真空碳热还原—酸浸联合工艺制备碳化钛研究

发布时间：2018-02-10 06:59

  本文关键词： 真空 碳热还原 碳化钛 含钛高炉渣 酸浸　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：Ti C熔点高、硬度好、化学稳定性好,广泛应用于切削模具、金属陶瓷,耐热合金和硬质合金,我国钒钛磁铁矿高炉冶炼工艺使得原矿中超过50%的钛资源进入炉渣中(Ti O2含量22%-25%),常称之为含钛型高炉渣,是我国特有的含钛高炉渣,是一种具有利用价值的二次钛资源,但自上世纪70年代实现钒钛磁铁矿高炉渣冶炼以来,这种有价二次资源一直未实现工业化利用,堆积量超过7000万吨,且现在每年仍有350万吨到400万吨的产量,造成钛资源极大浪费的同时,带来了严重的环保压力,本研究提出真空碳热还原联合酸浸新工艺,进行含钛高炉渣制备Ti C的基础研究,拟通过本论文的研究,获得硅钛分离,降低二次污染,获得Ti C的理论基础和优化实验条件。为我国含钛高炉渣高效综合利用提供实验研究基础。主要结论如下:①炉渣成分为五种主要氧化物组成时(Ca O-Si O2-Mg O-Al2O3-Ti O2):Ti O2被C还原生成Ti C的过程中,有着众多的中间产物的生成,在常压下1000℃以下,Ti3O5,Ti2O3,Ti O中间产物先于Ti C生成。随着温度升高和压力减小,Ti C更容易得到。常压和真空下,Ca O和Al2O3难还原,反应温度高;常压下,Si O2和Mg O还原难度大,但随着真空度的增加,可实现Si O2到Si O,Mg O到Mg的还原。②炉渣成分为四种主要化合物时(Ca Ti O3,Ca Fe(Si O3)2,Ca Mg(Si O3)2和Mg Al2O4):还原难易程度Ca Ti O3Ca Fe(Si O3)2Ca Mg(Si O3)2Mg Al2O4。103Pa压力下,反应起始温度为1200℃,还原Ca Ti O3可得到Ti C,当压力达到100Pa时,反应起始温度低于900℃。Ca Fe(Si O3)2被C还原,生成Ca O,Fe和Si O,103Pa压力下,还原温度低于1300℃。Ca Mg(Si O3)2碳热还原也会随着压力的降低逐渐被还原而得到Ca O,Mg,Si O。Mg Al2O4被C还原生成Mg和Al相对较难。③含钛高炉渣还原产物优势区图结果表明:可通过调节体系氧分压和温度得到纯度Ti C区域,且Ti C会随着温度的升高和压力的降低,稳定存在区间持续变大。Si C和Ti C共同的稳定存在区间会随着温度的升高而变大,随着压力的降低而减小。④常压、保护性气氛条件下,含钛高炉渣还原难度大。现场渣经高能球磨后再真空碳热还原,可得到Ti C产物,但能耗较高。⑤一定粒度的含钛高炉渣在合适的真空度、还原温度及渣碳质量比条件下,真空碳热还原还原后,经进一步酸浸处理后,可得到纯Ti C.
[Abstract]:Tic has high melting point, good hardness and good chemical stability. It is widely used in cutting dies, cermets, heat-resistant alloys and cemented carbides. The blast furnace smelting process of vanadium titanomagnetite in China makes more than 50% titanium resources in the raw ore enter into the slag with 22- 25o 2 content, which is often called titanium-bearing blast furnace slag. It is a unique titanium-bearing blast furnace slag in China and is a kind of secondary titanium resource with utilization value. However, since the smelting of vanadium-titanomagnetite blast furnace slag in -30s, this valuable secondary resource has not been industrially utilized, with an accumulation of more than 70 million tons, and now there are still 3.5 million to 4 million tons of output per year. This paper presents a new technology of vacuum carbothermal reduction combined with acid leaching to prepare tic from titanium-bearing blast furnace slag. Through the research in this paper, the separation of silicon and titanium is obtained. Reduce secondary pollution, The theoretical basis and optimized experimental conditions of tic were obtained, which provided the experimental research basis for the efficient comprehensive utilization of the blast furnace slag containing titanium in China. The main conclusions are as follows: (1) when the slag is composed of five main oxides, Ca O-SiO _ 2-Mg O-Al _ 2O _ 3-TiO _ 2o _ 2 / TIO _ 2 / TIO _ 2 coating is obtained. In the process of reducing to Ti C, There are many intermediate products. The intermediate products of Ti _ 3O _ 5 and Ti _ 2O _ 3O _ 3O _ 3O _ 3O _ 3O _ 2O _ 3O _ 2O _ 3O _ 2O _ 3Ti _ 2O _ 3Ti _ 2O _ 3 are formed before tic under 1000 鈩，

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