Inhibition of gangue minerals in molybdenum ore and its effect on the removal and inhibition of effluent

Volatile ash is specifically referred to herein as a naturally laminable silicate which is a three-layered mineral of a layered silicate. Typical minerals include talc, pyrophyllite, sericite, ophiolite stone, mainly talc. The silicate tetrahedron in the silicate forms a layered silicate by a total side polymerization of three oxygens. Their greatest feature is that they can be easily opened in a direction that is completely parallel to the layers.
The layered silicate has two layers and three layers. The three-layered silicate has a neutral or non-electrical neutrality in the sandwich layer. Easy floating gangue talc, pyrophyllite is electrically neutral, three-layer silicate. The distinction is shown in Figure 1. Kaolin is a typical two-layer silicate.
Figure 1 Classification and side view of layered silicate
Talc [Mg 3 Si 4 O 10 (OH) 2 ] forms a Si—O/Mg—OH/Si—O sandwich layer: a Mg—OH layer filling is sandwiched between two Si—O layers. It is like a molybdenum -type sandwich layer. Pyrophyllite [Al 2 Si 4 O 10 (OH) 2 ] forms a similar Si—O/Al—OH/Si—O sandwich layer. They are electrically neutral in each of their sandwich layers. Thus, when the sandwich layer is superposed with the sandwich layer, only the molecular bonds formed by van der Waals forces are combined. This is similar to the superposition of the molybdenite S/Mo/S sandwich layer and the sandwich layer. When talc and pyrophyllite are stressed, the fracture surface is also fractured by van der Waals force, forming a "face" similar to molybdenite. Obviously, talc and pyrophyllite are also natural floatable minerals. According to Evas, the structure of the talc is shown in Figure 2.
Figure 2 talc structure diagram (single oblique structure)
The "face" formed by the van der Waals force fracture of talc and pyrophyllite has a strong hydrophobicity. The "edge" formed by the cleavage of Si-O bond and Mg-OH bond and water spontaneously act as an oxidation zone, which determines the relationship between ξ-potential and pH (similar to molybdenite).
The talc surface ξ-potential versus pH and with natural hydrophobic sulfur and hydrophilic quartz , bentonite , see Figure 3.
Figure 3 ξ-potential versus PH
Talc 1 Furtenau
Talc 2 Brienau, Karl
Quartz 1 Furtenau Quartz 2 Iwasaki
The relationship between the recovery of talc and pyrophyllite measured by Woodfill and pH, and the comparison with natural floatable mineral sulfur is shown in Figure 4.
Figure 4 Sulfur, talc, pyrophyllite PH and recovery
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It can be seen from the figure that the talc surface potential and flotation characteristics are different from the hydrophilic quartz, and closer to the very hydrophobic sulfur, showing good natural floatability.
When encountering talc-containing molybdenum ore in mineral processing , it will be very difficult to produce qualified molybdenum concentrate. In 1983, the Sidaogou Molybdenum Plant used a conventional agent to float talc-containing molybdenum ore. The molybdenum concentrate produced contains less than 30% molybdenum.
There are several common methods for separating molybdenite-talc:
(1) roasting-reverse flotation method: the roasting method can be different, but both of them can burn off the hydrocarbon oil adsorbed on the surface of the molybdenum ore to make it deactivate; and then, through reverse flotation, select talc and other easy-to-float gangue (Foam product) produces qualified molybdenum concentrate (in-tank product).
The US Cyprus company Pima Copper -Molybdenum Plant contains ore containing talc, resulting in molybdenum concentrate containing less than 40% molybdenum, sometimes even 10% to 15%. The unqualified molybdenum concentrate is calcined at 260 ° C through a seven-layer multi-layer furnace to remove the mineral oil film adsorbed on the mineral to deactivate it. After calcination, the product is subjected to slurry-reverse flotation, and qualified molybdenum concentrate (in-tank product) and talc-containing medium ore (foam product) (sending water and metallurgy treatment).
The United States Anaconda company Shuangfeng copper and molybdenum plant used spray drying to remove the oil on the surface of molybdenite, and then obtained the qualified molybdenum concentrate by reverse flotation. The production results are shown in Table 1.
Table 1 Bimodal spray drying - reverse flotation separation effect
Product
Grade (%)
Distribution rate (%)
Remarks
Mo
Insolubles
Mo
Insolubles
Combined
Molybdenum concentrate
Insolubles
Give mine
51.10
11.52
38.20
7.44
61.04
25.63
85.51
14.94
100.00
23.14
76.66
100.00
In-tank product
Foam product
Cu-Mo sorting product
Roasting-reverse flotation method is difficult to control the temperature, the temperature is too high, (such as ≥400 °C) molybdenum ore is easy to oxidize; too low, the oil is difficult to remove. In addition, the amount of ore containing talc is only very small, which will have a great impact on the yield of molybdenum concentrate before sorting, which will cause a large change in the amount of calcined material.
(2) Direct anti-molybdenum-reverse flotation: In 1972 and 1975, Anaconda Laboratory applied for patents and established a semi-industrial test plant in Shuangfeng Plant in 1973. They used low concentrations of lignosulfonate and lime milk to inhibit molybdenum ore, flotation talc and other easily floating sheet silicates, instead of spray drying, good results. Industrial test results are shown in Table 2.
Table 2 Bimodal anti-molybdenum selection flotation test plant indicators
Product
Yield%
Grade (%)
Distribution rate (%)
Remarks
Mo
Insolubles
Cu
Mo
Insolubles
Cu
Molybdenum concentrate
Insoluble product
Give mine
70.05
29.95
100.00
45.87
10.41
35.21
15.22
64.52
30.58
1.12
2.08
1.42
91.11
8.89
100.00
34.25
65.75
100.00
53.86
46.14
100.00
In-tank product
Foam product
The amount of lignosulfonate depends on the molybdenum grade of the feedstock, usually from 1800 to 2700 g/t. When the dosage is insufficient, the molybdenum ore is not well suppressed and easy to float; the amount is too high, the foam is large and tough, and it is difficult to control. Dosing time should be more than 8min, the pH value is required to be 11.91, and the recovery rate is the highest.
(3) Inhibition of talc float molybdenum ore: The Pima selection plant applied Canadian patent (981,841) in 1975, adding zinc sulfate (or aluminum sulfate) and sodium silicate in a slurry of 5% to 15% concentration, they It can inhibit talc. In 1975, the average molybdenum content of molybdenum concentrate produced by this method was increased from 40% (calcination method) to 43%, thus replacing the roasting-reverse flotation separation process.
In the study of the removal of easy-floating gangue from molybdenum concentrate in Dexing Copper Mine, the Beijing Municipal Institute of Mining and Metallurgy proposed a process of “filtering-activated carbon-degrading-carboxymethyl cellulose to inhibit insoluble matter” and achieved good results. .
Mica also based three layered silicate, which partially based Al 3+ isomorphous substitution, the lower the Si 4+, composition Si (Al) O / Al- OH / Si (Al-O) sandwich. Due to the different electricity prices of Si 4+ and Al 3+ ions, the sandwich layer is no longer electrically neutral. At this time, when the sandwich layers are superposed, the cation K + is required to be trimmed and bonded, thereby constituting muscovite. Obviously, the mica fracture bond is a polar ionic bond without hydrophobic conditions. The structure is shown in Figure 1.
Sericite is an alkaline silicate with a fairly wide composition range. Д.C. Bielyan pointed out that sericite is composed of 80% to 85% muscovite, 10% to 15% nano-mica, 5% to 7% biotite, and has a fine scaly structure. There are not many studies on its nature. According to the easy-floating nature of sericite, Rastun incorporates it into natural floatable minerals. However, it must be pointed out that no data has been found to prove that sericite has van der Waals bonding.
When sericite is contained in the ore, it is difficult to obtain a qualified molybdenum concentrate. In order to reduce the selectivity of sericite, it is recommended that the rough selection operation does not add sodium carbonate (do not make the pulp PH too high, the foam is sticky), and the water glass dosage is strictly limited, not too much.
CF Maslova proposed that in order to obtain qualified molybdenum concentrate, before the selection, the demineralization of the mixed concentrate was selected. The -20μm fine mud contains higher sericite, and the qualified concentrate can not be obtained by the flotation process. Therefore, this part is separately subjected to the wet leaching extraction process. For the products with fine mud removal, there are few sericites, and the qualified phase concentrates can be selected by flotation.
Qu Li et al buoyant containing a copper sheet silicate gangue minerals - were studied molybdenum, ore containing 10% mica (phlogopite, muscovite, sericite), 3% talc. They Cu - Mo flotation, the use of the mineral treated separately (hydrometallurgical or other) processes, instead of coal and oil with an aromatic hydrocarbon, water glass to increase the capacity of 5000g / t (which limits the amount of water glass USSR Maslowa On the contrary), supplemented hexametaphosphate and sodium phosphate to inhibit the gangue minerals, molybdenum experimentally obtained finally closed 52.28%, 83.19% recovery of molybdenum concentrate quality.
In short, it is quite difficult to obtain qualified molybdenum concentrate for ore containing easy-flow gangue, or to obtain qualified molybdenum concentrate, or to undergo qualified processes such as reverse flotation or roasting to obtain qualified products. The method must be determined through experimentation.

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