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Study on New Process of Desiliconization in Bauxite Ore Dressing
New Process silica bauxite dressing removal
Yang Ju Fang Qixue Huang Guozhi Zheng Guibing
Abstract: On the basis of in-depth analysis of the process mineralogy characteristics of bauxite, it absorbs the advantages of the primary grinding process and the classification-flotation process, and applies the advanced theory and technology of beneficiation to develop a new process. The flash flotation principle and the coarse subdivision selection technology were applied to the bauxite sorting process creatively, and the ideal result was obtained. The concentrate yield reached 83.09%, the aluminum-silicon ratio was 12.61, and the aluminum oxide recovery rate was 90.39%.
Key words: bauxite ore dressing; flotation desiliconization; new process; selective grinding; coarse subdivision
CLC number: TD923 Document code: A
The silica-containing minerals such as kaolinite, Yili, and pyrophyllite are the main gangue minerals in bauxite and the most harmful impurities in alumina production. The formation of sodium aluminosilicate (called sodium silicon slag in the production of silicon during the dissolution of silicon) causes both the loss of aluminum and the alkali consumption, and at the same time makes the alumina production process complicated and the production cost high.
How to economically and effectively remove the silica in the ore, increase the aluminum-to-silicon ratio of the bauxite, provide high-quality raw materials for alumina production, thereby reducing production costs, rationally utilizing China's bauxite resources and promoting China's alumina industry. The fundamental guarantee for sustainable development.
Since the 1950s, China has started to study the desiliconization technology of bauxite ore dressing, summed up experience in research work, and continuously made technological innovations and made great progress. In order to further optimize the flotation process, the coarse-grained enriched organisms are captured, the fineness and fineness of the concentrate are reduced, the beneficiation cost is reduced, the dewatering and filtration performance of the concentrate is improved, and the beneficiation is better than that of the bauxite ore. The new technology for tackling the results provides a basis for the construction design of the bauxite ore dressing plant of Shandong Aluminum Corporation. On the basis of in-depth analysis of the process mineralogy characteristics of bauxite, it absorbs the advantages of the primary grinding process and the grading-flotation process, and applies advanced theory and technology of beneficiation, for example, flash flotation technology. A new process newly developed. The flash flotation principle and the coarse subdivision selection technique are creatively applied to the bauxite sorting process to obtain ideal results. With the strong support of Shandong Aluminum Company, on July 28, 2001, three programs were successfully completed (stage grinding one sorting process, classification-flotation process and selective grinding-rough subdivision selection process). Compared with the re-election test, the cumulative test results of the nine programs in the three programs are shown in Table 1. The test results show that the selective grinding-coarse subdivision selection process is advanced in technology, economical and easy to implement. This scheme is recommended as the basis for the design of the bauxite ore dressing plant of Shandong Aluminum Corporation, and it is recommended to consider the use of coarse-grained fast flotation technology and its supporting equipment in the design process.
Table 1 Results of the consecutive trials of the three options /%
Process technology
Selected fineness
/-75μm
product name
Yield
Grade
A/S
Al 2 O 3 recovery
Al 2 O 3
SiO 2
Stage grinding
One time selection
67.4
Concentrate
Tailings
Raw ore
81.40
18.60
100.0
69.05
36.20
62.94
5.78
10.78
11.94
5.84
89.30
10.70
100.0
Grading-flotation
79.2
Concentrate
Tailings
Raw ore
83.85
16.15
100.0
67.95
37.74
63.07
6.36
10.84
10.68
5.82
90.34
9.66
100.00
Selective grinding
- coarse subdivision
62.9
Concentrate
Tailings
Raw ore
83.09
16.91
100.0
68.71
35.89
63.13
5.45
10.82
12.61
5.83
90.39
9.61
100.0
1 Research on developing new processes
1.1 Research basis of the new process
China has studied the desiliconization technology of bauxite ore dressing and has made great progress in recent years. The specific performances are as follows: (1) The technical idea of ​​using diaspore-rich L. sylvestris as a target for capture and recovery is applied to the demineralization of bauxite ore, and the size of the bauxite-type bauxite inlay is solved. The finest contradiction between aluminum concentrate size and alumina recovery. (2) The bauxite ore fineness is reduced from 95% to 75μm to 70%-75%-75μm, which ensures the selection index and coarse ore concentrate size, and is used for subsequent dewatering filtration and Bayer process for dissolution of red mud. Conditions are provided. (3) Developed a compound high-efficiency dispersant to achieve effective dispersion of the pulp. The high-efficiency combination collector was used to enhance the collection of diaspore and Fulian organisms to achieve effective desiliconization and maximum recovery of the target mineral. (4) The concentration of selected concentrates is about A/S9, the recovery rate of Al 2 O 3 is 70%, the concentration of A/S11 is above or more, and the recovery rate of Al 2 O 3 is about 89%. During the “Ninth Five-Year Plan†period, research progress on desiliconization of bauxite ore was accelerated. Beijing Mining and Metallurgical Research Institute and its fraternal units have done a lot of basic theoretical research and solid and detailed experimental work on desiliconization of bauxite ore in response to the inherent process mineralogy characteristics of low-grade diaspore-type bauxite in China. . For the first time at home and abroad, the industrial test of the new process of producing alumina by bauxite ore dressing desiliconization-Bayer process was completed, and good technical and economic indicators were obtained, which not only broke through the low recovery rate of desiliconized alumina in bauxite ore dressing in China for many years. The difficult situation has greatly promoted the industrialization process of desiliconization in bauxite ore dressing in China, laying a solid foundation for further optimization of process technology conditions and process structure.
1.2 Theoretical background for the development of new processes
The background of the selective grinding-coarse subdivision process theory is that the coarse flotation properties are obviously different, and the specific surface energy of the coarse and fine particles is different, so the amount and speed of the adsorbing agent are different; The agitation strength required for fine particles is different; the concentration of slurry required for coarse and fine flotation is different; the coarse particles require a shorter mineralized bubbling float path; the fine particles are easy to coagulate. Therefore, narrow-grained, coarsely subdivided, and separately adapted to the coarse-grain and fine-grain flotation process environment is to increase the yield of coarse-grain diaspore-rich continuous organisms or monomers, improve fine-grain sorting efficiency, and avoid ore. Mud deteriorates the flotation process, reduces the cost of chemicals, etc., thereby achieving the purpose of economically and efficiently recovering useful minerals while improving the ratio of concentrate to aluminum and silicon.
1.3 Characteristics of the new process
Selective grinding-rough subdivision selection process, which absorbs the advantages of one-stage grinding process and grading-flotation process, applies advanced theory and technology of beneficiation, for example, flash flotation technology, etc. The principle of rapid flotation and coarse subdivision selection technology are applied to the bauxite ore dressing process. The essence is that in the grinding and grading circuit, the coarse-grained fast flotation technology is adopted, and the coarse-grain flotation machine and the high-efficiency collector are used to quickly capture the coarse-grain diaspore monomer and the rich-linked organism in the grading return sand. To obtain the final concentrate product (called concentrate 1), fine grain (graded overflow) into the conventional flotation circuit selection, producing concentrate (called concentrate 2) and tailings. Overcoming the special requirements of the flotation environment when the coarse and fine particles are mixed at the same time, the coarse particles quickly float out, shortening the flotation time, improving the effect of the coarse-grain collector, and improving the fine-grain-level sorting efficiency. Reduce the fine-grained gangue into the concentrate, improve the dewatering performance of the concentrate, and reduce the total amount of collector, thus saving the cost of sorting.
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2 new process selection test
2.1 test ore sample
The sampling design, organization and implementation of the sampling test sample were completed by Shandong Aluminum Company. The ore sample was delivered to the Beijing Research Institute of Mining and Metallurgy in April 2001, approximately 20 tons. The ore sample is coarse, medium and closed, and the ore is processed to -3mm, mixed, sampled and analyzed, and stored for future use. Its mineral composition is shown in Table 2. The main mineral in the ore is a diaspore, a small amount of boehmite. The silicon-containing gangue minerals are illite, kaolinite, pyrophyllite, chlorite, and the like. Other mineral anatase, rutile, brookite, goethite, water and the like goethite. There is also a slight amount of montmorillonite, water white mica, zircon, tourmaline, quartz and the like. The results of multi-element analysis of raw ore are shown in Table 3.
Table 2 Mineral composition and content of ore /%
Mineral
Content
Mineral
Content
Bauxite
Boehmite
64.63
Anatase
Rutile
Iron ore
3.18
Illite
21.83
Kaolinite
Chlorite
Pyrophyllite
Montmorillonite
2.14
Goethite
Water needle iron ore
Hematite
6.23
quartz
micro-
Zircon
micro-
tourmaline
micro-
Other minerals
1.99
Table 3 Analysis results of main chemical components of ore /%
element
Al 2 O 3
SiO 2
Fe 2 O 3
TiO 2
K 2 O
Na 2 O
CaO
MgO
Caustic soda
A/S
content
62.73
10.81
6.41
3.10
2.06
0.054
0.042
0.25
12.72
5.80
2.2 Small test
The main research work carried out in the small-scale experiment of grinding-rough subdivision selection process is to develop a strong combined flocculant for coarse flotation, preferably a fine flotation high-efficiency dispersant to determine the appropriate fineness of the candidate. On the basis of the conditional test, a closed circuit test is carried out. The test flow is shown in Figure 1. The test results are shown in Table 4.
Fig.1 Selective grinding- rough subdivision selection process, small closed circuit test procedure and chemical conditions
Table 4 Closed-circuit test results of selective grinding- rough subdivision selection process/%
New process technology
product name
Yield
Grade
A/S
Al 2 O 3 recovery
Al 2 O 3
SiO 2
Selective grinding
- coarse subdivision
Concentrate 1
Concentrate 2
Concentrate
(concentrate 1 + concentrate 2)
Tailings
Raw ore
27.91
54.89
82.80
17.20
100.0
68.21
70.20
69.53
35.54
63.68
7.20
5.05
5.78
34.46
10.71
9.47
13.90
12.03
1.03
5.94
29.89
60.51
90.40
9.60
100.0
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2.3 re-election test
Based on the small test process, appropriately adjust the dosage of the agent, determine the appropriate grinding fineness and flotation concentration, use the grinding and grading closed circuit cycle, re-classify the overflow, grade the return sand through the coarse particle fast flotation, flash speed Select concentrate (called concentrate 1), fine grain (graded overflow) into the conventional flotation circuit, after one rough selection, one sweep, three selections to obtain concentrate (called concentrate 2), process flow and Figure 1 is basically the same. The test was carried out at a co-option scale of 50 kg/h and a daily treatment capacity of 1.2 t. At the same time, a stage grinding process was also carried out (using grinding and grading closed loop, one rough selection, one sweeping, sweeping tailings, classification by classifier, grading coarse returning mill, grinding and re-election, graded overflow The flow is the final tailings, the coarse concentrate is refined by secondary selection to obtain the concentrate) and the classification-flotation process (using the grinding and grading closed loop, the graded overflow is again graded, and the returning sand is directly used as the concentrate output, overflowing into The conventional flotation circuit is subjected to a rough selection, a sweep selection, a sweeping tailings to a classifier, a coarse grain returning mill, and a re-election, and a graded overflow is the final tailings. , obtained the confinement comparison test of concentrates, the cumulative test results of 9 consecutive classes of three programs are shown in Table 5.
Table 5 Results of the consecutive trials of the three schemes /%
Process technology
product name
Yield
Grade
A/S
Al 2 O 3 recovery
Al 2 O 3
SiO 2
I: Stage grinding
One time selection
Concentrate
Tailings
Raw ore
81.40
18.60
100.0
69.05
36.20
62.94
5.78
10.78
11.94
5.84
89.30
10.70
100.0
II: Grading - flotation
Concentrate
Tailings
Raw ore
83.85
16.15
100.0
67.95
37.74
63.07
6.36
10.84
10.68
5.82
90.34
9.66
100.0
III: Selective grinding
- coarse subdivision
Concentrate
Tailings
Raw ore
83.09
16.91
100.0
68.71
35.89
63.13
5.45
10.82
12.61
5.83
90.39
9.61
100.0
2.4 Comparison of three programs
The re-election to the test results as the basis, the scale of 1500t ore daily processing terms, referring to Shenyang Aluminum Magnesium Design Institute submitted "dressing - Bayer alumina production of new technology industrial test technical and economic feasibility report," 1999 bauxite The denitrification industry test data of mineral processing and the practice of mineral processing in large-scale aluminum mines in China were carried out. The cost estimation of three schemes and the comparison of main technical and economic indicators of the re-election experiments were carried out. The results are shown in Table 6.
Table 6 Comparison of the main technical and economic indicators of the three options for the trial
Program
I: Stage grinding
One time selection
II: Classification
-Flotation
III: Selective grinding
- coarse subdivision
Concentrate yield /%
Concentrate aluminum to silicon ratio
Concentrate recovery rate /%
Selected fineness /%
-75μm
Concentrate fineness /%
-75μm
Mineral processing cost
/(元·t -1 )
Mineral processing cost
/(元·t -1 dry concentrate)
81.40
11.94
89.30
67.4
75.80
15.35
67.68
83.85
10.68
90.34
79.2
77.70
14.01
62.50
83.09
12.61
90.39
62.9
73.86
13.15
55.89
It can be seen from Table 6 that Scheme III is superior in both technical indicators and economic indicators. Compared with the scheme I, not only the processing cost of the ton concentrate is reduced by more than 11 yuan, but also the concentrate yield is 1.69%, the concentrate aluminum-silicon ratio is 0.67, and the concentrate recovery rate is 1.09%. Compared with the scheme II, the concentrate recovery The rate and productivity are similar, but the ratio of concentrate to aluminum and silicon is 1.93, and the processing cost per ton of concentrate is about 6 yuan.
3 selective grinding - the thickness of the new separation process Review
In the case of the 1998 de-siliconization and re-election test of the bauxite ore in Henan Province and the trial process and the pharmaceutical system of the de-siliconization industry in the bauxite ore dressing in Henan in 1999, the original grinding and floating process was followed, that is, “a stage grinding of one stage†The process (the raw ore rough grinding is selected, the coarse-grained medium-mineral returning mill is re-grinded, combined and sorted), after conducting in-depth research work on the pharmaceutical system, the technical indicators obtained this time are in 1998 and the industrialization indicators in 1999. The test indicators were similar, but the dosage of the drug decreased and the cost of the drug decreased.
Scheme II is the “grading-flotation†process proposed in the 1998 trial and the industrial trial of the “stage grinding of one stage†process in 1999 and the “grading-flotation†process of the Zhongzhou bauxite mine completed in 2001. A technical solution developed on the basis of production. After the original grinding is as fine as 75%-80%-75μm, it is classified by the sorting machine, and the coarse-grained product is directly produced as concentrate. The yield is about 15%-20%, and the fine-grained grade enters the flotation circuit. Get concentrate 2 and tailings. Compared with Scheme I, the advantage is that the amount of minerals entering the flotation operation will be reduced by about 30%, the chemical consumption and flotation slurry will also be reduced, and the ore dressing cost can be reduced; the disadvantage is that the concentrate is produced in a graded manner, and the fluctuation Large, difficult to control, when the aluminum or silicon ratio of the ore is fluctuating, especially when it is low, it is difficult to guarantee the aluminum-to-silicon ratio of the concentrate.
Scheme III "Selective grinding-rough subdivision selection" process is based on the process mineralogy characteristics of bauxite in China, based on summarizing the existing work, applying advanced theory and technology in the field of mineral processing, a newly developed new process, It is a new substantial progress after the inclusion of bauxite in fineness from 95% to 75μm to 70% to 75% to 75μm in 1998; the “rough subdivision†technique is creatively applied to bauxite. Choosing, there is a new pioneering work in the bauxite ore dressing process. Due to the obvious difference between the coarse-grained and fine-grain flotation properties, the narrow-grained graded, coarsely subdivided and selected to accommodate the flotation environment of the coarse-grained and fine-grain flotation processes respectively, is to improve the coarse-grained diaspore-rich continuous organism or The basic recovery of monomer capture rate, improved fine particle sorting efficiency, avoiding sludge deterioration of flotation conditions and reducing the cost of chemicals. The results of this re-election test fully prove the advanced nature and economic rationality of the program III. Compared with Scheme I, not only the processing cost of ton concentrate is reduced by more than 11 yuan (including 2.2 yuan for pharmacy), but also the concentrate yield is 1.69%, the concentrate aluminum-silicon ratio is 0.67, and the concentrate recovery rate is 1.09%. Compared with Scheme II, the recovery rate and yield of concentrates are similar, but the ratio of concentrate to aluminum and silicon is 1.93, and the processing cost per ton of concentrate is 6.61 yuan (of which the agent saves 0.86 yuan). The advantage is that the selected grain size is coarse (grinding fineness is 60%-65%-75μm), and most of the coarse particles are quickly selected in the grinding classification circuit, which improves the grinding classification condition and avoids over-grinding of the target mineral; Fine particles enter the conventional flotation, the amount of minerals is small, and there is no large-scale circulation of flotation tailings classification operation and medium-mine returning mill, and the consumption of chemicals, ball consumption and energy consumption will be greatly reduced.
4 conclusion
1. The process of "selective grinding-rough subdivision selection" is based on the process mineralogy characteristics of bauxite in China. The diaspore-rich and the medium-grade connected sound bodies are used for the purpose of capture and recovery, and selective grinding is carried out. Further coarsening and selection of fineness (60%~65%-75μm) is a new substantial improvement after the bauxite inclusion fineness is reduced from 95% to 75μm to 70%-75%-75μm in 1998. . The “rough subdivision†technology is creatively applied to the bauxite ore sorting, which is another new pioneer in the bauxite ore dressing process.
2. Developed a new technology of “selective grinding-rough subdivision†and completed small trials and re-election experiments. When the ratio of aluminum or silicon in the ore is 5.83, the concentrate yield is 83.09%, the concentrate aluminum-silicon ratio is 12.61, and the alumina recovery rate is 90.39%.
3. The results of this re-election test fully prove the advanced nature and economic rationality of the new process technology. Compared with Scheme I, not only the processing cost of ton concentrate is reduced by more than 11 yuan (including 2.2 yuan for pharmacy), but also the concentrate yield is 1.69%, the concentrate aluminum-silicon ratio is 0.67, and the concentrate recovery rate is 1.09%. Compared with Scheme II, the recovery rate and yield of concentrates are similar, but the ratio of concentrate to aluminum and silicon is 1.93, and the processing cost per ton of concentrate is about 6 yuan (of which the agent saves 0.86 yuan).
4. The technical indicators of this consecutive test are stable and reliable, and the process flow and the pharmaceutical system are simple and easy.