I. Introduction
Shizhuyuan metal ore is rich in valuable elements tungsten, molybdenum, bismuth and fluorite and other large polymetallic deposit. The ore body is thick and concentrated, and it is divided into four ore belts I, II, III and IV from top to bottom. Among them, the middle part of the III ore belt is a Yunying-skarn type ore with a high grade of valuable elements, called the rich ore section, which is the target of mining and treatment in the early stage of the mine and for a long time in the future.
Prior to the design, the Shizhuyuan Mine has three production plants, using fatty acid agents as tungsten flotation collectors, and the main ore flotation process to treat the ore-rich ore-rich ore with a total treatment capacity of 800 t/d. The indicators are different, and it is better to choose 200t/d.
Second, the nature of the ore
#矿带富矿段 Ore is skarn-yunyingyan tungsten-molybdenum ore. The main tungsten minerals are scheelite , wolframite , illusion, semi-artificial wolframite and a small amount of tungsten. The ratio of scheelite to wolframite is 7:3. The strontium mineral is mainly stibnite. The molybdenum mineral is mainly molybdenite. The fluorine-containing mineral is fluorite. The main gangue minerals garnet, quartz, feldspar, white mica.
The useful minerals in the ore are unevenly embedded in fine particles, which are densely symbiotic with each other and difficult to separate. Determined by microscope: the average particle size of stibnite is only 0.010mm, the average particle size of scheelite is 0.028mm, the average particle size of scheelite is 0.03mm, the average particle size of molybdenum is fluorite The average particle size was 0.078 mm. Through the determination of mineral monomer dissociation degree and beneficiation fineness test, it is beneficial to comprehensively recover the optimum grinding fineness of four minerals of tungsten, molybdenum, niobium and fluorite to -0.074mm and account for 90%. The results of multi-element chemical analysis of raw ore are listed in Table 1.
Table 1 % of raw ore chemical analysis results
Third, mineral processing test research
The value of tungsten in ore accounts for more than 50%. Due to the symbiosis of black and white tungsten, it is difficult to recover the ore. Through the "Eighth Five-Year Plan" scientific and technological research, we have mainly established two major types of test programs: "mainly heavy-floating and main-floating". Both major types of trials have carried out small trials, expanded continuous trials and industrial trials. The test indicators are listed in Table 2 and Table 3.
Table 2 % of main dry-floating process industrial test results
Fourth, the design and implementation of mineral processing technology
The III ore belt is rich in various valuable elements such as tungsten, molybdenum, niobium and fluorite. The design mainly considers the separation and recovery of four ores of tungsten (black tungsten and white tungsten), molybdenum, niobium and fluorite.
The molybdenum and antimony ore are mainly in the form of sulfide ore such as molybdenite and stibnite, and the qualified concentrate is obtained by conventional flotation. The recovery of tungsten ore is due to the symbiosis of black and white tungsten, which is difficult to coexist with fluorite, calcite and calcium-containing garnet. Different process schemes have significant differences in the recovery of tungsten. Therefore, the key to the beneficiation process design is the selection and design of the tungsten ore sorting process.
(1) The main floating process plan is a major breakthrough in floating tungsten technology.
In 1996, the main full float process industrial test achieved good indicators. The results are shown in Table 3.
Table 3 % of industrial test results of trunk full float scheme
From the table (it is known that except for the black tungsten concentrate recovery rate is lower than the main gravity-floating process industrial test index, the other concentrate recovery rate is higher than the latter.
The key to achieving good indicators in the main floating process is the application of new tungsten-loading agents. The test shows that the new agents CF and GY have good collection performance for black and white tungsten minerals under natural pH conditions, and have the advantages of high concentrate grade and high recovery rate, and at the same time, the fluorite recovery tailing water treatment and Product dewatering operations also bring convenience. It also has a series of advantages such as simple process, centralized concentration of valuable elements, less number of sorting operations, less equipment, small plant area, low investment, and convenient operation and management. To this end, the CF method and the GY method are a major breakthrough in the traditional tungsten-selecting technology, providing a technical basis for the process design of the 1000t/d plant.
(II) Process design of trunk heavy-floating process transition to trunk full float process
Although the CF and GY new agents achieved breakthroughs in floating tungsten technology during the test, when the 1000t/d plant was designed, the new agent has not been promoted and applied in the production of tungsten plant, and it needs to be improved and improved. To this end, the beneficiation process design can not be completed in one step, directly using the full flotation process.
In order to ensure the recovery rate of tungsten minerals, especially black tungsten minerals, the traditional re-election method is considered in the design. In the grinding circuit, a simple re-election operation is used to recover part of the coarse-grained monomer tungsten, and the fine-grained part is floated. The fatty acid is used as a collector of tungsten ore for sorting and recycling. From the industrial test indicators, this heavy-floating process is not as good as the full float process, but it is to improve the recovery rate of black tungsten after being put into production under certain conditions, and to be the final transition when conditions are ripe. The simplest and most effective process measures created by the full float process. The main gravity-floating process design is shown in Figure 1.
Figure 1 Main dry-floating process
When the conditions are ripe, in order to smoothly realize the transition from the main gravity-floating process to the main floating process, the following considerations have been made in the process design of the process design:
1. Simplify re-election. That is, the full-closed process of re-election and grinding of the industrial test is changed to the semi-closed process of the return of the spiral chute, so as to reduce the number of re-election equipment , plant area and water and electricity consumption. In addition, the former heavy sulfide ore mixed concentrate is incorporated into the mixed concentrate in the main flotation process to carry out the separation operation.
2. Enhance the adaptability of the grinding circuit. Practice has proved that the use of grinding and fine screen closed circuit is more conducive to the re-election of the grain size assurance, while the design still uses the mill and the spiral classifier closed circuit; to ensure the stability of the classification, but also to adapt to the future main floating process Requirements.
3. Considering the independence of the plant from the configuration, the former heavy equipment is centrally disposed in a factory to reduce its impact on the main flotation operation.
4. Simplify the black tungsten fine mud sorting process and use fine mud flotation new agent to ensure the grade and recovery rate of black tungsten concentrate.
The process design indicators for the main gravity-flotation process are listed in Table 4.
Table 4 Main dry weight - flotation process design indicators%
(3) Implementation of the main floating process
Considering the beneficiation process, the implementation of the main gravity-floating process can solve the problem of over-grinding of tungsten ore due to multiple grinding classification, achieving the purpose of early harvesting and over-collection of tungsten ore and increasing tungsten recovery rate. However, due to the large amount of mines that were roughed before entering, the re-election line was long, and the total amount of equipment needed for the entire front was large. The equipment occupied by the equipment was large and the investment cost was high. At that time (1996), Party A raised funds. Faced with a large gap, the heavy-floating beneficiation process is difficult to complete and put into production at one time. After deliberation with Party A and the relevant units, the construction of the main phase will be carried out in stages, that is, the main flotation process will be implemented first, and the construction will be suspended in the former part. Its purpose is: 1, can alleviate the shortage of funds; 2, can shorten the construction period, put into production as soon as possible, early benefits; 3, provide new mineral processing conditions for the new pharmaceuticals to be put into production as soon as possible. However, the research on new tungsten flotation reagents from 1997 to 1998 has made new progress. Therefore, the main floating process of the final production of 1000t/d plant is shown in Figure 2.
Figure 2 1000t/d plant production process
Fifth, production practice
The 1000t/d plant of Shizhuyuan was completed in October 1998. It has been successfully tested and has been produced normally. The recovery rate of tungsten has exceeded 200t/d, which is close to the design index. The production index of 1000t/d is listed in table.. Fluorite is not recycled yet.
Table 5 Production index of 1000t/d plant selection
Conclusion
1. The CF method and the GY method of floating tungsten technology are major breakthroughs in the traditional heavy-floating process. With the continuous development and advancement of science and technology, the new pharmaceuticals CF and GY will provide a broader development prospect for the flotation of tungsten.
2. Practice has proved that the process design of the 1000t/d plant is successful and advanced.
3. With the continuous improvement of the production technology level and the continuous improvement of the pharmaceutical system, the production index of the 1000t/d plant will soon reach or even exceed the design index.
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