Development of indigenous column flotation technology at NML for the beneficiation of low-grade ores

NML Madras Centre has designed and developed indigenous automated flotation columns as part of its long term R&D program on the utilization of low-grade ores of India. Both laboratory size and semi-commercial flotation columns were extensively field tested in different mineral processing plants owned by Hindustan Copper Limited, Hindustan Zinc Limited, Kudremukh Iron Ore Company Limited, Sociedade De Fomento Industrial Limited, Bharat Gold Mines Limited, Gujarat Mineral Development Corporation Limited and Indian Rare Earths Limited for the beneficiation of copper, lead and zinc, iron, gold, fluorspar and sillimanite. State-of-the-art equipment was incorporated in both laboratory and semi-commercial flotation columns. Advantages of column flotation technology over conventional flotation machines and salient features of the NML flotation column were discussed in the present paper. Flotation test results obtained both by flotation column and conventional cells were compared. The paper also highlights the potential of column flotation technology in achieving better metallurgical results

Studies on the Beneficiation of Barite

Barite is extensively used as drilling mud in oil exploration operations. Beneficiation of barite by flotation was investigated using cationic and anionic collectors. Commercially available fatty amines such as Armoflote 17 and Liquid B50 were tried as collectors to float gangue minerals (reverse flotation) whereas oleic acid was used for direct flotation of barite. Effect of collector concentration on flotation was studied and the results were discussed. Barite concentrate assaying 96% BaSO4 with less than 1% SiO2 could be obtained by single stage flotation using cationic collectors. Zeta-potential measurements were conducted to study the interaction of cationic collectors on silica and anionic collector on barite. While cationic collectors were found to adsorb on silica by electrostatic interaction, oleic acid was found to adsorb on barite by chemisorption. Advantage of reverse flotation over direct flotation technique was discussed

Characterization of Srikurmum and Navaladi Beach Placer Minerals

Two different beach placer samples from Srikurmum of Andhra Pradesh and Navaladi of Tamilnadu were collected and characterized in terms of their total heavy mineral content by heavy media as well as magnetic separation studies. Navaladi beach placer sample contains higher amounts of total heavy minerals than that of the Srikur-mum beadh. Mineralogical analysis on both the samples revealed high amounts of garnet and minor quantities of ilmenite. The particle size of garnet is coarser than that of ilmenite. EPMA results indicated that garnet is of almandine variety. The Eastern Ghats metarnotphic belt, covering both the areas, is considered to be the source of these beach placer minerals

Value Addition of Indian Iron Ore Fines by Column Flotation - Few Case Studies

The Government of India highlighted Processing and utili-zation of iron ore fines as a prerequisite to meet the domestic raw material requirements for the projected 110 million tonnes of domestic steel production by the year 2019-20 in the National Steel Policy announced in Nov-ember 2005. This would require 190 million tonnes of iron ore. The depletion of high grade iron ore and increased generation of fines during mining and handling and demand for high grade iron ore fines for export has necessitated the processing of low to medium grade fines. The R&D efforts undertaken at NML-Madras Centre, India in this direction have been highlighted. Flotation in general and Column Flotation in particular appear to be promising in addressing this problem. This would also mitigate the environmental problem created by the dumping of huge quan-tities of low and medium grade iron ore fines. Three case studies involving iron ore fines of varying silica and alumina content from Goa and Bellary-Hospet regions of India were discussed. The results clearly indicate the feasibility and significance of flotation process in treat-ing the fines to obtain marketable concentrates

Alteration characteristics of manavalakurichi beach placer illmenite, Tamilnadu.

The mineralogy and alteration characteristics of beach placer ilmenite from the Manavalakurichi coast were investigated by optical microscopy and electron probe microanalysis. Mineral chemistry by electron probe micro-analysis indicated ;enrichment of TI02, MgO, AI203, Cr203, Si02. K20, V205,. CaO and Na20 in the altered products ofilmenitc:. while there was a loss of iron oxide, maganesc oxide and zinc oxide from the ilmenite grains during weathering leading to leucoxen

Beneficiation of a Low Grade Limestone by Flotation Column

Beneficiation of a Low-grade limestone sample from Salem, Tamilnadu was carried out by pilot scale flotation column. Mineralogical studies have revealled that quartz, freldspar, pyroxene and biotitic as gangue minerals while pyrite, in trace quantitiew, appear as opaque along with dominating calcite. Reverse flotation was tried using two different commercial amines viz. Chem750F and Flotamine-D. The studies clearly suggest that it is possible to produce a limestone concentrat assying around 96-97% of CaCO3 with less than 1% SiO2

Reverse flotation studies on an Indian low-grade iron ore slimes

The present investigation deals with the recovery of iron values from the screw classifier overflow slimes from an iron ore washing plant by means of reverse cationic flotation as an alternate to direct anionic flotation. Selectivity index, an indicator of separation efficiency, was chosen as the response parameter for optimizing the quantity and evaluating a series of generically same but chemically different cationic collectors used in reverse flotation and for further optimization of other flotation process parameters. In the optimization, the main variables investigated were percent solids, collector and depressant dosage. An increase in the iron content of the concentrates is obtained with concomitant reduction in Si02 and Al203levels

Beneficiation of Gold Ore by Flotation Column: A Pilot Scale Study

During the first phase of the study, laboratory size flotation column was installed within the premises of flotation plant of M/s BGML to study the amenability of column technology for the benefIciation of gold. Encouraged by the results, semi-commercial flotation column designed and developed by NML Madras Centre was installed in the flotation circuit to evaluate its performance and also to instil confidence. The results obtained both by laboratory and semi-commercial size flotation columns clearly indicated that the columns can perform better than the conventional cells. It was observed that high quality concentrates assaying 40 to 50 ppm of gold could be achieved by flotation column, whereas conventional cells could produce hardly 10 to 15 ppm of gold concentrates

Processing of iron ore fines by column flotation – Part I & part II

The Government of India highlighted Processing and utilization of iron ore fines as a pre-requisite to meet the domestic raw material requirements for the projected 110 million tonnes of domestic steel production by the year 2019-20 in the National Steel Policy announced in November 2005. This would require 190 million tonnes of iron are. The depletion of high grade iron are and increased generation of fines during mining and handling and demand for high grade iron are fines for export has necessitated the processing of low to medium grade fines. The R&D efforts undertaken at NML-Madras Centre, India in this direction have been highlighted. Flotation in general and Column Flotation in particular appear to be promising in addressing this problem. This would also mitigate the environmental problem created by the dumping of huge quantities of low and medium grade iron are fines. Three case studies involving iron ore fines of varying silica and alumina content from Goa and Bellary-Hospet regions of India were discussed. The results clearly indicate the feasibility and significance of flotation process in treating the fines to obtain marketable concentrates

Mineralogy and Geochemistry of a low grade iron ore sample from Bellary-Hospet sector, India and their implications on beneficiation.

Detailed studies were conducted on iron ores of Bellary-Hospet sector using microscope, XRD, TG, and EPMA techniques. The results indicate that hematite is the major iron oxide mineral with minor amounts of goethite, magnetite, martite and limonite with quartz and clay as major gangue. There is no evidence of the presence of any iron silicate and iron carbonate minerals. Trace amounts of pyrite were observed under the microscope and is the only iron sulphide phase. Microscopic studies also indicated that most of the quartz grains are present as inclusions within the hematite and magnetite grains. XRD studies revealed hematite as the major mineral with subordinate amounts of goethite, quartz and kaolinite confirming to the microscopic findings. Qualitative mapping and quantitative EPMA studies on these ores indicated the presence of gibbsite as the only alumina bearing phase and apatite as phosphorous bearing mineral. Traces of alumina, present as solid solution in the iron oxide minerals, has also contributed Al2O3 to the ores. Electron microscopic studies revealed that gibbsite grains are in the size range of 10 to 50 microns and are intimately and intricately associated with the iron oxide phases. Major elemental analyses of 47 representative iron ore samples of various types were analyzed to deduce the source of silica and alumina’s contributing phases in the ore and their interrelationships. The geochemistry data revealed negative correlation of Fe2O3 with silica and alumina thus indicating there is no iron silicatephase as well as alumina contribution from iron oxide minerals in the form of solid solution is insignificant. Positive correlation of silica with alumina indicates that the clay is the major contributing mineral for both the silica and alumina phase and presence of gibbsite. The role of gangue minerals and the interrelationship of silica, alumina and iron oxide, with reference to beneficiation are discussed. Jigs and heavy media cyclones for this type of ores can be used but at the cost of poor yield because of complex nature of alumina distribution. As long as alumina and silica mineralization is not too fine and the ore composed of magnetite/hematite with coarse grained quartz, magnetic route is the most effective. Since the quartz grains are too fine and their distribution is very complex for the Bellary-Hospet sector ores, flotation in general and column flotation in particular seems to be more effective