过氧化氢与TS-1/2稳定剂法脱硫工艺的生产实践

阐述了过氧化氢与TS-1/2稳定剂法脱硫技术的原理及特点.采用w（H2O2）27.5％的过氧化氢溶液作为吸收剂,回收SO2后可产生w（H2SO4）20％ ～30％的稀硫酸并返回干吸工序使用,脱硫效率高,脱硫后排放的尾气中ρ（SO2） ＜200 mg/m3,远低于新国标规定的排放限值.     

过氧化氢脱硫法在硫酸工业尾气处理中的应用

二氧化硫是硫酸工业尾气中的主要有害成分,其处理工艺的研究一直以来都是硫酸工业的重要工作内容。阐述了用过氧化氢法脱硫技术的原理及特点;经工业化应用,效果稳定可靠,采用w(H2O2)=0.1%～1.0%的过氧化氢做脱硫剂,可回收w(H2SO4)=20%～30%的稀硫酸并返回干吸工序,脱硫效率高,脱硫后排放的尾气中ρ(SO2)<20 mg/m3,远低于新国标排放限值的要求。     

过氧化氢与TS-1/2稳定剂法脱除硫酸尾气中二氧化硫的应用

二氧化硫是硫酸尾气中的主要有害成分,其处理工艺的研究一直以来都是硫酸工业的重要工作。阐述了过氧化氢法脱硫技术的原理及特点;采用w(H2O2)27.5%的过氧化氢作脱硫剂,可回收w(H2SO4)20%~30%的稀硫酸并返回干吸工序,脱硫效率高,脱硫后排放的尾气中ρ(SO2)20mg/m3,远低于新国标排放限值。     

双氧水法硫酸尾气脱硫实践

介绍了天津渤大硫酸工业有限公司双氧水尾气脱硫装置的工艺流程、主要设备、控制仪表和运行情况。为确保尾气达标排放,该装置在脱硫塔后增加一级电除雾器,排放气体ρ(SO2)为200mg/m3,硫酸雾质量浓度为5 mg/m3。针对w(H2O2)27.5%双氧水的储存使用、尾气排放设备腐蚀等问题,提出了相应的优化措施。     

湿法过磷酸钙生产中矿浆浓度的确定

两个方面:(1)矿浆的流动性满足生产要求;(2)产品的水分满足标准要求。现以开阳矿为例,浅析过磷酸钙生产中矿浆浓度(此文均指矿浆中水的质量分率)的确定:磷矿化学组成(见表1),硫酸浓度w(H2SO4)98%。表1　开阳磷矿组成%w(P2O5)w(SiO2)w(CaO)w(MgO)w(Fe2O3)w(Al2O3)w(I.L)34.22.9952.191.260.830.34.591　过磷酸钙生产中硫酸理论用量(1)　磷矿石中氟磷酸钙Ca5(PO4)3F与硫酸H2SO4反应消耗的硫酸量1000kg磷矿中P2O5消耗H2SO4量:　　1000×0.342×1.61=550.62kg式中　1.61为1kgP2O5消耗H2SO41.61kg。(2)　磷矿中其它成分消耗H2SO4…     

液相催化氧化法脱除烟气中SO2的研究

采用含Mn2 的吸收液催化氧化脱除烟气中SO2,研究了吸收液硫酸浓度、吸收液催化剂浓度、气体分布器和气体流量等控制条件对SO2的吸收率的影响。试验结果表明,采用w(MnSO4)为0.05%~1.00%的吸收液,其中的w(H2SO4)为2%~6%,选择理想的吸收设备,脱硫率可达98%以上。针对中小型燃煤锅炉中的废气和硫酸生产尾气,液相催化氧化法是一种很有前途的脱硫方法。     

SO4^2—改性交联蒙脱土固体酸催化合成水杨酸正丁酯

制备了SO4^2—改性硅锆双组分交联蒙脱土固体酸催化剂(SO4^2—／SiZrM)，用于水杨酸(C7H6O3)和正丁醇(C4H10O)的酯化反应，与传统酯化反应催化剂浓硫酸、磷钨酸、硫酸铁铵以及其他单组分交联剂交联的蒙脱土做酯化反应的催化剂相比，SO4^2—／SiZrM有更好的催化活性。考察了带水剂的选择、酸酵量比[n(C7H6O3)：n(C4H10O)]、催化剂用量[w(SO4^2—／SiZrM)]、反应时间(t)、反应温度(θ)对催化合成水杨酸正丁酯(C11H14O3)的影响，并对合成的产物进行了折光率、红外光谱分析。酯化反应的最佳条件为：C4H10O为带水剂、n(C7H6O3)：n(C4H10O)＝1：1．65、催化剂占酸投料质量的百分比为w(SO4^2—／SiZrM)＝6．5％、t＝6h、θ＝120～135℃，水杨酸的转化率可达88．22％，产物中w(C11H14O3)＞99．9％。     

脱硫石膏在水泥生产中的试验

<正>1脱硫石膏的小磨试验(1)脱硫石膏的化学成分分析。脱硫石膏外观呈细腻粉状、比较潮湿(水分为20%),其w(SO3)=40.91%,水硫比=0.37;而进厂的天然石膏的w(SO3)=34.56%,水硫比=0.34;脱硫石膏主要成分为CaSO4·2H2O,与天然石膏基本相似。     

加压注浆法用于酸槽(罐)快速补漏

目前,过磷酸钙生产稀硫酸一般采用钢壳、内有防腐衬里的硫酸储槽(罐)。对于w(H2SO4)76%硫酸,在常温下亦可采用钢制储罐。但通常考虑酸温、酸浓的波动,特别是当采用稀硫酸回流的流程时,w(H2SO4)常低于76%,因而也和对待稀硫酸一样,采用钢壳内有防腐衬里的硫酸储罐(普通过磷酸钙工艺设计手册,化学工业出版社,第166页)。其最经济的也是较为普遍采用的衬里防     

7-乙基-喜树碱的合成

以喜树碱为原料合成了7 乙基 喜树碱。考察了多种因素对反应的影响,确定了较理想的反应条件:3g喜树碱,4 5mL丙醛,1 8mLw(H2O2)=30%的双氧水,2 5gFeSO4·7H2O,9mLw(H2SO4)=98%的浓硫酸,在2～3℃反应1 5h,粗产品收率88%,以HPLC分析,w(7 乙基 喜树碱)=93 8%。     

汽车粉碎残渣中提取金属:不同浸出体系的初步实验结果(英文)

The study is focused on the extraction of valuable metals from automotive shredder residue (ASR) by different leaching solutions. First, ASR samples were roasted at 600 °C to simulate a thermal treatment processing. Distil ed water, citric and sulphuric acid were preliminarily investigated, thus two further full factorial systems entailing H2SO4–H2O2 and H2SO4–H2O2–Fe3+ were tested. The preliminary experimental results showed that 0.1 mol·L?1 H2SO4 solution extracted 100%of Cu, Fe and Zn, whereas citric acid leached 100%of Zn and Pb, 59%of Fe and 62%of Cu;whereas, H2SO4–H2O2 and H2SO4–H2O2–Fe3+(Fenton's) leaching media showed that Cu, Fe and Zn can be extracted simultaneously and completely from the ASR ashes before final disposal.     

Effects of mechanical activation on the digestion of ilmenite in dilute H2SO4

The commercial sulfate process for pigment production uses concentrated sulfuric acid(N 85 wt% H_2SO_4) as feeding material and discharges 8–10 tons of spend dilute acid(20 wt% H_2SO_4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO_2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model(SCM), incorporation of particle size distribution(PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid(60 wt% H_2 SO_4) practicable and the re-use of spend acid becomes possible and economical.     

双极膜电渗析法连续制备聚合硫酸铁

研究了双极膜电渗析法连续制备聚合硫酸铁（PFS）的工艺。主要考察了电流密度、原料补充液中硫酸亚铁和硫酸的摩尔比以及原料补充液流速对产品PFS各性能指标（盐基度、全铁含量、pH、密度等）和过程能耗的影响。研究结果表明：电流密度从10mA/cm²增加到20mA/cm²时,盐基度从8.59%显著增加到11.32%,去浊率从84.31%逐渐增加到95.34%,但当电流密度大于20mA/cm² 时,盐基度和去浊率稍有下降,过程能耗最高可达4.26kW·h/kg H₂SO₄,酸液罐酸浓度最高可达0.45mol/L;原料补充液中硫酸亚铁和硫酸的摩尔比从2.01增加到4.08时,盐基度从8.69%增加到11.38%,去浊率从94.96%逐渐增加到95.88%,能耗在3.05~3.15kW·h/kg H₂SO₄ 范围内变化,酸液罐酸浓度约为0.38mol/L;原料补充液流速从1mL/min增加到3mL/min时,盐基度从11.52%下降到6.75%,去浊率从95.92%逐渐降低到75.61%,同时,能耗从3.09kW·h/kg H₂SO₄下降到2.77kW·h/kg H₂SO₄。     

Electrochemical behaviour of the antimony electrode in sulphuric acid solutions—III. identification of corrosion products after long-term polarization

During the oxidation of pure antimony (Sb) in sulphuric acid (H₂SO₄) solutions a passivating layer is formed on the electrode surface. In the early stage of oxidation the layer consists of amorphous Sb oxide and/or hydroxide, but with longer oxidation times aggregates of whisker-like crystals of a trivalent oxidation product, Sb₄O₄(OH)₂SO₄, are formed. The identification of this compound was done by ex situ X-ray powder diffraction, and the result was confirmed by electron microprobe and X-ray photoelectron spectroscopic analysis. By means of an extraction procedure succeeded by atomic absorption spectrometric analysis it was shown that the Sb ions dissolved during the oxidation exist in H₂SO₄ in the trivalent state even at potentials well above the equilibrium potential of the Sb(V)/Sb(III) couple.     

Pt-H2SO4/Zr-montmorillonite:An efficient catalyst for the polymerization of octamethylcy-clotetrasiloxane,polymethylhydrosiloxane and hexamethyldisiloxane to low-hydro silicone oil

The liquid phase ring-opening of octamethylcy-clotetrasiloxane (D4) was investigated over Pt-H2SO4/Zr-montmorillonite catalyst.Montmorillonite(Mt),Zr-Mt,H2SO4/Mt,H2SO4/Zr-Mt and Pt-H2SO4/Zr-Mt were also detected for evaluation.The catalysts were characterized by X-ray fluorescence,X-ray diffraction,nitrogen adsorption-desorption,NH3-TPD and pyridine-FTIR measurements.In comparison to activate clay which is used in the industry of catalyst,Zr-Mt catalyst displayed stronger acidity and more excellent catalytic activity in the polymerization of D4,polymethylhydrosiloxane(D4H)and hexamethyldisiloxane(MM)to low-hydro sili-cone oil.Relative to Zr-Mt,the acidity of H2SO4/Zr-Mt was noticeably improved and the catalyst exhibited a higher capability of ring-opening of D4conversion and yield of low-hydro silicone oil.To enhance the stability of H2SO4/Zr-Mt catalyst,a small amount of metals(Pt)was doped.The nitrogen adsorption-desorption results indicated that pore textural parameters of the Pt-H2SO4/Zr-Mt had not changed with larger specific surface area.Compared with H2SO4/Zr-Mt,the total acidity of Pt-H2SO4-Zr/Mt catalyst retained,but the content of the Br?nsted acid increased and the content of the Lewis acid decreased.The Pt-H2SO4-Zr/Mt catalyst displayed higher catalyst reproducibility.After 40 h reaction of polymerization,the yield of low-hydro silicone oil decreased from 93% to 42% over H2SO4/Zr-Mt catalyst,while the yield of low-hydro silicone oil reduced from 93% to 78% over Pt-H2SO4/Zr-Mt catalyst.A sharp decrease in catalytic activity after 35 h of Pt-H2SO4/Zr-Mt catalyst was detected.Furthermore,Pt-H2SO4/Zr-Mt was completely regenerated under appropriate condition and appeared good repeatability in the D4,D4H and MM to low-hydro silicone oil.     

Synthesis,characterization and electrochemical evaluation of anticorrosion property of a tetrapolymer for carbon steel in strong acid media

A novel tetrapolymer(TP) consisting of carboxylate, sulphonate, phosphonate and sulfur dioxide based comonomers was synthesized using Butler cyclopoymerization technique. The synthesized tetrapolymer was characterized using FTIR,1 H-NMR,~(13)CNMR and elemental analysis. The performance of the tetrapolymer as a corrosion inhibitor for St37 carbon steel in 15% HCl and 15% H_2SO_4 acid media was assessed using electrochemical impedance spectroscopy(EIS), linear polarization resistance(LPR), potentiodynamic polarization(PDP) and electrochemical frequency modulation(EFM) techniques. The influence of addition of a small amount of KI on the corrosion inhibition efficiency of TP was also assessed. Results obtained showed that the tetrapolymer moderately inhibited the corrosion of St37 steel in the acid media with protection efficiency of 79.5% and 61.1% at the optimum concentration of 1000 mg·L~(-1) studied in HCl and H_2SO_4 media respectively. On addition of 5 mmol·L~(-1) KI to the optimum tetrapolymer concentration, the protection efficiency was upgraded to 90.6% and 93.5% in HCl and H_2SO_4 environment, respectively. The enhanced performance of the polymer in the presence of KI is due to synergistic action deduced from synergism parameter(S1) which was found to be greater than unity.The tetrapolymer afforded the corrosion inhibition of St37 steel in the acid media by virtue of adsorption of the polymer molecules on the steel surface which was confirmed by ATR-FTIR analysis of the adsorbed film extracted from the steel surface. TP + KI formed complex with St37 steel surface in H_2SO_4 solution but not in HCl solution.     

硫酸-糖蜜酒精废液浸出软锰矿的动力学(英文)

The kinetics of reductive leaching of manganese from low grade pyrolusite in dilute sulfuric acid in the presence of molasses alcohol wastewater was investigated. The shrinking core model was applied to quantify the effects of reaction parameters on leaching rate. The leaching rate increases with reaction temperature, concentrations of H 2 SO 4 and organic matter in molasses alcohol wastewater increase and ore particle size decreases. The leaching process follows the kinetics of a shrinking core model and the apparent activation energy is 57.5 kJ·mol –1 . The experimental results indicate a reaction order of 0.52 for H2SO4 concentration and 0.90 for chemical oxygen demand (COD) of molasses alcohol wastewater. It is concluded that the reductive leaching of pyrolusite with molasses alcohol wastewater is controlled by the diffusion through the ash/inert layer composed of the associated minerals.     

Some experimental observations of aerosol formation in the photo-oxidation of sulphur dioxide

The formation of particles in the u.v. photolysis of ppm concentrations of SO₂ in pure nitrogen and in nitrogen-oxygen mixtures has been studied in a flow system. Both the number of particles and the mass of the H₂SO₄ aerosol produced was determined over a range of SO₂ and water vapour concentrations.

In the near u.v. (λ = 290–400nm) the mass conversion of SO₂ to H₂SO₄ was too small to be measured, but particles were detected on a condensation nucleus counter above a threshold SO₂ concentration when the H₂SO₄ formation rate was sufficient to achieve an appreciable nucleation rate. The number of stable particles formed increased with water vapour concentration at a given H₂SO₄ production rate. These experimental data agree reasonably well with recent theoretical calculations of aerosol nucleation and growth rate in the H₂SO₄/H₂O system.

At short wavelengths (λ = 185 nm) a much higher H₂SO₄ formation rate was achieved. Although nucleation occurred at < 1 per cent r.h. the aerosol growth process was slow at low water vapour concentrations. A r.h. of 30 per cent was required for the incorporation of the bulk of the H₂SO₄ into the aerosol phase.     

新型纳米SO42-/TiO2催化剂制备及催化合成醋酸丁酯

采用高压水热法合成纳米锐钛矿相TiO₂前驱体,通过H₂SO₄溶液浸渍制备系列新型SO₄^2-/TiO₂催化剂,采用XRD、TG-DTG和TEM对其结构和形貌进行表征,并用于催化醋酸与正丁醇的酯化反应,考察H₂SO₄溶液浓度、浸渍时间和反应时间对酯化率的影响。结果表明,在H₂SO₄浓度1 mol·L^-1、浸渍时间12 h和反应时间180 min条件下,酯化率高达99.2%,催化剂具有优异的催化性能和较佳的重复使用性。     

Kathodisches Verhalten von konzentrierter Schwefelsäure

The cathodic behaviour of 85–100% sulphuric acid was investigated in relation to cathode material, temperature and water concentration. The basic curve is situated at relatively negative potentials in 85–92% sulphuric acid; electroreductions are therefore possible in this solvent. At low water concentrations, the basic curve rises to much more positive potentials, due to the reduction of the H₂SO₄ molecule. A sequence with various cathode materials is obtained, which follows the well known sequence for the hydrogen overpotential.

A “prewave” (at –140 mV(sce) for mercury and +500 mV (sce) for platinum cathodes) increases strongly in water-poor systems. It is explained as the reduction of solvated SO₃, which is in equilibrium with H₂SO₄. The electron number is 2.

Practical consequences in reference to the material for electrodes and diaphragms for electro-reductions in this system are discussed.

Zusammenfassung

Le comportement cathodique de l'acide sulfurique à 85–100% a été étudié en relations avec la substance cathodique, la température et la teneur en eau. La courbe de base se situe à des potentiels relativement négatifs dans l'acide sulfurique à 85–92%; les électro-réductions sont par conséquent possibles dans ce solvant. Pour de faibles teneurs en eau, la courbe de base atteint des potentiels plus positifs, ce qui est dû à la réduction de la molécule H₂SO₄. On obtient un ordre de classement des diverses substances cathodiques; il concorde avec celui bien connu relatif aux surtensions d'hydrogène.

Une “pré-vague” cathodique (à −140 mV (sce) pour le mercure et +500 mV (sce) pour le platine) s'élève notablement dans les systèmes pauvres en eau. Elle s'explique par la réduction de SO₃ solvaté en équilibre avec H₂SO₄. Le nombre d'électrons est 2.

L'on discute les conséquences pratiques relatives aux matériaux des électrodes et aux diaphragmes utilisés pour les électro-réductions dans de tels systèmes.