Study on Beneficiation Process of Low Grade Copper Ore

First, the nature of the ore

A mineral arsenic, sulfur and copper deposit, containing ore types of secondary enrichment copper sulfide. Metal mineral content (5.9%), mainly useful for metallic minerals pyrite, blue chalcocite - chalcocite, covellite, enargite - block enargite small to trace amounts of sulfur and iron-tin copper, (arsenic) beryllium copper ore, chalcopyrite, porphyrite, azurite, etc. Among the copper minerals, the Lanhui copper deposit accounts for 0.8% of the total minerals, and the sulfur, arsenic copper ore and copper blue account for 0.2%. Pyrite is the main sulfur mineral, accounting for 4.9%. The gangue minerals are mainly quartz , accounting for 53.8%, followed by 35.2% alumite and dickite, and 11% clay minerals. The results of multi-element chemical analysis of raw ore are shown in Table 1.

Table 1 Results of multi-element chemical analysis of ore

It can be seen from Table 1 that the main valuable components in the ore are copper, sulfur and associated beneficial components such as gold, silver , lead , zinc , tin, etc., and the harmful element is arsenic. Arsenic is mainly found in sulfur-arsenic copper ore. Except for copper and sulfur, the content of other elements did not reach the content standard for comprehensive evaluation. The ore contains 0.58% copper and is a low grade copper ore. A small amount of associated gold can be enriched in the copper concentrate and does not have to be recycled separately.

The minerals in the ore are mainly coarse-grained, and the process grain size of the main copper minerals is +0.074mm, which is more than 85%. The pyrite has a particle size of 0.01 to 0.60 mm, which is mostly 0.08 to 0.40 mm, and about 75% of pyrite has been dissociated when it is broken to -2 mm. When the original ore milled to a fineness of -74m accounted for 60% to 70%, the monomer dissociation degree of various metal minerals was above 85%; however, some copper minerals were distributed among the pyrite particles, cracks and yellow. Iron ore contains or is continuously distributed, or is distributed in a star-shaped distribution between gangue minerals and is associated with gangue minerals. This part of copper-sulfur minerals has a complicated relationship. It is difficult to dissociate the monomers under rough grinding conditions, which makes separation difficult. Therefore, it is considered to be properly finely ground or mixed with fine concentrate and then ground.

The phase analysis results of copper are shown in Table 2.

Table 2 Results of copper chemical phase analysis in ore

Second, the determination of the selection process

Copper sulfide is the main mineral of copper, and flotation is the main method of mineral processing . According to the nature of the ore, the main purpose of this study is to select copper, which is associated with gold recovery in copper concentrates, and comprehensive recovery of sulfur when economically feasible. The recovery of the remaining useful components is not considered at this time. Because the main copper mineral in the ore is blue-copper copper, the floatability is very good, and the size of the inlay is coarse. Therefore, by exploring the test and combining the ore process mineralogical research results, it is determined that the flash flotation after a rough grinding is adopted. Part of copper, copper and sulfur mixed after re-grinding and sorting process, under the conditions of copper minerals basically reaching the monomer dissociation, flashing high-grade easy-selection copper minerals, reducing the copper minerals caused in the middle ore circulation Loss; the remaining more difficult to float copper minerals and pyrite mixed flotation, after re-grinding copper sulfur is fully dissociated and then sorted.

Third, the beneficiation test

(a) a rough grinding and tailing

The metal minerals in the ore are coarser in grain size, and the test results of easy monomer dissociation of different grinding fineness are shown in Table 3. See Figure 1 for the test procedure. The results show that when the grinding particle size changes between -50μm and 50%~87%, the loss rate of copper in tailings is low, and the change is not big; when the original ore is milled to -74μm, the content is 51%. The grade of copper in the mine is 0.024%, and the loss rate is only 2.66%, which can be completely discarded as qualified tailings. Therefore, a section of grinding can be used to remove tailings by coarse grinding (fineness -74μm content of 5l%).

Table 3 Grinding fineness test results

Figure 1 Copper rough selection test procedure

(2) Flash floating high-grade copper mineral

The Lanhui copper deposit in the ore is the main copper-bearing mineral, accounting for more than 70% of the total copper content. In addition, it also contains some arsenic-containing copper minerals. Generally speaking, the Lanhui copper mine and the sulphur arsenic copper ore are good in floatability and easy to float. This part of the floatable mineral only needs to add a small amount of selective collector , which is very short flotation time. A high quality one-step copper concentrate can be selected. Compared with the conventional copper selection scheme (see Table 4), the copper flotation recovery rate is similar, but the copper grade is higher.

Table 4 Comparison of flash flotation scheme and conventional copper selection scheme

(3) Flotation process conditions

1, rough selection of suitable pH

The ore contains a large amount of pyrite, so lime is used as the pH adjuster for the slurry, and the addition of lime during the grinding process can also inhibit the pyrite. The amount of lime used has a great influence on the floating copper index. The effect of different lime addition on the rough copper selection test is shown in Figure 2. The test procedure is shown in Figure 1. With the increase of lime addition, the grade and recovery rate of copper coarse concentrate gradually increased, and the grade of copper coarse concentrate increased gradually, and then decreased to 1500g/t. The suitable amount of lime was 1000-1500g/t.

Figure 2 lime test results

2, float copper collector type and dosage test

Flash float copper, the choice of copper mineral collector is very important. In this experiment, the selectivity of copper collectors such as xanthate, Z-200, ethylsulfide, SP, xanthate/butylammonium black drug was investigated, and the screening test of collector was carried out. The test results are shown in Table 5, and the test flow is shown in Figure 1. The results show that SP has better flotation effect and its copper grade and recovery rate are higher. As the amount of use increases, the copper recovery rate increases, but the grade also decreases. A suitable amount of collector is about 10 g/t. The results of the SP collector dosage test are shown in Figure 3.

Table 5 Copper collector selection test results

Figure 3 Collector SP dosage test results

3. Test of copper-sulfur mixed flotation collector

The copper-sulfur mixed float is carried out in a weakly alkaline medium. The butyl xanthate has a strong ability to capture pyrite in a weakly alkaline medium. As a collector of copper-sulfur minerals, a mixed collector is considered. Test conditions: the tailings after the flash float copper is used as the ore supply, in order to suppress the entrainment of the gangue minerals, an appropriate amount of water glass is added before the collector, and the conditions of the mixed collectors in different proportions are tested. The test results of copper and sulfur mixed float collectors are shown in Table 6. The test results show that the butyl xanthate is mixed with the butyl ammonium black drug, and the suitable ratio is butylammonium black drug: butyl xanthate = 1:2. The suitable dosage of the combined collector is butylammonium black and butylxanthate, respectively, 15 and 30 g/t.

Table 6 Test results of copper-sulfur mixed float collector

4, copper and sulfur separation test

Lime is an effective and inexpensive inhibitor in the separation of copper and sulfur. Due to the close relationship between some copper minerals and pyrite, it is difficult to dissociate the monomers under rough grinding conditions, and the metal minerals must be further dissociated by re-grinding to create conditions for the separation of copper and sulfur. At the same time, re-grinding can also remove the residual agent adsorbed on the mineral surface, and the fresh mineral surface appears, which is beneficial to the full inhibition of pyrite by CaO, thereby improving the separation effect of copper and sulfur. Test conditions: The copper-sulfur mixed concentrate was used as the ore, and the conditions of re-grinding and no-grinding, and adding different inhibitors were tested. The results of copper and sulfur separation test are shown in Table 7. The test results show that the regrind of the mixed concentrate and the addition of lime-based inhibitors, the grade and recovery rate of the copper concentrate are significantly improved, and the recovery rate of the sulfur concentrate is also improved. It can be seen that re-grinding can significantly improve the separation effect of copper and sulfur. From the results in Table 7, it can be seen that the addition of lime 800g / t and sodium sulfite 200g / t in the mill after the separation index of copper and sulfur is slightly better, comprehensive consideration, the choice of copper and sulfur separation operating conditions for regrind fineness -74μm95%, while in the mill Add lime l000g/t.

Table 7 Copper and sulfur separation test results

Table 8 Small closed circuit test results

Steering Oil Tank

Plastic Steering Tanks,Auto Plastic Oil Tanks,Oem Plastic Steering Tanks,Oem Steering Oil Tank

Ningbo Yongxin Auto Parts Manufacturing Co., Ltd. , https://www.yongxinautoparts.com