Fluorinated mineral fluorite , the only raw material for the production of hydrofluoric acid, is the main solvent for steelmaking and an additive for the production of aluminum . It is also an important additive for the glass industry and the basic raw material for the fluoride salt industry. In recent years, domestic and foreign demand for fluorite increases every year, is expected within the next few years, the demand for fluorite ore will continue to maintain an upward trend, is a limited liability company Integrated float tungsten tailings from the recovery of non-ferrous metals as Shizhuyuan Fluorite provides a good opportunity.

The persimmons of the Shizhuyuan polymetallic mine are rich in resources, and the fluorite reserves account for 74% of the national associated fluorite reserves, accounting for 5% of the national fluorite reserves. Shizhuyuan Nonferrous Metals Co., Ltd. has three multi-metal selection plants. The annual processing capacity is about 700,000 tons. In addition to the recovery of tungsten, molybdenum , niobium , iron and sulfur, the pace of fluorite recovery is being tightened. The fluorite content of the floating tungsten tailings is generally 18% to 22%, and the amount of fluorite is about 140,000 tons. Calculated at the current selling price, the value is more than 70 million yuan.

For the recovery of phoenix in Shizhuyuan, many research units and universities in China have conducted long-term and fruitful research. Due to the nature of the ore tailings Shizhuyuan floating tungsten complex, a wide variety of minerals, fluorite content is not high, and partial small disseminated grain size and other reasons, research over the years in order to float - Magnetic-based fluorite mineral processing, although a small test The effect is good, but in actual production, due to many factors restricting flotation, the floating-magnetic process is difficult to obtain stable high-quality, high-recovery fluorite concentrate, which is the main cause of fluorite recovery in Shizhuyuan. the reason.

Studying the new process of strong magnetic-flotation-desiliconization fluorite ore dressing, magnetic grouping of floating tungsten tailings, separating weak magnetic minerals containing silicon, non-magnetic products and flotation flotation, flotation of concentrates The final fluorite condition is obtained after desiliconization. For the floating tungsten tailings containing 22.89% of CaF ₂ , the fluorite obtained by the new process contains CaF ₂ 97.84%, SiO ₂ 0.95%, CaCO ₃ 0.64%, and CaF ₂ recovery rate of 69.97%. The new process enables stable and easier access to high-quality, high-recovery fluorite conditions for industrial production of fluorite.

1. The nature of the floating tungsten tailings of Shizhuyuan

Among the Shizhuyuan floating tungsten tailings, fluorite is the main target mineral for separation. Other minerals for comprehensive recovery include garnet , a small amount of magnetite, and wolframite . Non-purpose minerals are mainly quartz , feldspar and calcite , as well as chlorite, epidote, biotite , muscovite, hornblende and tremolite . The floating tungsten tailings sample contains 22.89% of CaF ₂ , 48.89% of SiO ₂ and 3.68% of CaCO ₃ , and the grain size of quartz is in the range of 0.010 to 0.043 mm.

The analysis results of the ore screening are shown in Table 1. The mineral composition is shown in Table 2.

Table 1 analysis of ore screening

Table 2 Mineral composition

The analysis shows that the floating tungsten tailings contain 22.89% of CaF ₂ and the content is not high. The fluorite is mainly distributed at -0.043 mm, the yield is 55.39%, and the CaF ₂ occupancy is 70.82%. The yield of the +0.043mm fraction in the ore is 44.61%, and the CaF ₂ occupancy is 29.18%. This grade-level fluorite has more continuum, which is the main reason for the high silicon content of fluorite concentrate.

Second, the test results and discussion

(1) Process and test results

The fluorite ore dressing principle process and results are shown in Figure 1 and Table 3.

Figure 1 Fluorite ore dressing principle process

Table 3 Test results of new process of fluorite ore dressing

The new process of fluorite beneficiation is preceded by magnetic separation, and the floating tungsten tailings are magnetically grouped by weak magnetic and strong magnetic separation. The weak magnetic separation recovers the strong magnetic minerals in the floating tungsten tailings, and the selected magnetites are obtained. The strong magnetic separation divides the floating tungsten tailings into two parts. The magnetic part contains weak magnetic minerals such as wolframite and garnet, and the black tungsten intermediate and garnet concentrate products are obtained by gravity separation. The non-magnetic part is subjected to fluorite flotation, and the fluorite flotation adopts a rough one-sweeping process, and the flotation concentrate is desiliconized to obtain the final fluorite concentrate.

It can be seen from the principle process and results that the new fluorite ore dressing process is actually a process for comprehensive resource recovery of the Shizhuyuan floating tungsten tailings. In addition to the fluorite situation, the new process also considers the recovery of wolframite and garnet.

(2) Stable product quality

The pure mineral fluorite grade of Shizhuyuan is 98%～99%. The fluorite of different colors of different mines has slightly different calcium fluoride content. The secondary product fluorite concentrate is required to contain CaF ₂ ≥97%, SiO ₂ ≤1%, and CaCO ₃ ≤1%. The CaF ₂ grade of fluorite concentrate is very different from the pure ore grade, and the impurity content is very low. It can be considered that among all the mineral products of Shizhuyuan Nonferrous Metals Co., Ltd., the purification requirement for fluorite concentrate is the highest.

The fluorite ore dressing process of the original research promoted the consideration and change of the process route by the instability of the floating-magnetic beneficiation process and the lessons of multiple industrial tests and production commissioning.

The new process is magnetically selected first, and the floating tungsten tailings are magnetically grouped. The fluorite grade of the non-magnetic product after the grouping is improved, and the mineral composition is simplified to optimize the fluorite flotation feeding and reduce the pressure of flotation. The non-magnetic product is concentrated and then floated with fluorite, so that the ore concentration and concentration of fluorite flotation are easy to control. At the same time, the concentration operation can remove the remaining chemicals and fine mud ore in the slurry, reduce their interference to the flotation process, greatly enhance the stability of fluorite ore dressing, and thus more easily obtain high-quality fluorite concentrate, and the quality of the concentrate is more Guaranteed.

(3) Suitable for ore properties

The average specific magnetic susceptibility of the main minerals in the floating tungsten tailings ^{[1-2] is} shown in Table 4.

Table 4 The average specific magnetic susceptibility K of the main minerals in the floating tungsten tailings is K/(10 ^-6 C·G·S·M·cm ³ ·g ^-1 )

As can be seen from Table 4, the average specific magnetic susceptibility of wolframite, pyrite, garnet, biotite, hornblende, epidote, and chlorite is 19.96 to 63.0 (10 ^-6 C·G·S· M·cm ³ /g), the magnetite is higher. The specific magnetic susceptibility of fluorite, scheelite , calcite, quartz and feldspar is -0.50 to 0.51 (10 ^-6 C·G·S·M·cm ³ /g). The average specific magnetic susceptibility of the two groups of minerals is significantly different, which provides a good basis for the floating tungsten tailings according to the magnetic grouping.

Since minerals such as garnet with higher specific magnetic susceptibility are silicon-containing minerals, the earlier the removal, the better the quality assurance of fluorite concentrate for fluorite flotation, so the magnetic group is more suitable for the ore of floating tungsten tailings. nature.

(4) Prominent comprehensive recovery

The new process uses magnetic grouping to highlight the comprehensive recycling capabilities. The floating tungsten tailings are first selected by the weak magnetic first machine, which not only recovers the magnetite, but also prevents the mesh of the strong magnetic separator from being blocked. The magnetic products selected by strong magnetics are mainly black tungsten ore and silicon-containing garnet, biotite, hornblende, epidote, chlorite and other minerals. The density of black tungsten ore and garnet is different from that of amphibole, epidote, chlorite and other minerals. After gravity separation, black tungsten ore and garnet concentrate can be obtained.

The test obtained the black tungsten in the ore containing WO ₃ 30.44%, the recovery rate of the floating tungsten tailings was 15.22%, and the recovery rate of the original ore was increased by 3.5% to 4.5%. The yield of garnet concentrate is 11.68%, the mineral content is 90.2%, and the mineral recovery rate is 39.61%. The garnet can be used as abrasive material, cement admixture, filler and other uses. The recovery and popularization of garnet will greatly improve the comprehensive utilization rate of the Zhuzhuyuan mineral resources and the economic benefits of the enterprise.

(5) Comparison and selection of collectors

Fluorite flotation is usually carried out using oleic acid as a collector. Due to the poor selectivity of oleic acid, the selection of coarse concentrates is difficult. Especially when the ambient temperature is low, the dispersion of oleic acid in the slurry is poor, and the beneficiation effect is greatly reduced. In order to adapt to the local climate of Shizhuyuan and overcome the shortage of oleic acid collector, the oleic acid was modified. The comparison between the two modified oleic acid T-9, GO5 and oleic acid is shown in Figure 2.

Figure 2 Comparison of the selection effect of modified oleic acid and oleic acid

It can be seen from Fig. 2 that the oleic acid has the lowest beneficiation efficiency and the best efficiency of GO5 in the three collectors. When the dosage range is 300g/t, the beneficiation efficiency is 57.71%.

(6) Selection of selected inhibitors

Fluorite-selected inhibitors are important for fluorite purification and for recovery. Shizhuyuan fluorite selection inhibitors include CF, HN and other combination agents ^[3] . The newly screened N03 inhibitor has strong adaptability to the maglev process and has very good effects. The inhibitory effects of the N03 inhibitor and the oily water glass combination agent NL and NS are shown in Table 5.

Table 5 Comparison of the effects of three inhibitors

Third, the conclusion

The new magnetic-floating fluorite ore dressing process magnetically groups the floating tungsten tailings, simplifies the mineral composition of fluorite flotation, optimizes flotation feeding, eliminates and reduces the magnetic silicon-containing minerals and residual chemicals for the flotation process. influences. The process is suitable for the ore nature of floating tungsten tailings, the process is stable, and the quality of fluorite is high. The process highlights the comprehensive recovery of useful minerals in floating tungsten tailings. In addition to obtaining high quality and high recovery fluorite concentrate, it can also recover magnetite, wolframite and garnet minerals, and improve the persimmon bamboo. The comprehensive utilization rate of the mineral resources of the park and the economic benefits of the enterprise.

references

[1] Zhang xianhua, Zhang zhonghan.Study on the recovery of fluorite from wolfram flotation tailings in Shizhuyuan concentrator[A]//Proceedings of 4 ^_th International Symposium on East Asian Resources Recycling Technology [C].Beijing:International Academic Publishers, 1997 :336-341.

[2]Zhou Weizhi.Study on the Associated Fluorite of Polymetallic Mine in Shizhuyuan[J].Journal of Guangdong Nonferrous Metals,1993,3(2):81-87.

[3] Xu Shi. Ore Feasibility Study [M]. Beijing: Metallurgical Industry Press, 1987: 305.

[4] Preparation of reference materials for mineral processing design. Reference materials for mineral processing design [M]. Beijing: Metallurgical Industry Press, 1972: 694.

[5] Zhu Jianguang. Several problems of fluorite flotation [J]. Foreign metal ore dressing, 2004, (6): 4-9.

[6]林日孝.Study on flotation of polymetallic ore fluorite in Shizhuyuan by GF combination agent[J].Journal of Guangdong Nonferrous Metals,2001,5(1):9-12.

Author unit:

South China Normal University: Ye Zhiping

Guangzhou University: He Guowei

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