的飞灰会吸附一定量的逃逸氨,导致飞灰表面物理性质改变,进而引起燃煤锅炉尾部受热面腐蚀、堵塞,影响火电机组安全稳定运行。本文对某300 MW燃煤火电机组SCR脱硝系统前后4个不同位点飞灰进行取样,并对飞灰吸附的氨和酸性气体进行测量。结果表明:随着尾部烟道沿烟气流程烟气温度的降低,灰中吸附氨质量分数增加,除尘器中有一定的低温停留时间,灰中吸附氨质量分数增加明显;灰对三氧化硫的吸附量较大,其变化趋势与烟气中三氧化硫质量分数的变化趋势较为吻合,SCR脱硝系统后沿程灰吸附的氯化氢质量分数逐渐降低;灰表面对氨逃逸和酸性气体均有吸附作用,且这两者之间相互促进,其吸附质量分数均随温度降低而升高,进而引起尾部受热面腐蚀、堵塞。 展开更多
关键词 燃煤电厂 SCR烟气脱硝 吸附 氨逃逸 受热面 腐蚀
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灰分对柴油机微粒捕集器性能及再生的影响 预览
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作者 郎建平 刘倩 +2 位作者 张治强 段娜 任永凯 《内燃机与动力装置》 2019年第4期75-79,共5页
针对柴油机微粒捕集器(diesel particular filter,DPF)再生的可靠性问题,分析DPF灰分的主要成分及来源,灰分在DPF中的沉积过程,灰分对DPF效率及再生过程的影响。分析表明灰分的主要来源是润滑油,为了满足柴油机润滑要求,润滑油中添加了... 针对柴油机微粒捕集器(diesel particular filter,DPF)再生的可靠性问题,分析DPF灰分的主要成分及来源,灰分在DPF中的沉积过程,灰分对DPF效率及再生过程的影响。分析表明灰分的主要来源是润滑油,为了满足柴油机润滑要求,润滑油中添加了大量的金属成分,产生大量的灰分影响DPF的再生过程。针对灰分的成分及沉积方式,提出使用低金属含量润滑油降低DPF灰分沉积、采用高压空气反吹作为DPF的主要清灰措施。 展开更多
关键词 DPF再生 润滑油 灰分 柴油机
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虾青素油灰分测定的不确定度评定
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作者 田树兴 蒋子华 《食品安全质量检测学报》 CAS 2019年第8期2281-2284,共4页
目的建立虾青素油灰分测定的不确定度的评定斱法。方法采用国标斱法GB5009.4-2016《食品中灰分的测定》第一法对虾青素油灰分进行测定,依据JJF1059.1-2012《测量不确定度评定与表示》对测定中的各分量分析量化,评定出被测量的标准不确... 目的建立虾青素油灰分测定的不确定度的评定斱法。方法采用国标斱法GB5009.4-2016《食品中灰分的测定》第一法对虾青素油灰分进行测定,依据JJF1059.1-2012《测量不确定度评定与表示》对测定中的各分量分析量化,评定出被测量的标准不确定度和扩展不确定度,给出各分量对不确定度的贡献。结果通过计算,相对标准不确定度u_c(x)=0.019 g/100 g,扩展不确定度U=0.038 g/100 g。结论此次评定不确定度的主要来源为灰分质量m引入的,样品质量M引入的不确定度贡献很小。对重量法测样品灰分的不确定度评定时,其分量不确定度的贡献大小不是恒定的,不确定度贡献的大小应根据样品中灰分质量来判断。 展开更多
关键词 虾青素油 灰分 不确定度 评定
配合煤灰分及粘结指数对焦炭质量的影响 预览
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作者 刘新波 亓海燕 +1 位作者 纪召毅 房杰 《河南冶金》 2019年第4期7-8,53共3页
焦炭中的灰分作为高炉冶炼过程中的有害成分,其全部来源于配合煤,配合煤的粘结指数可以反映其粘结性和结焦性,对焦炭质量具有重要的影响。统计某焦化厂配合煤的灰分、粘结指数及焦炭的热性质和冷强度,对配合煤灰分、粘结指数对焦炭质量... 焦炭中的灰分作为高炉冶炼过程中的有害成分,其全部来源于配合煤,配合煤的粘结指数可以反映其粘结性和结焦性,对焦炭质量具有重要的影响。统计某焦化厂配合煤的灰分、粘结指数及焦炭的热性质和冷强度,对配合煤灰分、粘结指数对焦炭质量的影响进行了分析研究。结果表明:配合煤灰分与焦炭的抗碎强度(M40)和反应后强度(CSR)呈负相关关系,与焦炭的耐磨强度(M10)和反应性(CRI)呈正相关关系;粘结指数与M40和CSR呈正相关关系,与M10和CRI呈负相关关系。研究分析灰分及粘结指数对焦炭质量的影响,有利于指导生产。 展开更多
关键词 灰分 粘结指数 焦炭质量 热性质 冷强度
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PVC-U型材配方灰份及型材密度与轻钙添加份数对应关系研究 预览
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作者 唐圣奎 张雄 唐达磊 《塑料助剂》 2019年第4期41-44,共4页
通过直接灼烧法和浸渍法对不同轻钙添加份数的未增塑聚氯乙烯(PVC-U)配方型材的灰分及密度进行了检测,研究分析了未增塑聚氯乙烯型材轻钙添加份数与检测的灰分、理论灰分及密度数据间的对应关系,利用Origin软件拟合出了未增塑聚氯乙烯... 通过直接灼烧法和浸渍法对不同轻钙添加份数的未增塑聚氯乙烯(PVC-U)配方型材的灰分及密度进行了检测,研究分析了未增塑聚氯乙烯型材轻钙添加份数与检测的灰分、理论灰分及密度数据间的对应关系,利用Origin软件拟合出了未增塑聚氯乙烯型材灰分及密度与轻钙添加份数间的对应关系曲线。结果表明,PVC-U型材中轻钙添加份数与其灰分或密度呈直接线性关系,可通过灰分、密度检测数据快速准确推算未增塑聚氯乙烯型材配方中轻钙等无机物添加份数。 展开更多
关键词 未增塑聚氯乙烯 型材 灰分 密度
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Investigation of the medium calcium based non-burnt brick made by red mudand fly ash:durability and hydration characteristics 预览
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作者 Ying-tang Xu Bo Yang +4 位作者 Xiao-ming Liu Shuai Gao Dong-sheng Li Emile Mukiza Hua-jian Li 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第8期983-991,共9页
Red mud is a type of highly alkaline waste residue produced in the process of alumina smelting by the Bayer process.Based on the idea of medium calcium content,solid wastes such as red mud and fly ash were used to pre... Red mud is a type of highly alkaline waste residue produced in the process of alumina smelting by the Bayer process.Based on the idea of medium calcium content,solid wastes such as red mud and fly ash were used to prepare non-burnt bricks;and the mass ratio of CaO/SiO2 was selected in the range of 0.88–1.42.Mechanical properties and durability were investigated with a compressive strength test.X-ray diffractometry(XRD),scanning electron microscope(SEM),and Fourier transform infrared spectroscopy(FTIR)techniques were used to characterize the hydration characteristic.The environmental performance was analyzed by Inductively Coupled Plasma Mass Spectrometry(ICP).The results indicated that the mechanical properties and the durability were optimal when the mass ratio of CaO/SiO2 was 1.23.The hydration products were mostly C–S–H gel,ettringite,Na4Ca(Si10All6)O32·12H2O and Ca3Al2(SiO4)(OH)8.They were responsible for the strength development,and the CaO/SiO2 mass ratio of 1.23 had the best polymerized structure.The results of an environmental performance test showed that the heavy metals in the raw materials were well-solidified in the brick.Therefore,this paper provides an effective solution for use of solid wastes in building material. 展开更多
关键词 MEDIUM CALCIUM content red MUD fly ash non-burnt BRICK
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Hydration Kinetics of Municipal Solid Wastes Incineration (MSWI) Fly Ash-Cement
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作者 阚黎黎 ZHANG Li SHI Huisheng 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第3期596-603,共8页
Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, a... Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, and hydration degree, Ca(OH)2 content, were also calculated and analyzed. According to the experimental results, the induction period was elongated, the second heat evolution peak was in advance, and the third hydration heat peak could be detected due to MSWI fly ash pozzolanic reaction. The hydration reaction rate was controlled by nucleation kinetics in the acceleration period and then by diffusion in the decay period, but in the deceleration period, the hydration experienced a dual controlling reaction of autocatalytic chemical reaction and diffusion. The hydration rate of blended cement was faster. Ca(OH)2 content increased before 14 days. 展开更多
关键词 MUNICIPAL solid waste INCINERATION (MSWI) FLY ASH HYDRATION heat kinetics HYDRATION degree
Effect of Nano Silica on Hydration and Microstructure Characteristics of Cement High Volume Fly Ash System Under Steam Curing
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作者 马保国 梅军鹏 +4 位作者 TAN Hongbo LI Hainan LIU Xiaohai JIANG Wenbin ZHANG Ting 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第3期604-613,共10页
The influences of nano silica (NS) on the hydration and microstructure development of steam cured cement high volume fly ash (40 wt%, CHVFA) system were investigated. The compressive strength of mortars was tested wit... The influences of nano silica (NS) on the hydration and microstructure development of steam cured cement high volume fly ash (40 wt%, CHVFA) system were investigated. The compressive strength of mortars was tested with different NS dosage from 0 to 4%. Results show that the compressive strength is dramatically improved with the increase of NS content up to 3%, and decreases with further increase of NS content (e g, at 4%). Then X?ray diffraction (XRD), differential scanning calorimetry-thermogravimetry (DSCTG), scanning electron microscope (SEM), energy disperse spectroscopy (EDS), mercury intrusion porosimeter (MIP) and nuclear magnetic resonance (NMR) were used to analyze the mechanism. The results reveal that the addition of NS accelerates the hydration of cement and fly ash, decreases the porosity and the content of calcium hydroxide (CH) and increases the polymerization degree of C-S-H thus enhancing the compressive strength of mortars. The interfacial transition zone (ITZ) of CHVFA mortars is also significantly improved by the addition ofNS, embodying in the decrease of Ca/Si ratio and CH enrichment of ITZ. 展开更多
关键词 NANO SILICA CEMENT high volume fly ash HYDRATION pozzolanic reaction PORE structure interfacial transition zone
Flux mechanism of compound flux on ash and slag of coal with high ash melting temperature
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作者 Chengli Wu Beibei Wang +1 位作者 Jiuqiang Zheng Hanxu Li 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第5期1200-1206,共7页
The melting temperature of Z coal ash was reduced by adding calcium–magnesium compound flux(WCaO/WMgO=1). In the process of simulated coal gasification, the coal ash and slag were prepared. The transformation of mine... The melting temperature of Z coal ash was reduced by adding calcium–magnesium compound flux(WCaO/WMgO=1). In the process of simulated coal gasification, the coal ash and slag were prepared. The transformation of minerals in coal ash and slag upon the change of temperature was studied by using X-ray diffraction(XRD). With the increase of temperatures, forsterite in the ash disappears, while the diffraction peak strength of magnesium spinel increases,and the content of the calcium feldspar increases, then the content of the amorphous phase in the ash increases obviously. The species and evolution process of oxygen, silicon, aluminum, calcium, magnesium at different temperatures were analyzed by X-ray photoelectron spectroscopy(XPS). The decrease of the ash melting point mainly affects the structural changes of silicon, aluminum and oxygen. The coordination of aluminum and oxygen in the aluminum element structure, e.g., tetracoordinated aluminum oxide, was changed. Tetrahedral [AlO4] and hexacoordinated aluminoxy octahedral [AlO6] change with the temperature changing. The addition of Ca2+ and Mg2+ destroys silica chain, making bridge oxide silicon change into non-bridge oxysilicon;and bridge oxygen bond was broken and non-bridge oxygen bond was produced in the oxygen element structure. The addition of calcium and magnesium compound flux reacts with aluminum oxide tetrahedron, aluminum oxide octahedron and silicon tetrahedron to promote the breakage of the bridge oxygen bond. Ca2+ and Mg2+ are easily combined with silicon oxide and aluminum oxide tetrahedron and aluminum. Oxygen octahedrons combine with non-oxygen bonds to generate low-melting temperature feldspars and magnesite minerals, thereby reducing the coal ash melting temperatures. The structure of kaolinite and mullite was simulated by quantum chemistry calculation, and kaolinite molecule has a stable structure. 展开更多
关键词 COAL ASH and SLAG COMPOUND FLUX X-ray photoelectron spectroscopy Transformation of mineral STRUCTURE STRUCTURE of kaolinite and mullite
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