难处理铅锌矿酸浸渣回收硫酸铅的工艺研究

采用氯化钠-硫酸混合溶液对铅锌矿难处理酸浸渣进行浸出,对浸出液稀释,制备硫酸铅,考察了氯化钠浓度、液固比、时间、温度和硫酸浓度等因素对酸浸渣的浸出影响和考察稀释倍数、时间等因素对沉淀硫酸铅的影响。结果表明,在氯化钠浓度为330 g/L,液固比为7∶1,时间为1.5 h,温度95℃,硫酸浓度为1 mol/L的条件下,铅的浸出率为82.1%;在浸出液稀释倍数为2.5,静置时间7 h的条件下,硫酸铅的沉淀率为93%,产品纯度为99.1%。铅的回收率为76%,比传统方法提高30%以上。     

火试金灰皿在乙酸-H2O体系中铅的浸出动力学

火试金灰皿是铅试金灰吹过程产生的废物,其综合处置对减少重金属污染和铅资源循环利用具有重要意义。灰皿主要成分为Al2O3和烧结MgO,熔点分别高达2054和2852℃,严重影响火法熔炼的正常进行。实验选用乙酸-H2O体系,可以有效避免镁铝氧化物的影响,分析了铅的浸出热力学过程,考察了乙酸过量系数、浸出温度、反应时间、搅拌速度、液固比等因素对铅浸出率的影响,并进行了浸出动力学研究。结果表明,溶液中乙酸根离子摩尔分数增加,铅离子与乙酸根离子更易形成难电离的乙酸铅络合物;在乙酸过量系数1.6、液固比6:1、温度80℃、搅拌速度200 r/min、反应40 min的优化条件下,铅的一次浸出率为98.31%,浸出渣进行二次浸出,浸出率为95.53%,总浸出率达99.96%;铅的浸出过程符合缩粒反应模型,反应速率受扩散控制,符合1-2/3φ-(1-φ)2/3=kt动力学方程,反应表观活化能Ea=38.949 kJ/mol。     

三水合乙酸铅在空气气氛下的热分解特性

通过热重分析技术(TG-DTA)和热重红外联用分析技术(TG-FTIR)等热分析技术研究三水合乙酸铅晶体在空气气氛条件下的热分解过程。其热分解过程中主要存在二氧化碳、丙酮和乙酸等中间产物。热解过程的关键转变温度为61.4℃、204.9℃、256.8℃、293.6℃、348.7℃。焙烧后铅粉的氧化度能够达到95%以上,视密度比传统球磨氧化铅粉低,吸水值高于传统的球磨氧化铅粉。研究结果对于三水合乙酸铅作为前体制备铅粉提供了参考依据。     

铅酸电池企业含铅废料湿法再生新技术

铅酸蓄电池目前仍然占据二次电池的最大市场份额,其生产过程中产生的含铅废料的回收仍以危废公司收集后采用传统火法冶炼再生为主,存在SO2污染严重、能耗高等问题。本文提出一种以柠檬酸结合氨水为浸出剂的湿法回收含铅废料的新工艺,制备柠檬酸铅前体,经过低温焙烧获取新型超细铅粉,并对该工艺浸出反应机理进行了初步探讨。新工艺的脱硫率能够达到99.9%左右,柠檬酸铅前体经过375℃低温焙烧,可制备氧化度超过93.0%的新型铅粉,与传统球磨氧化铅粉相比较,具有粒径较小、比表面积大等优点。新型铅粉经过循环伏安法（CV）分析,初步显示出良好的充放电的循环可逆性,所制备铅粉可以直接回用制备新电池。本文的研究为铅酸电池企业含铅废料的回收利用提供了一条新的途径。     

Coleaching behavior of lead of incineration ash waste mixtures

In this paper, the authors reported the coleaching behavior of lead of incineration ash waste mixtures, i.e., fabric filter residues [called fly ash (FA)] and semidry scrubber residues [called reaction product (RP)]. The leaching potential of lead metal of those mixtures was estimated by toxicity characteristic leaching procedure (TCLP) with acidic extractant. And it was found to be under the controls of dissolution rate and interparticulate interactions. The author has developed a linear regression equation to fit the coleaching behavior well, the equation is basing on the chemical compositions of (RP/FA) mixtures. The impact of this study is that the leaching toxicity of mixture could be reduced to be nonhazardous, just only to adjust the mixing ratio of these two ash wastes. And the authors are able to use these ash wastes for wider recycling applications without any intermediate stabilization treatment.     

沉淀转化法回收酸浸渣中铅的酸溶工艺研究

以金精矿焙烧-酸浸除杂后的酸浸渣与碳酸氢铵反应生成的转化渣为原料,进行酸溶浸铅工艺研究。通过正交实验考察了液固质量比、浸出pH和浸出时间等因素对铅浸出率的影响,得到最佳工艺条件：浸出液固质量比为2∶1、浸出液pH=0.5、浸出时间为2 h。在此条件下,金属铅浸出率可达83%。     

Lead recovery from waste frit glass residue of electronic plant by chemical-electrochemical methods

This work aims at recovering lead from frit glass waste of electronic plants by using the electrochemical method comprising two successive steps of lead leaching and electrodeposition. In the leaching step, it was found that nitric acid and acetic acid are better solutions for the dissolution of lead oxide compared with sodium hydroxide, hydrochloric acid, and sulfuric acid. More than 95% of the lead was leached by 0.1 M nitric acid or 0.5 M acetic acid at 0.5% weight by solid volume. In the electrodeposition step, more than 95% of lead can be removed with high current efficiency from the leaching solution at an optimum current density. The values of the optimum current density of 0.5 and 1 M acetic electrolytes were between 8.8–10 mA/cm², whereas those for 0.1 M and 0.5 M of nitric acid were 15 and 27.5 mA/cm², respectively.     

ZEOLITE SYNTHESIS FROM PAPER SLUDGE ASH VIA ACID LEACHING

Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content due to the presence of calcite fillers. Acid leaching with HCl was used to reduce the Ca content so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Zeolitic products were synthesized from raw ash and leached ash through reaction with 2.5 M NaOH solution at 80°C. In the case of the original ash without acid leaching, the concentration of Al in the alkali solution always exceeded that of Si during the synthesis, and hydroxysodalite with a low Si/Al ratio (1:1) was formed. In the case of the leached ash, the concentration of Si always exceeded that of Al during the synthesis, and zeolite-P with a higher Si/Al ratio (5:3) was formed. Hydroxysodalite and zeolite-P crystallization was saturated after 6 h of reaction, and the product from leached ash had a higher CEC (approximately 150 cmol/kg) than that from original ash (approximately 40 cmol/kg). Both the decrease in the Ca phase in the leached ash and the corresponding increase in the Si and Al amorphous phases play an important role in zeolite synthesis.     

ZEOLITE SYNTHESIS FROM PAPER SLUDGE ASH VIA ACID LEACHING

Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content due to the presence of calcite fillers. Acid leaching with HCl was used to reduce the Ca content so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Zeolitic products were synthesized from raw ash and leached ash through reaction with 2.5 M NaOH solution at 80°C. In the case of the original ash without acid leaching, the concentration of Al in the alkali solution always exceeded that of Si during the synthesis, and hydroxysodalite with a low Si/Al ratio (1:1) was formed. In the case of the leached ash, the concentration of Si always exceeded that of Al during the synthesis, and zeolite-P with a higher Si/Al ratio (5:3) was formed. Hydroxysodalite and zeolite-P crystallization was saturated after 6 h of reaction, and the product from leached ash had a higher CEC (approximately 150 cmol/kg) than that from original ash (approximately 40 cmol/kg). Both the decrease in the Ca phase in the leached ash and the corresponding increase in the Si and Al amorphous phases play an important role in zeolite synthesis.     

硅胶固载氧化镓非均相催化合成乙酸丁酯

在氧化镓固载量为20%,500℃焙烧2 h的条件下制备了硅胶固载氧化物型非均相酯化催化剂Ga2O3/S iO2,用于催化合成乙酸丁酯,考察了催化剂用量、n(正丁醇)∶n(乙酸)、环己烷用量、反应时间、带水剂用量和催化剂重复使用性等因素对酯化率的影响。结果表明,该催化剂催化合成乙酸丁酯的适宜反应条件为:乙酸0.2 mol,n(正丁醇)∶n(乙酸)=1.8,催化剂1.25 g,回流反应1 h,酯化率达99.62%。     

次氧化锌浸取净化新工艺

研究了以炼铅厂含锌烟灰为原料,经盐酸浸取、高锰酸钾氧化、锌粉置换制备氯化锌溶液的工艺。以锌的浸出率最高,杂质铅的浸出率最低,铁、锰、铅、镉、铜脱除最彻底为目标,实验得出最佳的酸浸和净化条件：40 g次氧化锌、71 mL浓盐酸、130 mL水在30 ℃下浸取50 min后,过滤,洗涤滤渣,滤液定容为250 mL,取200 mL滤液,滤液中加高锰酸钾0.013 6 g,10 ℃下氧化2 h后过滤,取200 mL二次滤液向其中加锌粉0.12 g,40 ℃下反应50 min后过滤,得浓度为1.63 mol/L的氯化锌溶液。在上述工艺条件下,锌的浸出率为94.2%,氯化锌溶液中杂质离子含量满足HG/T 2323-2012《工业氯化锌》中优等品的要求,可用来生产符合GB/T 19589-2004《纳米氧化锌》规定的Ⅰ类纳米氧化锌。     

合成乙酸异丁酯的催化剂研究进展

介绍了稀土金属氧化物、相转移催化剂、氨基磺酸、杂多酸、硫酸铁铵及无机盐等催化剂催化合成乙酸异丁酯的研究结果,其中氨基磺酸、杂多酸、硫酸铁铵、FeCl3·6H2O和CuCl2·2H2O的催化活性高,产品质量好。作者以硅胶负载四氯化锡为催化剂,合成乙酸异丁酯最佳反应条件为:乙酸为0.1mol,醇酸比为1.5∶1,催化剂用量为1.5g,反应时间为4h,反应温度150℃,最终转化率为93.87%。SnCl4/SiO2作为催化剂,活性高,选择性好,对设备无腐蚀,可重复使用。     

Bioinspired synthesis of novel teeth‐like hierarchical architecture polyaniline/lead tungstate nanocomposites with photoluminescence property

Large‐scale one‐step synthesis of novel teeth‐like hierarchical architecture polyaniline (PANI)/lead tungstate (PbWO4) nanocomposites has been achieved from aqueous solution by in situ polymerization at room temperature. The reaction conditions, such as pH value and the molar ratio, are found to play a crucial role in controlling the size and morphology of the products. The model of “nucleation‐growth‐assembly” is proposed to explain formation mechanism of the teeth‐like PANI/PbWO₄ nanocomposites. Interestingly, the larger size and higher crystallinity are beneficial to the improvement of photoluminescence (PL) intensity. POLYM. COMPOS., 35:516–522, 2014. © 2013 Society of Plastics Engineers     

K系维生素中间体β-甲基萘醌的合成工艺研究

本实验研究了一种新颖且环境友好的β-甲基萘醌的合成方法。该方法以冰醋酸为溶剂,OP-10为乳化剂,过氧化氢作为氧化剂,氧化p-甲基萘制取β-甲基萘醌。分别考察了反应温度、反应时间、β-甲基萘与冰醋酸摩尔比等因素对β-甲基萘醌转化率和收率的影响。从而得到较优反应条件为：反应温度100℃;反应时间4h;n（β-甲基萘）：n（冰醋酸）为1：16;n（β-甲基萘）：n（H2O2）为1：11;OP-10用量0．05ml／g（β-MN）。在此条件下,β-甲基萘醌的转化率可达96％,收率可达52％。     

N-甲酰-L-天冬氨酸酐的合成研究

N-甲酰-L-天冬氨酸酐是合成阿斯巴甜的中间体,为了减少副产物的生成,探索出工业生产中最佳的反应条件。以甲酸、乙酸酐和L-天冬氨酸为原料,氧化镁为催化剂,合成N-甲酰-L-天冬氨酸酐。探讨了反应温度、反应时间、甲酸、乙酸酐和催化剂的用量对反应收率和产物熔点的影响。结果表明,最佳的反应条件为:反应温度50℃,反应时间5 h,物质的量比n(氧化镁)∶n(甲酸)∶n(乙酸酐)∶n(L-天冬氨酸)=0.01∶1.2∶2.5∶1.0,此时产物的纯度较好,收率为85.5%。     

Fischer-Tropsch Synthesis: Reaction Pathways for 14C-Labeled Acetic Acid

Reaction pathways for ¹⁴C labeled acetic acid (at both carboxylic and methyl positions) added during Fischer-Tropsch synthesis over a doubly promoted fused iron catalysts were studied in a CSTR at 100 psig, 270 °C and ca. 90% CO conversion. The addition of acetic acid slightly affected the CO conversion but results in a significant reduction in H₂ conversion. Both the unlabeled and labeled acetic acid addition caused a large decrease in the alkene ratio for C₂ hydrocarbons as compared to an increase for the C₃ and C₄ hydrocarbons suggesting a direct formation pathway of ethane from added acetic acid. The 1-alkene/2-alkene fraction was found to increase significantly when acetic acid was added and returned to the original value once the addition is terminated, indicating inhibition of hydrogenation activity of the catalyst by acetic acid. Distribution of ¹⁴C suggests some C–C bond rupture and direct formation of ethane from labeled acetic acid. In the case of 1-¹⁴C labeled acetic acid addition, the gradual increase of the relative molar activity (¹⁴C content per mole) with carbon number reveals that ¹⁴C containing part of acetic acid initiate chain growth and also participates in the chain propagation for hydrocarbon formation in FTS. When acetic acid labeled at methyl position was added, the results indicated that ¹⁴C containing part of acetic acid participates in chain initiation only. The addition of acetic acid decreases methane and methanol selectivity while it increases ethanol, acetaldehyde and acetone selectivity in FTS. Reaction of acetic acid during FTS was found to produce products like ethyl butanoate, ethylene glycol, and its ether, 1,2-diethoxyethane which are not generally observed in the normal FTS product spectrum. The results indicate that acetic acid is not a significant intermediate in FTS with an iron catalyst. ¹⁴C-distribution in most of the labeled oxygenate compounds are consistent with the hydrogenation of the acetic acid to acetaldehyde and/or ethanol as primary products followed by secondary reaction of these two primary oxygenate products.     

三价铁离子浓度对As(V)-Fe(II)-Fe(III)体系沉淀臭葱石的影响

在常压、95℃、初始pH=1.5的条件下,研究了As(V)–Fe(II)–Fe(III)体系中初始Fe(III)浓度对砷的去除率和臭葱石合成的影响。结果表明,溶液中初始Fe(III)/As(V)摩尔比为0时,沉淀产物为结晶度良好的臭葱石,但砷的去除率仅为24.3%,沉淀浸出砷浓度高于国标规定的浓度限值5 mg/L。溶液中初始Fe(III)/As(V)摩尔比大于0时,在升温过程中生成了无定形砷酸铁,当初始Fe(III)/As(V)摩尔比不超过1.6时,砷酸铁反应8 h后转化为臭葱石;随初始Fe(III)/As(V)摩尔比增大,砷的去除率增大,臭葱石沉淀的结晶度降低、浸出砷浓度降低;其中,初始Fe(III)/As(V)摩尔比为0.8和1.6时,臭葱石沉淀的浸出砷浓度低于5 mg/L,适合安全堆存。当初始Fe(III)/As(V)摩尔比大于1.6时,无定形砷酸铁反应8 h仍不能转化成臭葱石,砷的去除率降低,沉淀浸出砷浓度超标,不适合安全堆存。     

钒铅锌矿硫酸浸出提取钒锌

钒铅锌矿含有多种有价金属,V品位高,具有较高的经济价值。本工作采用硫酸浸出法从该矿中提取钒锌,对浸出过程热力学进行分析,通过条件实验研究硫酸浓度、液固比、浸出时间、搅拌速率、浸出温度等条件对钒、铅、锌等主要有价金属浸出率的影响。结果表明,在较高pH值及较高温度下,浸出液中V会出现水解,含V的水解产物留在浸出渣中影响V浸出率。得到最优浸出条件为：硫酸浓度200 g/L,液固比3:1,浸出时间30 min,搅拌速率200 r/min,浸出温度为30℃。最优条件下V浸出率可达97.90%,Zn浸出率为97.11%,Fe浸出率<1%,Pb浸出率<0.01%。动力学分析结果表明,浸出过程的反应速率受扩散过程控制。酸浸过程使V和Zn进入浸出液,Pb和Fe留在浸出渣中,所得浸出液可使用离子交换或萃取法分离V和Zn。浸出渣中含钒0.41wt%、锌0.61wt%、铁15.50wt%、铅47.70wt%,主要成分为PbSO₄和FeO(OH),可返回火法炼铅系统。     

N-甲酰-L-天冬氨酸酐的合成

在乙酸酐溶剂中 ,以氧化镁为催化剂 ,L 天冬氨酸与甲酸进行甲酰化反应并脱水生成N 甲酰 L 天冬氨酸酐。考察了温度、时间、甲酸和乙酸酐用量比对反应的影响 ,得到了优化的反应条件为 :反应温度 5 0℃ ,反应时间 5h ,甲酸与L 天冬氨酸的物质的量比为 1 6∶1 0 ,乙酸酐与L 天冬氨酸的物质的量比为 2 3∶1 0 ,此时产物收率达 90 35 %。     

Preparation,Characterization of Dawson-type Heteropoly Acid Cerium (III) Salt and Its Catalytic Performance on the Synthesis of n-Butyl Acetate

A novel cerium (III) salt of Dawson type tungstophosphoric acid (Ce₂P₂W₁₈O₆₂·16H₂O) was prepared by doping cerous nitrate in H₆P₂W₁₈O₆₂·13H₂O powder and characterized by thermogravimetry and differential thermal analyses (TG/DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), pyridine infrared spectroscopy (Py-IR) and scanning electron microscopy (SEM). Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol. The effects of various parameters such as molar ratio of n-butanol to acetic acid, reaction temperature, reaction time, and catalyst amount have been studied by single factor experiment. The results show that Ce₂P₂W₁₈O₆₂·16H₂O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate. The optimum synthetic conditions were determined as follows:molar ratio of n-butanol to acetic acid at 2.0:1.0, mass of the catalyst being 1.44% of the total reaction mixture, reaction temperature of 120 ℃ and reaction time of 150 min. Under above conditions, the conversion of acetic acid was above 97.8％. The selectivity of n-butyl acetate based on acetic acid was, in all cases, nearly 100%. The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction. It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products. Compared with using sulfuric acid as catalyst, the present procedure with Ce₂P₂W₁₈O₆₂·16H₂O is a green productive technology due to simple process, higher yield, catalyst recycling and no corrosion for the production facilities.