二-(2-乙基己基)磷酸酯与单烷基磷酸酯协同萃取湿法磷酸中铁离子的研究

以二-(2-乙基己基)磷酸酯(P204)与单烷基磷酸酯(P538)作为协同萃取剂、磺化煤油为稀释剂,从模拟湿法磷酸溶液中萃取Fe3+,研究萃取时间、萃取剂浓度、萃取相比、萃取温度对Fe3+萃取效果的影响.结果表明,当萃取时间为25 min、萃取剂浓度为2 mol/L、萃取相比为2:1、萃取温度为25℃时,铁的单级萃取率...     

单级萃取-反萃取同时分离回收磷酸中铀和稀土

使用单级萃取-反萃取工艺,从湿法磷酸(WPA)中回收铀和稀土的新工艺,既简单又易于控制,因为它只涉及酸性介质。该工艺是基于用二(2-乙基己基)磷酸(DEPA)和磷酸三丁酯(TBP),从湿法磷酸中萃取铀和稀土。发现DEPA是唯一有效的,它稳定并且易于反萃取。其它的有机磷酸酯易水解,并且很难反萃取。用含有酸性氟化物的介质,对稀土和铀进行反萃取。对于铀来说,以六价(U~(6+))形成被萃取,铀由于Fe~(2+)还原成4价(U~(4+))不萃取状态,而进入到反萃取液中。稀土和铀(U~(4+))以氟化物形式立刻沉淀下来。铀以UF_42.5H_2O或一种四价化合物沉淀,这与反萃取液有关。这种沉淀物是一种“绿色的饼”。将“绿色的饼”先在氮气中400℃下脱水后,用F_2氧化成高纯六氟化铀。稀土部份由钇族组成,其中钇是主要元素。 上述工艺比两级萃取-反萃取投资费用低,对于绿色湿法磷酸,其运行成本大约是30美元/kg。     

单级萃取—反萃取同时分离回收磷酸中铀和稀土

使用单级萃取－反萃取工艺，从湿法磷酸（ＷＰＡ）中回收铀和稀土的新工艺，既简单又易于控制，因为它只涉及酸性介质。该工艺是基于用二（２－乙基己基）磷酸（ＤＥＰＡ）和磷酸三丁酯（ＴＢＰ）和磷酸三丁酯（ＴＢＰ），从湿法磷酸中萃取铀和稀土。发现ＤＥＰＡ是唯一有效的，它稳定并且易于反萃取。其它的有机磷酸酯易水解，并且很难反萃取。用含有酸性氟化物的介质，对稀土和铀进行反萃取。对于铀来说，以六价（Ｕ＾６＋）形成被     

高酸度磷矿酸解液中镁离子的分离研究

本文以二-(2-乙基己基)磷酸酯(P204)和苯甲酸为复合萃取剂,在pH为-0.36的条件下,对磷矿酸解液中的镁离子进行萃取研究。考察了P204与苯甲酸的比例、稀释剂种类、萃取时间、复合萃取剂体积分数、萃取相比(O/A)对提取镁离子效果的影响。结果表明,选用磺化煤油作为稀释剂,当有机相中P204∶苯甲酸=1∶1,复合萃取剂体积分数为30%,磺化煤油体积分数为70%,萃取相比为2∶1,萃取时间为20 min时,镁离子的萃取率可达到63.56%,且此时磷矿酸解液中P2O5的回收率高于99%。这一研究实现了高酸度条件下镁离子的高效提取,对于湿法磷酸的净化具有重要价值。     

磷酸三丁酯萃取净化盐酸法湿法磷酸的工艺研究

以磷酸三丁酯为萃取剂对湿法磷酸采用溶剂萃取法进行净化,探索了萃取工艺条件.得出该萃取体系对湿法磷酸较为适宜的萃取工艺条件为：在室温下进行萃取,萃取相比为4,盐酸加入量为原料磷酸的6％,此时P205萃取率为62.9％.净化后的稀磷酸通过浓缩、除杂、脱色后得到w（H3PO4）85％食品级磷酸产品.     

利用磷酸三丁酯在硫酸-磷酸体系中萃取净化低浓度湿法磷酸工艺的研究

研究了利用磷酸三丁酯在硫酸-磷酸体系中萃取净化低浓度湿法磷酸工艺,获得了萃取性能较好的萃取体系。实验表明,稀释剂（煤油）添加量为磷酸三丁酯与稀释剂总质量的10％时,萃取净化较佳工艺条件为：萃取相比4,萃取温度40℃,搅拌时间15min,硫酸添加量为原料湿法磷酸的1％;SO42^-去除率-80％,Fe、Al去除率99％以上,P2O5,损失率约60％,所得净化稀磷酸P2O5,7．5％,可作为热法磷酸吸收剂。     

协同萃取净化湿法磷酸中镁离子的研究

以质量分数39%的湿法磷酸为研究对象,采用酸-酯复合萃取剂及酯-酯复合萃取剂对湿法磷酸中的镁离子进行净化研究。研究结果表明:在酸性萃取剂二壬基萘磺酸(DNNSA)含量固定的情况下,磷酯类萃取剂磷酸二异辛酯(P204)在一定范围内产生正协同作用;在磷酯类萃取剂PS含量固定时,添加P204可完全产生正协同作用,且PS与P204复合萃取剂的协同萃取效果优于DNNSA与P204复合萃取剂的协同萃取效果;当PS质量分数为62.20%、P204质量分数为7.17%时,镁离子的萃取率最高,可达57.4%。     

溶剂萃取法脱除湿法磷酸中锰离子的实验研究

利用四川大学自主研发的萃取剂P1萃取湿法磷酸中的锰离子,研究反应时间、反应温度、相比、初始锰离子浓度、SO3以及P2O5含量对锰离子萃取率的影响。结果表明:萃取剂P1对湿法磷酸中锰离子有良好的萃取效果,在相比为3时,P1对锰离子的单级萃取率约为35%;反应温度、初始锰离子浓度对锰离子的萃取率在实验范围内几乎无影响;氢离子浓度越高,锰离子的萃取率越低。     

磷矿伴生稀土提取研究进展

磷矿中伴生的稀土含量虽少,但它却是一种潜在的稀土资源,对其进行提取研究具有重要意义。介绍了国内外磷矿伴生稀土的概况。综述了磷化工过程提取稀土的方法及研究进展。对未来磷矿伴生稀土提取技术的研究进行了探讨。磷矿主要用于生产磷酸和磷肥,湿法为生产磷酸和磷酸盐的主要方法。根据分解酸的不同,湿法磷酸工艺包括盐酸法、硝酸法和硫酸法。指出:硫酸法是生产磷酸的主要方法,如何提高稀土在磷酸中的富集程度,同时研发高效、经济的萃取剂,将是今后提取稀土的主要研究方向。     

赤泥磷酸浸出液中稀土的萃取行为研究

赤泥是铝土矿生产氧化铝过程中产生的固体残渣，含有铁、硅、铝、钛及稀土等多种有价组分。在已预先分离赤泥中大部分铁、硅、铝、钛的前提下，采取溶剂萃取的方式对赤泥磷酸浸出液中的稀土作进一步分离与纯化，研究了在中性磷型萃取剂TBP、酸性磷型萃取剂P204和P507分别作用下，稀土La、Ce、Sc、Y以及主要杂质组分Al、Fe、Ti、Ca的萃取行为，结果表明：TBP对稀土的萃取效果较差，P507对稀土Sc、Y及杂质Fe、Ti的萃取能力较强，P204萃取稀土的能力优于P507;采用质量分数2%P204作为萃取剂，在溶液pH为1.5、相比为1∶3的条件下，磷酸浸出液中Sc、Y的萃取率分别为90%、99%,La、Ce及杂质Fe、Al、Ti、Ca萃取率均低于5%;将P204质量分数升至20%,La、Ce萃取率可分别达到85%、95%。因此可通过采用P204分步萃取的方式有效分离磷酸浸出液中的稀土。     

Recovery of lanthanides from kola apatite in phosphoric acid manufacture

The paper presents the results of bench-scale studies for the recovery of lanthanides from Kola apatite in the phosphoric acid production by a two-stage hemihydrate-dihydrate wet-process. The second stage of the process (hydration of hemihydrate) provides the best conditions for the recovery of lanthanides. In the postulated recovery process use is made of solvent extraction for the removal of lanthanides during hydration of hemihydrate, and precipitation-stripping for the removal of lanthanides from the solvent. Lanthanides are recovered in the form of Ln-enriched concentrates with an efficiency of 80–85%. The process does not disturb the phosphoric acid production, and additionally purifies the by-product gypsum, so that it can be utilized.     

Application of Polybutadiene-Based Polymeric Surfactants in Liquid Membrane Separation

Abstract

New polybutadiene-based surfactants (LYF) were synthesized by sulfonation of liquid polybutadiene with acetal sulfate at an elevated temperature, and their properties in a liquid surfactant membrane (LSM) separation process were examined by comparison with the two polyisobutylene-based surfactants ECA4360 and EM301. It was found that LYF surfactants had satisfactory overall properties as regards stability, swelling, and demulsification of the W/O emulsion in the cases of both acidic and caustic internal aqueous phases.     

高含磷制药废水处理试验研究

以台州某药业公司高磷废水为研究对象,分别采用CaCl2沉淀法和鸟粪石结晶法对其进行试验研究.探讨了CaCl2投加量和pH值对废水中总磷去除率的影响,并在此基础上研究了pH值、n(N)∶n(P)、n(Mg)∶n(P)对鸟粪石生成的影响.试验结果表明,在水样进水总磷的质量浓度(以P计)为374.50 mg/L,pH值为10...     

污泥发酵液中磷回收的优化研究

确定鸟粪石沉淀法回收污泥发酵液中磷的最佳优化工艺参数。在单因素试验的基础上,采用响应曲面分析法对鸟粪石沉淀法回收污泥发酵液中PO43--P和NH4+-N的影响条件进行了优化分析和探讨。采用实验设计软件Design-Expert的中心组合设计,以pH、Mg/P摩尔比为自变量,以PO43-P回收率为响应值进行分析,预测最佳优化工艺参数。预测结果:pH 9.58,镁磷比值1.2时,污泥发酵液回收磷效果最好,PO43--P去除率可达90.70%。通过试验验证,预测值与实验值接近。响应曲面分析法对鸟粪石沉淀法回收污泥发酵液中氮磷的工艺参数优化合理。     

以D2EHPA-TOPO为载体的乳化液膜体系萃取磷酸中La（Ⅲ）的工艺及传质机理研究

通过以二（2-乙基己基）磷酸酯／氧化三辛基膦（D2EHPA／TOPO）为流动载体,磺化聚丁二烯（LYF）为表面活性剂,液体石蜡为膜增溶剂,煤油为稀释剂,盐酸为内水相的W／O型乳液,与含La（Ⅲ）的磷酸的外水相进行萃取的过程,制备了W／O／W的双重乳化液膜体系,用单因素法考察了载体浓度,表面活性剂浓度,内相酸度,水乳比等对液膜提取率的影响,确定了最佳工艺条件,迁移率达94．21％以上。并以单浓度递变斜率法研究了载体浓度,表面活性剂浓度,磷酸浓度,H2PO4^-浓度,水相平衡H^＋浓度对分配比的影响,推导出了该乳化液膜的传质机理所经历的步骤。传质机理中包括萃取-反萃表达式,和协萃物组成La（H2PO4）L2（HL）2·（H3PO4）·2TOPO。     

钒渣钠化焙烧熟料浸出液除磷工艺研究

以钒渣钠化焙烧熟料浸出后得到的含钒溶液为原料,分析了二水硫酸钙在碱性条件下对含钒溶液中磷的去除机制,研究了二水硫酸钙用量、溶液pH、反应时间、反应温度等因素对磷去除率、钒损失率以及溶液中五氧化二钒与磷质量浓度比的影响。研究结果表明：在弱碱性条件下,二水硫酸钙可有效去除含钒溶液中的磷,磷去除率达到70%以上、钒损失率小于1%、五氧化二钒与磷质量浓度比大于2 300,满足后续沉钒的要求。确定的除磷工艺条件：二水硫酸钙与磷物质的量比为5.3,溶液pH为9.0,反应时间为30 min,反应温度为25 ℃。除磷后的含钒溶液经沉钒、洗涤、煅烧得到五氧化二钒产品,沉钒率大于99%,五氧化二钒产品质量满足YB/T 5304—2011《五氧化二钒》中99级的要求。     

长泥龄改良A2/O工艺的短程硝化反硝化除磷

为解决传统A²/O工艺硝化与除磷泥龄(SRT)之间的矛盾,进一步提高低C/N(P)比生活污水同步脱氮除磷效率,采用一种改良A²/O工艺在长SRT条件下处理生活污水.试验结果表明,该工艺可有效筛选和强化反应器内活性污泥,并大量富集长SRT的反硝化除磷菌(DPAO).通过亚硝酸盐氧化菌(NOB)淘洗阶段后,反应器在SRT=19.6d、A²O段污泥浓度(MLSS)=5.5 g·L^-1、水力停留时间(HRT)=8.2 h、污泥回流比(R)=90%、硝化液回流比(r)=250%、溶解氧(DO)=1.5～0.3 mg·L^-1,间歇曝气段HRT=4 h、曝气周期1 h曝气1 min(DO=0.3～0.5 mg·L^-1)、沉淀59 min条件下长期运行,COD、NH₄⁺-N、TP和TN的平均去除率分别为88.71%、99.2%、93.77%和89.52%,出水亚硝化率(NO₂^--N/NO_x^--N)可达97.2%,DPAO占聚磷菌(PAO)比为95.5%.污水中约72.96%的COD被DPAO合成PHA除磷,15.75%的COD由异养反硝化消耗,约41.96%和31.31%的N分别通过反硝化除磷和异养反硝化去除.剩余污泥主要由DPAO和反硝化菌增殖产生,分别占82.74%和17.24%,较传统脱氮除磷途径减少了58.76%的碳源消耗和44.6%的污泥排放.     

Application of the Stover–Kincannon kinetic model to nitrogen removal by Chlorella vulgaris in a continuously operated immobilized photobioreactor system

BACKGROUND: The aim of this study was to evaluate the ammonium nitrogen removal performance of algae culture Chlorella vulgaris in a novel immobilized photobioreactor system under different operating conditions and to determine the biokinetic coefficients using the Stover–Kincannon model. RESULTS: The photobioreactor was continuously operated at different initial ammonium nitrogen concentrations (NH₄‐N₀ = 10–48 mg L⁻¹), hydraulic retention times (HRT = 1.7–5.5 days) and nitrogen/phosphorus ratios (N/P = 4/1–13/1). Effluent NH₄‐N concentrations varied between 2.1 ± 0.5 mg L⁻¹ and 26 ± 1.2 mg L⁻¹ with increasing initial NH₄‐N concentrations from 10 ± 0.6 mg L⁻¹ to 48 ± 1.8 mg L⁻¹ at θ_H = 2.7 days. The maximum removal efficiency was obtained as 79 ± 4.5% at 10 mg L⁻¹ NH₄‐N concentration. Operating the system for longer HRT improved the effluent quality, and the percentage removal increased from 35 ± 2.4% to 93 ± 0.2% for 20 mg L⁻¹ initial NH₄‐N concentration. The N/P ratio had a substantial effect on removal and the optimum ratio was determined as N/P = 8/1. Saturation value constant, and maximum substrate utilization rate constant of the Stover–Kincannon model for ammonium nitrogen removal by C. vulgaris were determined as K_B = 10.3 mg L⁻¹ d⁻¹, U_max = 13.0 mg L⁻¹ day⁻¹, respectively. CONCLUSION: Results indicated that the algae‐immobilized photobioreactor system had an effective nitrogen removal capacity when the operating conditions were optimized. The optimal conditions for the immobilized photobioreactor system used in this study can be summarized as HRT = 5.5 days, N/P = 8 and NH₄‐N₀ = 20 mg L⁻¹ initial nitrogen concentration to obtain removal efficiency greater than 90%. Copyright © 2008 Society of Chemical Industry     

The beneficial role of intermediate clarification in a novel MBR based process for biological nitrogen and phosphorus removal

BACKGROUND: A novel membrane bioreactor (MBR) is described, employing an intermediate clarifier. Unlike the established function of a final clarifier in a conventional biological nutrient removal system, the role of an intermediate clarifier has rarely been studied. Thus, this work focused on explaining the fate of nutrients in the intermediate clarifier, as influenced by the hydraulic retention time (HRT) of the preceding anaerobic bioreactor. RESULTS: The system was tested with two different anaerobic/anoxic/aerobic biomass fractions of 0.25/0.25/0.5 (run 1) and 0.15/0.35/0.45 (run 2) using synthetic wastewater. The major findings of the study were that phosphorus (P) removal was affected by the role of the intermediate clarifier. In run 1, P was removed at a rate 0.16 g d⁻¹ in the intermediate clarifier while in run 2, additional P was released at 0.49 g d⁻¹. The nitrogen (N) removal efficiencies were 74 and 75% for runs 1 and 2 respectively, while P removal was 91 and 96%. P uptake by denitrifying phosphate accumulating organisms (DPAOs) accounted for 41–52% of the total uptake in the MBR. CONCLUSIONS: This study found that the intermediate clarifier assisted chemical oxygen demand (COD), N, and P removal. With respect to the fate of P, the intermediate clarifier functioned as an extended anaerobic zone when the HRT of the preceding anaerobic zone was insufficient for P release, and as a pre‐anoxic zone when the anaerobic HRT was adequate for P release. Copyright © 2008 Society of Chemical Industry     

进水C/P比对A2/O工艺性能的影响

我国当前面临着严重的水体富营养化问题,A²/O工艺是一种有效的同步脱氮除磷工艺,但其中进水C/P比是其运行效果的重要影响因素,为深入考察不同进水C/P比对A²/O工艺运行性能的影响,试验设计了4种进水C/P比 (55、45、34、23),研究了A²/O工艺中COD、总氮、磷和污泥特性的变化.实验结果表明,当进水C/P比小于32时,磷的去除效果随C/P比的降低而线性降低;当进水C/P比高于32时,磷的去除效果稳定在90%～98%,出水磷浓度小于0.5 mg•L^-1.但是C/P比的变化,对COD和总氮的去除率影响较小,平均去除率分别高于90%和75%.而剩余污泥中磷含量则随C/P比的下降而增加.实验发现,不同C/P比系统均存在反硝化除磷现象,可以实现“一碳两用”,有利于氮磷去除效果的提高.