DEVELOPMENT OF COLUMN FLOTATION TECHNOLOGY AT NATIONAL METALLURGICAL LABORATORY (CSIR) National Metallurgical Laboratory (NML) Madras Centre by its extensive R&D efforts had developed indigenous automated laboratory, pilot and commercial flotation column units. The Centre made a pioneering effort in demonstrating the technology by installing and conducting feasibility studies at the plant premises of various mineral beneficiation industries in our country. Design, Development & Field Tests of Lab Column Fully automated laboratory model flotation column was designed, fabricated and extensively field tested for various ores and minerals at different mineral processing plants. Internal spargers of several types were developed to suit different applications. Special attention was paid in sparger design to generate required bubble size and bubble flux to suit a wide range of applications. The overall column design facilitates the variation of column height, feed injection point, froth depth etc. Specification of Lab Column: Diameter - 74mm Height - 10m, variable several flanged sections. Sparger - Internal different porosities The sparger is of internal type fitted with sintered bronze disc of desired porosity. Differential Pressure Transmitter (DPT) coupled with a micro processor based dual-loop controller was adopted to maintain the interface between slurry and froth. The interface can be visualised from display on the LCD screen of the controller. At the steady state, the interface level could be maintained within +/- 2 cm. Various electronic gadgets were incorporated to monitor and record the variables like airflow, slurry flow, wash water flow etc. The NML lab column and the centralized control panel is shown below. DPT Column Programmable Controller Discharge Valve Column Control Strategy
Field Tests: Hindustan Copper Ltd., Malanjkhand (Copper) Kudremukh Iron Ore Co. Ltd., Kudremukh (Iron) Gujarat Mineral Development Corporation, Ahmedabad (Fluorspar) Gujarat Mineral Development Corporation, Ahmedabad (Cu-Pb-Zn)) Hindustan Zinc Ltd., Udaipur (Agucha, Lead-Zinc) Hindustan Zinc Ltd., Udaipur (Dariba, Lead-Zinc) Bharat Gold Mines Ltd., KGF, Karnataka (Gold) Chronological Activities of the field tests with Laboratory Flotation Column Year Project Title Sponsor Test Site 1987 1988 1989-91 1992-93 Exploratory project on fine particle processing by new techniques Development of 3 types of cells conventional column, electro-column & combination. Design & development of fully automated flotation column with stateof-the instruments Amenability studies at Malanjkhand copper project copper ore Ministry of Mines Ministry of Mines NML Internal resources Hindustan Copper Ltd NMLMC NMLMC NMLMC Malanjkahand, M.P 1993-94 Feasibility studies at Kudremukh Iron Ore Company Ltd. Kudremukh Iron Ore Co. Ltd. Kudremukh, Karnataka 1994-95 Fluorspar beneficiation at Gujarat Mineral Development Corpn. Gujarat Mineral Development Corpn Kadipani, Gujarat 1995-96 Column flotation of Pb-Zn ore at Agucha, HZL Hindustan Zinc Ltd. Agucha, Rajasthan 1996-97 Column flotation of Pb-Zn ore at Dariba, HZL Hindustan Zinc Ltd. Dariba, Rajasthan 1997-98 1998-99 2007-08 Beneficiation of multi metal ore at Ambaji, GMDC Cu-Pb-Zn ore Amenability studies at Bharat Gold Mines Ltd. Gold ore Beneficiation of siliceous limestone from Jayanthipuram deposit Gujarat Mineral Development Corpn Bharat Gold Mines Ltd. Madras Cements Ltd., Chennai Ambamatha, Gujarat Kolar Gold Fields, Karnataka NMLMC
Commercialization of Laboratory Flotation Column After field tests the laboratory column was standardized and erected an automatic systems to NMDC R&D Centre Hyderabad by participating in a global tender. The system was installed and is being utilized for the beneficiation R&D studies of iron ore fines. One more system was installed at the Department of Mining Engineering, Golden Valley Institute of Technology, KGF, Karnataka for their curriculum introduced in B.Tec. Course. 1999 Transfer of Fully Automated Laboratory Column to N M D C R&D Centre, Hyderabad 2001 Transfer of Fully Automated Laboratory Column to G V I T, KGF, Karnataka Design, Development & Demonstration of Pilot/Semi-commercial Column The experience gained in design and development of laboratory and pilot size columns and the successful execution of in plant trials at different mineral processing plants with a wide range of ores, culminated in the development of a semi-commercial column to treat part of the plant stream (50-100 tpd). Accordingly, a 500 mm dia. column (maximum height 14 metres with flanged sections) equipped with suitable pumps, electronic level controls, magnetic flow meters, automatic sampling valves etc. has been incorporated. Different types of bubble generators (spargers) have been designed, suitable to process various minerals that too in plant conditions. Salient Features of NML Pilot Column 0.5m dia. column with variable height Indigenous sparging system (No need of high pressure water, similar to external spargers can maintain on-line)
Microprocessor based level control Auto pneumatic sampling Digital flow measuring systems - air, water, feed Centralized control panel Unique facility in India (Mobile) To understand the implications at larger scale operation and also to confirm the amenability tests of laboratory scale, semi-commercial (0.5M dia) size flotation column was developed, tested and demonstrated at various plants. Extensive field trials were conducted by installing the pilot column in the following mineral beneficiation plants of our country to popularize and demonstrate the column flotation technology. Bharat Gold Mines Ltd., KGF (Gold ore) Gujarat Mineral Development Corporation Ltd., Kadipani (Fluorspar) Indian Rare Earths Ltd., OSCOM, Chatrapur (Sillimanite) Sociedade de Fomento Industrial Pvt. Ltd, Goa. (Iron ore) Calpro Mineral Technologies Ltd., Salem (Limestone) JSW Ltd., Tornagallu (Iron ore) Tata Steel, Joda (Iron ore) Chronological Activities of the field tests and Demonstrations with Pilot Flotation Column Year Project Title Sponsor Test Site
1996 1996-97 1999-00 2001-02 2002-03 2003-04 2004-05 2006-07 2008-09 Design & development of semicommercial, 0.5m dia column with automatic controls. Demo of 0.5M dia flotation column for gold ore beneficiation at BGML Field testing of 0.5M dia column at Kadipani, GMDC, for fluorspar beneficiation Demo of flotation column for sillimanite beneficiation at OSCOM, Orissa Column flotation of iron ore fines at Fomento, Goa Demo of 0.5M dia flotation column for the beneficiation of Limestone at Salem Studies on the Beneficiation of Garnet Amenability studies at JSW Steel Ltd. 0.5M dia semi-commercial column Pilot Scale Column Flotation Studies on the Iron Ore Fines at JEIM NML Internal resources Bharat Gold Mines Ltd. Gujarat Mineral Development Corpn Indian Rare Earths Limited Sociedade De Fomento Industrial Ltd. Calpro Mineral Technologies India Pvt. Ltd. Indian Ocean Garnet Sands Co. Pvt. Ltd. Jindal South West Steels Ltd. TATA Steel Ltd. NMLMC Kolar Gold Fields, Karnataka Kadipani, Gujarat OSCOM, Chatrapur, Orissa Madgau, Goa Salem, Tamilnadu Tuticorin, Tamilnadu Vijayanagar, Ballery, Karnataka Joda, Barbil, Orissa This exercise created lot of interest and confidence in the industrial circles on column flotation technology which lead the industry to adopt this technology in their operations. Design, Installation & Commissioning of Commercial Scale Flotation Columns Based on the successful demonstration of semi-commercial flotation column (0.5 m diameter) for the beneficiation of sillimanite and limestone, commercial size columns were designed and commissioned for the following industries.
(a). Indian Rare Earths Limited, OSCOM, Chatrapur, Orissa: A commercial size flotation column of 1.3 m dia and 10 m height was designed to treat 7 t/h of sillimanite for IREL and installed at OSCOM, Chatrapur. The column is equipped with state-of-the-art electronic gadgets for the effective control of the slurry/froth interface, slurry feed, air and wash water flow rates. An indigenously developed ceramic spargers were incorporated to with stand the highly abrasive sillimanite particles. The column was successfully commissioned during November 2005. The performance of the flotation column was evaluated and it was observed that the column produced excellent metallurgical results for the designed capacity. The sillimamnite concentrate assaying 98% (after magnetic separation) with the recovery of 90% was obtained from flotation column. With the introduction of the flotation column in the sillimanite circuit, the production of sillimanite has been increased by about 40%.
(b). Calpro Mineral Technologies India Pvt. Ltd.: The Salem district of Tamilnadu is bestowed with many limestone deposits owned by small mine owners. Namakkal of Salem district is famous for poultry industry. Calcium in the form of CaCO 3, is an essential ingredient in the poultry feed and the demand is about 100 t/d. Since limestone is used to supplement Calcium content, it should be free from contamination of chemicals. Also the silica content in limestone should be less than 2%. Hence, reverse flotation where in gangue/silica materials are floated was adopted. A commercial size flotation column of 1.2 m diameter was designed to treat 6 t/h of limestone and installed at the mines site of M/s Calpro Mineral Technologies India Pvt. Ltd., Salem. The column is completely automatic and indigenous in all respects.
(c). Indian Rare Earths Limited, Chavara, Kerala: Satisfied with the performance and operation of NML column at OSCOM, Chatrapur for the beneficiation of sillimanite, M/s IREL decided to install another flotation column in their mineral separation plant at Chavara, Kerala. The column is similar to the column at OSCOM in design and capacity which has to treat 6TPH of sillimanite.. The plant is commissioned in 2009 and is in operation to the designed capacity.
Installations of Commercial NML Flotation Columns Year Industry Service 2005-06 2006-07 Orissa Sands Complex, Indian Rare Earths Ltd. Chatrapur Calpro Mineral Technologies India Pvt. Ltd., Salem Flotation of Sillimanite Beneficiation of Limestone by Reverse flotation 2007-09 Indian Rare Earths Ltd. Chavara Flotation of Sillimanite Column Size & Capacity Dia 1.3 m 150 tpd Dia 1.2 m 150 tpd Dia 1.3 m 150 tpd Development of indigenous spargers - the vital component of flotation column Sparging system is the heart of a flotation column. The sparger construction is schematically shown in the above figure. Sparger consists of a porous tube connected to a metal tube through a suitable connector. The other end of the metal tube is joined to a flexible tube whose end is connected to the air header. Air flow is regulated by a ball valve and monitored by a rota-meter. Air-header is connected to an array of spargers. The air-header consists of 32 outlets equally distributed. Each outlet is fixed with a isolation ball valve. Air to spargers can be cut off selectively, if required, by isolation ball valve connected to the sparger assembly.
Publications on Column Flotation: Peer Reviewed International Journals : 08 Peer Reviewed National Journals : 02 International & National Conference Proceedings : 19 Internal Project Reports : 18 Recognitions / Awards: Binani Gold Medal for Best Paper (IIM) - - - - - -- 1994 Khare Award for Best Paper (IIME) - - - - - - - - 1998 Altekar Award for Best Technology (NML) - - - - - - - - 2002 Altekar Award for Best Technology (NML) - - - - - - - -- 2005 Mineral Beneficiation Award (IIME) - - - - - - - - - - -- 2006 National Mineral Award (Min. of Mines) - - -- - - - - -2006 MOU with McNally Bharat Engineering Co. Ltd., Bangalore Looking at the success of NML Flotation column in the beneficiation of sillimanite and limestone M/s McNally Bharat Engineering Company Limited, a leading mineral processing equipment manufacturer and marketing organization showed interest in marketing the NML flotation column technology. Both the organizations come to an agreement and signed an Memorandum of Understanding in 2008. The salient feature of the agreement is14.5% on the invoice value will be remitted to NML by McNally Bharat Engineering Co. Ltd. towards premium and royalty on each supply of flotation column. Since then the following organizations were placed the orders to procure the various columns. 1. Pilot flotation column of 0.5m diameter and 14m height with the state of the equipments and fully automatic controls - M/s RBSSN, Hospet, Karnataka. Cost: Rs.28.00 lakhs Supplied, erected and commissioned. 2. Fully automatic standard 74mm diameter laboratory flotation column with advanced controls NEIST (CSIR), Jorhat, Assam. Cost: 18.00 lakhs Successfully commissioned and working satisfactorily at NEIST Laboratory. 3. 70 tph capacity flotation column for the beneficiation of barites at Mangampet, AP M/s Andhra Barites Corporation Ltd., Kadapa, Andhra Pradesh. Cost: 100.00 lakhs Work is in progress.