Characterization study was conducted to confirm the mineral phases and their relative distribution in the studied sample.Two stage conventional cell flotation studies were carried out to beneficiate the limestone plant rejects.Column flotation can be utilized for better grade and recovery of the concentrate.The developed process can produce required grade limestone concentrate for cement industries.
Investigations were carried out on lime stone rejects (1mm) generated at a lime stone washing plant in southern India. These rejects contain 12.09% CaO, 2.95% MgO, 10.73% Al2O3, 4.99% Fe2O3, 43.05% SiO2 and 24.92% LOI. Mineralogical studies including SEM-EDAX, XRD, FTIR and TGA were conducted to confirm relative distribution of minerals in the flotation feed and products. These studies revealed that feed sample consists of quartz and calcite as the major minerals with minor amounts of montmorillonite and dolomite whereas flotation concentrate dominantly consists of calcite, and tailings mostly of quartz and montmorillonite. A commercial grade sodium silicate, oleic acid and MIBC were used as depressant, collector and frother respectively in flotation studies. The effects of different operating parameters were evaluated for both conventional and column flotation. Two stage conventional cell flotation results indicate that a cleaner concentrate of 42.50% lime (CaO) content could be obtained at a yield of 15.65%. The lime (CaO) content of the concentrate was further enhanced up to 44.23% at 20.73% yield using single stage column flotation. The column flotation is more efficient in comparison to the conventional cell for treating this sample. A process flowsheet was developed to treat these rejects based on the studies carried out. This process can minimize the waste generation and the concentrate generated during this process can be directly utilized in the Indian cement industries.
Attempts have been made to recover the additional calcium values from the limestone plant rejects by flotation as a beneficiation technique. The characterization study indicates, quartz and calcite are the major minerals present in this sample, while concentrate is highly upgraded with calcite content, by rejecting mostly quartz and clays in the tailing. Systematic studies have been conducted at different operating conditions using conventional cell and column flotation. A concentrate of 42.50% CaO content at an yield of 15.65% is produced by two stage conventional cell flotation from the limestone rejects with 12.09% CaO. Further enhancement in grade and yield of the concentrate could be achieved using single stage column flotation. The process flowsheet developed can be adopted to treat these rejects for production of cement grade concentrate.
Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 1% in the concentrate so that it became satisfactory for use in the paper or rubber industries. The limestone sample was crystalline and constituted primarily of calcite that contained quartz, feldspar, pyroxene, and biotite as gangue minerals. Quartz is the major silicate gangue whereas feldspar, pyroxene, and biotite exist in minor to trace quantities. Traces of pyrite were also observed within the sample. A reverse flotation process was adopted where the silicate gangue minerals were floated using two different commercial cationic collectors: Chem-750 F or Floatamine-D. The studies clearly suggest it is possible to produce a limestone concentrate assaying around 9697% CaCO3 containing less than 1% SiO2. The effect of feed flow rate, percent solids, froth depth, and wash water on the grade and recovery of the CaCO3 concentrate is discussed.
Our advanced mineral washing systems aresuitable for beneficiation of lower gradelimestone ore. By reducing the cut-offgrade, we are able to deliver significantefficiencies to your mining operation.
Lower Grade Ores are treated as waste and are dumped in the mines,occupying huge space. It is also an environmental hazard.CDE Cement Tech transforms these wastes to recover usable productsfor use in cement making. Through intense scrubbing and wetclassification almost 70-90% of the waste is recovered as high valuemineral.
Our modular designs can accept both freshly generated fines from thecrushing circuit as well material from old dumps. Depending on the feedgrade, CaO content can be improved significantly and the silica level keptwithin acceptable limits.
A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, K2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data.
Vijayakumar T.V., Rao D.S., Rao S.S., et al. (2005) Beneficiation of a low grade limestone by flotation column. In Proc. of Int. Sem. on Mineral Processing Technology (eds. Venugopal R., Sharma T., Saxena V.K., and Mandre N.R.) [M]. pp.194207. TATA Mc-Graw-Hill Publishing Company Limited, New Delhi.
Rao, D.S., Vijayakumar, T.V., Prabhakar, S. et al. Geochemical assessment of a siliceous limestone sample for cement making. Chin. J. Geochem. 30, 3339 (2011). https://doi.org/10.1007/s11631-011-0484-8