Recovery of valuable metals from waste diamond cutters through ammonia–ammonium sulfate leaching

Copper and zinc were recovered from waste diamond cutters through leaching with an ammonia–ammonium sulfate system and air as an oxidant. The effects of experimental parameters on the leaching process were investigated, and the potential–pH(E–pH) diagrams of Cu–NH_3–SO_4^(2-)–H_2O and Zn–NH_3–SO_4^(-2)–H_2O at 25°C were drawn. Results showed that the optimal parameters for the leaching reaction are as follows: reaction temperature, 45°C; leaching duration, 3 h; liquid-to-solid ratio, 50:1(mL/g); stirring speed, 200 r/min; ammonia concentration, 4.0 mol/L; ammonium sulfate concentration, 1.0 mol/L; and air flow rate, 0.2 L/min. The results of the kinetics study indicated that the leaching is controlled by the surface chemical reaction at temperatures below 35°C, and the leaching is controlled by diffusion through the product layer at temperatures above 35°C.

Studies on Recovery Efficiencies of Phenols from Phenol Fraction Using Alkali Treatment

Experiments were conducted for the extraction of phenols from the phenol fraction obtained from the coal tar distillate. The phenol fraction for the present investigation has been procured from Visakhapatnam Steel Plant, Visakhapatnam whose composition is known. The phenol fraction from coal tar distillate can be treated for extracting phenols using caustic soda. An attempt has been made to find out whether the existing practice of using only 8%-15% can be modified by increasing the strength of sodium hydroxide and also explore the possibilities of substituting the sodium hydroxide with KOH as an extractant. The different streams of liquids obtained during experimentation have been analyzed by gas chromatograph. Salient features of the study are that higher concentrations of the alkali significantly improved the separation efficiencies of phenols and also regenerate the phenolate with higher phenol content. Increase in the alkali strength has greatly improved the separation as well as the phenol content in the regenerated phenols. Disposal of effluents containing phenols may lead to environmental problem of ground water pollution and the study throws a light on the removal of phenols from the effluents to the extent possible by using higher strength alkali solutions.

Parameters Optimizing of Ammonia-Recovery System in the Modified Equipment of Flax Fiber

A detailed analysis of operational process and principle of ammonia-recovery system in the modified equipment of flax fiber,which will be applied to parameters optimizing of the ammoniarecovery system as a foundational principle,is presented. According to the principle,an ammonia compressor,whose working conditions are based on key operational parameters of the whole ammoniarecovery system, is the mainly energy-consumption part of ammonia-recovery system in the modified equipment of flax fiber. A generally mathematical model based on work efficiency of an ammonia compressor is founded,which is available to rate effective work and energy consumption of the ammonia compressor. The optimum operation-efficiency of the ammonia compressor is chosen as the goal to analyze and calculate the key operational parameters of the ammonia-recovery system. In the above analyzing and calculating,a mathematical model on ammonia flowing from the reactor to the register 1 is developed,in order to provide further understanding of the principle of an ammonia-recovery system. At the meantime,the ammonia flow regime in the pipeline and the process of ammonia inflation and deflation from the reactor to the register 1 are taken separately into account in the model. An iterative method is for obtaining parametric solutions of the mathematical model on ammonia flowing from the reactor to the register 1 and the key operational parameters of the ammoniarecovery system. A parametric analysis is put forward to complete showing the ammonia velocity or the state of the reactor and the register 1. The key optimized parameters will be achieved in term of the minimum efficiency after comparing the work efficiencies of an ammonia compressor at different working conditions.

Efficient extraction of phenol from wastewater by ionic micro-emulsion method:Anionic and cationic

Phenolic wastewater is one of the priorities in the field of wastewater treatment,which poses a serious threat to the human health and nature environment.In this paper,cationic cetyltrimethylammonium bromide(CTAB)and anionic sodium oleate(Na OL)microemulsions were utilized to extract phenol from the wastewater.The optimal extraction factors were investigated by exploring the effects of microemulsion composition ratio and extraction conditions on the phenol extraction performance.Furthermore,the enhanced extraction mechanism of phenol by cations microemulsions is illustrated by studying the extraction process of cationic and anionic microemulsions in the extraction of phenol.The optimum components were obtained:surfactant concentration of 0.2 mol·L^(-1),isoamyl alcohol volume of 30%,internal aqueous phase concentration of CTAB microemulsion of 0.05 mol·L^(-1),and internal aqueous phase concentration of Na OL microemulsion of 0.09 mol·L^(-1).The extraction efficiencies were 96.44%and 82.0%when using CTAB and Na OL microemulsions under optimal conditions(water-emulsion ratio of 5,contact time of 9 min,extraction temperature of 298.15 K,and p H of 9),confirming the enhanced extraction of phenol by CTAB cationic microemulsion.It was analyzed that the enhanced extraction of CTAB microemulsion was due to the electrostatic adsorption of cations with phenol root ions.

鸟粪石沉淀法处理高浓度氮磷废水研究进展

随着节能低碳理念的深入发展,鸟粪石沉淀法因其较高的氮磷回收效率和相对低能耗的优势,近年来成为高浓度氮磷废水处理和资源化利用的热点方向之一。系统地对国内外鸟粪石沉淀法处理污水的相关文献进行了梳理,从新兴处理对象及方案、回收反应器构型开发、低成本镁源开发、高效结晶、晶体分离提纯等方面,总结了相关研究成果。此外,结合环境毒理性、处理成本、综合资源化利用等角度对鸟粪石沉淀法的发展前景和趋势进行预判,为相关研究提供参考。

氨氮短期胁迫与恢复对克氏原螯虾的影响

为探究氨氮胁迫与恢复对克氏原螯虾抗氧化和免疫酶活性及组织结构的影响,将体质量(6.33±0.73)g的克氏原螯虾暴露于0、20、40、60、80 mg/L 5个氨氮质量浓度下,比较胁迫48 h时及恢复48 h后,各组肝胰腺、鳃和血清的抗氧化和免疫酶活性以及各组肝胰腺和肌肉组织结构的变化。试验结果显示:氨氮对克氏原螯虾幼虾24、48、72、96 h的半致死质量浓度分别为359.37、238.09、196.34、162.00 mg/L,安全质量浓度为16.20 mg/L。胁迫48 h后,除20 mg/L试验组外,其余试验组肝胰腺的总超氧化物歧化酶活性较对照组显著增强,80 mg/L组鳃的总抗氧化能力显著降低、过氧化氢酶活性显著增强,80 mg/L组血清的总超氧化物歧化酶活性显著增强;恢复48 h后,60 mg/L组肝胰腺和鳃的丙二醛含量较对照组显著上升,80 mg/L组鳃的过氧化氢酶活性较对照组显著增强,60 mg/L组血清的总抗氧化能力较对照组显著上升,其他试验组酶活性均恢复至对照组水平。氨氮胁迫48 h,随着氨氮质量浓度的升高,肝胰腺管腔逐渐变形、转运泡增大,鳃的呼吸上皮细胞开始脱落、微血管腔受损;恢复48 h后,肝胰腺的组织结构基本恢复正常,40、60、80 mg/L组鳃局部呼吸上皮细胞脱落,微血管腔受损。试验结果表明,20 mg/L质量浓度的氨氮胁迫48 h即会对克氏原螯虾抗氧化和免疫酶及组织结构造成损伤,解除胁迫48 h后可得到修复。克氏原螯虾经40、60、80 mg/L质量浓度的氨氮胁迫48 h后恢复48 h,鳃仍处于应激状态。

Aqueous ammonia solution cooling absorption refrigeration driven by fishing boat diesel exhaust heat

A solution cooling absorption（SCA）approach is proposed to modify the aqueous ammonia absorption refrigerat-ion cycle using the strong solution from the absorber to cool the forepart of the absorption in the cycle for reclaiming some portion of absorption heat.As a consequence of raised temperature at the inlet,the strong solution partially boils at the outlet of the solution heat exchanger,and diminishes the thermal heat consumption of the heat source.The calculation results show that the coefficient of performance（COP）of this modified cycle is about 28.3% higher than that of the traditional cycle under typical conditions;while the required heat transfer area of the total heat exchangers of the cycle is somewhat less than that of the traditional one.The capacity of refrigeration with the new absorption cycle is more than doubled in contrast to the adsorption scheme with an identical configuration.It is sufficient to supply a fishing boat the chilling capacity for preservation of fishing products with the modified cycle chiller driven by its diesel engine exhaust.

电化学介导的氨氮回收:原理、现状与展望

当前的氮循环模式存在人工固氮/脱氮过程重复耗能、可持续性不佳的问题。针对氨氮的污染-资源双重属性特征,污水中氨氮的资源化处理技术亟须研发。在各种氨氮回收技术中,电化学技术具有反应快速、装备简单、操作便捷等优势,已经成为热门研究方向。综述电化学介导氨氮回收技术的研究与发展现状:围绕电化学系统中不同形态氨氮的迁移转化机制,主要介绍3种回收技术的主要原理,包括电驱迁移与界面吸附、阴极还原促进汽化和阳极氧化促进沉淀;进一步聚焦电极与膜材料对氨氮回收性能的强化作用,分析电容去离子与膜技术(基于阳离子交换膜、疏水透气膜、双级膜的工艺)的能效水平,指出多过程耦合的氨氮汽提技术在降低能耗与提升效率方面的良好前景;展望双碳背景下技术革新的内在需求,建议未来从系统高性能元件开发、能量削减与功能拓展/智慧化运行等方向推进电化学介导氨氮回收技术的高质量可持续发展。

改性煤气化细渣精选炭吸附废水中苯酚性能研究

煤气化细渣是一种产量大且含碳量高的固体废弃物,用煤气化细渣中残炭制备的多孔吸附剂处理废水中的苯酚可达到以废治废的目的。通过氨水浸渍和微波辐照相结合的手段对精选炭进行改性以增强其对苯酚的吸附能力,采用Box-Behnken响应曲面法设计改性实验,选定浸渍时间、氨水质量分数和用量、精选炭投放量、微波辐照时间及功率等作为设计变量,以苯酚去除率为响应值,通过方差分析和响应面分析,研究了模型的可靠性及各变量之间的交互影响关系。结果表明:经过响应面模型预测及验证后得到了氨水浸渍和微波辐照改性的最佳工艺条件为氨水质量分数25%、浸渍时间660 min、氨水用量153 mL、微波辐照时间6 min、辐照功率550 W、氨水浸渍的精选炭投放量2.9 g,在此条件下得到的改性精选炭苯酚去除率达92.31%,实验值与预测值基本一致;对改性精选炭进行分析表征及吸附评价发现,改性后的精选炭酸性官能团(羧基、内酯基、羟基)含量和平均孔径分别下降了84%和47%,碱性官能团、总孔体积和比表面积分别提高了86%,43%和108%。

厌氧氨氧化处理煤化工酚氨废水的研究进展

厌氧氨氧化(Anammox)脱氮具有能耗低、无需投加碳源、污泥产量低和温室气体排放量少等优点,在煤化工酚氨废水处理领域具有广阔的应用前景。本文运用引文分析软件VOSviewer对Anammox处理酚氨废水的研究进展进行了文献计量学分析,综述了Anammox在酚氨废水处理方面的研究进展,梳理了Anammox工艺应用于酚氨废水处理时所面临的技术难点,探讨了酚类物质对Anammox脱氮的毒性胁迫及毒性缓解对策,以期为Anammox应用于煤化工废水处理提供参考。

不同氮肥类型对稻-油轮作氨挥发和氮肥利用率的影响

水稻-油菜(稻-油)轮作是我国代表性轮作方式之一,然而不合理的氮肥施用导致稻-油轮作系统氮肥利用率下降和氮素流失。为此,本研究采用随机区组设计,以不施氮肥(CK)为对照,设尿素(UF)、缓释肥+尿素(SF)、尿素+硝化抑制剂+脲酶抑制剂(DF)和生物炭+尿素(BF)4个处理,拟探明不同氮肥类型对稻-油轮作系统氨挥发和氮肥利用率的影响。结果表明,不同氮肥类型显著影响NH_3挥发、氮肥利用率与作物产量。1)各处理水稻季氨挥发均高于油菜季。与CK相比,UF、SF、DF和BF处理周年累积NH_3挥发量分别显著提高1.6倍、1.0倍、1.1倍和0.8倍。与UF相比,SF、DF和BF周年累积NH_3挥发量分别显著降低20.5%、19.7%和30.9%。2)与UF相比,SF、DF和BF油菜季氮肥吸收利用率分别提高27.9%、10.3%和19.3%,水稻季氮肥吸收利用率分别提高49.3%、32.8%和41.5%。3)与UF相比,SF、DF和BF油菜产量分别提高6.7%、2.8%和4.3%,水稻产量分别提高36.7%、14.0%和23.4%。与UF相比,SF油菜季经济效益提高24.3%,SF、DF和BF水稻季经济效益分别提高70.7%、21.1%和1.1%,其中SF经济效益最高。本研究结果表明,缓释肥+尿素能显著减少稻-油轮作NH_3挥发损失,并更有效地提高氮肥利用率、作物产量和经济效益,是一项经济生态的施肥模式。

气隙膜蒸馏回收绿色氨水性能研究

回收沼液中的氨氮可实现低成本和低碳足迹的氮肥生产.理论上气隙膜蒸馏能以绿色氨水形式将沼液中氨氮加以回收,然而该方面的研究还较少.本文对气隙膜蒸馏以氨水形式回收沼液中氨氮的具体性能进行了研究.采用单因素实验分别研究了气隙厚度、进料温度、初始氨氮浓度和进料流速等因素对模拟沼液中氨氮回收效率的影响.结果表明氨通量和水通量均随着进料温度的增加而增加,随着气隙厚度的增加而降低.进料流速为90 mL/min时,氨氮分离因子和氨氮脱除率均为最高值.基于单因素实验结果,采用正交实验探究气隙膜蒸馏回收氨氮的最佳实验变量组合.结果表明,气隙厚度3 mm、进料温度54℃、初始氨氮浓度800 mg/L和进料流速90 mL/min是以氨氮分离因子为评价参数时的最佳实验变量组合.

离子液体萃取分离液相中酚类物质的研究进展

离子液体包括咪唑类、胆碱类、铵类、季类、吡啶类、吡咯烷类等,是一种具有难挥发、不易燃、对热稳定、溶解能力强等优点的绿色溶剂,可充当高效萃取剂或萃取添加剂,用于液相中酚类物质的萃取分离。本文系统地介绍了不同类型离子液体萃取液相中酚类物质的机制和性能,全面追踪了离子液体萃取分离液相中酚类物质的最新研究进展,深入解析了离子液体萃取液相中酚类物质过程的影响因素,整体上分析了离子液体萃取液相中酚类物质存在的问题,最后展望了离子液体萃取液相中酚类物质的发展前景。未来离子液体萃取液相中酚类物质技术的发展方向为以下三个方面:一方面,开发低黏度、低水溶性、低毒性、低成本、高稳定性、高萃取率、高选择性、容易生物降解的离子液体;另一方面,离子液体容易与萃余相分离,回收后的离子液体可多次循环使用且能保持较好的萃取性能;最后,离子液体萃取剂与萃取器要高度统一、有机结合,才能达到最佳的萃取效能。

PVDF疏水膜冷凝处理含氨湿气过程的研究

研究了膜冷凝(MC)法处理含氨湿气的过程,基于自行搭建的小试装置,选择不同孔径聚偏氟乙烯(PVDF)商品膜,考察了MC过程中进料气体污染物浓度、进气流量、进气温度、膜表面温度差ΔT及膜孔径等因素对MC的水回收性能和凝结水中NH_(3)-N含量的影响规律.结果表明,进料气体流量为1.0 L/min,NH_(3)-N质量浓度为400 mg/L,进料温度为50℃且ΔT为20℃时,可以获得较高的水回收性能和较低NH_(3)-N含量的凝结水.

克劳斯硫回收装置尾气创新技术改造

山西中煤平朔能源化工有限公司硫回收装置装置采用荷兰荷丰技术,国内首次采用“克劳斯单元+氨洗单元+酸浓缩单元”的生产工艺,针对该工艺不能满足新形势下环保的要求,通过对硫回收系统改造和耦合锅炉氨法脱硫装置,提出创新的提出解决办法,降低尾气中二氧化硫排放,为环保装置设计和改造提供创新的解决思路,创出一定经济效益和环保效益。

焦化厂蒸氨制浓氨水工艺改进与优化

针对焦化厂剩余氨水蒸氨运行中存在的设备腐蚀、浓氨水含萘高、蒸氨废水控制不稳定等突出问题,并就产生原因进行分析,针对性采取工艺改造优化方案。运行实践中稳定了蒸氨塔操作,去除了浓氨水中S^(2-)、CN^(-)、萘等杂质,优化了工艺参数控制范围,提高了浓氨水品质,降低了蒸氨系统现场设备腐蚀。

煤化工硫黄回收装置尾气SO_(2)排放控制措施

介绍了煤化工行业“两头两尾”和氨法吸收的硫黄回收装置工艺原理和工艺流程,并结合煤化工硫黄回收装置实际生产情况,从减少SO_(2)的产生量和提高SO_(2)吸收效果两方面分别讨论了控制排放尾气中SO_(2)浓度的措施。减少SO_(2)产生的主要措施有合理控制配氧量、控制反应器床层温度、控制硫冷凝过程等;提高SO_(2)吸收效果的主要措施有合理控制硫铵液pH值、保证硫铵液浓度和循环量等,为同类煤化工行业硫黄回收装置提供借鉴。

二异丙基醚中总酚含量的测定方法研究

采用溴化容量法测定二异丙基醚中的总酚含量时,二异丙基醚会对测量产生干扰,严重影响测量结果的准确性。可先利用氢氧化钠溶液与二异丙基醚中的酚反应生成酚钠,再用水浴加热的方式将二异丙基醚蒸发,消除干扰物质二异丙基醚,然后冷却样品,并调节其pH值至中性后,再采用溴化容量法即可准确测定二异丙基醚中的总酚含量。将该方法进行加标试验,测得回收率在96.4%~102.2%,相对标准偏差小于3%。

液氨变色问题分析及解决思路探讨

液氨合格品是无色透明的,当液氨外观带颜色时,会严重影响其销售价格及销售量。针对液氨带色现象进行了排查,排除了装置操作参数、油含量、脱硫剂对液氨带色的影响,初步认为是液氨中的挥发酚类所致。因此,在氨压机后增上了液氨脱色设施,以活性炭作为吸附剂,液氨脱色设施投用后,液氨不再显现红色,但后期液氨呈绿色。说明该脱色剂对挥发酚类具有一定脱除效果,但容易饱和,也说明有多种显色物质共同起作用。随后做了蒸发-冷凝试验,确认该工艺对液氨脱色有效。

氨法磷酸铁废水处理专利技术综述

本文主要分析了采用“硫酸亚铁+双氧水+磷酸+磷酸二氢铵”的氨法工艺合成磷酸铁生产过程中产生的高浓度废水;针对磷酸铁废水具有高氮、高磷、高硫酸根的特点,收集整理了近年来磷酸铁废水处理的专利;并将这些专利技术归纳分类成了零排放技术、回用与资源化技术、磷酸铵镁法、传统石灰法、硫酸钡沉淀法五大类;针对五类典型专利分别进行了简单的分析介绍;给出了技术对比;最后对磷酸铁废水处理专利技术进行了展望,磷酸铁废水零排放与资源化处理技术是最有前途的。