Mechanical beneficiation and tailing process technology of black rock vanadium ore

China's black rock series vanadium ore resources are very rich, including stone coal type vanadium ore in many provinces across the country. Most of these vanadium do not have independent minerals, and most of them exist in other minerals in the adsorption state or isomorphism; and the vanadium containing grade is low. More than 1% or even lower. At present, the vanadium extraction process is basically aimed at low-grade raw ore that has not been enriched by mechanical beneficiation , and all of them enter the roasting or dissolution process of chemical method, and the production cost is high. In addition, the vanadium price is unstable in recent years, which causes the investment and production of vanadium industry. It is very confusing, so carrying out this work is of great significance to the development and utilization of vanadium resources.

The test sample is selected from this type of larger vanadium ore in a certain area of ​​Hubei.

First, the nature of the ore

(1) Multi-element analysis of raw ore

The results of multi-element analysis of raw ore are shown in Table 1.

Table 1 Results of multi-element analysis of raw ore

(II) Semi-quantitative analysis of mineral X-ray diffraction

The results of semi-quantitative analysis of X-ray diffraction of mineral samples are shown in Table 2.

Table 2 Semi-quantitative analysis results of X-ray diffraction of ore samples

Second, theoretical analysis of mechanical beneficiation

The ore contains 4% illite and vanadium-containing mica and 91% quartz.

Quartz is a three-dimensional skeleton formed by the common vertices of (SiO ₄ ) male tetrahedrons. The rupture along each surface is possible but difficult.

Illite is a weathering product of mica. Their structural unit is a three-layer type, that is, a silicon-oxygen layer (Si ₂ 0 ₅ ) _n ^2n- connected by a Si0 ₄ tetrahedron. This layer itself has hexagonal symmetry. Due to the close size of Si ⁴⁺ , the ion A1 ³⁺ can replace Si ⁴⁺ disorderly or orderly. The double layer between the structural unit layers is the ion K ⁺ and Na ^{+ with} smaller electric cost and larger radius. The Si-0 bond in the layer is much stronger than the bond between the layers. The mineral breakage mainly breaks along the (001) surface layer, while the (110) and (010) faces are also common fracture surfaces. It has been reported that vanadium in vanadium mica replaces Al ³⁺ located between mica structural layers.

During the process of breaking or grinding the ore, the structure of each mineral is bound to be destroyed, and thus the surface electrical properties are changed. For quartz and mica minerals, there are mainly two types of differences in properties. It is a mineral hardness. The Mohs hardness of quartz is 7 and the mica mineral is 2 to 3. The second is the surface property of minerals. The internal bonds of quartz are all Si-0. The mica minerals have Al-0 and Si-0 bonds, and the Si ⁴⁺ is replaced by A1 ³⁺ or V ³⁺ between the layers of such minerals, resulting in insufficient positive charge in the crystal lattice. The surface should be negatively charged. For the layers, the fractures of Al-0 and Si-0 of the two minerals and the possible effects on flotation are now analyzed. Both the Al-0 and Si-0 bonds contain components of ionic bonds and covalent bonds. The more components of the ionic bond, the greater the polarity of the bond, the more easily the bond is broken, and the nature of the mineral surface changes, making the mineral The floatability change, for the composition of the ionic bond in the polar covalent bond formed by the two atoms A and B, Pauling proposed an empirical formula:

Number of ionic types =

Xa and Xb are the electronegativity of A and B atoms respectively. After consulting relevant data, the electronegativity of 0 is 3.44, the electronegativity of A1 is 1.83, and the electronegativity of Si is 1.54. The -0 ion bond has more components than Si-0, so Al-0 is more susceptible to cracking during machining.

In summary, it is considered that the mica minerals have more electric charge than the surface of the quartz, and it is easier to form chemical adsorption in the slurry, while the physical adsorption of quartz is more, because the intensity of the two adsorptions is greatly different. Thus, under suitable pharmaceutical conditions, there are differences in surface properties, making it possible to separate.

Third, the test results and discussion

(1) Grading test

The ore contains 91% quartz, which has a high hardness. It may form a difference in particle size with other minerals during crushing or grinding. For different sizes of -2mm ore and -74μm 60% grinding fineness For screening, the results of the -2mm raw ore screening are shown in Table 3. The results of the product screening after grinding are listed in Table 4.

Table 3 - 2mm raw ore classification test results%

Table 4 % of classification test results when grinding to -74μm 60%

It can be seen from the test results in Table 4 that direct sieving without grinding is difficult to achieve the purpose of tailing; however, after direct grading, the vanadium grade of -74 μm is enriched, and the yield of +74 μm is close to 80%. trend. According to the analysis, due to the high hardness of quartz, it will be enriched in the coarse-grained stage during the crushing and grinding process, and there are layered silicate mineral mica in the ore. These minerals have different cleavage during the grinding process. The granularity of the faces is inconsistent, so the limitation of throwing tails by grading alone is very large.

(2) Flotation test

In summary, the minerals in the ore have different surface properties. It is possible to separate by flotation. For this reason, the flotation test is carried out by the staged dosing segmentation process. The test results are shown in Table 5.

Table 5 % of single flotation test results

It can be seen from the test results that the flotation tailings V ₂ 0 ₅ content is 0.32%, which has a certain separation effect, but the yield is only 25.10%. The reason for the analysis is that the ore contains easily muddy mica minerals. It can be seen from the results of the sieve analysis in Table 4 that the yield of -38μm is 44.97%, and the vanadium-containing grade is high. It is the target mineral for flotation. Due to the large amount of floating particles, the non-target minerals will be trapped, resulting in a large concentrate yield. The result of low grade. Therefore, a single flotation tailing scheme is not suitable, and it is necessary to consider joint tailing with other processes.

(3) Joint process test

As mentioned above, the limitation of the ore by grading to achieve tailing is very large, and the flaky dissociated minerals will follow the light minerals during the re-election process. The equipment of the spiral concentrator can be used to grind fine minerals in the grinding. Light minerals and flake minerals are concentrated in one year's products. When combined with flotation, the mineral mud that interferes with flotation is also enriched in this mineral, which has the advantage of reducing the amount of flotation agent. Therefore, it is believed that the suspended sludge will be selected in advance by spiral beneficiation, which will improve the flotation effect.

Taking into account the characteristics of the ore properties, as well as the results of the classification test and the flotation test, the joint process of “grading-flotation”, the combined process of “spiral beneficiation-flotation” and the combined process of “grading-screw beneficiation-flotation” were selected. . The process of grading operation in the test is directly to -2mm ore, graded with 74μm sieve, +74μm product for grinding, grinding fineness is -74μm60%, spiral beneficiation-flotation combined process test directly for -2mm ore Grinding, grinding fineness is -74μm70%, the test results are shown in Table 6.

Table 6 Joint Process Test Results%

Compared with the three processes, the grading-flotation combined process tailings vanadium grade is too high, it is not suitable; the grading-helical beneficiation-flotation combined process and the spiral beneficiation-flotation combined process are more complicated and the indicators are similar. Therefore, it was determined that the “spiral beneficiation-flotation” joint process was used for tailing.

(4) Comprehensive condition test

The tailing test was carried out according to the "spiral beneficiation-flotation" joint process, and the raw materials for chemical vanadium extraction were produced. The test results are shown in Table 7.

Table 7 Spiral Concentrator Re-election - Flotation Process Material Enrichment Results %

Seen from the test results, a spiral concentrator - flotation process disposable yield 46.97%, 0.30% grade, 14.96% metal loss rate of the tailings, chemical extraction entering vanadium grade increased to 1.49%, the increase of the cost per ton of mineral The original mine does not exceed 20 yuan.

(5) Chemical vanadium test

Considering the effect of flotation of chemicals on chemical vanadium extraction, a direct comparison between vanadium extraction from raw ore and vanadium extraction from enriched concentrates was carried out. The test results are shown in Tables 8 and 9.

The test results show that the addition of flotation reagent has no effect on the vanadium extraction index. It is thus concluded that the mechanically-mineralized material entering the chemical vanadium can significantly reduce the production cost.

Table 8 % of raw vanadium direct test results

Table 9 Vanadium extraction test results of enriched materials%

Fourth, the conclusion

(1) Through the analysis of the mineral properties and crystal structure of the layered silicate minerals of quartz and mica, and the calculation of the ionic bond components which are more likely to cause surface properties in the Al-0 and Si-0 bonds, the mica minerals and Two differences in hardness and surface properties compared to quartz can result in separation in mechanical beneficiation.

(2) Through the direct classification of raw ore, the comparison of single-flotation and combined process data and the analysis of ore characteristics, it is concluded that the re-election-flotation combined process is more suitable for the ore tailing, and the process can be discarded and the yield can be discarded by 46.97%. The tailings with a grade of 0.30% and a metal loss rate of 14.96% increased the grade of vanadium entering the chemical to 1.49%.

(3) Compared with the direct chemical extraction of vanadium from the ore, the experimental indicators are close, indicating that the ore dressing agent has little effect on the chemical vanadium extraction; and abandoning nearly 50% of the tailings to make the chemical extraction of vanadium The amount of minerals is reduced by half, the grade of vanadium in the furnace is increased, the beneficiation process is simple and easy, and the production cost of vanadium extraction can be significantly reduced.

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