复杂高铋物料中铅的Na2EDTA滴定法测定

复杂高铋物料中,铋、砷、锑、锡四元素含量高且共存时会影响铅的测定。特别是铋含量高时对铅的测定影响大。实验用EDTA—酒石酸联合掩蔽铋、砷、锑、锡,在稀硫酸介质中以硫酸钾为沉淀剂,使铅生成硫酸铅钾复盐沉淀而与铋、砷、锑、锡、铁、铜、锌、铝、钴、镍等干扰离子分离,沉淀以乙酸-乙酸钠浸取,二甲酚橙为指示剂,Na2EDTA滴定法测定铅。试验进一步优化了测定条件,确定最佳条件：硫酸（1 1）加入量为7mL、硫酸钾用量为5g、煮沸时为5min、沉淀陈化时间为2h、EDTA 50g/L 加入量为10mL、酒石酸用量为0.5g,铅的回收率99.70% ～100.65%。将实验方法应用于测定复杂高铋物料中铅,标样BY0111-1与给定值一致,相对标准偏差（n=11）RSD 0.20%～0.23%,满足生产测试要求。     

硫酸铅分离-EDTA滴定法测定铜闪速冶炼烟尘中的铅

建立了用硫酸形成硫酸铅沉淀加以分离,再用EDTA络合滴定法测定铜闪速冶炼烟尘中铅量的方法。试样用盐酸、硝酸、硫酸、氟化氢铵和高氯酸溶解,用硫酸沉淀铅与其它干扰元素分离,沉淀溶解于乙酸-乙酸钠缓冲溶液中,以巯基乙酸掩蔽铋,抗坏血酸掩蔽铁,二甲酚橙作指示剂,用Na2EDTA标准滴定溶液滴定溶液中铅含量,采用火焰原子吸收光谱法测定滤液中铅含量加以补正。实验结果表明,沉淀时硫酸(1+24)加入量为50mL,无水乙醇加入量为10mL,乙酸-乙酸钠缓冲溶液加入量为30mL。方法相对标准偏差(RSD)在0.35%～1.5%,加标回收率为在99.0%～101%。完全满足生产控制分析的要求,同时也可以作为类似物料中铅分析的参考方法。     

Na_2EDTA滴定法测定复杂高铋物料中铅

复杂高铋物料中铋、砷、锑、锡4种元素含量高且共存时会影响铅的测定。特别是铋含量高时对铅的测定影响较大。实验用EDTA-酒石酸联合掩蔽铋、砷、锑、锡,在稀硫酸介质中以硫酸钾为沉淀剂,使铅生成硫酸铅钾复盐沉淀而与铋、砷、锑、锡、铁、铜、锌、铝、钴、镍等干扰离子分离,沉淀以乙酸-乙酸钠浸取,二甲酚橙为指示剂,Na2EDTA滴定法测定铅含量。实验进一步优化了测定条件,确定的最佳条件:硫酸(1+1)加入量为7mL、硫酸钾用量为5g、煮沸时为5min、沉淀陈化时间为2h、EDTA(50g/L)加入量为10mL、酒石酸用量为0.5g,铅的加标回收率99.7%~104%。将实验方法应用于测定复杂高铋物料中铅,标准样品BY0111-1的测定值与给定值一致,相对标准偏差(n=11)RSD 0.20%~0.23%,满足生产测定要求。     

硫酸铅分离-EDTA滴定法测定铜闪速冶炼烟尘中的铅

建立了用硫酸形成硫酸铅沉淀加以分离,再用EDTA络合滴定法测定铜闪速冶炼烟尘中铅量的方法。试样用盐酸、硝酸、硫酸、氟化氢铵和高氯酸溶解,用硫酸沉淀铅与其它干扰元素分离,沉淀溶解于乙酸-乙酸钠缓冲溶液中,以巯基乙酸掩蔽铋,抗坏血酸掩蔽铁,二甲酚橙作指示剂,用Na2EDTA标准滴定溶液滴定溶液中铅含量,采用火焰原子吸收光谱法测定滤液中铅含量加以补正。实验结果表明,沉淀时硫酸(1+24)加入量为50 mL,无水乙醇加入量为10 mL,乙酸-乙酸钠缓冲溶液加入量为30 mL。方法相对标准偏差(RSD)在0.35%~1.5%,加标回收率为在99.0%~101%。完全满足生产控制分析的要求,同时也可以作为类似物料中铅分析的参考方法。     

EDTA滴定法测定分银渣中的铅含量

采用氟化铵-盐酸-硝酸-高氯酸溶解样品,加入氢溴酸除去样品中的砷、锑、锡等共存元素,加入硫酸将样品中的铅转化为硫酸铅沉淀,通过过滤与其它元素分离,滴定前加入巯基乙酸掩蔽铋,在乙酸-乙酸钠缓冲体系下,以二甲酚橙为指示剂,建立了采用EDTA络合滴定法测定分银渣中铅含量的方法。实验方法用于测定分银渣中的铅含量,测定结果的相对标准偏差(RSD,n=11)为0.32%～0.90%,加标回收率为100%～102%。能够满足日常测定需求。     

EDTA滴定法连续测定铅精矿中铅和锌

建立了EDTA滴定法连续测定铅精矿中铅和锌的方法。试样用盐酸、硝酸、硫酸和氯酸钾分解。铅通过硫酸铅沉淀与其他干扰元素分离,沉淀溶解于乙酸-乙酸钠溶液中。在滤液中加入氨水、氟化钾使铁等干扰元素沉淀并与锌溶液分离。用二甲酚橙作指示剂,EDTA分别滴定溶液中的铅和锌。研究中测定了能力验证NILPT(2010)-0211铅精矿样品10-1和10-2中铅和锌,结果满意。     

沉淀分离-EDTA滴定法测定铜闪速冶炼烟尘中的锌量

称取0.5 g试样,用盐酸、硝酸、硫酸分解,铅以硫酸铅沉淀的形式分离。以过硫酸铵为氧化剂,氨性溶液中沉淀分离铁、锰等共存元素,加氟化物掩蔽铝、硫脲掩蔽铜,调节溶液pH=5.0~6.0,加入碘化钾消除镉的干扰,以二甲酚橙为指示剂,用EDTA标准溶液滴定。将沉淀物重新溶解,用原子吸收光谱法测定其中的锌量。在0.2%~10.0%范围内结果重现性良好,重复测定7次,相对标准偏差(RSD)在0.32%~0.76%,样品加标回收率为99.4%~100%。方法的准确度和精密度可以满足分析需求。     

EDTA滴定法测定矿石中铅含量的方法改进

对以往测定铅的方法进行了改进。消解样品的体系为盐酸-硝酸-硫酸和氟化铵,氟化铵(200 g/L)的加入量为3 mL;硫酸加入量为10 mL,浓度为1+1;硫酸铅沉淀静止时间为45 min;除去铋干扰的方法为调节溶液的pH值用EDTA溶液进行分步滴定;将过滤后的滤液进行回收测定,与滴定的结果相加以得到最终结果,滤液中铅含量的大概范围为0.13 %~0.27 %。本方法的精密度为0.12%~0.15% ,准确度为0.24%~0.43%。     

碘量法测定废杂铜屑中的铜含量

采用硝酸-盐酸溶解样品,在硫酸体系下加入氢溴酸,使得氢溴酸与试样中的砷、锑、锡等元素反应生成易挥发的溴化物,从而消除其干扰,滴定前用氟化氢氨掩蔽铁,在pH=3.0～4.0的范围采用碘量法测定废杂铜屑中的铜含量。用于测定金属样废杂铜屑中铜的含量,测定结果的相对标准偏差(RSD,n=7)为0.20%～0.25%,加标回收率在98.8%～101%,方法简单准确,能够满足日常检测需求。     

复杂矿石中锡的碘量法测定

用经典的碘量法测锡具有快速、操作简便的优点,但对某些含干扰元素的复杂矿物必须经过分离才能测定。干扰元素主要有砷、铜、钨、钼、锑、钒、铬、铋、硝酸根及亚硝酸根等。本法利用在EDTA二钠的碱性溶液中铍、锡均可生成不溶性氢氧化物这一特点,将试样以碱熔分解后,以EDTA为掩蔽剂,加入硫酸铍作载体,在氨性介质中使锡和铍共沉淀而与干扰元素钨、钼、钒、铜、砷、锑、铋、铬(Ⅵ)分离;钛、铬(Ⅲ)也与锡、铍一起沉淀,但铬(Ⅲ)以过氧化钠熔矿后已氧化至六价而不干扰,钛量少于24毫克时也不影响测定。     

氢化物发生-原子荧光光谱法(HG-AFS)测定特硬铅合金中硒和碲

建立了氢化物发生-原子荧光光谱法(HG-AFS)测定特硬铅合金中硒和碲的分析方法。试样经硝酸和酒石酸溶解,硫酸沉淀分离基体铅元素。移取部分试液,在40%盐酸介质中直接用氢化物发生-原子荧光光谱法(HG-AFS)测定样品中的硒;另移取部分试液,加入氢溴酸挥发除去砷、锑、锡、硒等元素,在40%盐酸介质中用氢化物发生-原子荧光光谱法(HG-AFS)测定样品中的碲。考察了测定的最佳条件、铅及共存元素对测定的影响。测定硒和碲的相对标准偏差分别为7.5%～9.3%和3.6%～13.0%,加标回收率分别为88%～92%和98%～102%。准确度和精密度均能满足分析需要,具有较强的实用性。     

电感耦合等离子体发射光谱法测定粗二氧化碲中 铜、铅、锑、铋、砷和硒

粗二氧化碲作为碲精炼或碲化工产品生产的重要原料,其中共存元素铜、铅、砷、锑、铋、硒含量的准确测定对于生产过程质量控制和贸易结算具有重要意义,但目前没有粗二氧化碲中铜、铅、砷、锑、铋、硒含量检测的标准分析方法。采用王水和饱和氟化氢铵分解试样,在王水和酒石酸介质中,选用Cu 327.393 nm、Pb 220.353 nm、Sb 217.582 nm、Bi 223.061 nm、As 193.696 nm、Se 196.026 nm为分析谱线,采用电感耦合等离子体发射光谱(ICP-AES)法测定粗二氧化碲中铜、铅、锑、铋、砷和硒含量。各元素校准曲线的相关系数均大于0.999;铜、铅、锑、铋、砷和硒的检出限分别为0.0004%、0.0005%、0.0006%、0.0007%、0.0004%和0.0007%,定量检出限分别为0.0012%、0.0016%、0.0020%、0.0025%、0.0013%和0.0025%。按照实验方法测定5个粗二氧化碲样品中铜、铅、锑、铋、砷和硒,测定结果的相对标准偏差(RSD,n=7)为0.79%~4.8%,加标回收率为96.0%~103%。方法简单,精密度和准确度较高,可用于测定粗二氧化碲中铜、铅、砷、锑、铋、硒含量。     

Analysis of tellurides of lead and tin by automatic titrations

An analytical method based on automatic potentiometric EDTA and redox titrations was developed for the analysis of tellurides of lead and tin.First, the sum of lead and tin is titrated at pH 4.5 by adding a known excess of EDTA and back-titrating with a standard lead solution. After addition of ammonium fluoride to mask the tin, the EDTA released from the Sn-EDTA complex is titrated with standard lead solution. Alternatively, after the determination of total lead and tin, lead may be determined by back-titration with standard lead on a separate sample aliquot using tartaric acid to mask the tin. Tellurium is separated as tellurous acid, which is then dissolved in a dilute sulfuric acid solution and oxidized by permanganate at room temperature; the excess permanganate is back-titrated with iron(II) solution automatically. This titration may also be used to determine tellurium in the presence of lead and tin after treatment with perchloric acid. Accuracies of 0.1-0.2% can be obtained.     

Determination of tin in titanium alloys

Tin-titanium alloys are becoming increasingly important; consequently a good method is needed for the determination of tin in this type of material. In this paper an accurate iodometric procedure is proposed for the determination. The sample is dissolved in sulfuric acid and the titanium oxidized with potassium permanganate. Tartaric acid is added and the tin precipitated with hydrogen, sulfide. The sulfide precipitate is dissolved in a mixture of sulfuric, perchloric and nitric acids and the solution evaporated to fumes of sulfuric acid. Water and hydrochloric acid are added, and the tin is reduced with lead and antimony trichloride and titrated with iodine. A study was made of the interfering elements that might be found in titanium alloys. The effect of antimony trichloride in reducing interference from copper was investigated. The method is recommended for titanium alloys containing 0.05 to 5.0 per cent. tin.     

碘量法测定铜冶炼烟尘中铜

试验研究了铜冶炼烟尘中铜含量的测定方法,试料用盐酸、氢氟酸、硝酸、高氯酸及硫酸分解,氢溴酸除去砷、锡、锑,硫酸除去硒的干扰。进一步对滴定条件和共存元素的干扰及消除进行了试验,最终确定了最佳条件。按照实验方法测定6个铜冶炼烟尘样品中铜量,结果的相对标准偏差为0.22%~0.65%,精密度高,准确度好。样品加标回收率在98.92%~100.38%之间, 适用于铜冶炼烟尘中铜含量为5.00 %～65.00 %的测定。     

Spectrophotometric determination of bismuth in copper and cartridge brass by the iodide method

An improved spectrophotometric method is proposed for the determination with iodide of trace amounts of bismuth in copper and cartridge brass. The sample is dissolved in nitric acid and the bismuth is separated from the copper by an ammoniacal precipitation in the presence of iron(III) hydroxide as a gathering agent. The hydroxide precipitate is dissolved in hydrochloric acid, sulfuric acid is added, the solution is evaporated to a few ml, hydrobromic acid is added to volatilize the antimony and tin, and the solution is evaporated to fumes of sulfuric acid. The bismuth iodide color is then developed with a composite potassium iodide—sodium hypophosphite reagent. Factors affecting the bismuth iodide color are investigated.     

Influence of volatile hydride-forming elements on antimony determination by atomic-absorption spectrometry with hydride-generation

A study was undertaken to determine the interfering effects of arsenic, bismuth, germanium, lead, selenium, tin and tellurium on trace determination of antimony by atomic-absorption spectrometry with hydride-generation. A 1% NaBH(4) solution was used as reductant and a small amount of oxygen was added to the hydrogen produced, to support the combustion and atomization of SbH(3). The interference from selenium in the determination of antimony is removed if potassium iodide-ascorbic acid solution or copper sulphate is added to the sample solution. The interference of tin and tellurium can also be avoided by adding potassium iodide-ascorbic acid solution. A possible interference mechanism is discussed.