硫酸根对联合制碱工艺影响研究

联合制碱工艺母液循环使用，随着生产运行，易造成系统母液中硫酸根的积累，影响产品质量及系统的稳定生产。查定我公司联碱装置母液中硫酸根含量，从理论上分析了硫酸根引起的制碱相图变化，在此基础上，探究了硫酸根积累对生产造成的影响，对联碱装置的高效稳定运行提出了相关建议。     

联碱洗盐精制除硫酸根工艺方法探讨

本文针对我公司原有联碱洗盐精制方法进行分析,目前盐水精制除钙镁工艺方法较多．而联碱法纯碱系统加入的是固态洗盐,联碱母液的封闭循环系统会出现硫酸根杂质积累的问题．将对纯碱和精铵产品质量产生重大影响。本文介绍几项不同生产工艺除硫酸根的方法．搞好洗盐脏卤循环使用的精制除硫酸根工作。     

原盐质量对联碱生产的影响机理浅析

我公司采用原盐直接加入联碱生产系统的方法,原盐中杂质对生产影响很大。分析了原盐杂质中的钙镁离子、硫酸根离子对联碱生产的影响机理,并具体描述了杂质在生产过程中引起的不良影响。     

国内文摘(220—231)

<正> 摘220 TQ114.105.4 铅电极电位滴定联碱母液中的硫酸根——陈永德;《大化科技》1987,N3,18～22页以铅离子选择电极作指示电极,以饱和KCl—40%异丙醇、6%KNO_3双接界甘汞电极为参比电极,采用硝酸铅标准液作为滴定液,电位滴定联碱母液中SO_4~(2-)的方法。分     

成品洗盐中钙、镁、硫酸根杂质的降低

为了进一步降低成品洗盐中钙、镁、硫酸根杂质的含量．提高联碱法纯碱和氯化铵产品的质量。结合钙、镁、硫酸根杂质是否在氯化钠晶体内部的想法．对溢流榴所带细盐（粒径较小）和相对粒径较大的成品盐中的杂质含量进行分别测定。结果发现：粒径较小的溢流盐中的钙、镁含量要远低于成品盐的含量．硫酸根杂质含量略低于成品盐的．这不但为生产带来益处，同时也印证了氯化钠晶体内却有少量钙、镁杂质。     

新法脱除硫酸根技术

新法脱除硫酸根技术袁斌（辽宁省锦西化工部锦西化工研究院１２５００１）目前，在我国氯碱企业中普遍采用钡法脱除盐水中的硫酸根离子。随着盐水中硫酸根离子浓度的升高，钡法的处理费用增大。特别是有一些掺卤制碱的企业，硫酸根的处理费用巨大，影响了掺卤比例的提高，...     

全卤制碱硫酸根平衡的探讨

依据全卤制碱的有关工艺数据，通过衡算，从理论上论证了技改工艺除硫酸根的可行性和经济性。     

含芒硝盐用于联碱生产的讨论

本文对含芒硝盐用于联碱生产进行了探讨，认为芒硝介入联碱母液中，对联碱生产既有利，也有弊，但联碱产品质量很难提高、联碱母液平衡难控制及影响单位产品消耗是含芒硝盐联碱的致命缺点。对自建制盐厂的大型联碱企业要进一步提高纯碱产品质量，原盐必须除硝，并对制盐的提硝方法进行了简述。     

氨碱废液溶采二层盐制备优级液体盐工艺研究

针对内蒙古吉兰泰盐湖补水困难、二层盐硫酸根含量高、氨碱废液排量大后处理困难等技术难题,分别探究了二层盐饱和卤水混配氨碱废液制备液体盐工艺,以及氨碱废液混兑蒸馏水后溶采二层盐制备液体盐工艺。通过在线拉曼实验,测得该反应达到平衡需要1 h以上;探究了机械搅拌速率、化学反应时间、氨碱废液与蒸馏水混配比例等因素对液体盐氯化钠、硫酸根、钙离子含量的影响。结果表明：在硫酸根和钙离子物质的量比为1∶1、25 ℃、300 r/min条件下,氯化钙和硫酸钠的反应过程是二水硫酸钙结晶过程的速率控制步骤;二层盐饱和卤水混配氨碱废液制备液体盐工艺中,在相同条件下,反应120 min后分离可获得优级液体盐;氨碱废液混配蒸馏水后直接溶采二层盐制备液体盐工艺中,氨碱废液与蒸馏水体积混配比例为1∶（5.55~6.36）、25 ℃、300 r/min条件下,反应120 min后分离可获得优级液体盐。     

联碱发展的展望

阐述了联碱发展的必要性、紧迫性,以及联碱发展具备的必须条件,并对联碱若干技术问题进行了分析,提出了今后联碱的发展方向。     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.