Column Control Strategy

DPT

Discharge Valve

Programmable

Controller

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.

Column

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 Exploratory project on fine particle processing by new techniques

Ministry of Mines NMLMC

1988 Development of 3 types of cells – conventional column, electro-column & combination.

Ministry of Mines NMLMC

1989-91 Design & development of fully automated flotation column with state-of-the instruments

NML Internal resources NMLMC

1992-93 Amenability studies at Malanjkhand copper project – copper ore

Hindustan Copper Ltd 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 Beneficiation of multi metal ore at Ambaji, GMDC – Cu-Pb-Zn ore

Gujarat Mineral Development Corpn

Ambamatha, Gujarat

1998-99 Amenability studies at Bharat Gold Mines Ltd. – Gold ore

Bharat Gold Mines Ltd. Kolar Gold Fields, Karnataka

2007-08 Beneficiation of siliceous limestone from Jayanthipuram deposit

Madras Cements Ltd., Chennai

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 Design & development of semi-commercial, 0.5m dia column with automatic controls.

NML Internal resources NMLMC

1996-97 Demo of 0.5M dia flotation column for gold ore beneficiation at BGML

Bharat Gold Mines Ltd. Kolar Gold Fields, Karnataka

1999-00 Field testing of 0.5M dia column at Kadipani, GMDC, for fluorspar beneficiation

Gujarat Mineral Development Corpn

Kadipani, Gujarat

2001-02 Demo of flotation column for sillimanite beneficiation at OSCOM, Orissa

Indian Rare Earths Limited

OSCOM, Chatrapur, Orissa

2002-03 Column flotation of iron ore fines at Fomento, Goa

Sociedade De Fomento Industrial Ltd.

Madgau, Goa

2003-04 Demo of 0.5M dia flotation column for the beneficiation of Limestone at Salem

Calpro Mineral Technologies India Pvt. Ltd.

Salem, Tamilnadu

2004-05 Studies on the Beneficiation of Garnet

Indian Ocean Garnet Sands Co. Pvt. Ltd.

Tuticorin, Tamilnadu

2006-07 Amenability studies at JSW Steel Ltd. 0.5M dia semi-commercial column

Jindal South West Steels Ltd.

Vijayanagar, Ballery, Karnataka

2008-09 Pilot Scale Column Flotation Studies on the Iron Ore Fines at JEIM

TATA Steel Ltd. 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 CaCO3, 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 Column Size & Capacity

2005-06 Orissa Sands Complex, Indian Rare Earths Ltd. Chatrapur

Flotation of Sillimanite Dia 1.3 m 150 tpd

2006-07 Calpro Mineral Technologies India Pvt. Ltd., Salem

Beneficiation of Limestone by Reverse flotation

Dia 1.2 m 150 tpd

2007-09 Indian Rare Earths Ltd. Chavara Flotation of Sillimanite 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.