铝热还原氟钛酸钠法制备钛铝合金的酸洗除氧研究

Study on Removal of Oxygen by Acid Pickling of Titanium Aluminum Alloy Prepared by Thermite Reduction of Sodium Fluorotitanate

二段铝热还原氟钛酸钠法制备钛及钛合金具有流程短、成本低、绿色化的特点,有一定的工业化应用前景。但在工业规模试生产中发现,部分钛铝合金产物存在氧含量过高等问题。依据酸洗可溶解钛铝合金表面自然形成的氧化膜从而降低氧含量的原理,探究草酸+盐酸的混合酸浓度、液固比、浸出时间、反应温度、粉末粒度等工艺条件对酸洗除氧效果的影响。结果表明:在1%草酸+5%盐酸、液固比10∶1、浸出时间6 h、反应温度30℃、粉末粒度<75μm的条件下酸洗除氧效果最佳,可将钛铝合金中的氧含量从1.79%降低至0.79%。该酸洗工艺也同样适用于低氧钛铝合金,可将氧含量从0.366%降低至0.178%。

The preparation of titanium and titanium alloy by two-stage aluminothermic reduction of sodium fluorotitanate has the characteristics of short process,low cost and greenization,and has the prospect of industrial application.However,in the industrial scale trial production,it was found that some of the titanium aluminum alloy products had high oxygen content.The principle of acid pickling is used to dissolve the naturally formed oxide film on the surface of titanium aluminum alloy to reduce the oxygen content.The effects of concentration of mixed acid of oxalic acid and hydrochloric acid,liquid-solid ratio,leaching time,reaction temperature,powder particle size and other process conditions on the deoxidation effect of acid pickling were investigated.The results show that the oxygen content of titanium aluminum alloy can be reduced from 1.79%to 0.79%under the conditions of 1%oxalic acid+5%hydrochloric acid,liquid-solid ratio of 10∶1,leaching time of 6 h,reaction temperature of 30 ℃ and powder particle size less than 75 μm.For low oxygen titanium aluminum alloy,the oxygen content can be reduced from 0.366%to 0.178%by this pickling process.