高盐高砷酸性废水的处理研究

采用多级絮凝沉淀方法对高盐高砷酸性废水进行处理,用20%的石灰及5%氢氧化钠溶液调节废水的p H值,一次曝气除砷硫酸铁用量为n(Fe)∶n(As)=3.5,二次曝气除砷硫酸铁用量为n(Fe)∶n(As)=10,可大量去除废水中的盐和砷,处理后的废水达到国家排放标准的要求。     

地聚物材料固化含砷废渣抗硫酸盐侵蚀性能研究

用磷渣-粉煤灰基地聚物材料对含砷废渣进行固化处理,研究含砷固化体的抗硫酸钠侵蚀性能,考察不同硫酸钠浓度、干湿循环次数等因素对固化体质量、抗压强度、砷毒性浸出特性的影响,并采用XRD和SEN分析硫酸钠侵蚀前后固化体的物相组成及形貌变化.结果表明:当干湿循环为1～4次时,材料强度可提高11％～21％;当干湿循环为5～8次时,固化体结构在干湿周期性作用下被破坏,逐步出现微孔、大孔,固化体的结构缺陷致使固化体抗压强度降低(5％～20％),砷浸出率增大,但其不超过0.3％,可见含砷地聚物材料固化体有较强的抗硫酸盐侵蚀性.     

亚硝酸钠法生产聚合硫酸铁新进展

酸性条件下,以亚硝酸钠为催化剂,以氧气为氧化剂,一步法生产聚合硫酸铁。实践证明:密闭条件下,于350 kg水中投加1 t全铁含量为20%的硫酸亚铁,配以98%浓硫酸的110 kg,以20 kg亚硝酸钠作为催化剂,以10~11 MPa的工业氧气5~6瓶作为氧化剂,55℃下催化氧化硫酸亚铁制备液体聚合硫酸铁可以在3 h内完成反应,生产出符合国家标准的高效净水剂。此生产工艺大大缩短了反应完成时间,提高了生产效率。又因为是密闭条件下反应,也大大减少了亚硝酸钠对环境的污染。是一种制备聚合硫酸铁的理想方案。目前,此工艺已经应用于本公司的实际生产。     

Raman Microprobe Investigation of Oxygen and Carbon Dioxide Dissolution from Bubbles in Silicate Glasses Containing Arsenic Oxide

Raman microprobe analysis was used to investigate the changes in the relative concentrations of oxygen and carbon dioxide found in bubbles in silicate glasses containing different amounts of arsenic oxide, sodium nitrate, and/or sodium nitrite after various heat treatments. As expected, analysis of the spectral data clearly indicated that addition of arsenic oxide to the glass accelerates the relative rate of oxygen dissolution with respect to carbon dioxide. Addition of either sodium nitrate or sodium nitrite to the glass composition containing arsenic oxide generates a relative rate of oxygen dissolution that is intermediate between those for the glass containing no refining agent and the silicate glass containing only arsenic oxide. This relative rate of oxygen dissolution is closely related to the amount of As³⁺ that is present in the glass.     

含砷钴镍渣中砷碱介质氧化浸出机理

研究了某厂ZnSO4溶液砷盐净化工艺产生的含砷钴镍渣中砷在惰性和氧气气氛的碱介质中的氧化浸出机理. 结果表明,砷氧化浸出与温度、介质碱浓度、浸出气氛均密切相关. 在惰性气氛、碱介质中,渣中CuO和Cu2O均可作为砷氧化浸出的氧化剂,在80℃及以下低温下,CuO对低价砷起主要氧化作用,还原产物为Cu2O,砷最高浸出率不超过53%;在100℃及以上较高温下,CuO和Cu2O均参与低价砷的氧化浸出过程,还原产物均为单质Cu,最高浸出率约为90%;在氧气气氛、碱介质中,砷浸出率可达98%以上,除O2作为氧化剂直接氧化浸出砷外,渣中的铜可作为O2与低价砷之间电子传递的载体,强化氧化反应.     

从废锌铁合金中制备硫酸锌

介绍利用废锌铁合金机械零件为原料制备硫酸锌的方法。趁热过滤除去合金中的铜、砷。用黄铁矾法除去大部分铁,通过蒸发、冷却结晶、离心脱水,可最终使硫酸锌的含量达98%以上。     

Conditions for Producing Amber and Brown Glass

Dependences are identified that characterize redox reactions in the production of amber and brown glasses from batches using sodium sulfate with an excessive reducing agent or blast furnace slag. All reactions and resulting color shades are related to partial oxygen pressure. Boundary values for producing steady amber glasses are identified. The reducing potential of batches found by the oxydimetry method can be expressed via partial oxygen pressure, and it is recommended to determine this potential for tinted and clear glasses.     

Recycling wood pulping chemicals by molten salt electrolysis: cyclic voltammetry of mixtures containing Na2CO3 and Na2SO4

We are investigating a novel electrochemical pathway for efficient recycling of inorganic chemicals from the kraft pulping process. To analyse this process, cyclic voltammetry was conducted on molten salts containing sodium carbonate, or sodium carbonate and sodium sulfate on gold and nickel/nickel oxide electrodes. Pure sodium carbonate at 860 °C was determined to exhibit oxidation to carbon dioxide and oxygen. Electrochemical reduction proceeded to both sodium metal and to sodium oxide and either carbon or carbon monoxide. A mixture with a 2.36:1 molar ratio of sodium carbonate to sodium sulfate at 860 °C was investigated where the anode again displayed carbonate oxidation. The cathode reactions are the reduction of sulfate ions to form sulfide and oxide ions and carbonate reduction to oxide ions and carbon monoxide. Separated cell operation to avoid oxide ion oxidation appears necessary according to the cyclic voltammetry. Nickel oxide was found to be a stable anode material in a sodium carbonate molten salt. This paper, based on cyclic voltammetry results of oxide ion production, is the first step towards a technical electrolysis process for recausticizing of molten smelt for the kraft pulping process.     

三种三价铁吸附剂除As（V）性能的比较

为从铁化物中筛选到经济有效的除砷材料,首先研究了pH和铁砷比对砷吸附效果,随后考察了铁砷化合物的还原性溶解对砷释出的影响。结果表明Fe（Ⅲ）化合物去除As（V）效果较好,最佳去除pH为5～8,铁砷比越大,砷的去除率越高。此外,当以氯化铁、硫酸铁作为吸附剂时,吸附后砷的溶出率与吸附剂中Fe（Ⅲ）的还原率呈正相关,在硫酸铁溶液中两者的相关系数最高达0．98。但当Fe（Ⅲ）以固体氧化铁存在时,还原后砷的溶出率与铁的溶出率的相关系数偏低。     

液体脂肪醇硫酸盐的生产及应用性能

简单介绍了液体脂肪醇硫酸钠的反应原理和工艺流程,对在生产过程中影响产品质量的因素进行了研究,得到了在生产过程中维持工艺空气的露点在-60℃以下、硫磺流量稳定、产品浓度不超过35％等条件,可生产出高质量的产品。通过对液体脂肪醇硫酸钠基本性能的测试,得出液体脂肪醇硫酸钠具有优异的去污、起泡、乳化和生物降解性能。同时,通过研究液体脂肪醇硫酸钠在洗洁精、洗衣粉和牙膏中的应用,得到的液体脂肪醇硫酸钠可代替部分脂肪醇聚氧乙烯醚硫酸钠、烷基苯磺酸钠和固体脂肪醇硫酸钠在洗洁精、洗衣粉和牙膏中的应用。     

ADC发泡剂缩合母液综合利用新工艺

探讨了从ADC发泡剂缩合母液中提取联二脲、硫酸钠、氯化铵的工艺路线,反应条件及各种影响因素,小试结果表明:改进工艺后可从缩合母液中提取无水硫酸钠(平均质量分数为96.1%)、氯化铵(平均质量分数为95.6%);1 L缩合母液可回收联二脲1.61 g、硫酸钠133.4 g,氯化铵42.3 g.     

连续氧化还原滴定法测定玻璃澄清剂中的砷和锑

介绍了一种氧化还原滴定法连续、快速测定玻璃澄清剂中的砷和锑的方法。试样经硫酸-硫酸钾分解,滤纸片将试样中全部的五价锑和五价砷定量还原为三价。采用硫酸铈和溴酸钾作为氧化滴定剂,将三价的砷和锑定量氧化为五价。通过精密度和准确度实验表明,该方法标准偏差小于0.1,回收率为96%～105%。测试方法稳定,数据结果可靠。     

聚合硫酸铁的制备

本文介绍了以硫酸亚铁为原料,氧气为氧化剂,亚硝酸钠为催化剂．在实验条件下进行催化氧化制备聚合硫酸铁．探讨了反应温度、硫酸用量、助催化剂和催化剂用量对反应速率及产品质量影响。     

超临界水氧化法选冶难选金矿石的初步实验

介绍了超临界水氧化法(SCWO)选冶难选金矿石的初步实验,采用SCWO技术,在反应温度550oC、操作压力25 MPa及反应时间10 min时,使难选金矿石回收率从≤35%提高到92.8%.在超临界氧化反应过程中,有机物被氧化为CO2和水,S氧化为硫酸盐,沉积于渣中;虽然As被氧化生成As2O3,但由于几乎不溶于超临界流体,最终固定在渣中. 氧化反应后排放的超临界水清洁,符合国家《污水综合排放标准》,并且不排放有害气体,整个选冶过程符合清洁生产工艺要求.     

Removal of Molybdate and Arsenate from Aqueous Solutions by Flotation

Abstract

Ion flotation and adsorbing colloid flotation have been studied in this paper for the effective removal of molybdenum(VI) and arsenic(V) from dilute aqueous solutions. These different flotation methods were also compared. Ion flotation using a cationic surfactant (dodecylamine) as collector, as well as adsorbing colloid flotation using ferric hydroxide as coprecipitant (or sorbent) and an anionic surfactant (sodium dodecyl sulfate) as collector were examined. Laboratory-scale experiments were conducted in order to assess the effects of the following parameters on the efficiency of the process: pH value, dosages of chemical reagents, initial concentrations of arsenic and molybdenum, and the presence of foreign anions, such as Cl^- and SO² ₄ ^-. In practical applications, ion flotation or adsorbing colloid flotation may be selected according to the concentration of arsenic, molybdenum, and also the initial [Mo]/[As] molar ratios in solution.     

低含量砷羟基亚乙基二膦酸的制备

在酸性条件下,用硫化钠作还原剂和沉淀剂,还原-沉淀脱除普通工业品羟基亚乙基二膦酸(HEDPA)中的杂质砷。系统考察了硫化钠加入量、溶液pH、反应温度、反应时间、搅拌速度等因素对脱砷效果的影响,其适宜反应工艺条件为:n(硫化钠)∶n(砷)=4∶1,pH=0.5,反应温度50℃,反应时间2h,搅拌速度90r/min。在该工艺条件下脱砷率达99.3%,可制得高品质低含量砷羟基亚乙基二膦酸(HEDPA),其砷的质量浓度为0.28mg/L,可广泛用作日用化学品添加剂和药物合成的原料。     

乙二醇与硫酸钠复合对粉煤灰火山灰活性影响的研究

探讨乙二醇与硫酸钠复合对粉煤灰不同时期火山灰活性的影响.结果表明:将一定掺量的乙二醇与硫酸钠复合掺入可以不同程度地提高粉煤灰早期、中期与后期的火山灰活性,其中早期的激发作用效果最大,后期的激发作用效果最小.且随着粉磨时间的延长,各水泥试样的3d、7d及28d抗压强度比值均有明显的提高但增幅下降.无论是否粉磨及粉磨时间长...     

高收率高稳定性过碳酸钠的制备

以碳酸钠和双氧水为原料制备过碳酸钠。考察了反应温度、反应时间、原料配比、后处理工艺等因素对过碳酸钠产品收率和稳定性的影响。适宜工艺条件：反应温度为15 ℃、反应时间为30 min、复合稳定剂（聚丙烯酸钠-硅酸钠-硫酸镁）加入量为碳酸钠质量的1%、碳酸钠与双氧水物质的量比为1∶（1.5~1.6）。在此条件下,制得过碳酸钠产品活性氧含量较高。结晶后,利用双氧水溶液对晶粒进行洗涤,于50 ℃下干燥3 h,过碳酸钠产品收率可达到88%,活性氧质量分数可达到14.75%。过碳酸钠产品存储35 d后,活性氧质量分数仍可达到13.90%,稳定性较好。     

含有磁黄铁矿的铁矿石选别中硫的活化

铁矿石选矿中用硫酸铜和氟硅酸钠活化磁黄铁矿，使最终铁精矿合流量降至０．５％以下。指出硫酸铜和氟硅酸钠是磁黄铁矿石较好的活化剂与分散剂。     

High-Temperature Chemistry of Glass Furnace Atmospheres

The chemical nature of species in glassmelting furnace exhaust streams was thermodynamically analyzed using a computer program. These analyses indicate that the primary material which will condense out of such atmospheres is liquid sodium sulfate. It is postulated that the amount of sodium is controlled by equilibrium between the bath and the atmosphere. Given this assumption, higher sulfur contents decrease the sodium content, and higher chlorine increases the sodium content. Variations in the hydrogen-to-carbon ratio caused by using different fuels have only a modest effect on the condensation. Potassium behaves similarly to sodium but condenses at a somewhat lower temperature. It is believed that entrained dust particles serve as nucleation sites. The CaO and MgO particles derived from batch carryover and spalled refractories can be converted to the sulfate and dissolved in the liquid sodium sulfate, whereas the simultaneous presence of SiO₂ can lead to a glasslike oxide mixture.