应用硫酸亚铁铵滴定法测定钛铝钒合金中钒时,存在试样较难溶解且试样中较高含量钛易水解干扰终点颜色判断的问题.实验采用硝酸-氢氟酸-硫酸体系溶解试样,通过加入氢氧化钠使其与基体钛发生反应生成三钛酸钠沉淀的方法实现了钛与钒的分离,于硫-磷混酸介质中,用高锰酸钾将滤液中的钒全部氧化为五价钒,以亚硝酸钠还原过量的高锰酸钾,再用尿素分解多余的亚硝酸钠,以N-苯代邻氨基苯甲酸为指示剂,用硫酸亚铁铵标准溶液滴定钒,建立了硫酸亚铁铵滴定法测定钛铝钒合金中钒的方法.共存元素干扰试验说明试样中的共存元素不干扰测定.将实验方法应用于测定两个钛铝钒合金试样中的钒(质量分数在3% ～6% 之间) ,结果的相对标准偏差(RSD,n＝6)为0. 20% 和0. 25%.按照实验方法测定6个钛铝钒合金试样中钒,结果与火焰原子吸收光谱法(FAAS)测定值相一致.%There were some problems during determination of vanadium in titanium-aluminum-vanadium al-loy by ammonium ferrous sulfate titrimetry .For example ,the sample was hardly dissolved .Moreover ,the high-content titanium in sample was easily hydrolyzed ,which would interfere with the judgment of color at titration endpoint .After the sample was dissolved in nitric acid-hydrofluoric acid-sulfuric acid system ,so-dium hydroxide was added to react with matrix titanium to form sodium trititanate precipitate ,realizing the separation of titanium and vanadium .In mixed sulfuric acid-phosphoric acid medium ,vanadium in fil-trate was fully oxidized to pentavalent vanadium with potassium permanganate .The excessive potassium permanganate was reduced with sodium nitrite ,and then the excessive sodium nitrite was decomposed with urea .The content of vanadium was titrated with ammonium ferrous sulfate standard solution with N-phe-nylanthranilic acid as indicator .Consequently ,a determination method of vanadium in titanium-aluminum-vanadium alloy was established by ammonium ferrous sulfate titrametry .The interference tests of coexis-ting elements indicated that the coexisting elements in the sample did not interfere with the determination . The content of vanadium with mass fraction in range of 3%-6% in two titanium-aluminum-vanadium alloy samples was determined according to the experimental method .The relative standard deviation (RSD,n＝6) was 0.20% and 0.25%,respectively .The proposed method was applied for determination of vanadium in six titanium-aluminum-vanadium alloy samples ,and the results were consistent with those obtained by flame atomic absorption spectrometry (FAAS).
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