Study on Separation Technology of Copper and Sulfur in Low Alkali Medium

For a long time, no matter what kind of copper-containing minerals, are made of high alkaline copper sulfur separation medium. The most important feature of the high alkali process is that the operation is stable when copper and sulfur are separated, and the main production (copper concentrate) is superior. Both the copper concentrate grade and the recovery rate can achieve satisfactory results. However, the use of high alkaline medium, so that the traditional process there are unavoidable deficiencies: low as accompanying elements recovery, especially precious metals have a strong inhibition, seriously affect the recovery of gold and silver associated. In addition, due to the use of high alkali medium, the sulfur in the copper tailings is strongly inhibited, and the sulfur tailing can be achieved only by the activation process such as sulfuric acid or acidic water. In order to overcome the problem of the defect of sulfur selection in traditional high alkali process and the low recovery rate of associated elements, we have made a lot of experimental research and industrial practice on the new process of separation of copper and sulfur in low alkali medium for several years, and achieved satisfactory progress. The relevant research is now introduced as follows.

First, small experimental research

(1) Ore properties and test route

1. Ore properties

(1) Mineral composition

A mine is a very large porphyry copper deposit, and the ore is a fine vein-disseminated ore. Ore mineral composition is relatively simple, mainly metallic minerals pyrite and chalcopyrite, chalcocite, followed again tennantite, bornite like. The ore has a certain degree of mud and oxidation, and the oxidation rate is generally 3% to 4%. Among the primary ores, metal sulfide minerals generally account for 4% to 5% of the total ore, and gangue minerals account for about 95%. Gangue minerals are quartz, sericite, followed by chlorite, calcite, feldspar, and a small amount of biotite, epidote, hornblende, mica, kaolin, gypsum and the like. The ore is also accompanied by a small amount of precious metal minerals, mainly 碲 silver gold, silver and gold, natural gold and so on. The multi-element analysis of the samples is shown in Table 1.

Table 1 Multi-element analysis results of samples (%)

(2) Main mineral particle size embedding characteristics

Pyrite is a metamorphic, semi-automorphic crystal, which is distributed in the gangue in the form of disseminated or fine veins, and is partially agglomerated. The particle size is generally 0.03-0.4mm, and the coarse particles are mostly, and the largest one can reach 1mm. Pyrite is often referred to as a residue by chalcopyrite.

The chalcopyrite is shaped like a crystal, and the fine particles are unevenly embedded in the gangue. The particle size is generally 0.005-0.5mm, mostly in the range of 0.01-0.05mm, and the maximum particle size can reach 1mm. The sulfide minerals that coexist with it mainly include pyrite and molybdenite , and molybdenum ore is sometimes a residue, and the two are often interlaced together.

Molybdenum ore is a scaly, film-like aggregate attached to the gangue mineral cleavage or fissure surface, and is often impregnated in the gangue. It forms fine veins with quartz or chalcopyrite and pyrite. The particle size is fine, generally 0.025-0.2mm, sometimes up to 0.6mm. The main mineral that symbiotics with it is chalcopyrite.

The gold minerals in the ore are in two states. One is granularly embedded between the metal mineral particles, and the particle size is 3-10 μm. Some irregular granular gold is produced between sericite, mica minerals and quartz particles with a particle size of about 30 μm. Another form of the emulsion droplet-like inclusions occur in the chalcopyrite, pyrite, tennantite, galena, sulfur, bismuth, lead ore and other minerals needle, the particle size of several microns to several tens microns, the former Majority. The vast majority of gold is present as an independent mineral.

Silver is mainly found in metal sulfides and metal oxides. Among the single minerals, galena contains the highest silver, followed by arsenic bismuth ore. For different types of ores, silver in chalcopyrite and pyrite There is a certain difference in quantity, and most of the silver is also present in the ore as an independent silver mineral.

2, small test route

A mine ore is a large low-copper low-sulfur ore. The associated elements gold, silver and molybdenum are mainly related to chalcopyrite. The various metal sulfide minerals are closely related. Therefore, the small test uses copper sulfide, etc. in low alkali medium. Mixed flotation, mixed concentrate and re-grinding, adding new inhibitor K202, still separating copper and sulfur in low alkali medium, and separating the copper tail to select sulfur in the original slurry to maximize the recovery of various useful components in the ore. , to obtain the greatest economic benefits.

(2) Small test results

1. Condition test The raw ore is coarsely ground to -200 mesh and 65.16%. When a small amount of lime is used to adjust the pH of the medium to about 7-8, copper and sulfur are mixed. In the mixed flotation stage, conditions such as grinding time, amount of collector, and amount of foaming agent were tested. The effect of the amount of mixed collector on the indicator is shown in Figure 1. It can be seen from Fig. 1 that the suitable amount of the yellow medicinal amount in the mixed selection is preferably 65 g/t.

Figure 1 Relationship between yellow medicinal amount and sorting index

The effect of the amount of foaming agent on the index during mixing is shown in Figure 2. It can be seen from Fig. 2 that the amount of the foaming agent No. 2 oil at the time of mixing is preferably 75 g/t.

After coarse grinding and flotation, the copper-sulfur mixed concentrate must be ground again before separation to make the copper-sulfur minerals fully dissociate, creating conditions for copper-sulfur separation. Taking into account the on-site production conditions, the regrind fineness in the test was determined to be -200 mesh and 93.8%.

After mixing and re-grinding, the method of adding a small amount of lime is still used to control the pH of the medium to about 8 to carry out copper-sulfur separation flotation.

In the separation stage of copper and sulfur, the conditions of grinding time, the amount of inhibitor K202 and the amount of butyl ammonium black drug were tested.

The effect of the new inhibitor K202 on the separation of copper and sulfur is shown in Figure 3. As can be seen from Fig. 3, in the separation of copper and sulfur, the amount of the inhibitor K202 is preferably 30 g/t. K202 is a new type of inhibitor of iron sulfide mineral. In the copper-sulfur separation stage, adding a small amount of K202 can inhibit the action of pyrite, which can save a lot of lime and reduce the pH value of the copper and sulfur separation stage. Conducive to the comprehensive recovery of associated components.

When copper and sulfur are separated, the influence of the amount of collector butylammonium black on the selection index is shown in Fig. 4. As can be seen from Fig. 4, the amount of the reagent butylammonium black drug at the time of separation of copper and sulfur is preferably 3 g/t.

After the separation of copper and sulfur, the second selection, the second sweep, the qualified copper concentrate, the copper tail into the puree sulfur phase.

When sulfur is floated, it does not dehydrate, does not remove the drug, does not adjust the slurry, and does not add any medium pH adjuster. As long as a certain amount of sulfur-selective collector Dinghuang is added, the sulfur can be selected.

The effect of Ding Huang on the results when sulfur is selected is shown in Figure 5. It can be seen from Fig. 5 that when sulfur is selected from the pure pulp, the amount of the reagent Dinghuang is preferably 40 g/t.

2. The small closed circuit test indicators for small closed circuit test are shown in Table 2.

Table 2 Small closed circuit test results

3. Analysis of the results of the small test

After rough grinding of raw ore, mixed flotation of copper, sulfur, gold, silver and molybdenum in low alkali medium. After mixing and refining, the new inhibitor K202 can be successfully used in low alkali medium to separate copper and sulfur. Copper concentrate grade and The recovery rate meets the test contract requirements. The grade of sulfur concentrate is as high as 43.12%, the recovery rate of sulfur is more than 98%, and the comprehensive recovery rate of sulfur is more than 75%.

Second, industrial trials

(1) Industrial test results

The industrial test was carried out in the second stage of the field grinding from August to October 1995. The test also set up a comparison system of the same scale. The purpose of the test is to reduce the amount of lime, to achieve the separation of copper and sulfur in the low alkali medium and to achieve the sulfur in the pure slurry, and to comprehensively recover the copper, sulfur, gold, silver and molybdenum. The industrial test results are shown in Table 3.

Table 3 Industrial test results

(II) Analysis of industrial test results

The results of industrial tests show that the mixed flotation is carried out in a low alkali medium, and the mixed concentrate is re-milled, and the new inhibitor K202 can be used for the separation of copper and sulfur in a low alkali medium. Compared with the traditional lime high alkali process of the comparison system, the new process copper concentrate grade is 0.36% higher, the comprehensive recovery rate of copper is 0.4% lower, and the gold recovery rate in copper concentrate is 4.75% higher. The grade of sulfur concentrate obtained from sulfuration of raw pulp is 43.19%, the recovery rate of sulfur is 68.5%, and the comprehensive recovery rate of sulfur is 40.17%. According to the test cumulative data, the lime dosage of the new process can be reduced by 70% compared to the lime process. Therefore, the low alkali medium is conducive to on-site production management, which is conducive to the comprehensive recovery of associated components in the ore, which is conducive to improving the economic and social benefits of the mine.

Third, industrial trial production

Industrial trial production was carried out at the site on the scale of Q=10000t/d from June to November 1996. It was carried out under the conditions of the original production process, equipment and grinding fineness. The trial production also increased the copper tail. The sulfur selection operation and the comparison system of the same scale were set. The purpose is to further improve the new process of copper and sulfur separation and verify the process indicators of industrial tests, in preparation for the comprehensive and large-scale application of new processes.

The industrial trial production results are shown in Table 4.

Table 4 Industrial trial production results

As can be seen from Table 4, in the industrial trial production, the copper concentrate grade of the new process is 25.16%, and the comprehensive recovery rate of copper is 84.67%. Compared with the lime process, the grade of the new process copper concentrate is 0.82% higher, and the comprehensive recovery of copper The rate is 0.04% lower, the recovery rate of gold in copper concentrate is 5.35%, the recovery rate of molybdenum is 4.90%, and the recovery rate of silver is 3.35%. The grade of sulfur concentrate obtained from sulfuration of raw pulp is 43.11%, the recovery rate of sulfur is 69.63%, and the comprehensive recovery rate of sulfur is 39.54%. Its indicators are in complete agreement with industrial test indicators. According to the statistical results of the test production, the amount of lime used in the trial production of the new process is only 29% of the traditional process lime, which can reduce the amount of lime by 71%. Moreover, the industrial trial production time is long, spanning the summer, autumn and winter seasons. There are many types of ore treatment, complex varieties and small fluctuations in process indexes, which proves that the new process is stable and reliable, and can completely replace the lime process for industrial production.

Fourth, the characteristics of the new process of separation of copper and sulfur in low alkali medium

The new process carries out the mixing and separation of copper, sulfur, gold, silver and molybdenum in natural pH and low alkali medium with a small amount of lime, which is beneficial to the comprehensive recovery of mineral resources and can greatly improve the recovery rate of associated elements such as gold and molybdenum. The new process can significantly reduce the amount of lime used. Compared with the lime process, the new process in industrial trial production can reduce the amount of lime by 71%, which is conducive to production management, can save a lot of energy consumption and freight, can reduce the pressure on the construction industry and agriculture, and has greater social benefits. .

After the separation of copper and sulfur in the new process, the copper tail can directly carry out the sulfur selection in the original slurry, without adjusting the slurry and not activating, which greatly facilitates the subsequent sulfur selection operation and improves the economic benefit of the sulfur selection operation.

The new process of separation of copper and sulfur in low alkali medium can make full use of the original process and equipment to organize production, and the cost of technical reform is low, which is easy to organize and promote.

The new process has strong adaptability to ore, and the seasonal temperature difference has little influence on the selection index, which is easy to operate and manage on site. The new type of inhibitor K202 used in the new process is tested by the epidemic prevention department. It is colorless, odorless, non-toxic, soluble in water, low in dosage and convenient to use.

Low Alkaline Medium copper sulfur separation process, may be used in addition to copper, but can also be used in mines, copper sulfur prospect molybdenum, copper, pyrite, sulfur, copper ore, cobalt, copper, sulfur, gold, copper sulfur zinc lead ore, and other very broad.