In the  present paper, an  attempt  has been to bene-ficiate beach sand minerals of Maharastra coast. For this purpose, beach sand mineral samples were  collected from two different coastal places namely; Pirawadi and Kother-wadi area. The samples obtained were subjected for chara-cterization & beneficiation studies. The characterization studies were mainly carried out by mineralogical analyses. The mineralogical analyses indicated 12-15% Ilmenite, 5-7% Magnetite and 65-70% Quartz in Pirawadi sample. Similarly Kotherwadi  sample showed the presence of 10-12% Ilmanite along with 40-45% quartz. The studies also indicated the increased heavy mineral concentration in finer size (-75 11) fractions.  Further,  the beneficiation  studies were carried out  using  Perm  roll  magnetic separator using different variables such as particle size, magnetic inte-nsity, roll speed, splitter position etc. From the studies it was possible to recover 80-85% magnetic minerals under different conditions

Gujar, A R

Mandre, N R

Prabhu, S

Venugopal, R

English

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Proceedings of the International Seminar on Mineral Processing Technology - 2006, Chennai, India. pp. 519 - 523. Processing of Beach Sand Minerals of Maharastra Coast N.R. Mandre', S. Prabhu', A.R. Gujar2 and R. Venugopal' Dept. of Fuel and Mineral Engineering, Indian School of Mines Dhanbad (Jharkhand) 826 004 2 National Institute of Oceanography, Goa 403 004 Abstract In the present paper, an attempt has been made to beneficiate beach sand minerals of Maharastra coast. For this purpose, beach sand mineral samples were collected from two different coastal places namely,. Pirawadi and Kotherwadi area. The samples obtained were subjected for characterization and beneficiation studies. The characterization studies were mainly carried out by mineralogical analyses. The mineralogical analyses indicated 12-15% Ilmenite, 5-7% Magnetite and 65-70% Quartz in Pirawadi sample. Similarly Kotherwadi sample showed the presence of 10-12% Ilmanite along with 40-45% quartz. The studies also indicated the increased heavy mineral concentration in finer size (-75 11) fractions. Further, the beneficiation studies were carried out using Perm roll magnetic separator using different variables such as particle size, magnetic intensity, roll speed, splitter position etc. From the studies it was possible to recover 80-85% magnetic minerals under different conditions. INTRODUCTION India has large reserves of beach sand minerals in the coastal stretches around the country. Among these, ilmanite is the largest constituent of the minerals other being rutile, leucoxene, zircon, sillimanite, garnet and monazite. Ilmenite and rutile are exploitable minerals of beach sand and they also occur in fully liberated state. The exploration studies of these minerals indicated the estimation around 630 mt out of which ilmanite contributes to 348 mt (Rao, et. Al. 2001, Mohan and Rajamanickam 2001). The reserves of beach sand mainly occur in: Eastern India i.e. Andhra Pradesh, Orissa, and Tamilnadu. Western India: Kerala, Karnataka and Marharastra area. From the literature it may be observed that only three deposits, namely chavara in kerala, manaval kuruchi in Tamilnadu, and Chatrapura (OSCOM) in Orissa are under commercial exploitation. Manaval kurichi with 20-40% HM extends about 7 km and mainly rich in ilmanite along with monozite in recoverable proportion. Chavara deposit having 40-70% HM extends for aout 22 km from Kayamkulam to Neendakara is rich in high grade ilmanite. Unlike these deposits, Chatrapura with 20% HM has deposit extending over 18 km and contains medium to low grade ilmanite (Mukherjee 1998). Apart from these it may be observed that significant exploration work has been carried out on beach sand deposits of Maharastra coast (Gujar 2004). It has also been reported that appreciable quantity of ilmanite occur between Jaigad to vijay durg. Apart from these variable quantities of ilmanite and magnetite were reported around Ratnagiri district. Therefore, in the present paper, an attempt has been made to beneficiate beach sand minerals from Pirawadi and Kotharwadi area in Ratnagiri district of Maharastra coast. EXPERIMENTAL A. Material Preparation Beach sand samples were collected from Pirawadi and Kotharwadi area in Ratnagiri districts of 519 100 al" 80 g 60 E 40 rs 20 0 —111F—Kotharwadi 100 	 200 	 300 Size in microns 400 Fig.1: Size Analyses of the Beach Sand Samples 	 Fig. 2: Dense Media Analyses of the Beach Sand Samples 100 0 P. 80 4' 60 2 40 20 0 0 	 100 	 200 	 300 	 400 	 500 Size in microns Processing of Beach Sand Minerals of Maharastra Coast Maharastra coast and the samples obtained were about 250 micron in size and were initially subjected for drying. Representative samples were prepared from the dried samples and subjected for de sliming process and dried. B. Size Analysis and Dense Medium Analysis The representative sample obtained from both the deposits were subjected for size Anlysis using standard laboratory sieves. Further, in order to know the heavy minerals present the representative samples were subjected for dense media separation using bromoform as the media with different size fractions. C. Mineralogical Studies To identify the different mineral constituents present in samples, the representative samples were subjected for the mineralogical analyses. From the mineralogical studies approximate percentage of different minerals and their presence in finer size fractions were also assessed. RESULTS AND DISCUSSIONS Size Analysis and Dense Media Analysis The results of the studies are given in Figure land 2. From Figure 1, it may be observed that the 80% passing size for the Pirwadi sample was found to be 270 micirons whereas for the Kotharwadi sample 80% passing size was found to be 380 microns. Therefore, here it may be said that the Kotharwadi sample was more coarse grained than that of the Pirwadi sample. From Figure 2 it may be seen that the finer size fractions contain more heavy minerals rather than coarse size-fractions. As reported in size analysis the dense media analysis has also reported the heavy minerals in fine size fractions in Pirawadi sample than that of Kotherwadi sample. Table I: Mineralogical Analysis of Pirawadi Sample Mineral Percentage Grain size (p) °AMineral in — 75p. size fraction Quartz and feldspar 65-70 100-400 4-5 Ilmenite 12-15 40-100 55-60 Sea Shell 5-7 ---- 1-2 Magnetite 5-7 40-100 - Goethite 5-7 100-300 traces Stamolite 2-5 -- 10-15 Iron oxide and amphibole 1-2 ---- 10-15 Zircon, Gamet,Chlorite Traces --- Traces 520 Proceedings of the International Seminar on Mineral Processing Technology Mineralogical Studies Mineralogical studies of the samples indicated that both the samples predominantly consists of quartz and feldspar. Other constituents being ilmanite, sea shell, magnetite, goethite etc. The results of the studies are given in Table I and II Comparison of the results shows that the magnetite is present in significant quantity in Pirawadi sample. However, the Kotherwadi sample showed magnetite content in traces. Therefore, from the mineralogical studies it may be said that the presence of the higher amount of magnetite in Pirawadi sample may affect the beneficiation process. C. Beneficiation Studies From the characterization studies it was observed that the heavy mineral constituents are concentrated in —150 micron size fractions. Therefore, the beneficiation studies were carried out using these size fractions only. Table H: Mineralogical Analysis of Kotharwadi Sample Mineral Percentage Grain size (p.) % Mineral in — 100g size fraction Quartz and feldspar 40-45 100-400 8-10 Ilmenite 10-12 40-150 60-65 Sea Shell 35-40 ---- 4-5 Iron oxide 5-7 ---- 10-15 Amphibole traces ---- 2-3  Stamolite 1 ---- traces Zircon, Garnet, Chlorite, Monazite, Magnetite Traces --- Traces The beneficiation process was carried out by using Perm-Roll Magnetic separator (Laboratory model), During the studies effect of different variables such as, magnetic intensity, splitter angle and speed of roll were analysed and are discussed below. In order know the effects of different variables initially some experiments were carried at different magnetic intensities of 11000 to 14000 Gauss at a roll speed of 100 rpm. The results of the studies carried with both the samples are given in Figure 3. From Figure 3 it may seen that a maximum recovery of 79 and 73% can be obtained at 14000 G using a roll speed of 100 rpm. From the results it may also be observed that the recovery of magnetic minerals in Kotherwadi sample is higher than that of the Pirawadi sample. This phenomenon may be attributed to the grain size of the magnetic minerals in the sample. From the mineralogical studies it may be observed that fine size grains (-75 11 ) and present in Pirawadi sample than that of Kotherwadi sample (-100 if ). From the studies it was also observed that significant amount of magnetite was recovered in Pirawadi sample, which was indicated by the reddish brown colour of the concentrate. Hence, from the studies it was inferred that it may not be possible to recover a clean concentrate of Ilmenite from Pirawadi sample as the magnetite present in the beach sand mineral contaminate the Ilmenite concentrate. Therefore, further studies were carried out using Kotherwadi sample. For this purpose studies were carried out using magnetic intensities of o 13000 and 14000 Gauss. At different magnetic roll speed and splitter position. The results of the studies are given in Figures 4 and 5. From the figures it may be observed that the recovery of the magnetic mineral was increased with increase in roll speed and there was a marginal effect of splitter position on the recovery. From the results it may also be seen that a maximum recovery of 83.73 and 85.79% magnetic mineral could be obtained at 13000 and 14000 Gauss and a roll speed of 140 rpm. 521 t 	 80 72 75 E 0  70 co ;38 65 —4—Splitter 5.8 —II—Splitter 13.61 --A—Splitter 21.55 85 c E 	 80 0 75 70 65 60 	 80 	 100 	 120 	 140 Roll speed in rpm • 90 0 Y) 85 4.0 E "5 7e 80 g E 75 ce 70 —0—Solider 5.8 —a—Splifter 13.61 - —Splitter 21.55,72  70 	 80 	 100 	 120 	 140 Roll speed in rpm Processing of Beach Sand Minerals of Maharastra Coast 60 - —•—Piravadi 8 	 55 - I —a— Kotharwadi w 50 10000 11000 12000 13000 14000 15000 Magnetic Intensity (Gauss) Fig. 3: Effect Magnetic Intensity on Recovery of 	 Fig. 4: Effect of Roll Speed on the Recovery of Magnetic Minerals at a Roll Speed of 100 rpm 	 Magnetic Minerals at 13000 Gauss Fig. 5: Effect of Roll Speed on the Recovery of Magnetic Minerals at 14000 Gauss CONCLUSIONS From the studies following conclusions were drawn: 1. Size analysis and dense media analysis have indicated that the Pirawadi sample comprises of smaller size fractions compared to Kotharwadi sample and both the samples have indicated that the heavy minerals are concentrated in the finer size fraction than that of the coarser size fraction. 2. The mineralogical studies indicated that the of quartz and feldspar as the Major constituents. Other constituents being ilmanite, sea shell, magnetite, goethite etc. 3. From the beneficiation studies it may be concluded that better results were obtained in case of Kotharwadi sample compared to Pirawadi sample which may be attributed to the presence of heavy minerals in finer size fractions (-75i) as well as high amount of magnetite (5-7%) in the Pirawadi sample compared to coarser size fractions ( —1500 as well as negligible amount of magnitite in Kotharwadi Sample. ACKNOWLEDGEMENTS Authors are thankful to the financial support received from CSIR Net work project, 'Capacity building for coastal placer mining and processing' under X plan. REFERENCES [1] Gujar, A. R. (2004) Placer mineral exploration: Contribution and future projection of MO, in Placer 2004 (Eds.). V. J. Loveson and D. D. Misra, Allied Publishers PVT Ltd. 522 Proceedings of the International Seminar on Mineral Processing Technology [2] Mukherjee, T. K. (1998) Mining and processing of Titanium minerals in India, Metals Materials and Processes Vol 10, pp 85-98 [3] Mohan, P. M. and Rajamanickam G. V., Indian Beach Placers- A Review, hand book of placer mineral deposits, G. V. Rajamanickam (Editor) New Academic Publishers, 151 Edition. [4] Rao, A. Y., Nagabushanam, B., Dash, A. K., Ratul Paul and Ravi, G. S. 2001 Present exploitation status and future prospects of beach placers and their industrial applications: in Some aspects of Mineral development in India, (Eds.) Subba Rao, K. V. and Rajasekhar Reddy, D. Andhra University, Published by GSI and Andhra University. 523 

Processing of Beach Sand Minerals of Maharastra Coast

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Processing of Beach Sand Minerals of Maharastra Coast

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