Study on Beneficiation Process of Difficult-Selected Lead Oxide Ore from Shizhu

Changes in the composition of lead oxide zinc ore variety, ease of beneficiation vary widely, affected by the mud of ore, degree of oxidation, its performance and determine alternative process flow, it has a great influence. This paper will present the results of a beneficiation process for a highly muddy ore.

First, the nature of the ore

The Shizhu Oxide Lead-Zinc Mine is a residual deposit. It is probably the accumulation of waste materials from the ancient people. The grade of the ore is not high. It is muddy and oxidized all the year round, resulting in extremely deep oxidation and high mud content.

(1) Multi-element and phase analysis

The analysis results of the chemical composition of the ore and the phase of the zinc phase are shown in Tables 1 and 2, respectively. The lead and zinc grades of the ore are not high and the oxidation rate is extremely high. The oxidation rate of zinc is as high as 95.4%, and 36% is silicate and zinc ferrite , and only 59.3% of zinc carbonates with good floatability are available.

The ore also contains about 12% iron, which is equivalent to about 20% of the ore's ore. In the process of forming the ore oxidation zone, limonite often adsorbs and exchanges zinc ions, which is also the reason for the high content of zinc ferrite in the ore.

According to the process of mineralogy, the main metal ore minerals hemimorphite, calamine, and a small amount of white galena gangue minerals quartz, limonite, chlorite.

(2) Granular composition of ore

The unbroken ore samples were sieved and analyzed, and the results are shown in Table 3.

Another major feature of ore is that mud is particularly serious. Unbroken ore, the metal distribution rate of -74μm accounts for T67.26%, the metal distribution rate of -10μm is as high as 77.25%, and the yield of -5μm is 45.6%, which is extremely rare in general ore. The distribution of zinc metal in the -5 μm class is 22.75%, and this part of the metal is obviously difficult to recycle.

(ii) Mineral embedding characteristics

In the study of process mineralogy, the output grain size and embedding state of zinc oxide minerals were determined by electron microscopy. It was found that the output grain size of zinc oxide minerals in the ore was extremely uneven. Some monomeric zinc oxides have a particle size of 1-2 mm, and many zinc oxide minerals have a particle size of only 3-5 μm. Most of them are encapsulated or associated with iron oxide minerals. Fine-grained, wrap-around zinc oxide minerals can also cause difficulties in recovery.

Second, zinc oxide mineral recovery process research

In order to recover the zinc oxide minerals in the ore, we used a conventional amine flotation process and studied the main factors affecting the flotation of the amine process.

(1) Sludge problem

The most important factor affecting the flotation of zinc oxide by the amine method is the slime. Generally, it is necessary to remove the slime before the flotation by the amine method. Recently, there have been many reports on direct flotation of zinc oxide without mud removal, but there are still few ore concentrates that have actually been realized in production. In fact, the amine flotation does not completely prevent the presence of slime. Because the cyclone is de-sludged, the -5μm fine mud will not be completely removed. There is always a certain amount of -5μm fine mud in the slurry, just for Different ores, the fine mud that is allowed to exist is not the same, which is why some ore can do not de-float flotation, but some other ore can not do one of the important reasons. The mud content of the stone column oxidized ore is particularly high, and it is obviously difficult to remove the mud flotation. We have studied this.

1. The original slime must be removed.

The ore-containing grade of -l0μm is as high as 48.44%. The ore is directly flotation after crushing and grinding. When the concentration of the slurry is 20%-25%, the slurry is paste-like in the flotation tank and cannot be floated. Therefore, the method of washing and de-slipping the ore before the crushing is adopted, and a large amount of the original slime is removed first. The laboratory used a Φ30mm cyclone to remove the slime at a pressure of 245 kPa. Desliming conditions are listed in Tables 4 and 5.

It can be seen that after washing and de-sludge, most of the slime can be removed, the yield is above 50%, the zinc loss rate is about 25%, the majority of the slime is fine particles, and the -5μm fraction accounts for 78 of the slime. %, zinc loss accounts for 80% of the total zinc loss in the slime. This part of the material obviously should not enter the mineral processing operation.

2. The influence of secondary slime

After the primary slime is de-sludged, it is crushed, ground and then floated with lead oxide and zinc oxide. When grinding, some secondary slime was formed. Whether it needs to be removed or not, the research results are also compared. The test results are listed in Table 6.

If the secondary slime is not removed, the zinc oxide can be floated by amine method. When the coarse concentrate contains 17.33%, the recovery rate of flotation operation is 73.72% (57.06% for the original ore), which indicates the secondary slime. The interference is much smaller than the original slime; at the same time, according to the results of the removal of the original slime (Tables 1, 2, 3), the removal rate of -5μm is 89.32% when the original slime is removed. The amount of detachment is 40.73%, and 4.87% of the -5 μm primary slime remains in the washing and sinking sand. After grinding, the zinc oxide is floated without deliming, and they do not destroy the flotation process. Ammonia floatation of zinc oxide allows for the presence of a certain amount of slime in the slurry. However, after removing the secondary slime, although the slime yield is 10%-15% and the zinc loss is more than 5%, the flotation index is still improved, and the recovery rate is slightly improved, which also indicates that the -10μm fine mud is still There is a certain interference, and zinc oxide in these fine muds is difficult to enter the concentrate during flotation.

(2) Collector problem

1. The floatability of zinc oxide minerals in mineral samples is extremely poor. A large amount of collector is required to float well. Generally, long-chain first amines are used to float zinc oxide ore. The amount of amines is mostly 100-300g/t. However, the stone pillar is a zinc oxide ore mainly composed of siliceous gangue. Under the above dosage, zinc oxide does not float up substantially (see Figure 1). Only when octadecylamine of 600g/t or more is added at a time, zinc oxide is more Good recovery rate, which is obviously related to the long-term accumulation of these ores is strongly muddy and oxidized.

2, the use of oleic acid and octadecylamine mixed use, can improve the flotation index, greatly reducing the amount of amine

The use of mixed amines, or the combination of amines with xanthate, amines and other chelating anion collectors, can improve the flotation index of zinc oxide ore. However, there have been no reports of mixing amines with fatty acids. Most zinc oxide ores always contain more carbonate gangue. In view of the characteristics of less carbonate gangue in Shizhu zinc oxide ore, we tried to mix amine and oleic acid to achieve good results. The test results are shown in Table 7.

Adding 50g/t oleic acid to octadecylamine can reduce the amount of octadecylamine by 1/3 (200g/t). Compared with 600-800g/t octadecylamine alone, the recovery rate is increased by 5%-8 %. However, further increase in the amount of oleic acid does not replace octadecylamine, nor does it improve the flotation index.

Our research shows that the use of a mixture of amine and oleic acid in a collector is useful for the flotation of certain zinc oxide ores.

(3) Vulcanizing agent problem

Contrary to the case where the collector consumption is extremely large, the amount of sodium sulfide required for the flotation of the stone pillar zinc oxide ore is not large. The test results are shown in Figure 2.

Good flotation results can be obtained with 2000 gt sodium sulfide, which is rare in zinc oxide ore flotation. Because the collector we used in the test is a combination of octadecylamine + oleic acid, it is likely that the amount of sodium sulphide will be reduced after the proper addition of oleic acid.

(4) The influence of iron oxide minerals

The ore contains more iron oxide minerals, mainly in the form of limonite. Their effects on the flotation index are manifested in two aspects, one is the consumption of chemicals, and the other is the increase of zinc loss. After strong magnetic separation to remove most of the iron oxide minerals, zinc oxide flotation can improve the flotation index (see Table 8). Compared with the non-magnetic separation of iron, the amount of amine can be reduced by 1/3 after iron removal, which indicates that the limonite mineral is consumed by flotation reagent; in addition, the zinc grade in the iron product is relatively high, indicating that limonite There are very fine zinc oxide minerals in the middle, and some zinc may exist in the same state of the same state. These zinc cannot be recovered into the zinc oxide concentrate.

However, the floating lead tailings are not magnetically selected, and the zinc oxide is directly delimed. As long as the amount of sodium sulfide and the collector are increased to a large extent, the flotation effect is also consistent with the effect of selecting zinc oxide after magnetic separation and degreasing of the floating lead tailings. . Increasing the dosage of the drug is more appropriate than increasing the amount of the drug.

Third, a reasonable process

Through experimental research, it was determined that the zinc oxide ore of the stone column was treated by the process shown in FIG.

(1) Remove the primary slime beforehand. It can not only improve the flotation index, but also reduce the processing capacity of the concentrator by 50%, and also ensure the smooth flow of the crushing process.

(2) Establish a lead oxidation flotation cycle. Recycling a portion of lead oxide minerals with simple chemicals to increase economic efficiency.

(3) Instead of using magnetic separation to remove iron, a second desilting operation is used. Removal of secondary slime can ensure stable production without complicating the process.

Fourth, the conclusion

(1) For the zinc oxide ore containing up to 50% of the original slime (-10μm), which is severely muddy and oxidized, the flotation was successfully carried out, and a reasonable process flow was obtained.

(2) In the process of flotation of zinc oxide by amine method, the influence of slime is very large, and the influence of primary slime is much larger than that of secondary slime. A certain amount of slime can be allowed in the flotation process, but not too much.

(3) Limonite also has a relatively large disturbance to the flotation of zinc oxide.

(Iv) The new collector compositions - the mix of oleic acid with an amine, can improve the flotation effect, reducing agent consumption, less number of calcium magnesium ore mineral content, is of great significance.

references

[1] Sun Chuanqi. Mineral processing technology and equipment in the contemporary world - the tenth annual survey of mineral processing (Wang Fuliang et al. Lead-zinc ore beneficiation) [M]. Beijing: Science Press, 2006.87-1 18.

[2] Sun Chuanqi. Mineral processing technology and equipment in the contemporary world - the tenth annual review of mineral processing (Zhu Jianguang. Mineral processing chemicals) [M]. Beijing: Science Press, 2006, 378-392.

[3] Shi Daomin. Yang Wei. Lead oxide zinc ore flotation [M]. Kunming: Yunnan Science and Technology Press, 1996.87-118.

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