【作者】 董海刚；

【导师】 姜涛； 郭宇峰；

【作者基本信息】 中南大学 ， 钢铁冶金， 2010， 博士

【摘要】 本研究为国家自然科学基金委国家杰出青年科学基金“矿物工程与物质分离科学”项目(批准号：50725416)资助课题。我国攀西地区钛资源丰富,已探明储量8.7亿t(以TiO2计),属岩矿型钛铁矿资源,选矿所得钛铁精矿结构致密,钙、镁等杂质含量高。为了大规模高效利用该地区的钛资源,我国对攀西地区钛铁精矿制取高品位富钛料的方法进行了大量研究,选择了生产规模大、效率高的电炉熔炼法作为主要技术途径,并投入了工业化生产。但是电炉熔炼法获得的钛渣TiO2品位低,钙、镁等杂质含量高,不能直接用作氯化法钛白生产及海绵钛制取的原料。因此,研究开发从电炉钛渣中进一步除去钙镁等杂质的理论及新技术,对攀西地区钛资源的大规模高效利用具有十分重要的现实意义。本文以攀钢高钙、镁电炉钛渣为研究对象,综合运用热力学原理及X-射线衍射、光学显微镜和扫描电镜等现代微观测试手段,对电炉钛渣的性质、酸浸过程杂质的溶出行为、活化焙烧-酸浸除杂技术和基础理论进行系统研究,开发出高钙、镁电炉钛渣制备优质人造金红石的新技术。取得以下结论：(1)攀钢电炉钛渣TiO2含量为72.42%,主要杂质元素为Fe、Mg、Ca、Al、Si,其中CaO+MgO的含量达到9.57%；主要矿物相为黑钛石固溶体和硅酸盐矿物,其相对含量分别为87.6%和8.2%,二者呈镶嵌状态分布,杂质元素Mg、Fe、Al集中分布在黑钛石固溶体中,Si、Ca集中分布在硅酸盐矿物中。(2)钛渣加压酸浸杂质溶出行为研究表明,加压酸浸不能有效去除杂质,钛渣TiO2品位仅能提高到75%左右；酸浸过程添加NH4HF2能强化钛渣中硅酸盐矿物的溶解,但固溶于黑钛石中的Fe、Mg、Al等杂质溶出效果差,钛渣TiO2品位也仅能提高到80%左右。固溶于黑钛石固溶体中的Fe、Mg、Al等杂质溶出效果差是导致酸浸不能有效去除杂质、显著提升钛渣TiO2品位的主要原因。(3)钛渣钠化焙烧-酸浸研究表明,将Na2CO3与钛渣按质量比3：7混合,在900℃下焙烧2h,焙烧产物采用两段硫酸沸腾浸出,能够有效去除杂质,获得TiO2品位为92.23%,回收率92%左右,CaO+MgO含量为0.78%的人造金红石。(4)对钛渣与Na2CO3混合物料进行机械活化处理,能强化钛渣钠化焙烧-酸浸除杂的效果,在焙烧、酸浸条件与未机械活化时相同的条件下,获得TiO2品位为94.61%, CaO+MgO含量为0.68%的人造金红石。(5)钠化焙烧-酸浸机制研究表明,钛渣添加Na2CO3焙烧后,钛渣中的黑钛石与发生Na2CO3反应,生成了钛酸钠、铁酸钠、以及Na-Fe-Ti-O系和Na-Mg-Ti-O系固溶体；钛酸钠、铁酸钠、以及非化学计量Na-Mg-Ti-O系固溶体中的杂质具有良好的酸溶性能,在酸浸过程中被溶出,Na-Fe-Ti-O系固溶体较为稳定,其中的杂质仅能部分被溶出,上述化合物中的钛组分转变为金红石型和锐钛型TiO2,从而有效去除了杂质,显著提升了人造金红石的TiO2品位。(6)机械活化强化钛渣钠化焙烧-酸浸除杂效果的机理在于,机械活化处理改善了钛渣与Na2CO3反应的动力学条件,并使矿物晶格缺陷增加,晶胞体积增大,提高矿物晶格内能和反应活性,从而强化钛渣与Na2CO3的化学反应,促进黑钛石固溶体向钛酸钠、铁酸钠、以及Na-Fe-Ti-O系和Na-Mg-Ti-O系固溶体的转变,提高了杂质的溶出效果。(7)还原-锈蚀法富钛料活化焙烧-酸浸除杂研究表明,活化焙烧-酸浸法具有良好的原料适应性,在与处理钛渣条件相同的情况下,获得了TiO2品位在95%以上,CaO+MgO含量为0.69%的人造金红石。本文基于固相反应原理及机械活化理论,开发出了高钙镁电炉钛渣活化焙烧-酸浸除杂制备优质人造金红石新工艺,并对新工艺的机理进行了深入研究,形成了高钙镁电炉钛渣活化焙烧-酸浸除杂的理论基础。将活化焙烧-酸浸除杂新工艺用于处理还原-锈蚀法富钛料,取得了良好的效果,表明新工艺具有良好的适应性,适于处理高钙镁钛资源。本研究为大规模高效利用我国攀西地区的钛资源开辟了一条新的途径。更多还原

【Abstract】 Titanium resource reserves are rich in Panxi area of China, and the proved titanium resource reserves are up to 870 million tons, belonging to rock-type ilmenite ore resources. The obtained ilmenite concentrate by beneficiation is with compact structure and high content of Ca, Mg and other impurities. To use the titanium resources in Panxi area of China on a large scale and effectively, many works for the production of Ti-rich material using Panxi ilmenite concentrate have been carried out. The high efficient and large-scale electric furnace smelting method has been chosen as main technical way and put into industrial production. However, the obtained titanium slag by electric furnace smelting from Panxi ilmenite with high content of Mg and Ca contained low TiO2 grade and high Mg and Ca content, which can not be used directly for production of titanium white by chlorination process and sponge titanium. Therefore, developing new technologies to get rid of impurities in the titanium slag is of great significance for the large-scale and efficient utilization of Panxi titanium resources.In this work, the titanium slag with high content of Mg and Ca from Pangang Company was taken as raw material, and the characteristics of titanium slag, impurities removal behavior in acid leaching process, the fundamental of activation roasting-acid leaching was systematically investigated. Based on the investigations, a new technology of producing high-quality synthetic rutile from titanium slag with high Ca and Mg content has been developed. The obtained conclusions were as follows.(1) In the titanium slag, TiO2 content was 72.24%, main impurities were Fe, Mg, Ca, Si and Al, especially, CaO+MgO content was up to 9.57%. The main mineral phases were anosovite solid solution and silicate minerals with mosaic structure, and the contents were 87.6%and 8.2%, respectively. Mg, Fe, Al impurities occurred mainly in anosovite solid solution, and Si, Ca occurred mainly in the silicate minerals.(2) The study of impurities dissolution behavior in the pressure acid leaching of titanium slag showed that pressure acid leaching could not remove impurities effectively, TiO2 grade of titanium slag only increased to about 75%. In the acid leaching process, adding NH4HF2 could strengthen dissolution of silicate minerals, however, the leaching effect of Mg, Fe, Al and other impurities dissolving in the anosovite solid solution was poor, and TiO2 grade of titanium slag was only about 80%. The poor dissolution effect of Mg, Fe, Al and other impurities dissolving in the anosovite solid solution was the main reason removing impurities and upgrading TiO2 significantly in the acid leaching.(3) The sodium salt-added roasting-acid leaching results showed that, Na2CO3 and titanium slag were mixed as mass ratio of 3:7, and roasted at 900℃for 2h, and the roasted product was leached by two periods sulphuric acid, and the leached residue was calcined, a synthetic rutile with 92.23% TiO2 grade and about 92% recovery and 0.78% CaO+MgO content was obtained.(4) The mechanical activation-sodium salt-added roasting-acid leaching showed that, after the titanium slag and Na2CO3 mixture being mechanically activated, under the same conditions as dealing with non-mechanically activated titanium slag, a synthetic rutile with 94.61% TiO2 grade and 0.68% CaO+MgO content was obtained.(5)The mechanism of sodium salt-added roasting-acid leaching showed that, the titanium slag adding Na2CO3 was roasted, sodium titanate, sodium ferrite, and the Na-Fe-Ti-O and Na-Mg-Ti-O system solid solution were produced. The impurities of sodium titanate, sodium ferrite and non-stoichiometric Na-Mg-Ti-O system solid solution substances had a good acid-solubility. During the leaching process, Na-Fe-Ti-O system solid solution was stable and the impurities were partially dissolved, and the titanium of the above compounds transformed rutile and anatase TiO2, which removed the impurities effectively and upgraded TiO2 of synthetic rutile significantly.(6) The mechanism of mechanical activation strengthening the impurities removal effect of sodium salt-added roasting-acid leaching was that mechanical activation improved the titanium slag and Na2CO3 kinetic conditions, and increased the mineral lattice defects, increased the cell volume, improved mineral lattice energy and reaction activity, which can strengthen the chemical reaction between Na2CO3 and titanium slag and promote the transformation of the anovosite into sodium titanate, sodium ferrite, Na-Fe-Ti-O and Na-Mg-Ti-O system solid solution and increase the impurities dissolution effect.(7) The activation roasting-acid leaching results of the Ti-rich material obtained by reduction-rust method showed that, under the same conditions as dealing with titanium slag, a synthetic rutile with 95%TiO2 grade and 0.69% CaO+MgO content.In this paper, based on the theories of the solid state reaction and mechanical activation, a new technology of producing high-quality synthetic rutile from titanium slag with high Ca and Mg content has been put forward its mechanism was systematically studied, and forming the fundamental of removing impurities from titanium slag with high Ca and Mg content by activation roasting-acid leaching technology. The new technology was used to deal with the Ti-rich material obtained by reduction-rust method, and good result was achieved. It is shown that the new technology has a good adaptability, and is suitable for titanium resources of high calcium and magnesium content. The study has opened up new way for large-scale and efficient use of titanium resources in Panxi area of China.更多还原