In order to develop the use of Yunnan indium zinc somewhere multi-metal sulfide ore, commissioned by a mining company in Kunming, Kunming detailed experimental study of beneficiation of mineral resources supervision and inspection center of the mine were, in order to obtain a reasonable beneficiation process and better The technical parameters, as well as the technical and economic indicators that can be obtained under the better sorting conditions, provide the basis for the design of the concentrator.
First, the nature of the ore
(1) The chemical composition of the ore
The results of multi-element analysis of raw ore are shown in Table 1-2, and the results of zinc phase analysis are shown in Table 3.
Table 1 Multi-element analysis results of raw ore% (1)
element | Zn | TFe | Pb | Cu | Ag/10 -6 | Ge/10 -6 | Ga/10 -6 | In/10 -6 | WO 3 | SiO 2 |
Quality score | 8.53 | 20.06 | 0.29 | 0.25 | 68.0 | 25.63 | 2.45 | 55.6 | 0.16 | 29.79 |
Table 2 Multi-element analysis results of raw ore% (2)
element | MgO | CaO | Al 2 O 3 | K 2 O | Na 2 O | MnO | S | P | As |
Quality score | 2.66 | 11.55 | 1.59 | 0.17 | 0.12 | 1.34 | 12.13 | 0.22 | 0.82 |
Table 3 % of zinc phase analysis results
Phase | Zinc sulfide | Zinc sulfate | Zinc oxide | Other zinc | Total zinc |
Quality score Occupancy rate | 8.35 95.21 | 0.015 0.17 | 0.28 3.19 | 0.12 1.43 | 8.77 100.0 |
As can be seen from Table 1-2, zinc has good recycling value, and rare metals such as silver , gallium , antimony and indium can be considered for comprehensive recycling.
It can be seen from Table 3 that the zinc occupation rate of zinc sulfide is 95.21%, and the zinc occupation rate of zinc is lower, which is beneficial to the improvement of zinc beneficiation recovery rate.
The analysis shows that the iron- sphalerite single mineral contains 47.34% zinc, 14.65% iron, 226×10 -6 indium, 13.5×10 -6 in gallium, 19.7×10 -6 in silver, and 0.8×10 -6 in strontium . Mine (iron sphalerite), rich in rare element indium. Due to the high iron content, the zinc concentrate grade will be low.
(2) Mineral composition and content of raw ore
The main metal minerals in the ore are iron sphalerite (17%) (small amount of sphalerite), pyrrhotite (14%) and arsenopyrite (1.8%). The main non-metallic minerals are diopside ( 24%), tremolite (11%), epidote (8%), mica (5%) and quartz (6%), etc., iron sphalerite is the main purpose mineral for mineral recovery.
(3) Embedding characteristics of major minerals
Iron sphalerite: It is the main zinc mineral in the ore, colorless, light yellow, oil-gold diamond, it is granular. Most particles were independently MARMATITE output, part of the magnetic pyrite, galena and copper ore or symbiotic with students, few parcels milky pyrrhotite or chalcopyrite, pyrrhotite individual is package. The formation time of iron sphalerite is earlier than that of pyrrhotite. It can be seen that pyrrhotite is distributed in fine veins in sphalerite, and most of them are disseminated in mineral particles such as tremolite, epidote and diopside. Between, a small number of fine veins in the ore fissure. Its particle size is generally from 0.05 to 3.2 mm and a maximum of 5 mm.
Pyrrhotite: It is the main metal sulfide in the ore. It is mostly granular and partially semi-self-granular. It is formed in the later stage of diagenesis, often wrapped or replaced by early tremolite and diopside, etc., often associated with iron sphalerite, chalcopyrite and magnetite. The particle size changes greatly, up to 5mm, generally 0.1~2mm, -0.1mm is about 15%, and the minimum is about 0.003mm.
Aromatic sand: The ore poisoning sand content is 1.8%, tin white, metallic luster, mostly in its shape. Observed under the microscope, it is irregular in shape and granular, the reflection color is white, the heterogeneity is strong, and some of it begins to change.
Second, mineral processing test research
(1) Selection of the selection process
Generally, the iron sphalerite selection method mainly includes preferential flotation, zinc-sulfur mixing and separation.
The main metal minerals in the ore are iron sphalerite, pyrrhotite and arsenopyrite. The main gangue minerals are diopside, tremolite, epidote, quartz and mica. For the recovery of zinc in the ore, the focus is to solve the problem of separation of iron sphalerite, pyrrhotite and arsenopyrite. Because the ore in the ore is quite buoyant, it is easy to float, so the iron sphalerite Effective separation from arsenopyrite has become a key technology to be solved.
In addition, the associated rare precious metals such as silver, gallium and indium are enriched in zinc concentrate products for comprehensive recycling.
In summary, the priority flotation is selected as the principle process flow for zinc selection.
(2) Grinding fineness condition test
“Over-grinding†and “under-grinding†are unfavorable for the recovery of zinc. In order to find a suitable fineness, 8kg/t of lime, 300g/t of copper sulfate, 120g/t of butyl xanthate and pine oil Under the condition of 50g/t, three different grinding fineness of -74μm accounted for 65%, 75% and 85%, respectively, and their effects on zinc selection were investigated. The test results are shown in Table 4.
Table 4 % of grinding fineness condition test results
Grinding fineness /-74μm | product name | Yield | Zinc grade | Zinc recovery |
65 | Concentrate Tailings Raw ore | 22.76 77.24 100.0 | 29.67 2.09 8.37 | 80.68 19.32 100.0 |
75 | Concentrate Tailings Raw ore | 23.02 76.98 100.0 | 33.51 1.36 8.76 | 88.06 11.94 100.0 |
85 | Concentrate Tailings Raw ore | 20.59 79.41 100.0 | 32.77 2.78 8.95 | 75.23 24.77 100.0 |
It can be seen from Table 4 that as the fineness of the grinding increases, the grade and recovery rate of the zinc concentrate first increase and then decrease. Therefore, a suitable grinding fineness of -74 μm accounts for 75%.
(III) Test of rough selection of lime
It is well known that iron sphalerite has the dual nature of sphalerite and pyrite, which means that the iron sphalerite can be significantly activated by both copper sulfate and lime. During the test of “sulphur suppression and floating zincâ€, it was found that pyrrhotite is easily inhibited by lime (high alkalinity), but the aerated sand is abnormally good and difficult to suppress. Therefore, strict control of the alkalinity of the slurry has become the key to the effective separation of iron sphalerite and arsenopyrite.
The test results of the rough selection of lime (pulp pH) conditions are shown in Figure 1.
It can be seen from Fig. 1 that with the increase of lime dosage, the pH of the pulp increases, the arsenic content in the zinc concentrate decreases, and the zinc recovery rate also decreases, indicating that the control of the pulp pH is iron sphalerite and pyrrhotite, poison. The key to sand separation. Low-volume lime, non-floating pyrrhotite and arsenopyrite are not easily inhibited, resulting in low grade of zinc concentrate and excessive arsenic content; while high lime dosage, some iron sphalerite will be inhibited, zinc The increase in recovery rate is unfavorable.
Considering the arsenic content and zinc recovery rate of the integrated zinc concentrate, the suitable amount of lime is 6-8 kg/t (pH 12.0～12.6), and the lime dosage is 8kg/t.
(4) Test on the condition of rough selection of copper sulfate
Copper sulfate has a significant activation effect on iron sphalerite, and the test results of the crude copper sulfate dosage condition are shown in Fig. 2.
It can be seen from Fig. 2 that when the amount of copper sulfate is increased from l00g/t to 300g/t, the grade of zinc concentrate is basically unchanged, and the recovery rate is remarkably improved; when the amount of copper sulfate is continuously increased to 400g/t, the zinc recovery rate is no longer improved. . Therefore, the preferred amount of copper sulfate is 300 g/t.
(5) Crude selection of butyl yellow medicinal, conditional test
The test results of crude butyl yellow dosage conditions are shown in Figure 3.
It can be seen from Fig. 3 that as the amount of butyl yellow is increased, the recovery rate of zinc concentrate is significantly increased, and the grade is gradually decreased. In terms of integrated concentrate grade and recovery rate, the preferred amount of butyl yellow is 150 g/t.
The optimization test results of the main technical conditions of rough selection show that the preferred grinding fineness is -74μm, accounting for 75%, the crude lime is 8kg/t (pH 12.6), the copper sulfate is 300g/t, the butyl yellow is medicinal. The amount is 150g/t.
(6) Open flotation process test
On the basis of the grinding fineness and the optimization of the chemical system conditions, the priority flotation open circuit test is carried out. The process flow is shown in Figure 4, and the test results are shown in Table 4.
Table 4 % of the preferred flotation open circuit test results
product name | Yield | grade | Recovery rate | |||
Zn | Ag(10 -6 ) | As | Zn | Ag | ||
Concentrate Middle mine 1 Middle mine 2 Middle mine 3 Middle mine 4 Tailings Raw ore | 15.32 2.75 4.78 3.18 0.76 73.21 100.0 | 47.45 20.69 9.81 2.53 1.19 0.74 100.0 | 113.51 68.0 | 0.076 0.82 | 81.31 6.36 5.25 0.90 0.10 6.08 100.0 | 25.57 100.0 |
It can be seen from Table 4 that under the preferred grinding fineness and chemical system conditions, the zinc ore concentrate yield can be obtained after the raw ore is sorted by a rough flotation, two selections, and two sweeps. 15.32%, grade 47.45%, recovery rate 81.31%, silver grade 113.51g/t, silver recovery rate 25.57%, total medium mine zinc recovery rate 12.61%, tailings zinc grade 0.74%, loss rate 6.08% technical and economic indicators.
The recovery rate of zinc concentrate is high, but the grade is low. The main reason is that the zinc mineral in the ore is mainly iron sphalerite, and the single mineral iron sphalerite contains 47.34% zinc.
(VII) Closed circuit flotation process test
During the open-circuit flotation process test, it was found that the selected mines were mainly gangue minerals, iron sphalerite and aerobic sands with good floatability. As mentioned above, the aerated sand with good floatability can be effectively restrained by repeated suppression of lime. In order to avoid the formation of a vicious circle in the flotation closed circuit and affect the quality of the zinc concentrate product, it is proposed to add the middle mine. In the selected operation, the foam product is returned to the rough selection, and the bottom product is discharged into the tailings, which is an innovative point in the process test. The closed-loop flotation process is shown in Figure 5, and the test results are shown in Table 5.
Table 5 % of closed circuit flotation process test results
product name | Yield/% | Grade/10 -6 | Recovery rate/% | ||||||||
Zn/% | Ag | Ga | Ge | In | Zn | Ag | Ga | Ge | In | ||
Concentrate Tailings Raw ore | 18.79 81.21 100.0 | 41.56 0.72 8.39 | 101 51.9 61.13 | 9.89 0.078 1.92 | 1.29 34.5 28.26 | 246 5.37 50.58 | 93.08 6.92 100.0 | 31.05 68.95 100.0 | 96.79 3.21 100.0 | 0.86 99.14 100.0 | 91.39 8.61 100.0 |
It can be seen from Table 5 that after the new closed-circuit flotation process of “one rough selection, two selections, two sweeps, and medium mine re-election†is selected, the yield of zinc concentrate can be 18.79% and the grade is 41.56%. The recovery rate is 93.08%; the tailings zinc grade is 0.72%, and the loss rate is 6.92%. The recovery effect of zinc is very good.
In addition, the silver grade enriched in zinc concentrate is 101g/t, the recovery rate is 31.05%, the gallium grade is 9.89 sand, the recovery rate is 96.79%, the indium grade is 246g/t, and the recovery rate is 91.39%. Associated beneficial rare metals have also been comprehensively recycled.
(VIII) Quality inspection of concentrate products
The main chemical composition analysis results of zinc concentrate products are shown in Table 6.
Table 6 Analysis results of main chemical components of zinc concentrate products
element | Zn | Cu | Pb | Fe | As/10 -6 | Ag/10 -6 | Ga/10 -6 | Ge/10 -6 | In/10 -6 | WO 3 |
Quality score | 41.56 | 0.93 | 0.19 | 20.88 | 580 | 101 | 9.89 | 1.29 | 246 | 0.059 |
Zinc concentrate contains 41.56% zinc, 0.93% copper, 0.19% lead, 20.88% iron and 580×10 -6 arsenic. The product quality has reached the quality requirements of commercial zinc concentrate.
Third, the conclusion
(1) The main metal minerals in the ore are iron sphalerite, pyrrhotite, poisonous sand, etc. The main gangue minerals are diopside, tremolite, epidote, quartz and mica.
(2) The preferred grinding fineness is -74μ.m, which accounts for 75%, the crude lime content is 8kg/t (pH12.6), the copper sulfate dosage is 300g/t, and the butyl yellow dosage is 150g/t.
(3) The arsenotic sand in the ore is very buoyant, easy to float and difficult to suppress, and needs to be inhibited by lime (high alkali) multiple times to effectively suppress it. This process research innovatively proposed the “new closed-circuit process for re-election of minesâ€, which effectively solved the problem of separation of iron sphalerite and arsenopyrite, and obtained zinc concentrate products with qualified quality.
(4) After the raw ore is selected by the preferential closed-circuit flotation process, the technical and economic indicators of zinc concentrate yield 18.79%, grade 41.56%, recovery rate 93.08%, tailings zinc grade 0.72%, loss rate 6.92%, zinc can be obtained. The recycling effect is very good.
(5) The silver grade enriched in zinc concentrate is 101g/t, the recovery rate is 31.05%, the gallium grade is 9.89g/t, the recovery rate is 96.79%, the indium grade is 246g/t, the recovery rate is 91.39%, and the beneficial rare metal is also associated. Obtained comprehensive recycling.
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