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选矿药剂通常用于调节矿物表面和浮选介质的物理化学性质,扩大有用矿物与脉石矿物间的亲疏水性差异,从而达到更好的分选效果。选矿药剂种类繁多,含有残留药剂的选矿废水直接外排会造成环境污染。生物降解作为一种新型生化处理方法,具有成本低、能耗少、无二次污染等优点,因此研究高效降解选矿废水中残留药剂的方法尤为重要。论述了当前黄药、黑药、羟肟酸类、松醇油等选矿药剂生物降解技术的研究进展,分析了影响降解效果的工艺因素和选矿药剂生物降解研究存在的主要问题,并对今后的研究工作进行展望。影响黄药生物降解效果的因素有黄药初始浓度、pH、温度,振荡速率、降解时间、碳氮比、氮源和金属离子等。外加碳源可促进黄药的降解。CS2、ROCSSH和单硫代碳酸盐是烃基黄药的主要降解产物,并伴有少许双黄药油液滴生成,属于一级酶促降解动力学。黄原酸盐分解的中间产物是过氧化黄原酸盐。不同外加碳源同样会促进黑苯胺药的降解。羟肟酸类捕收剂降解反应是一级反应动力学。影响对松醇油的降解因素有pH值、接种量、温度、摇床转速、松醇油初始浓度、反应时间等。针对选矿药剂生物降解研究存在的主要问题,今后的研究工作应借鉴相近领域的生物技术手段筛选出高效降解菌株,在降解机理上开展更深入研究,在分子水平上改造基因,利用基因工程技术构建新的降解菌株。同时,应加快选矿废水生物降解设备的研制。 相似文献
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通过薄层色谱、气相色谱、色质联用等技术,首次得到了油脂环氧化反应期间的脂肪酸环氧化反应规律:开始反应阶段,高含量不饱和脂肪酸反应速率高于低含量不饱和脂肪酸;环氧化反应期间,多不饱和脂肪酸首先生成单环氧酸,之后再逐渐生成二环氧酸,最后生成三环氧酸;富含亚麻酸的油脂环氧化反应时有更易于开环反应的趋向,其次是富含亚油酸的油脂,再次是富含油酸的油脂.实验结果表明,不同环氧油原料在进行环氧化反应时需要控制不同的反应条件,以避免开环副产物量的增加,从而制备得优质环氧油产品. 相似文献
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<正> CO和H_2反应除了可以生成甲醇外,通常还可生成二碳含氧化合物、混合醇、异丁醇和2—甲基丙醛等合氧化合物。这些含氧化物的碳—氧键均处于碳链的端部,它们的生成可以借助CO分子和金属表面物类的插入和加氢反应来解释。最近K.Kushihashi等报道,在CeO_2催化剂上,使用含水4%~8%的原料气(CO:H_2:N_2=1:1:0.5体积比),在653K和常压流动装置上反应生成烃类、醇类和酮类产 相似文献
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研究了用氧化硼抑制碳/碳复合材料的氧化反应。用浸渍工艺将不同量的抑制剂沉积在碳表面,由于部份抑制剂封闭了活性部位,所以降低了氧化速率。增大氧化硼含量会对氧生成一种流动的扩散阻挡层。这一保护层主要是有助于抑制效应。 相似文献
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《煤炭转化》2017,(5)
为了降低碳化钙合成温度,研究了碳(C)和氧化钙(CaO)合成碳化钙(CaC_2)过程所涉及反应的热力学,通过平衡常数法计算得到临界温度等热力学数据.计算结果表明:氧化钙与焦炭最低反应温度为氧化钙的塔曼温度(1 442℃),但由于反应物浓度低,反应速度缓慢;提高反应温度至1 882℃,固态氧化钙可与碳反应生成碳化钙,并随着碳化钙的积累,局部产生相变,发生界面反应,表现为液态氧化钙与碳反应生成碳化钙,临界反应温度降低为1 753℃.继续升高温度至2 222℃,生成的碳化钙能自催化氧化钙与碳反应生成碳化钙,但是当氧化钙过量而碳含量不足时,生成的Ca蒸气不能及时被碳吸收,则会造成Ca的流失,降低电石品质.计算结果进一步表明:降低CO分压可大幅度降低电石的临界生成温度,当CO分压为0.01 MPa时,固态氧化钙与碳的临界反应温度可降低至1 700℃,此时CaC_2的理论平衡摩尔分数为92.9%.不同条件下氧化钙与碳对比反应结果验证了热力学的分析,并且Ar气氛下1 620℃就可以合成CaC2也验证了低温合成电石的可能. 相似文献
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Vijay Kale R. Subbarao G. Lakshminarayana M. Bhagwant Rao 《Journal of the American Oil Chemists' Society》1991,68(8):583-584
C36 Dimer acids were esterified with various short-chain alcohols, namely 2-propanol, n-butanol, n-hexanol, n-octanol, 2-octanol
and 2-ethyl-1-hexanol by using sulfuric acid as catalyst and benzene as an azeotropic solvent. Various reaction parameters
were standardized. In case of isopropyl esters, acid-to-alcohol mole ratio of 1:5 and sulfuric acid concentration of 2% based
on the weight of dimer acids were found to be optimum. In case of straight-chain primary alcohols, namely n-butanol, n-hexanol
and n-octanol, 1:2.5 mole ratio of acid to alcohol and 1% by weight of sulfuric acid were found satisfactory. Esterification
reaction rates were determined from the fall in acid value of the product. The reaction followed pseudo first order kinetics.
The reaction rates increased with the increase in chainlength of straight-chain primary alcohols from n-butanol to n-octanol.
The rate of reaction decreased from n-octanol to 2-ethyl-1-hexanol to 2-octanol due to the branching of the chain in 2-ethyl-1-hexanol
and secondary nature of the −OH group in 2-octanol. 相似文献
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采用常规的失重法对聚天冬氨酸(PASP)在硫酸介质中对碳钢的缓蚀性能进行了研究。研究了聚天冬氨酸的用量、温度、硫酸的浓度等因素对其缓蚀性能的影响。得出聚天冬氨酸用量为0.2%,温度为30℃,硫酸浓度小于15%时对碳钢都有较好的缓蚀性能。用线性扫描伏安法和电化学阻抗谱对聚天冬氨酸的缓蚀机理进行了电化学研究,发现随着PASP浓度增加,金属的自腐蚀电位有变大的趋势,表明聚天冬氨酸应属于阳极型缓蚀剂;同时阻抗谱在高频区出现了半圆容抗弧,加入聚天冬氨酸的体系半圆半径变大,进一步验证了聚天冬氨酸对碳钢的缓蚀性能。 相似文献
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随着我国不锈钢粗钢产量逐年增大,对不锈钢进行酸洗而产生的酸洗废酸也在逐年增多。不锈钢酸洗排放的废硫酸溶液中含大量游离酸,根据本课题组开发的酸再生循环工艺,在有效回收废酸中有价金属离子的同时,使酸洗废酸中游离酸浓度增大得到再生硫酸。针对不锈钢酸洗废液中再生硫酸浓度较高、中和处理试剂消耗高、废渣产生量大的问题,研究了溶剂萃取法回收不锈钢酸洗废液中硫酸的工艺。研究发现,有机体系40%(体积分数)三(2-乙基己基)胺(TEHA)+50%异构十三醇+10% Exxsol D110为最优化组成,硫酸萃取率随TEHA浓度增加而升高,随温度升高萃取率降低,表明萃取反应为放热反应,计算所得萃取反应的ΔH=?7.5708 kJ/mol。根据萃取和反萃分配曲线分别绘制了McCabe-Thiele图,在30℃、相比A/O=1:2条件下,经过3级(理论)萃取,硫酸的萃取率可达79.8%以上;采用水作反萃剂,在30℃、相比A/O=1:1条件下,经过3级(理论)反萃,硫酸的反萃率可达85.5%。萃取、反萃动力学快,分相迅速,可满足工业连续生产要求。 相似文献
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以异丙醇、CS2、NaOH为原料,采用直接合成法生产黄原酸钠。反应温度为17℃、反应时间为4 h时,化合物的合成收率达92%以上,化合物的游离碱含量在1.5%以下。 相似文献
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对羟肟酸类捕收剂的浮选机理、羟胺法合成羟肟酸的原理和方法进行了介绍和分类;在考察醇、醇/水、水溶液和乳液4种肟化反应介质下工艺特点的同时,详细阐述了羟胺法改进工艺的研究进展;针对羟胺法的工艺特点和羟肟酸分子构效关系,提出了羟胺法合成羟肟酸的发展趋势。 相似文献
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By means of cyclic voltammetry, a study of the redox reactions has been made on stage 1 sulfuric acid-graphite intercalation compound (H2SO4-GIC) prepared by anodic oxidation of graphite in sulfuric acid electrolyte. It was found that further oxidation of the stage 1 GIC gives rise to the reversible ionization reaction of carbon atoms in the graphite basal plane and also of sulfuric acid molecules produced in the interlayer spacing. This ionization reaction and the reverse deionization reaction are responsible for plateaus observed in the current vs. potential curve. These redox reactions between the stage 1 GIC and its ionized state were analyzed in situ by means of X-ray diffractometry. 相似文献
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Carmen M. Cepeda-Jim nez M. Mercedes Pastor-blas Teresa P. Ferr ndiz-G mez Jos Miguel Martí n-Martí nez 《The Journal of Adhesion》2000,73(2):135-160
Modifications produced on a vulcanized styrene -butadiene rubber surface by treatment with sulfuric acid were studied and several experimental variables were considered.
The treatment of R1 rubber with sulfuric acid produced a noticeable decrease in contact angle which was mainly ascribed to an increase in surface energy due to the formation of sulfonic acid moieties and C=O bonds, and the removal of zinc stearate. The rubber surface swelled and became brittle as a result of the treatment, and when flexed microcracks were created. A rubber surface layer modification was produced with a consequent decrease in tensile strength and elongation-at-break values. The treatment enhanced the T-peel strength of R1 rubber/polyurethane adhesive joints and the locus of failure was cohesive in the rubber.
The optimum immersion time in H2SO4 solution was less than 1 min., and the reaction time in air was not found to be critical; the neutralization with ammonium hydroxide and the high concentration of the sulfuric acid (95 wt%) were essential to produce adequate effectiveness of the treatment. 相似文献
The treatment of R1 rubber with sulfuric acid produced a noticeable decrease in contact angle which was mainly ascribed to an increase in surface energy due to the formation of sulfonic acid moieties and C=O bonds, and the removal of zinc stearate. The rubber surface swelled and became brittle as a result of the treatment, and when flexed microcracks were created. A rubber surface layer modification was produced with a consequent decrease in tensile strength and elongation-at-break values. The treatment enhanced the T-peel strength of R1 rubber/polyurethane adhesive joints and the locus of failure was cohesive in the rubber.
The optimum immersion time in H2SO4 solution was less than 1 min., and the reaction time in air was not found to be critical; the neutralization with ammonium hydroxide and the high concentration of the sulfuric acid (95 wt%) were essential to produce adequate effectiveness of the treatment. 相似文献
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Carmen M. Cepeda-Jiménez M. Mercedes Pastor-blas Teresa P. Ferrándiz-Gómez José Miguel Martín-Martínez 《The Journal of Adhesion》2013,89(2-3):135-160
Modifications produced on a vulcanized styrene –butadiene rubber surface by treatment with sulfuric acid were studied and several experimental variables were considered. The treatment of R1 rubber with sulfuric acid produced a noticeable decrease in contact angle which was mainly ascribed to an increase in surface energy due to the formation of sulfonic acid moieties and C?O bonds, and the removal of zinc stearate. The rubber surface swelled and became brittle as a result of the treatment, and when flexed microcracks were created. A rubber surface layer modification was produced with a consequent decrease in tensile strength and elongation-at-break values. The treatment enhanced the T-peel strength of R1 rubber/polyurethane adhesive joints and the locus of failure was cohesive in the rubber. The optimum immersion time in H2SO4 solution was less than 1 min., and the reaction time in air was not found to be critical; the neutralization with ammonium hydroxide and the high concentration of the sulfuric acid (95 wt%) were essential to produce adequate effectiveness of the treatment. 相似文献