Large metal ores are considered low-grade ore, particularly a lower precious metal ores, non-ferrous metals grade, produced more than 90% of solid waste such metal ores in the mining, mineral processing, metallurgical processing and production process. In particular, the beneficiation tailings are the most typical. Over the years, due to the dual pressures of resource crisis and environmental crisis, countries around the world, especially developed countries, have paid more attention to the recycling of mineral resources. Sericite is present in one of the major non-metallic mineral tailings in the metal, which is in the form of fine mica group sweetlips output muscovite flake subspecies, as muscovite belonging to potassium aluminate layered structure of the high mineral. Its chemical formula is: Kal 2 [Si 3 AlO 10 ] (OH, F) 2 , the theoretical value of chemical composition: SiO 2 45.3%, Al 2 O 3 38.4%, K 2 O 11.8%, H 2 O 4.5%. Sericite has similar properties to muscovite, such as: sheet, elastic, tensile, compressive, shear resistant, flame retardant, heat resistant insulator and chemically stable, hygroscopic, water-absorbing, etc. Sense, adhesion and plasticity. Therefore, like muscovite, sericite can be widely used in rubber, plastics, coatings, insulation materials, building materials and other industries. This paper mainly introduces the recovery of sericite minerals in metal tailings and its application in rubber, coatings, plastics and other industries. First, the nature of raw materials The raw materials were taken from the beneficiation tailings of a gold mine in Shandong. The main chemical components of the raw materials are SiO 2 , Al 2 O 3 , CaO, K 2 O, MgO. The main constituent minerals are non-metallic minerals such as sericite, quartz and dolomite. The content of valuable metals is not high and has a recycling value. Non-metallic minerals include sericite and quartz. In this study, sericite was the main target of recovery. The results of chemical element multi-element analysis are shown in Table 1. The main minerals in the raw materials and their relative contents are shown in Table 2. Second, sericite recycling technology (1) Mechanism and basis The results of the content distribution of sericite in the range of raw materials and the dissociation degree of sericite showed that the majority of sericite were distributed in the fine fraction, and the sericite in the fraction below 10 μm accounted for 65.12%. Moreover, the particle size is substantially dissociated at this point. Therefore, it can be recovered by a mineral processing method mainly based on physical treatment. (two) process The process flow of sericite recovery is shown in Figure 1. Third, key technologies and innovations (1) Secondary recovery of valuable metals Although the content of valuable metals in tailings is very low, its presence affects the recovery process and product quality of sericite, so the valuable metals in the tailings must be recovered first. This will not only help improve the process conditions of sericite recovery, but also produce better economic benefits. The valuable metals in the tailings are mostly in the form of sulfides in the coarser fractions, and the basic monomers have been dissociated, which can be recovered by the common metal separation method. (2) Graded roughing Since most of the sericite minerals in the tailings are present in the fine particles of -0.037 mm, the crude materials are re-elected by the re-election method after the secondary recovery of the valuable metals. The spiral chute has the advantages of small footprint, low equipment investment, moderate sorting size, easy operation control, low power consumption, etc. It is very suitable for the classification of tailings. The yields of graded grit (+0.037 mm) and fine mud (-0.037 mm) using a spiral chute were 56.57% and 43.43%, respectively. Among them, the portion of -0.037 mm is 108.8% or less, and the average particle diameter is 5.34 μm. (3) Superfine hydrophobic flocculation flotation Among the tailings tested, non-metallic minerals such as quartz and dolomite are the main associated minerals of sericite minerals. To achieve the enrichment of sericite, the separation of sericite from other non-metallic minerals must be solved. Since the average particle size of the selected materials after classification is 5.34 μm, which is lower than the critical particle size (10 μm) of conventional flotation materials, and the serifity, specific gravity and specific magnetic susceptibility of sericite and quartz, dolomite and other minerals are similar. Conventional flotation technology is difficult to effectively separate sericite from quartz. Therefore, the search for highly selective collectors and high-efficiency inhibitors is the key to selecting sericite. After trial comparison and screening, the self-developed 3ACH was used as the collector of sericite and F-1 was the inhibitor of quartz, so that the sericite mineral particles were selectively captured by 3ACH, adhered to each other, and formed into flocs into the foam layer. Achieve effective separation from other non-metallic minerals. The test results are shown in Table 3. (4) Solid-liquid separation Due to the fine particle size of the flotation product, it is difficult to achieve the ideal solid-liquid separation effect by conventional solid-liquid separation technology. After trial and comparison, the combination technology and equipment of deep cone concentration-pressure filtration-strong flash drying are adopted. The dewatering efficiency of deep cone concentration is 3 times that of conventional concentration technology. The strong flash drying makes the material have large evaporation area, high efficiency, more than 30% energy saving than conventional technology, and can maintain the original particle size of the material without the need for crushing and grading. . Fourth, product technical indicators The results of multi-element analysis of sericin are shown in Table 4. The relative contents of sericite minerals are shown in Table 5. V. Environmental protection The technology further recovers valuable metal and non-metal minerals from tailings, reduces tailings emissions, and extends the life of the tailings pond. The process wastewater quality meets the national industrial wastewater discharge standards. Recycling is implemented in the process. The dust of the drying system is the product, which is recycled by the corresponding dust collection technology, and the secondary tailings can be used to produce building materials. Sixth, product application The use of various inorganic fillers in the rubber, plastics, coatings and other industries can not only reduce the production cost, but also impart some special functions to the above materials through the techniques of particle refinement and surface modification of inorganic fillers. The sericite layer structure, finer particle size, larger aspect ratio and specific surface area make it have excellent physical properties and stable chemical properties, and are widely used in many fields. (1) Application of sericite in rubber In the rubber products, the reinforcing filler is the basic raw material next to the raw rubber. The performance comparison between the sericite product and the commonly used rubber filler in styrene-butadiene rubber was investigated. The results are shown in Table 6. The results show that the reinforcing filling properties of sericite in styrene-butadiene rubber, such as hardness, breaking strength and tensile strength, are higher than those of general inorganic fillers, reaching the level of semi-reinforcing carbon black; The specific sulfur ratio is better and the scorch time is slower. At this time, it is very advantageous to improve the safety and adhesion of the rubber processing. It is worth mentioning that the important process performance of the tire side rubber, which is replaced by carbon black as a reinforcing filler, is greatly improved. The crack resistance is greatly improved. Carbon black is nearly 90,000 times higher). (2) Application of sericite in plastics The application of fillers in plastics varies considerably depending on the type and use of the plastic. As a common purpose, it can be summarized as follows: reducing the cost of the plastic product; improving the dimensional stability, heat resistance, hardness, weather resistance of the product; and imparting concealment. In addition, the use of fillers in individual applications has certain specific objectives, such as improving the mechanical strength of plastics and the like. The use of reasonable filler addition is very beneficial to ensure the quality of plastic products and reduce production costs. However, if the amount of addition is too high, the viscosity of the material will be too large and the fluidity will be lowered, which will make the processing of plastics more difficult. The formulation of sericite in PA-6 (polyamide-6) was investigated and the results are shown in Table 7. The thermal deformation of plastics shows from the test results that with the increase of the amount of sericite in PA-6, the tensile strength, flexural strength and heat distortion temperature of plastics show a significant upward trend. When the amount of sericite is 40PHR, the plastic heat distortion temperature is increased by 25°C, and at this time, the processing and molding process of the plastic still has little effect. It shows that sericite has good filling and modifying properties for plastics, which may increase the temperature and improve its mechanical strength. (III) Application of sericite in coatings The serpentine structure and chemical stability of sericite determine its broad application prospects in coatings. Its acid and alkali resistance, high temperature resistance, corrosion resistance and weather resistance are in line with the requirements of various coating materials for filling materials. There are data indicating that the amount of sericite added in the 107 waterborne interior wall coating can reach 30% to 35%, the coating has no agglomeration, sedimentation and flocculation; the coating film has a flat appearance and uniform light color; good hiding power, no shedding; water resistance Well, the water is soaked for 24 hours without falling off, not wrinkled; in line with JC361-85 industry standard requirements. The test was carried out on an epoxy two-component anticorrosive coating using sericite as a body pigment. The test results are shown in Table 8. The test results show that the main technical indexes (hardness, acid resistance, alkali resistance, gasoline resistance, water resistance, salt spray resistance, etc.) of the sericite epoxy two-component corrosion-resistant coating prepared by the test are higher than the relevant standards of automobile primer, reaching or Close to locomotive primer standards, excellent corrosion resistance. Seven, summary Sericite is one of the main non-metallic minerals present in metal beneficiation tailings. It can recover different grades of sericite products from tailings by using super-segmentation and ultra-fine hydrophobic flocculation flotation technology, through corresponding modification technology. Used in rubber, plastics, paints and other industries, and achieved good results. This technology has been industrialized in some non-ferrous metal mines. Built in 1998, Jiangxi Copper Industry Company silver lead zinc ore annual output of 3000t mountain sericite production line, built in 2001 with an annual output of 10000t sericite production line in Shandong Rushan cause gold products are sold rubber, paint and other industries. With the development of technology, sericite products continue to develop in the direction of miniaturization and functionalization, and their application fields will be further expanded into special materials and functional materials.
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Recycling design of sericite in tailings
Table 1 Results of chemical element multi-element analysis (%)
element
SiO 2
CaO
Al 2 O 3
MgO
K 2 O
Na 2 O
Cu
content
54.12
7.62
11.23
4.37
1.06
0.97
0.031
element
TFe
Mn
S
TiO2
As
Au(g/t)
Ag(g/t)
content
4.17
0.11
0.64
0.10
0.036
0.33
4.72
Table 2 Main minerals in raw materials and their relative contents (%)
Mineral name
Metal mineral
Magnetic iron ore, limonite
Sericite, muscovite
Quartz, chalcedony
Feldspar
content
1.1
3.0
34.2
33.7
6.1
Mineral name
Dolomite, main stone
Chlorite, kaolinite
Barite
other
total
content
17.3
2.9
1.3
0.4
100.0
Figure 1 Metallic beneficiation tailings recovery sericite principle process
Table 3 Small test and expansion of continuous experimental indicators (%)
product name
Small test indicator
Expansion indicator
Yield
grade
Recovery rate
Yield
grade
Recovery rate
S
Al 2 O 3
S
Al 2 O 3
S
Al 2 O 3
S
Al 2 O 3
Sulphur gold concentrate
0.83
38.47
10.21
47.87
0.78
0.78
38.36
10.33
46.58
0.75
Sericite first grade product
2.77
0.18
27.76
0.76
7.13
2.76
0.17
25.77
0.73
6.62
Sericite second grade
15.00
0.26
19.72
5.92
27.41
14.87
0.25
19.95
5.79
27.63
Sericite III
9.80
0.28
12.25
4.16
11.13
9.79
0.29
12.48
4.42
11.38
Secondary tailings
71.60
0.38
8.07
41.29
53.55
71.80
0.38
8.02
42.48
53.62
Feed mine
100.00
0.66
10.79
100.00
100.00
100.00
0.64
10.74
100.00
100.0
Table 4 Results of multi-element analysis of sericin chemistry (%)
product name
Al 2 O 3
SiO 2
K 2 O
Na 2 O
CaO
MgO
Cu
Pb
First grade
25.11
59.02
5.85
0.27
2.50
4.63
<0.01
<0.01
Second grade product
21.18
59.64
5.10
0.23
4.18
6.28
<0.01
<0.01
Third grade
15.20
64.13
3.72
0.26
5.94
7.03
<0.01
<0.01
product name
Zn
As
S
TFe
Fe 2 O 3
Mn
Au/(g/t)
Ag/(g/t)
First grade
<0.01
0.011
0.18
0.74
1.53
0.07
0.11
0.30
Second grade product
<0.01
0.018
0.19
0.85
1.67
0.07
0.13
0.27
Third grade
<0.01
0.019
0.19
0.88
1.74
0.08
0.12
0.25
Table 5 Relative content of sericite minerals (%)
product name
Sericite
quartz
Pyrite
Chlorite
Feldspar
First grade
96.1
1.0
0.2
0.1
0.1
Second grade product
64.5
30.9
0.2
0.4
0.4
Third grade
56.3
37.8
0.3
0.4
0.7
product name
Red limonite
Calcite
Barite
other
total
First grade
0.2
1.4
0.1
0.8
100.00
Second grade product
0.2
1.3
0.1
1.0
100.00
Third grade
0.6
2.6
0.3
1.0
100.00
Table 6 Comparison of performance of sericite and common rubber fillers in styrene butadiene rubber
Filler name
Sericite III
Sericite second grade
Sericite III
Activated coal powder
Hard clay
Semi-reinforcing carbon black
Vulcanizer
(153 ° C)
T10/min
1518
1218
1031
12
336
11
T90/min
2312
1934
2254
18
1636
1724
Vulcanization conditions 153 ° C
T
T
T
T
T
T
Hardness / (Shaoer)
60
58
54
62
56
68
Tear strength / MPa
15.6
12.2
8.1
5.5
11.7
19.6
Elongation at break/%
747
662
734
484
807
489
100% tensile strength / MPa
2.3
1.8
1.4
2.2
1.4
3.1
300% tensile strength / MPa
4.3
3.5
2.5
4.0
2.4
12.3
Permanent deformation (%)
50
32
20
14
35
11
Tear strength / (kN / m)
38.5
33.6
26.4
32.5
29.3
53.3
Elastic coefficient /%
49
52
53
51
48
47
Table 7 Test results of sericite filled plastic formula
Quantity (PHR)
0
10
20
30
40
Tensile strength / MPa
33.7
32.3
31.4
30.6
27.8
Bending strength / MPa
55.3
54.3
55.6
53.7
49.4
Notched impact strength (simple beam) / (kJ/m 2 )
15.9
13.2
13.9
12.8
10.7
Tensile deformation temperature (1.8MPa) / °C
71
74
79
86
90
Table 8 Technical specifications of sericite epoxy two-component corrosion-resistant coating
Serial number
project
test result
Related standards
Automotive primer
Locomotive primer
1
Paint film appearance
Smooth and smooth
-
-
2
Viscosity / s (coating - 4 cups)
26
50
-
3
Particle size / μm
60
Not more than 60
Not more than 50
4
Solid content /%
57.5
-
-
5
Drying time / h
Dry
1.5
Not more than 1
Not more than 4
Hard work
18
Not more than 24
Not more than 24
6
Flexibility / mm
1
-
-
7
Adhesion (cross) / level
2
0
1
8
Cupping test / mm
7.8
5
4.0
9
Pencil hardness / H
2
Not less than B
-
10
Acid resistance / (0.05mol / LH 2 SO 4 7h)
No blistering, no wrinkles, no discoloration
No bubbles, no wrinkles,
Allow slight discoloration
-
11
Acid resistance / (0.1mol / L NaOH7h
No blistering, no wrinkles, no discoloration
No bubbles, no wrinkles,
Allow slight discoloration
-
12
Gasoline resistance (6h)
No blistering, no wrinkles, no discoloration
No bubbles, no wrinkles,
Allow slight discoloration
-
13
Water resistance (168h)
No blistering, no rust
No blistering, no rust
-
14
Salt spray resistance (168h) / grade
350～430
2mm outside the cutting line,
Through the first level
No bubbles on the 500h board,
No rust; rust width 2mm at the cross scratch
(unidirectional)