Preliminary Design Concentration of Talc by Emphasis on Mineralogy…
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Preliminary Design Concentration of Talc by Emphasis on Mineralogy in the Malhamdar Index Mine in Iran A. Hajati Department of Mining, Iran University of Science and Technology, Arak Branch-Iran E-mail:
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ABSTRACT: Talc is one of the industrial minerals for paper, ceramic, paint, and textile, and rubber, plastic, cosmetic and etc industry. Mineralogy is one the applied science for definition of minerals structure in preliminary study at mineral processing engineering. By mineralogy, different aims are important. In this research, actions of mineral are studies in sample talc of two indexes, Talc-Sheest and Talc-dolomite in the Malhamdar village in around of Arak-Markazi state of Iran. The results of mineralogy studies are used in design of preliminary flow sheet concentration. By know of paragons minerals and vary them (specific gravity, breaking quality, chemical- physical surface, luster and etc) talc can separate of other minerals. In this index mine, talc, chlorite, dolomite, quartz, feldspar, ferrous mineral are known and By XRF test it consist MgO:(28–28.25)%, SiO2:(46.6–56)%, Al2O3:(2.36–8)%, CaO:(1.6–2.1)% and Fe2O3:(4–6)%. By attention of mineralogy studies and use of especial variation minerals, such as sizing, gravity, magnetite and etc, it able separation of talc. Finally, talc concentration arrived MgO: 30.5%, SiO2: 52.1%, Al2O3:5.12%, CaO:0.72% and Fe2O3:5.01%. Key Words: Mineralogy, Concentration, Gravity, Malhamdar, Talc.
1. INTRODUCTION There are important deposits of talc in China, Australia, Itly, France, Canada, U.S. and other countries. Talc, which is a soft, hydrous magnesium silicate (Mg3Si4O10(OH)2), is used in a wide range of industries including the manufacture of paint, paper, plastic medicine, cosmetic, ceramic, rubber, face and talcum powder, fire proof roofing, foundry facings, lubricants, linoleum and oilcloth, electrical insulation and pottery. Foundry is coming into being by lower heat metamorphism at dolomites with silica and separation of ultra basic rocks by hydrothermal effects. Talc can be divided into two groups as with magnesite and with carbonate. Talc includes 63.5% SiO2, 31.7% MgO and 4.8% H2O in ideal compositions. Talc deposits generally contain calcite, dolomite, chlorite, olivine, quartz, serpentine, graphite, mica and etc [1]. The market potentials of the various talc products depend on the surface properties of the mineral, which in turn vary with the ore type,
processing methods, particle size, surface treatment, (acid-base characterization, hydrophobic, hydrophilic, electro kinetic) [2]. Talc, as a mineral has unique surface properties. Particles of talc have the shape of platelets due to the layer structure of the mineral. The hydrophobicity of the basal surfaces arises from the fact that atoms exposed on the surface are linked together by siloxane bonds and hence, do not form strong hydrogen bonds with water [3]. In many of industrial applications, this dual surface property of the mineral plays an important role. The purpose of this study is to investigate some effective parameters for Preliminary design concentration of Talc by emphasis on mineralogy to determine optimum conditions minerolography in the Malhamdar index mine in Iran. 2. MINERALOGY STUDY
128 Talc is a hydrated magnesium silicate whit the theoretical formula Mg6[Si8O20](OH)4. The chemical composition of talc found in nature, however, is quite variable. It is an extremely soft mineral and is rated No. 1 in Mohs’ scale of hardness. It varies in color from snow-white to greenish gray and various shades of green. Its specific gravity ranges from 2.58 to 2.83. Talc usually derives a secondary mineral by alteration of other magnesium silicates such as serpentine, pyroxene or siliceous dolomite. Talc deposit can be classified into for major categories: (a) Steatite-Compact, (b) Soft Platy talc, (c) Tremolite talc and (d) Mixed talc ores. Talc is a mineral that meets criteria of a “sheet silicate” mineral. Its structure is like that of pyrophyllite except that the octahedral sites in the layers or sheets chemically pure talc is rarely found in nature commercial quantities [4].
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other minerals such as: pyrophyllite, seerpentine, anthophyllite, chlorite, tremolite and actinolite. Likewise, talc has different type, by attention of mineralogy complex, shap visible, purity, application of industry and etc. they are Steatite, soap stone, path stone, Renslaerite, French chalk, lava, filament and softness talc. By attention of different application of talc, study of mineralogy and knowledge of all suitable and gangue minerals for concentration and separation of gangue minerals are very important. For investigation of size distribution and concentration of minerals after sampling of feed, analyzed by screen in limit size of D1:(–10, +30 Mesh), D2:(–30, +120 Mesh), D3:(–120, +400 Mesh) and D4:(–400 Mesh). In figure 2, it has shown talc and other minerals, that is accessory.
2.1 Geographical and Mineralogy Case Study The Malhamdar village talc district is aboat of 75 km long, into west of Arak in Markazy state of Iran. This deposit is an exploration index and it’s not very active. By this study, it’s goad for ready and start of activity. In the Figure 1, it has shown a vein of this deposit.
Fig. 2: Minerals of talc, chlorite, carbonate and iron oxide at D2 size
Fig. 1: A part of Malhamdar deposit vein
This talc’s deposit is secondary mineral dolomite group. Some of associate minerals by XRD analysis are chlorite, dolomite, iron oxide, quartz and calcite. Ditto, by microscopy study this result accepted. Talc utilities in the industry have
Therefore, they are not liberated in large size. After crushing sample and size distribution in small size, it seems that, it has large degree of liberation minerals. Knowledge of minerals microscopy, relation of between, size distribution, degree of liberation and characteristic are important parameters into core design separation process flow sheet. 2.2 Size distribution and Degree of Liberation Study
129 chlorite and progenies of talc. Then a mount of Al2O3 remind on the >D1 screen.
Preliminary Design Concentration of Talc by Emphasis on Mineralogy…
Distribution of component (%)
80 70 60
MgO
50
SiO2
40
Al2O3
30
CaO Fe2O3
20 10 0 >D1
D1
D2 Size limit
D3
D4
Fig. 4: Distribution of component weight passing (%) 100 90 80 Comulative passing (%)
In nature, valuable minerals occur together with non-valuable species. Technological operation of the disjoining of valuable minerals from the rock matrices is performed by inducing the compressive failure of the ore fragments and reducing the size of the fragments to the dimensions ensuring the release of the majority of inclusions of the targeted mineral from the rock matrices of ores [5]. Thus, the ores are crushed and ground to fine sizes—to produce near singlemineral particles of the two phases, thus liberating the valuable phase from the gangue. Degree of liberation of ore is one of the important stages of ore processing for separation of gangue and minerals in greatest size possible. By this target, we will have the minimum rate of crushing and reduction energy of use and minimization of cost in the next stage and easily of separation minerals. Then, before of separation process by type deferent methods; it must be completely dissociated by one and one. [6–7]. Size distribution: The first stage, to determination of degree of liberation minerals into the ore is size classification. In figure 3 and 4 it has show, size distribution analysis and components weight passing percentage respectively. Coarse particle production by caving materials in this index, is almost 50 cm and d80 is 10.2 cm. nearly 60% weight is size limit (1 mm–10.2 cm) and under 10% weight is less than 2 mm. forethought of this results help for determination of rate crushing feed by grinding equipment and very important to design flow sheet processing of talc concentration. Another aim of crushing sample in laboratory test is, How distributed of minerals or components of them by attention of limit size? By this result, limit size that minerals concentrated determined for suitable crushing and simplify of separation process. The component of MgO and SiO2 are showing of Talc. Another gangue component is Al2O3, Fe2O3, CaO and other things. In Figure 4, percentage weight of CaO is great 52% in size limit D2. It’s passing of >D1 and concentrate on the D1. Then, it seems that by one suitable screen (0.5–1) inch among of mineral including of CaO will be removed. Almost, other minerals crushed by both. Also, Al2O3 relation to
70 60 50 40 30 20 10 0 10
100
1000
10000
100000
1000000
Size(Micron)
Fig. 3: Size distribution of feed in Malhamdar index
Degree of liberation: Liberation size can be determined by quantitative mineralogical test work on size fractions of ground ore, although this is considerably less common because it is costly, time consuming, and often technically difficult Liberation size is a function of the relevant physical or chemical process and may differ greatly between processes. There are different methods base on minerals property for the determination of degree of liberation in laboratory test. There method can be summarized: Image Analyzer, Heavy liquid and Magnetite. In this research, the microscopic particle accounting method is chosen for the defining of degree of liberation talc and other minerals. Relatively, this method is subtle of determination degree of liberation and action of mineralogy that duo to liberation of minerals by
130 reduce of size particle, structure of texture minerals, size of minerals, hardness and other things. By knowledge of these results, it will be help for analysis of design separation process in low coast operation and simplify flow sheet. In figure 5 it has shown degree of liberation minerals of Malhamdar index deposit.
Degree of Liberation (%)
100 90 Talc
80
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capacity percentage, entering, size and kind of minerals and other things. Microscopy study is very important to determined methods of separation, increase of grade and recovery, control type of minerals in concentrate and tailing, correction of line process, control efficiency of equipment, change of process and other things. Finally, applications of mineralogy in different methods of ore dressing talc in design flow sheet are in: Run of Mine, Milling, Separation and Production.
Chlorite
70
Quartz
60
Dolomite&Calsite
50
Iron minerals
40 > D1
D1
D2
D3
D4
Size Limit
Fig. 5: Flow diagram of degree of liberation minerals in Malhamdar index
By attention of Fig. 5, Iron oxide minerals in coarse particle and carbonate minerals (calcite and dolomite) in fine particle have large degree of liberation. In size limit D2 (120 Mesh) they have great of 80% liberation. To attend of slop liberation talc and chlorite, talc has a larger amount and slop than chlorite. There are many Hematite and Goethite minerals to cover the over minerals and dispersed all off them. All of minerals in great of 400 mesh have large than 90% liberation. By this result, iron oxide mineral must be crushed under size of 400 mesh, until we can separated them in other mineral.
4. RESULTS AND DISCUSSIONS After investigation and study, analysis of samples by XRD and microscopy, drawn of curves and other operation, results are: 1. Carbonate minerals have more slop of crushing and degree of liberation. 2. By screen size of (0.5–1) inch, CaO minerals can remove in first stage. 3. Talc mineral has more degree of liberation at compare by chlorite. 4. Iron oxide minerals are fine crystal and dispersed on the covering of other minerals and they have uniform of slop in degree of liberation. 5. Large size of sample feed is almost 50 cm and D80 is 10.5 cm. nearly 60% weight is size limit (1 mm –10.2 cm) and under 10% weight is less than 2 mm. 6. By attention of these results, it seems that continues of exploration and complete of them and mineral processing of Malmamdar talc is justify.
3. APPLICATION OF MINERALOGY IN FLOWSHEET DESIGN OF TALC
REFERENCE
One of the determine parameters in mineral processing design is investigation and study of ore condition in mineralogy and microscopic. Then mineral process engineer must be accurate in complex blending in parts of process. A lot of case study, only knowledge of grade is not enough, and must be determined kind of chemical component of minerals or metals in part of concentrate and tailing process. By microscopy study on thin or polished sections we will have
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Preliminary Design Concentration of Talc by Emphasis on Mineralogy…
[5] Shena, G. and Chiaruttini, C., a stereological posed mass balance for calculating the distributed efficiency of particle separation systems. International Journal of Mineral Processing 59 2, pp. 149-162, 2000.
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[6] Hajati, A., Khodadadi, A., Koleini, S.M., The Study of degree of liberation of Zinc and Iron Oxide Minerals Ore In bama Goshfill Mine, MP3-2003 Conference, Goa-India, 2003. [7] Nematollahi, H., Mineral processing, Tehran University, IRAN, 1990.