Recovery of titanium dioxide from iron tailings

China's titanium resources are very rich, and reserves rank first in the world. There are more than 20 provinces and regions in the country with titanium resources, mainly distributed in Panxi, Sichuan, Chengde, Hebei, Hainan, Guangxi and Guangdong provinces, with a resource reserve of about 750 million tons. The most important resource is titanium Panzhihua vanadium-titanium magnetic iron ore ilmenite reserves accounting for 97% of the original titanium reserves, out of the countries first. In recent years, China has accelerated the development and utilization of titanium resources.

Ilmenite is an important raw material for the production of titanium dioxide. The domestically produced ilmenite can not meet the demand of titanium dioxide industry, and the demand gap should be imported from abroad. In China, some iron ore tailings contain certain ilmenite, and it is of great significance to recover titanium from such iron tailings. In this study, an iron tailings test was carried out to recover titanium, and good results were obtained.

First, tailings properties

Process ore sample analysis showed that the metallic iron tailing minerals ilmenite, magnetite and pyrite, a small amount of yellow copper ore; non-metallic titanium minerals pyroxene, hornblende, and quartz. The multi-element chemical analysis results of the tailings are shown in Table 1.

As can be seen from Table 1, the component worth recovering in the tailings is titanium dioxide.

0.2kg of representative ore sample of -2mm was taken, and dry vibrating screening was carried out with a standard set of sieves. The products of each size class were weighed separately and sampled and tested. The results are shown in Table 2.

It can be seen from Table 2 that the grade of titanium in the coarse-grain grade is low, and the titanium is mainly distributed in the range of -0.2 mm, and the metal distribution rate accounts for 69.26% of the titanium.

Second, the test plan design

Studies on the properties of tailings indicate that the distribution of titanium in the tailings is mainly in the range of -0.2 mm. Effective means of recovering ilmenite are strong magnetic separation, re-election, flotation, and electrification. The density of ilmenite is about 4.7g/cm 3 , which is re-selected to achieve the separation of ilmenite and gangue. According to the magnetic difference of ilmenite and magnetite, weak magnetic separation can be used to select from ilmenite. Magnetite; ilmenite has weak magnetic properties, and can remove pyrite and gangue from ilmenite by strong magnetic separation; ferrotitanium can be removed by electric selection according to the difference of conductivity between ilmenite and phosgene Titanite in the mine to obtain high quality titanium concentrate.

Third, the test process and calculation results

According to the design process of the beneficiation process, it is determined that the ilmenite in an iron tailings is recovered by grinding, strong magnetic separation-shaker-flotation. Since the distribution of titanium in the tailings is mainly concentrated in the -0.5+0.074 mm grain size, the mine is first coarsely ground and ground to -200 mesh, accounting for 50%, first undergoing two strong magnetic separations, magnetic field strength. 994.725 kA/m abandoned tailings, strong magnetic separation concentrate and re-grinding to -200 mesh accounted for 70%, and then selected by shaker to obtain a shaker concentrate with a grade of 37.28%. Because of the low grade, it is shaken. The bed concentrate is flotation. The agents used for flotation are sulfuric acid, sodium fluorosilicate, oxidized paraffin soap and 2# oil. The number of quality processes is shown in Figure 1.

It can be seen from Fig. 1 that after one strong magnetic separation, the iron tailings can be thrown out of a tailings with a yield of 35.23% and a grade of 1.22%, and after one strong magnetic separation, a strong magnetic separation concentrate is carried out with a shaker. After re-election, the shaker concentrate with a grade of 37.28% can be obtained. The shaker concentrate can be obtained by 4 times of rough selection and 4 times of flotation, and the grade is 47.15%, the yield is 3.86%, and the recovery rate is 39.48. % of titanium dioxide concentrate.

Fourth, the conclusion

(1) The tailings contain 4.61% of titanium. Through the comprehensive process of grinding, strong magnetic separation-shaker-flotation, the qualified grade of titanium oxide can be selected with a grade of 47.15%, a yield of 3.86% and a recovery rate of 39.48%. mine.

(2) The tailings have a coarser grain size, the content of -0.074 mm is 25.39%, the coarse fraction of +0.2 mm is about 50%, and the grade of titanium in the coarse grade tailings is low, about 2.7%. In the case of grinding, two sections of grinding are used. One section of grinding fineness - 200 mesh accounted for about 50%, and the second section of grinding fineness - 200 mesh accounted for about 70%.

(3) The rough selection in the sorting process can be performed by strong magnetic separation or re-election. When using strong magnetic separation, the magnetic field induction intensity should be 0.6~0.9 T, and the high-time diopside will enter the magnetic product. At that time, ilmenite enters the tailings and reduces the recovery rate.

(4) The flotation conditions need to be strictly controlled, especially the amount of sulfuric acid added. If the concentration is insufficient, the concentrate grade is low, and the recovery rate is low.

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