Current status of copper ore ore beneficiation abroad

Copper- molybdenum ore is one of the main sources of molybdenum, while Chile, the United States, Canada, Peru, Mexico and the Soviet Union are the main countries for the recovery of molybdenum concentrate from copper-molybdenum ore. Foreign practice shows that the copper-molybdenum deposits mined in recent years have a minimum copper grade of 0.2-0.3% and a minimum molybdenum grade of 0.01-0.011%.
At present, foreign copper-molybdenum ore beneficiation has three characteristics: First, most of the mixed flotation and separation processes are used; second, rapid construction of large-scale new plants with modern and efficient processes, and the establishment of Pinto Valley selection from 1975 to 1980 alone. Plant (36,000 tons / day, the United States), Quawhorne plant (41,000 tons / day, Peru), La Calidad plant (900 tons / day, Mexico), Erdenettin Aub plant (40000) Tons/day), Kapuche Mekkh Plant (40,000 tons/day, Iran), Sachishman Plant (40,000 tons/day), Baghdad Plant (36,000 tons/day, USA); Vigorously strengthen the research of molybdenum recycling process. The beneficiation process indicators of the copper-molybdenum plant that has been put into production since the 1970s are shown in the table below.

Source: 1.A.Sutulov: Flotation Recovery of Molybdenite, Augustl 1977;
2.Min.Eng.October, 1982;
3.KомΠлексное ИсΠольэование Mниерального CьІрья 1981.No
1. Re-grinding operations Before the rough selection or selection of molybdenum in the separation process of copper-molybdenum mixed concentrate, re-grinding operations are often arranged. Many mills use small ball mills such as Sialita and Quawone. According to Shirley, in the selection of the by-product molybdenite concentrate, there must be at least one regrind. He said that the use of steel balls in regrinders is unlikely to produce large amounts of iron ions. Mine flow, but rubber lining must be used. However, Abramov of the Soviet Union believes that the future development trend is gravel grinding, because gravel grinding can make the mineral separation more complete, that is, using gravel for fine grinding, it will not affect the mooring activity of molybdenum ore, and can improve The selectivity of the flotation process produces a better quality molybdenum concentrate.
2. Separation of concentrates Molybdenum ore is generally separated from the mixed concentrate by two methods, one is copper-selective molybdenum, and the other is molybdenum-selective copper. U.S. processing plant is now only a few (e.g., Kober, silver bell, etc.) The second method, i.e., by inhibiting dextrin molybdenite, molybdenum concentrate obtained from the copper flotation tailings.
Copper-selective molybdenum is the main process for copper-molybdenum separation today. The process includes the following four steps:
First, the concentrated mixed concentrate is concentrated to remove excess agent from the mixed flotation circuit: the addition of the agent inhibits copper and pyrite, and sometimes the evaporation or roasting is used to destroy the residual agent.
Second, molybdenum rough selection This operation should be carried out under strict control of the dosage, pH and concentration.
Third, molybdenum selection aims to remove impurities such as quartz and talc that should not be present.
Fourth, the final molybdenum concentrate leaching This is to reduce the copper and other metal content. [next]
Concentration of mixed concentrate is an indispensable process before copper and molybdenum separation. After concentration, roughing and stirring can be carried out under optimal concentration conditions; the specifications of preparation and roughing equipment are greatly reduced, and investment is saved; Removal of the added agent from the copper flotation circuit, in particular, eliminates foaming agents that can severely affect molybdenum selection. Therefore, most copper preparation plants concentrate them to a concentration of 50 to 65% before separating the concentrate.
The inhibition of copper minerals is the key to the separation and separation of copper-molybdenum mixed concentrates. The main chemicals used are cyanide, Nokes (P2S5+NaOH) and sulfides, and the most used is sodium hydrosulfide.
In the separate roughing operation, the addition of sodium sulfide or sodium hydrosulfide to the mixed concentrate is a current trend, and the above-mentioned agent and steaming scheme is regarded as the best solution for the separation of copper and molybdenum concentrate. . The US Shuangfeng, Baghdad and Sialita plants, the Soviet Union's Balkhash, Azulak, Almarek, Kazaran plant and some Bulgarian plants have adopted this program, the effect depends on the pulp To what extent the sulphide concentration is close to the optimum value, because too high a concentration will impair the mooring activity of molybdenite, and insufficient concentration will not guarantee sufficient inhibition of copper and iron sulfide.
If the mixed flotation concentrate contains copper oxides, it may be economical to first use lime to dilute, destroy most of the collector , thereby reducing the amount of sulfur ions, and then performing sodium sulfate preferential flotation. The conditions for steaming are recommended to be: a temperature of 85 to 90 ° C, a time of 2 hours, and a lime content of 0.8 to 1.2 kg / ton of concentrate. Oxygen or air is usually blown in.
As can be seen from the table, most of copper molybdenum separation plant is selected from sodium sulfide and sodium hydrosulfide, and then the oil is employed as collector only Cologne on Using kerosene, then use of MIBC frother ( Methyl isobutyl methoxide). Some use pine oil, some choose water glass to suppress gangue, and use lime to inhibit pyrite.

Remarks: Except for kerosene used as collector for molybdenum in Cologne, other selected plants use fuel collectors.
*1 indicates addition to selection *2 indicates addition to molybdenum selection *3 indicates inhibition of pyrite *4 indicates suppression of gangue [next]
The main copper mineral is separated into a copper-molybdenum concentrate of the porphyrite. The AnumolD agent is generally mixed with sodium cyanide. The Pinto Valley plant uses sodium cyanide to enhance the inhibition of active copper and iron sulfide minerals by ammonium sulfide and Nokes agents.
Separation of copper-molybdenum concentrates with major copper minerals as chalcopyrite. It is considered that it is more effective to suppress copper sulfides with ferricyanide and ferrocyanide, provided that the copper minerals are fully oxidized and the pH of the pulp does not exceed 7.6. ~7.8.
Separation of copper-molybdenum concentrates with major copper minerals as chalcopyrite, such as the American Samueluel Plant and the Peruquipala Plant in Peru. In addition to ferricyanide and ferrocyanide, oxidizer hypochlorite is added. The acid salt, hydrogen peroxide, etc., allow the copper and iron sulfide to reach the desired degree of oxidation to ensure the inhibition of ferricyanide and the like.
Some ore contains a large amount of mud minerals. In order to improve the quality of molybdenum concentrate and metal recovery rate, the process of flotation or coarse grinding-vulcanization flotation-tailing re-election of mineral mud and ore may be used.
The separation process of copper-molybdenum concentrate is relatively simple. After molybdenum selection, it is selected for sweeping. The concentrate is returned to the ore box (such as Gibraltar, Rockex plant, etc.) or merged into rough concentrate (such as The Sialita Plant), or the medium-mine flotation (such as the Brenda plant), the rough selection (or sweeping) of the tailings is the finished copper concentrate.
3. Selection of molybdenum concentrate
In order to remove the impurities that should not be present, almost all copper and molybdenum plants in recent years have to select the molybdenum rough concentrates several times, usually 7 to 12 times, and in the selection process, Re-grind or re-grind in two stages. Some of the re-grindings are open circuits, some are closed with the cyclone, and one section is closed, and the tailings are returned to the previous one. The selected tailings of the Pima selection plant are merged 3 to 7 times and sent to grade and regrind. The copper-molybdenum mixed concentrate of the plant contains 27% copper and 0.5% molybdenum. In addition, it also contains a large amount of talc. Its floatation activity is similar to that of molybdenum ore. It is difficult to remove, often resulting in less than 40% molybdenum concentrate grade, sometimes even Less than 10 to 15%, this unqualified concentrate has been stored for future processing. In order to improve the quality of the concentrate, the factory has tried various methods and has not solved the problem. In 1975, Pima introduced a new method of molybdenum selection, which is to select the talc-containing molybdenum concentrate directly into the flotation tank for molybdenum-talc separation. Or the ore is first treated with a weak base strong acid (ammonium sulfate) salt solution, and then treated with a strong base weak acid (sodium silicate) salt solution. The selected molybdenum concentrate is sent to the dewatering, and the talc tailings are removed to the ore tank. The new process will increase the recovery rate of molybdenum concentrate from 40% to 43% (original grade 0.47% Cu, 0.015% Mo). According to reports, the new process is arranged on the original production site, no need to expand flotation operations. line.
The quality of molybdenum concentrates in the Shuangfeng Plant is often affected by changes in the properties of the ore. Plant selected in addition to containing a carbonate ore, but also contain many buoyant talcs phyllosilicate clay with aluminum oxide. These things will go into the coarse concentrate with the molybdenum ore, causing a large amount of concentrate, and the grade will drop, sometimes falling by as much as 15%. In order to solve this problem, the plant has repeatedly tested and used sulfonated lignin (a by-product of the paper industry) to suppress molybdenum ore for reverse flotation, to obtain gangue-containing foam products and in-slot products containing molybdenite. . Reverse flotation is carried out at a pH of 11.9, and the tailings produced are molybdenum concentrates, which are re-selected. Both the sulfonated lignin and the lime are stirred together with the slurry. The mixing and reverse flotation time is 20 minutes, the first selection time is 15 minutes, and the second selection time is 10 minutes. When the molybdenum concentrate has a high copper content, it is necessary to add 200 g/ton of xanthate. The selected operation can increase the molybdenum recovery rate of the concentrate by 10 to 13%. Under the condition of 45.8 to 51.8% of the molybdenum grade, the total recovery rate can be increased to 91.1% to 92.7%. If the closed-end selection process is used (the former mine returns to the previous selection tank), the recovery rate of molybdenum can be increased by 4 to 8%.
The molybdenum-selected ore from the Kebel plant contains a large amount of hard asphalt (carbonate minerals), and its planktonic activity is similar to that of molybdenum. Since 0.01 to 1.0% C is present in the feed to the molybdenum circuit, the total recovery of molybdenum fluctuates greatly, reaching 10 to 70%, with an average of 30%. In order to remove such impurities, the slurry is rinsed in a special tank before the molybdenum flotation. A selected concentrate to the cyclone treatment, the overflow containing hard asphalt particles is incorporated into the molybdenum selected tailings. In order to make the separation of the hard asphalt and molybdenum more complete, some other methods have been tried, and now Bartlex is being studied. The chute, in addition to successfully tried the Wilfley shaker.
4. The leaching of molybdenum concentrates has obtained molybdenum concentrates, and impurities such as copper, lead and iron are not up to standard. According to the quality standard of high quality molybdenum concentrate of Klemax Molybdenum Company of the United States: MoS ₂ should be 95%, Cu should be less than 0.15%, and Pb should be less than 0.05%. In the international market, the quality is a little worse, the price is much worse, such as the company's high-quality molybdenum concentrate on July 1, 1975, the price of 2.43 US dollars / lb, unqualified 2.236 US dollars / lb, actually 2.5 to 17 %. In order to reduce the content of these metals, some plants have adopted different leaching processes. [next]
The Brenda Concentrate contains 55.3% molybdenum and the grade is relatively high, but the copper and lead content is not satisfactory. To this end, the plant used a leaching process developed by Noranda to reduce impurities and improve concentrate quality. The principle and method of this process is: leaching Cu, Ca and Pb in molybdenum concentrate with copper chloride, ferric chloride and calcium oxide solution. Divalent copper chloride and ferric chloride (10 and 41 grams respectively) / ton concentrate) is an effective chlorinating agent for chalcopyrite and galena in a solution containing 20-30% calcium chloride and sodium chloride. Calcium chloride or sodium chloride is used to lower the pH and is used to increase Boiling point (Brenda is at 4,850 ft., leaching requires higher boiling point) and shortens leaching time. The most effective leachate of the Brenda plant molybdenum concentrate contains 1% divalent copper chloride, 10% ferric chloride and 30% calcium chloride. When leached at 100 ° C for 2 hours, the leaching rate of Cu and Pb was 98%, the leaching rate of Ca was 79%, and the dissolved molybdenum was less than 0.5%. The used leachate can be quickly regenerated by introducing chlorine gas. After each batch is immersed, 30% of the leachate is drained to control harmful elements such as copper and lead in the leachate. The copper content of the molybdenum concentrate after leaching decreased from 0.337% to 0.063%, the lead content decreased to 0.05%, and the molybdenum grade increased from 55.3% to 56.6%. After the concentrate has been cooled and washed twice (including filtration and re-slurry), the final filtration and drying are carried out.
The selected molybdenum concentrate of the Sialita Plant is 47-48% molybdenum. In order to further remove the copper contained and improve the quality, the plant uses a ferrous chloride leaching method. The process is to first filter and dry the molybdenum concentrate to a temperature of 2%, and then leaching copper (up to 2.5 to 3.0%) with ferrous chloride leaching solution to increase the molybdenum grade to 53 to 54%. The leached concentrate is filtered and dried, and calcined in two Ñ„.16 m roasters to obtain molybdenum trioxide, which has a grade of 60-61% and a sulfur content of less than 1%. It is sent to a ferroalloy workshop for preparation. Ferro Molybdenum. In order to reduce the copper content of molybdenum concentrate, the Cologne plant is leached with sodium chloride. The immersed product is filtered and repulped, and then sent to acid leaching to further reduce the copper content, and the acid leached molybdenum concentrate is finally used. Filter and dry.
5. Separation equipment Separation of copper-molybdenum mixed concentrate The commonly used flotation machines are Akitel flotation machine, Denver flotation machine and Wimco flotation machine. The two most used are the first two. The flotation machine is only used in Pinto Valley. The first two are pneumatic mechanical agitation and the latter are mechanical agitation. The volume of the flotation machine is not large, and the rough selection and sweeping are 1.13 to 2.83 ^m3 , and the selection is 0.68 to 1.4 ^m3 . The flat-panel Livali new plant is used for the rough selection of molybdenum concentrates and the first two selected Wimco 120 flotation machines with a tank volume of 8.5 ^m3 .
6. Comprehensive utilization of the comprehensive utilization of copper-bearing ore resources has received increasing attention. This is referred to as waste-free or waste-free beneficiation. The well-known Clemens molybdenum plant in the United States, in addition to recovering molybdenum concentrate with 54% molybdenum grade, also selected 50% S pyrite concentrate with molybdenum rough-choice tailings, containing 65% WO ₃ tungsten concentrate. Mine, tin concentrate containing 35% Sn and 5 kinds of monazite; US Mishen copper-molybdenum selection plant from the mixed flotation tailings by zinc rough selection and three times to obtain zinc concentrate; Soviet Al Mare The Kezheng plant captures 20 to 70 micron of monomeric gold particles using a hydraulic trap installed in the overflow of a section of the mill and an inter-selection tank with a hydrocyclone for processing a selected mixed concentrate. The total gold recovery rate is 74-78%; Magna and Sanmanuel also pay attention to the addition of by-product gold. The former uses a special structure of the trough to recover gold in the tailings gravity transport process. back; Li Yake Canada to recover byproduct bismuth; obtained from any processing plant further selection mixing free sulfur tailings containing mineral cobalt, arsenic, cobalt cobaltite minerals and mineral pyrite concentrate, can be used to suppress iron sulfate Sulfide, float it out.

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