高钙水体对磁铁矿浮选脱硫的影响机理与控制方法

发布时间：2018-07-17 18:57

【摘要】：铁矿石中的硫对其冶炼产品性能有严重的影响,因此含硫量是铁精矿质量的重要衡量标准,脱硫也是铁矿石选别过程中的必要工序。铁矿石中的硫主要为黄铁矿、磁黄铁矿及其他金属硫化物,通常情况下大部分硫化物都能够在磁选过程中去除,但强磁性的磁黄铁矿则易于进入磁选精矿,常需要进一步浮选脱除。陕西丹凤某高硫磁铁矿精矿含硫达到1.16%,含硫矿物基本为磁黄铁矿,浮选脱硫过程中多次选别仍然难以获得理想指标。分析现场影响因素发现,由于水体本身存在大量Ca~(2+),加上含钙矿物的溶解作用,造成矿浆中Ca~(2+)含量很高,认为可能是Ca~(2+)影响了磁黄铁矿的浮选性能进而影响了磁铁矿精矿浮选脱硫效果。本文围绕高钙水体中磁铁矿浮选脱硫这一问题,采用溶液化学分析和接触角测试、XPS、SEM-EDS及ICP-MS等微观测试分析手段,旨在明确Ca~(2+)对磁黄铁矿浮选特性的影响机理,并研究合适的方法强化高钙水体中磁铁矿浮选脱硫效果。通过纯矿物浮选试验考察了Ca~(2+)对磁黄铁矿浮选行为的影响,发现高钙水体中磁黄铁矿的可浮性显著降低。对比不同Ca~(2+)含量情况下硫酸铜活化效果发现,Ca~(2+)严重影响了Cu~(2+)对磁黄铁矿的活化效果,检测发现随着Ca~(2+)浓度的增加,铜离子在矿物表面的吸附量显著减小。SEM图片显示高钙水体中的磁黄铁矿表面出现大量白色小颗粒,EDS和XPS检测结果表明矿物表面钙含量显著增加,同时氧、硫的含量也有所增加,说明Ca~(2+)在磁黄铁矿表面生成一层硫酸钙亲水薄膜,这层亲水薄膜形成表面占位,阻止了Cu~(2+)对磁黄铁矿的活化作用。采用络合Ca~(2+)的方法消除Ca~(2+)的影响,分别试验了硝酸铵、柠檬酸氢铵、柠檬酸等络合剂,发现柠檬酸络合Ca~(2+)后再用硫酸铜活化,磁黄铁矿可浮性显著提高。柠檬酸用量为1×10-3mol/L,柠檬酸与硫酸铜的配比为1:2,pH在4-5之间,捕收剂丁基黄药用量为1.2×10-4mol/L时,磁黄铁矿回收率达到92.90%。分析表明柠檬酸络合矿浆中Ca~(2+),阻碍了CaSO4亲水薄膜的产生;同时还能够清洗磁黄铁矿表面氧化产生的Fe(OH)3,有效改善了Cu~(2+)对磁黄铁矿的活化效果。实际矿物试验中,当柠檬酸用量为600g/t、硫酸铜用量为200g/t、丁基黄药用量为120g/t时,得到的铁精矿中TFe含量为67.28%,硫的含量从1.16%降到0.14%,取得了比较理想的指标。研究为高硫磁铁矿脱硫等涉及磁黄铁矿浮选的难题提供了新的解决思路。
[Abstract]:Sulfur in iron ore has a serious impact on the performance of its smelting products, so sulfur content is an important measure of iron concentrate quality, desulfurization is also a necessary process in the process of iron ore separation. The sulfur in iron ore is mainly pyrite, pyrrhotite and other metal sulfides, most of which are usually removed during magnetic separation, but highly magnetic pyrrhotite is easy to enter magnetic concentrate. Further flotation removal is often needed. The sulfur content of a high sulfur magnetite concentrate in Danfeng Shaanxi is 1.16 and the sulfur bearing mineral is pyrrhotite basically. It is still difficult to obtain ideal indexes by multiple separations in the process of flotation desulphurization. By analyzing the field influencing factors, it is found that there is a large amount of Ca ~ (2) in the water body and the dissolution of the calcium bearing minerals, which results in the high content of Ca ~ (2) in the slurry. It is suggested that Ca2 may affect the flotation performance of pyrrhotite and further affect the desulfurization effect of magnetite concentrate. This paper focuses on the problem of flotation desulfurization of magnetite in high calcium water. By means of solution chemical analysis and contact angle measurement, such as XPSG SEM-EDS and ICP-MS, the effect mechanism of Ca ~ (2) on the flotation characteristics of pyrrhotite is clarified. The suitable method to enhance the flotation desulfurization effect of magnetite in high calcium water was studied. The effect of Ca ~ (2) on the flotation behavior of pyrrhotite was investigated through the flotation test of pure minerals. It was found that the floatability of pyrrhotite in high calcium water was significantly reduced. Comparing the activation effect of copper sulfate with different Ca2 content, it is found that Cu2 has a serious effect on the activation of pyrrhotite. It is found that the activation effect of Cu2 on pyrrhotite is increased with the increase of Ca2 concentration. The adsorption of copper ions on the mineral surface was significantly reduced. SEM images showed that a large number of small white particles appeared on the surface of pyrrhotite in high calcium water. The results of EDS and XPS showed that the calcium content on the mineral surface increased significantly, while the contents of oxygen and sulfur also increased. It is concluded that Ca2 formed a layer of calcium sulfate hydrophilic film on the surface of pyrrhotite, and this layer formed a surface occupied position, which prevented the activation of pyrrhotite by Cu2. The influence of Ca ~ (2) was eliminated by complexing Ca ~ (2). The complexing agents such as ammonium nitrate, ammonium citrate and citric acid were tested respectively. It was found that citric acid complexed Ca ~ (2) was activated with copper sulfate, and the floatability of pyrrhotite was improved significantly. When the dosage of citric acid is 1 脳 10 ~ (-3) mol / L, the ratio of citric acid to copper sulfate is 1: 2, pH is 4-5, and the amount of Ding Ji xanthate is 1.2 脳 10 ~ (-4) mol / L, the recovery rate of pyrrhotite reaches 92.90%. The results show that Ca2 in citric acid complex slurry hinders the formation of CaSO4 hydrophilic film, and that Fe (OH) 3 produced by oxidation on pyrrhotite surface can be cleaned, thus effectively improving the activation effect of Cu2 on pyrrhotite. In the actual mineral test, when the amount of citric acid is 600g / t, the amount of copper sulfate is 200g / t, and the amount of Ding Ji xanthate is 120g/t, the TFE content in the iron concentrate is 67.28%, and the sulfur content is reduced from 1.16% to 0.14%. The research provides a new way to solve the problems related to pyrrhotite flotation, such as desulphurization of high sulfur magnetite.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD923;TD951

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