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Minerals Engineering 34 (2012) 63–69
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Minerals Engineering
journal homepage: www.elsevier .com/locate /mineng
The liberation effect of magnetite fine ground by vertical stirred mill and ball mill
Xiao Xiao a,⇑, Guowang Zhang a, Qiming Feng b, Shouxiao Xiao a, Lilong Huang a, Xiang Zhao a, Ziqiang Li a
a Changsha Research Institute of Mining and Metallurgy, 966 South Lushan Road, Changsha 410012, Hunan, PR Chinab School of Minerals Processing & Bioengineering, Central South University, Changsha 410083, Hunan, PR China
a r t i c l e i n f o
Article history:Received 2 June 2011Accepted 8 April 2012Available online 17 May 2012
Keywords:Fine grindingSelective liberationFine grained magnetiteVertical stirred mill
0892-6875/$ - see front matter � 2012 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.mineng.2012.04.004
⇑ Corresponding author. Tel.: +86 731 8865 5709; fE-mail address: [email protected] (X. Xiao).
a b s t r a c t
A magnetite middling was used to compare the liberation effect of the magnetite fine ground by a verticalstirred mill and a ball mill. The magnetite middling contained a high content of magnetite intergrowthwith the particle size mainly distributed in the range of 40–150 lm. The new generated �38 lm productswere concentrated by magnetic separation. Particle size distribution, the degree of mineral liberation andsection micrograph of new generated �38 lm products were measured by laser particle size analyzer,mineral liberation analyzer (MLA) and scanning electron microscope respectively. It was found that stir-red milling improved the degree of liberation of magnetite selectively. The degree of liberation of mag-netite in new generated �38 lm product of stirred milling is 8.1% points higher than that of ball millingand stirred milling mainly improved the degree of liberation of magnetite in +10 to �38 lm size frac-tions. In the size fractions with identical P80, the degree of liberation of the magnetites in the productsof stirred milling is greater than that of ball milling, with the value varied from 2.4% to 29.1% points. Theiron grade of magnetic separation concentrate of stirred milling is 5.2% points higher than that of ballmilling. The average particle size of new generated �38 lm products by stirred milling is finer whencomparing with that by ball milling. The stirred mill was fit to use for fine grinding the middling witha high content of complex intergrowth, especially appropriated for milling P80 10–30 lm minerals to lib-erate more valuable metals.
� 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Stirred mills are increasingly used to regrind the fine dissemi-nated ores to liberate the valuable minerals with the obviousadvantage of high energy efficiency. Since early 1990s, tower millswere first used in metalliferous concentrating, other fine and ultra-fine mills such as IsaMill and Stirred Media Detritor (SMD) havebeen developed and used in the regrinding circuit (Gao et al.,2002; Davey, 2006). Stirred mills can be as much as 30–35% moreenergy efficient than tumbling mills when producing the same par-ticle sized product in fine grinding (Lofthouse and Johns, 1999).Studies for stirred mills have focused on the effect of mill typesand operation conditions on energy requirements, particle size dis-tributions and particle breakage rates (Wang and Forssberg, 2000;Kwade and Schwedes, 2002; Nesset et al., 2006; Shi et al., 2009).Little attention is given to the mineral liberation. However, the pri-mary purpose of fine grinding is to liberate valuable minerals fromthe intergrown gangues other than size reduction. Therefore, liber-ating the valuable minerals in a coarser particle size can be themost important measure to increase the efficiency of fine grinding.
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Different stress intensities of comminuting equipments couldbe corresponding to the specified breakage mechanisms of miner-als. It is believed that compression is more related to crushers, im-pact to ball mills and abrasion to stirred mills (Gao and Forssberg,1995). An ore that has been comminute to the same particle size intwo different mills may have improved on mineral liberation inone mill due to differences in these breakage mechanisms. Studieshave been carried out to compare the mineral liberation commi-nuted by ball mill (impact mechanism) and high pressure grindingrolls (HPGRs) (compress mechanism), but the results contradicteach other (Apling and Bwalya, 1997; Daniel, 2007; Vizcarraet al., 2010). Andreatidis (Andreatidis, 1995) investigated thebreakage and mineral liberation of sphalerite fine ground by a stir-red mill and a ball mill. He found that the results varied with theore properties. The stirred mill was more beneficial for grindingcomplex ores and improved the degree of liberation of sphaleritein the complex Pb–Zn ore.
In our previous work, we have found that the iron grade andrecovery of fine-grained magnetite can be improved by regrindingwith the stirred mill (Zhang et al., 2008, 2010; Xiao et al., 2011). Inthis study, we present an investigation on the liberation effect of atypical fine-grained magnetite rougher concentrate fine ground bya vertical stirred mill and a ball mill.
Rougher concentrate
Magnetic separation(80 mT)
Magnetic separation(25 mT)
Magnetic separation (80mT)
Magnetic separation (25mT)
Screening (400 mesh)
Screening (400 mesh)
Concentrate
Tailing
Tailing Middling sample Middling
Concentrate Tailing
Concentrate
Middling
Middling
+38µm fractions
-38µm fractions-38µm fractions
Sample Preparation
Fine grinding
Screening 400mesh
Micrograph analysis
Magnetic separation
Particle size analysis
Degree of Liberation measuring
New generated -38µm product
Sample Grinding-Screening - Magneticseparation- Analysis
Ground product
Particle size analysis
raw material
Fig. 1. Flowsheet of preparation of the samples from rougher concentrate and processing, analyzing of new generated �38 lm product.
10 1000
20
40
60
80
100
cum
ulat
ive
pass
ing
(%)
particle size (um)
Fig. 2. Particle size distribution of the feed of fine grinding (middling sample).
64 X. Xiao et al. / Minerals Engineering 34 (2012) 63–69
2. Experimental
2.1. Samples
The raw material was a magnetite rougher concentrate fromShizhuyuan nonferrous metal Co Ltd., Chenzhou city, PR China. Inthe ore dressing plant, the rougher concentrate was reground-magnetically separated to produce magnetite concentrate. In orderto improve the iron grade of concentrate, the rougher concentratemust be efficiently reground to 95% �38 lm content to liberatemore magnetite (Zhang et al., 2008). The iron grade of the concen-trate is not qualified yet.
Due to �38 lm magnetitie can be regarded as liberated particleapproximately, in order to compare the liberation effect better,+38 lm magnetitie was selected as the feed of the fine grinding.The �38 lm particles and liberated gangues in the rougher con-centrate were removed before fine grinding. The processing flow-sheet was depicted in Fig. 1.
The rougher concentrate was magnetically separated in threesteps to remove the liberated gangue and then sieved to removethe �38 lm size class particles. The +38 lm size fraction, namedas the middling sample, was the feed of fine grinding. The iron
grade of the middling sample was 31.2%. Most of the magnetitesin the sample were intergrowth with gangues (SEM photographswere displayed in the later section). The particle size of the mid-dling mainly distributed in the range of 40–150 lm, which wasdisplayed in Fig. 2.
60 70 80 90 100 110 120 130 14054
56
58
60
62
64
66
68
Fe g
rade
of c
once
ntra
te (%
)
magnetic field intensity (kA/m)
stirred mill ball mill
61.89 61.9462.74
63.29
57.62 57.66 57.6256.12
Fig. 3. Iron grades of concentrate of new generated �38 lm products in differentmagnetic field intensity.
70 72 74 76 78 80 82 84 86 88 90 92545556575859606162636465
grad
e (%
)
recovery (%)
stirred mill ball mill
Fig. 4. Iron grade vs. recovery of magnetite concentrate of new generated �38 lmproducts.
54
56
58
60
62
64
66
epar
atio
n Ef
ficie
ncy
(%) stirred mill
ball mill
X. Xiao et al. / Minerals Engineering 34 (2012) 63–69 65
The middling sample was then fine ground in the stirred milland the ball mill. The ground product was sieved to remove+38 lm size particles. The screened �38 lm size fraction wasdefined as the new generated �38 lm product of the fine grinding.The degree of liberation, particle size distribution, micrograph andiron grade of magnetic separation concentrate of the new gener-ated �38 lm product by ball milling and stirred milling were com-pared with each other.
Part of the new generated �38 lm products were classified byelutriation method. The product of stirred milling was classifiedinto �5 lm, +5 to �10 lm, +10 to �38 lm size classes, and theproduct by ball milling was classified into �10 lm, +10 to�20 lm, +20 to �38 lm size classes. The degree of liberation ofmagnetite and P80 of each size class and the whole size weremeasured.
2.2. Fine grinding and magnetic separation
Two kinds of mills, a vertical stirred mill and a ball mill, wereused to compare the liberation effect of the fine ground magnetite.The vertical stirred mill was a laboratory pin stirred mill. A six-pinstirrer was attached to the gearbox and had a variable speed. Thegrinding chamber of approximately 9 L was fitted on the gearboxshaft. 11 kg 4–6 mm steel balls were used as grinding media. Theball mill was a cone mill with the size u200 mm � 240 mm,11 kg 8–10 mm steel balls were selected. 0.5 kg samples were usedeach at a mass concentration of 60%. The fineness of ground prod-uct, represented as percent mass passing 38 lm, was controlled byvarying the time of grinding.
Rougher concentrate was magnetically separated in the u500electromagnetic separator. Magnetic separations of new generated�38 lm products were performed on the u100 magnetic separatortube in different magnetic field intensity.
2.3. Techniques
Particle size was tested by screening and laser particle size ana-lyzer. The degree of liberation and micrograph of the magnetitewere analyzed using scanning electron microscope and corre-sponding software.
Particle size distribution analysis was carried on the CILAS 1064laser particle size analyzer. The mass percent of �38 lm in sam-ples was determined by sieving with a sample screen. The degreeof liberation of magnetite in unsized new generated �38 lm prod-uct and the feed was measured by ImageJ 1.42q software based onthe photos continuously collected from the JEOL JSM-6490 LVscanning electron microscope on the section of the sample. Thedegree of liberation of magnetite in sized samples was analyzedby FEI scanning electron microscope and Mineral LiberationAnalyzer software (FEI Company).
60 70 80 90 100 110 120 130 140
52
S
magnetic field intensity (kA/m)
Fig. 5. the magnetic separation efficiency of new generated �38 lm products indifferent magnetic field intensity.
3. Results
3.1. Magnetic separation
Fig. 3 plots the iron grade of concentrates of new generated�38 lm products under different magnetic field intensity. The irongrade of concentration of the stirred milling is higher than that ofthe ball milling in the tested magnetic field intensity. The differ-ences vary from 4.3% to 5.8% points, with an average value of 5.2.It means a higher grade concentrate can be acquired by stirredmilling.
Fig. 4 depicts the iron grade vs. recovery of magnetite concen-trate of new generated �38 lm products. The efficiency ofmagnetic separation computed from iron grade and recovery
according to Fleming formula is shown in Fig. 5. Under all thetested magnetic field intensity, the separation efficiency of newgenerated �38 lm products by stirred milling is higher than thatby ball milling. The higher efficiency could be explained with high-er degree of liberation of new generated �38 lm products by stir-red milling.
b
b
c
c
d
d
e
a
b
b
c
c
d
d
e
Fig. 6. Intersect SEM photos of the feed.
Fig. 7. Intersect SEM photos for the products of vertical stirred milling.
66 X. Xiao et al. / Minerals Engineering 34 (2012) 63–69
Fig. 8. Intersect SEM photos for the products of ball milling.
0.1 1 10 100
0
20
40
60
80
100
cum
ulat
ive
pass
ing
(%)
particle size (um)
stirred mill ball mill
Fig. 9. Particle size distribution curve of new generated �38 lm products.
Table 1Representative values and their ratios of new generated �38 lm products.
Samples P20 P50 P80 P98 P98/P80
P98/P20
P80/P20
Product of stirredmill
3.4 6.6 13.2 24.0 1.8 7.0 3.9
Product of ball mill 5.7 12.7 22.8 42.2 1.9 7.4 4.0
0.1 1 10 100
0
20
40
60
80
100
cum
ulat
ive
pass
ing
(%)
particle size (um)
stirred mill ball mill
Fig. 10. Particle size distribution results of ground products of middling.
X. Xiao et al. / Minerals Engineering 34 (2012) 63–69 67
3.2. Section micrograph
Fig. 6 shows the SEM micrographs of the feed of the fine grind-ing (middling sample). Parts of magnetite particles are entirelyencapsulated binarily or ternarily in the gangue. Many cracks pres-ent in the locked particles, some cracks are transgranular, some arealong the phase boundaries (intergranular cracks) (displayed in aand b).
Abundant cracks also exist in the liberated magnetites, whichsegregate the single magnetite particle into small grains. The grainsize is less than 10 lm and majority of grains are less than 5 lm)(depicted in d and e).
The section micrographs of �38 lm products of the stirred mill-ing are displayed in Fig. 7. The magnetite particles in the new gen-erated �38 lm products of stirred milling are nearly completelyliberated with part of magnetite particles size less than 5 lm.The surface of the most particles is smooth and roundness.
Fig. 8 shows the section micrographs of�38 lm products of ballmilling. The majority of the magnetite particles are liberated, how-ever, there are still small parts of magnetites not disintegratedfrom the gangues.
3.3. Particle size distribution
Fig. 9 depicts particle size distribution of the new generated�38 lm products. It is obvious that the curve for the product ofstirred milling shifts to the left side and is steeper than that of ballmilling. It means that the average particle size of the productground by the stirred mill is smaller. Table 1 shows the represen-tative data of particle size distribution for the product of these twokinds of mills. It can be seen that the values for P20, P50, P80 andP98 of the magnetite particles by stirred milling are all smallerthan that by ball milling. At the same time, the ratios of P80/P20,P98/P20, P98/P80 of stirred milling are all smaller, which meansthe particle size distributions of the product by stirred milling isnarrower than that by ball milling.
Fig. 10 shows the particle size distribution data of the groundproducts (screening results show �38 lm mass content is 92.5%).The curve for the product of stirred milling shifts to the left sideand is steeper than that of ball milling, which is similar to that ofnew generated �38 lm products. Despite the same �38 lm masscontent, the average particle size of product by stirred milling issmaller than that by ball milling.
3.4. The degree of liberation of magnetite
Because the particle size distributions of �38 lm products ofstirred milling and ball milling is different, P80 is used to describethe particle size of the magnetite distributed in certain particle sizeclasses or size ranges when the degree of liberation is compared.
Involved size classes and P80 of new generated products groundby the stirred mill and the ball mill are displayed in Table 2. Thedegree of liberation of magnetite in three different particle size dis-
Table 2Involved size fractions and their P80 in the new generated �38 lm products groundby the stirred mill and the ball mill.
Stirred mill Ball mill
Size class P80 (lm) Size class P80 (lm)
�5 lm 4 �10 lm 8.6�10 lm 7.8 �20 lm 15.8+5 to �10 lm 8.6 +10 to �20 lm 18.7�38 lm 13.2 �38 lm 23.5+5 to �38 lm 15.2 +10 to �38 lm 25.0+10 to �38 lm 19.4 +20 to �38 lm 28.7
0
20
40
60
80
100
8.7
29.723.6
7.0
31.1
2.3 1.4
1.3
12.1
82.8
2.11.0
0.8Min
eral
dis
tribu
tions
(%)
>90% Liberated 75~90% Liberated 50~75% Liberated 25-50% Liberated 0~25% Liberated
90.9
5.2
stirred mill ball mill feed
Fig. 11. Magnetite liberation class of new generated �38 lm products and feed.
0~-10um +10~-38um0
20
40
60
80
100
80.990.889.2
% m
iner
al >
90%
libe
rate
d
Size fraction
stirred mill ball mill
91.0
Fig. 12. Magnetite liberation by size fraction for new generated �38 lm products.
5 10 15 20 25 300
10
20
30
40
50
60
70
80
90
% m
iner
al >
90%
libe
rate
d
P80 (um)
stirred mill ball mill
Fig. 13. Degree of liberation vs. P80 of new generated �38 lm magnetite.
4 8.6 13.2 15.2 15.8 19 23.5 28.70
10
20
30
40
50
60
70
80
90
100
% m
iner
al >
90%
libe
rate
d
P80 (um)
stirred mill ball mill
Fig. 14. Degree of liberation vs. P80 of new generated �38 lm quartz.
68 X. Xiao et al. / Minerals Engineering 34 (2012) 63–69
tribution classes was compared, the whole size class (�38 lm sizeclass), size classes with identical lower and upper ranges but theP80 is different (0 to �10 lm and +10 to �38 lm size classes)and size classes whose P80 is identical but the upper and lowerrange is different.
Fig. 11 displays the distribution of magnetites by liberationclass in the new generated �38 lm products and the feed. The lib-eration class of magnetite for the feed is bimodal with 53.3% in the>75 liberated class and 31.1% in the 0–25% class. The magnetite inthe >90% liberated (the magnetite in this class can be regarded asfree particles approximately) class is only 29.7%.
In the new generated �38 lm products, the majority of magne-tite is in the >90% liberated class. The percentage of magnetite inthe >90% liberated class of stirred milling is 8.1 points higher thanthat of ball milling. There still have a small fractions of magnetitedistributed in the 75–90% liberated class, in which the percentageof the product by ball milling is 6.9 points higher than that of stir-red milling.
Fig. 12 plots the degree of liberation of magnetites by size frac-tions with identical lower and upper range in the new generated�38 lm products. The degree of liberation with the value about90% of magnetite in product of stirred milling is not distinct inthe all tested size fractions. In the case of ball milling, the degreeof liberation of magnetite in the �10 lm size fraction is 8.3% pointshigher than that in the +10 to �38 lm size fractions.
The degree of liberation of the magnetites in the products ofstirred milling is greater than that of ball milling in the same sizefractions. In the �10 lm size fraction, the percentage of >90% lib-erated magnetite in the product of stirred milling is 1.8% pointshigher than that of ball milling, and it must be noticed that this dif-ference rises to 9.9% points in the +10 to �38 lm size fractions.This may indicate that magnetite can be liberated from gangue ina coarser particle size when fine grinding by the stirred mill.
The degree of liberation for magnetite in the size classes withidentical P80 of the new generated �38 lm product are plotted
in Fig. 13. The degree of liberation of magnetite by stirred millingincreases with a corresponding decrease in particle size, are almostmore than 90% in the all analyzed size classes. In the case of ballmilling, it is less than 90% in the all analyzed particle size.
In the size fractions with same P80 of the analyzed size classes,the degree of liberation of the magnetites by stirred milling isgreater than that by ball milling, with the value varies from 2.4%to 29.1% point. For example, in the size fraction with P8018.7 lm (+10 to �20 lm size class) of the product by ball milling,the degree of liberation for magnetite is 61.7%, which is far lessthan that by stirred milling in the size fraction with identical P80(+10 to �38 lm size class, 90.8%).
X. Xiao et al. / Minerals Engineering 34 (2012) 63–69 69
The above results indicate that stirred milling can liberate mag-netite with a higher degree, and a higher grade of concentrate canbe produced in the later magnetic separation pricess (this can befound from the magnetic results in Section 3.1). Stirred milling ismore appropriate for liberating P80 10–30 lm minerals than ballmilling.
The degree of liberation for quartz of new generated �38 lmproduct are plotted in Fig. 14. The degree of liberation of quartzeither by stirred milling or ball milling increases with a corre-sponding decrease in particle size. In the size fraction with identi-cal P80, the degree of liberation of quartz ground by the stirred millis about the same as that by the ball mill. This shows that stirredmilling improved the degree of liberation of magnetite selectively.
4. Discussions
The particle size, degree of liberation of magnetite and micro-graph of new generated �38 lm product fine ground by the stirredmill and the ball mill are compared with each other. When millingto the same �38 lm mass content, the average particle size of newgenerated �38 lm product by stirred milling is smaller than thatby ball milling with the content of �5 lm size particles more thanthat by ball milling. The SEM photos show that the surface of themagnetite particles ground by the stirred mill is smoother androunder than that by the ball mill. It can be concluded that the finerparticles may be produced from the progenitor particles withabundant cracks and the abrasion size reduction mechanism ofstirred milling (Gao and Forssberg, 1995; Hogg, 1999).
In the size class with identical P80, the degree of magnetite ofstirred milling is higher than that of ball milling, while the degreeof quartz of stirred milling is almost the same as that of ball mill-ing. It indicates that stirred milling can improve the degree of mag-netite selectively. This can be attributed to that the stress appliedto the mineral particles of the stirred mill is mainly attrition, whichcan rub out the gangues on the outer layer of the particle from themagnetite. The stirred mill is fit to use for fine grinding the mid-dling with a high content of intergrowth to enhance the mineralsto fracture along the interfaces, especially appropriated for millingP80 10–30 lm minerals to liberate more valuable metals.
Form the above results, it can be found that the liberation effectof magnetite can be improved by fine grinding with the stirred milland a higher grade concentrate can be acquired from the fineground product of stirred milling. To verify these results, the rawmaterial (magnetite rougher concentrate) was ground by the
78 80 82 84 86 88 90 92 94 9653545556575859606162636465
grade, stirred mill grade, ball mill recovery, stirred mill recovery, ball mill
grad
e (%
)
84
85
86
87
88
89
90
91
92
recovery (%)
-38 m mass content (%)µ
Fig. 15. The iron grade and recovery of magnetite concentrate magneticallyseparated from the ground rougher concentrate.
experimental stirred mill and ball mill. When grinding to the sameparticle size (95% �38 lm), the iron grade of concentrate (concen-trating in the same magnetic separation conditions) of stirred mill-ing is about 2% points higher than that of ball milling (see Fig. 15).
5. Conclusions
Stirred milling improved the degree of liberation of magnetiteselectively. In the all three different particle size distribution clas-ses compared, the degree of liberation of magnetite by stirred mill-ing is all higher than that by ball milling in the same size class. Thedegree of liberation of magnetite in new generated �38 lm prod-ucts of stirred milling was 8.1% points higher than that of ball mill-ing, and stirred milling mainly improved the degree of liberation ofmagnetite in +10 to �38 lm size fractions. In the size fractionswith identical P80 the degree of liberation of the magnetites ofstirred milling was greater than that of ball milling with the valuevaried from 2.4% to 29.1% points.
Stirred milling improved the efficiency of magnetic separationof ground magnetite and iron grade of the concentrate. The irongrade of magnetic separation concentrate of stirred milling is5.2% points higher than that of ball milling.
The stirred mill was fit to use for fine grinding the middlingwith a high content of complex intergrowth to improve the degreeof liberation of the target mineral. It was especially appropriatedfor milling P80 10–30 lm minerals to liberate more valuablemetals.
References
Andreatidis, J., 1995. Breakage Mechanism and Resulting Mineral Liberation in aBead Mill. Master of Engineering Science, thesis, University of Queensland,Australia.
Apling, A., Bwalya, M., 1997. Evaluating high pressure milling for liberationenhancement and energy saving. Minerals Eng. 10 (9), 1013–1022.
Daniel, M.J., 2007. Energy efficient mineral liberation using HPGR technology. Ph.D.thesis, University of Queensland, Australia.
Davey, G., 2006. Fine grinding applications using the Metso Vertimill grinding milland the Metso Stirred Media Detritor (SMD) in gold processing. In: Proceedings38th Annual Meeting of the Canadian Mineral Processors, Ottawa, pp. 153–169.
Gao, M.W., Forssberg, E., 1995. Prediction of product size distributions for a stirredball mill. Powder Technol. 84, 101–106.
Gao, M.W., Young, M., Allum P., 2002. IsaMill fine grinding technology and itsindustrial applications at Mt Isa Mines. In: Proceedings of the 34th AnnualMeeting of the Canadian Mineral Processors. Ottawa, Canada, pp. 171–188.
Hogg, R., 1999. Breakage mechanisms and mill performance in ultrafine grinding.Powder Technol. 105, 135–140.
Kwade, A., Schwedes, J., 2002. Breaking characteristics of different materials andtheir effect on stress intensity and stress number in stirred media mills. PowderTechnol. 122, 109–121.
Lofthouse, C.H., Johns, F.E., 1999. The Svedala (ECC International) detritor and themetals industry. Minerals Eng. 12 (2), 205–217.
Nesset Jan, E., Radziszewski, P., Hardie, C., Leroux, D.P., 2006. Assessing theperformance and efficiency of fine grinding technologies. In: 38th AnnualMeeting of the Canadian Mineral Processors, Ottawa, Canada, pp. 283–309.
Shi, F., Morrison, R., Cervellin, A., Burns, F., Musa, F., 2009. Comparison of energyefficiency between ball mills and stirred mills in coarse grinding. Minerals Eng.22, 673–680.
Vizcarra, T.G., Wightman, E.M., Johnson, N.W., Manlapig, E.V., 2010. The effect ofbreakage mechanism on the mineral liberation properties of sulphide ores.Minerals Eng. 23, 374–382.
Wang, Y.M., Forssberg, E., 2000. Product size distribution in stirred media mills.Minerals Eng. 13 (4), 459–465.
Xiao, X., Zhang, G.W., Li, Y.G., Jia, Y., Feng, Q.M., Xie, J.G., 2011. Intensifyingseparation of reverse flotation tailings from concentrator of baogang group byfine grinding with the stirred mill. Min. Metall., Eng. 31 (2), 32–34 (in Chinese).
Zhang, G.W., Li, Z.Q., Li, X.D., Zhao, X., Xiao, S.X., Gao, X.H., Xie, J.W., 2008.Application of vertical spiral agitating Mill in iron ore regrinding. Metal Mine383 (5), 93–95, in Chinese.
Zhang, G.W., Zhao, X., Li, Z.Q., Xiao, S.X., Huang, L.L., 2010. Research and applicationof vertical screw stirred mill. XXV. In: International Mineral ProcessingCongress, Brisbane, Australia, pp. 1437–1443.
