Designing Process for Concentration of a Low Grade Copper Ore

The paper deals with the results of chracterisation and flotation studies carried out on a low grade and complex copper ore sample with a view to design process for its concentration. Flotation studies were carried out under varying conditions of process parameters. Effects of gran-ulametry of the feed, dosage of sodium iso-propyl xanthate as collector, pH and gangue depressant dispersant were studied. Sulphidization technique and use of potassium octyl hydroxamate as auxiliary collector for flotation of oxidised minerals was observed to enhance copper recovery. Use of sodium silicate as depressant/dispersant for sili-ceous gangues helped in improving grade of copper conce-ntrate. Rougher followed by multi-stage cleaning were found necessary to produce a high grade copper concentrate. Based on the studies undertaken the process was designed for concentration of the low grade copper ore sample

Ammonia Gas Sensing Characteristics of Spin Coated Polyaniline Films

The conductive layer of emeraldine base polyaniline (PANI) thin film coated on silicon has successfully tested for ammonia. The bulk PANI powder was synthesized by oxidative polymerization of aniline using ammonium peroxidisulfate in an acidic medium and dissolved in N-methyl pyrrolidone (NMP) for coating the thin film on Silicon using spin coater. FTIR, UVvisible, and SEM were used to characterize the PANI thin film. The electrical conductivity of the PANI films has been studied by measuring the change in electrical conductivity by Four Probe Set up on exposure to ammonia gas (NH3) at different concentrations from 100 ppm to 500 ppm. margin

Sarmentine, a natural herbicide from Piper species with multiple herbicide mechanisms of action

Sarmentine, 1-(1-pyrrolidinyl)-(2E,4E)-2,4-decadien-1-one, is a natural amide isolated from the fruits of Piper species. The compound has a number of interesting biological properties, including its broad-spectrum activity on weeds as a contact herbicide. Initial studies highlighted a similarity in response between plants treated with sarmentine and herbicidal soaps such as pelargonic acid (nonanoic acid). However, little was known about the mechanism of action leading to the rapid desiccation of foliage treated by sarmentine. In cucumber cotyledon disc-assays, sarmentine induced rapid light-independent loss of membrane integrity at 100 µM or higher concentration, whereas 3 mM pelargonic acid was required for a similar effect. Sarmentine was between 10 and 30 times more active than pelargonic acid on wild mustard, velvetleaf, redroot pigweed and crabgrass. Additionally, the potency of 30 µM sarmentine was greatly stimulated by light, suggesting that this natural product may also interfere with photosynthetic processes. This was confirmed by observing a complete inhibition of photosynthetic electron transport at that concentration. Sarmentine also acted as an inhibitor of photosystem II on isolated thylakoid membranes by competing for the binding site of plastoquinone. This can be attributed in part to structural similarities between herbicides like sarmentine and diuron. While this mechanism of action accounts for the light stimulation of the activity of sarmentine, it does not account for its ability to destabilize membranes in darkness. In this respect, sarmentine has some structural similarity to crotonoyl-CoA, the substrate of enoyl-ACP reductase, a key enzyme in the early steps of fatty acid synthesis. Inhibitors of this enzyme, such as triclosan, cause rapid loss of membrane integrity in the dark. Sarmentine inhibited the activity of enoyl-ACP reductase, with an I50app of 18.3 µM. Therefore, the herbicidal activity of sarmentine appears to be a complex proces

Recovery of Values from Mining and Industrial Wastes

Studies were carried out on the recovery of valuesfrom wastesfrom magnesite mines and sponge iron plant. Rougher flotation followed by cleaning of the rougher float resulted in decreasing the silica content to below 1 % in thefinal concentrate from the magnesite mines 'waste dump' sample. The apparent porosity, bulk density and water absorption of the pelletsfired at 1750°C were 3.4-4.9%, 3.25 gm/cc and]-1-5% respectively. Results on the 'altered dunite rock'sample from the magnesite mines was also encouraging. Considering the beneficiation characteristics of coal and the associated impurities in the ESP-dust' and 'coal-char'samplesfrom sponge iron plant, a combination of magnetic separation and froth flotation was adopted for their processing. In the f nal products the ash could be brought down to -- 33 %

Beneficiation Studies on Low Grade Chromite Ores using Multi Gravity Separator

Chromite is the most important mineral of chromium and is essential raw material for the production of special steel and ferrochrome alloys. From the mineral conservation point of view it is necessary to maximize the utilization of low grade ores and minimize the high grade ore consumption. Generally low grade and finely disseminated ores need fine grinding, posing problem in recovering of chromium values. In many cases the finely ground feed does respond well to process involving simple gravitational force for recovering the valuable minerals, hence processing under higher G-force may be worth investigating. Multi gravity separator (MGS) is such an equipment which uses enhanced gravitational force for processing ultrafine particles. In the present study, a laboratory Mozley MGS was used for upgrading a low grade chromite ore assaying 26.8% Cr2O3. The chromite ore under study contained gangue minerals such as olivine, serpentine, chrysotile and magnetite. Liberation study on different size fractions reveals that 80% liberation occurs at a size 150μm. Considering the mineralogical information, as received ore was ground separately to three top sizes, namely -250μm, -150μm and -75μm respectively and were subjected to concentration using MGS separately. The other parameters such as drum speed and wash water flow rate were also varied to get the optimum condition with respect to grade and recovery. Under the optimum operating conditions, low grade chromite sample was upgraded to 41.1% Cr2O3 with 62% recovery using MGS

Designing Process for Beneficiation of Low Grade Iron Ore Samples from Orissa

The paper deals with the results of characterization and beneficiation studies carried on low grade iron ore samples from Orissa. Beneficiation of the two individual samples and their compostite based on gravity and magnetic separation techniques resulted in products with varying yield and grade of the products.The results of laboratory studies were validated through pilot scale trials. Based on the studies undertaken process was designed for bene-ficiation of the composite sample, comprising 60% S I and 40% S2, to a high grade product assaying over 65% Fe. Detailed material balance for the designed process was also undertaken

Designing Flotation Process for Lead-Zinc ore from Nepal

The paper deals with the development of a process based on froth flotation for the concentration of a lead-zinc ore from Ganesh-Himal region of Nepal. A detailed chara-cterisation and flotation studies were carried out under the varying process conditions. The ore was predomionantly made up of sphalerite and pyrite in association with sub-ordinate amount of galena, minor amount of pyrrhotite and chalcopyrite with dolomite as the major gangue. Under the optimum process conditions the rougher lead and zinc recovery were 96.3% and 90.8% respectively. Regrinding followed by three stage cleaning of the lead rougher conc-entrate resulted in cleaner concentrate assaying 79.11 % Pb with 83.4% recovery. Similarly two stage cleaning of the zinc rougher concentrate produced cleaner concentrate analysing 60.08% Zn with 80.4% recovery. Based on the studies undertaken a process flow-sheet for the conc-entration of the ore to individual lead and zinc concen-trates has been recommended

Characterization and its implication on beneficiation of low grade iron ore by gravity separation

Studies were undertaken on low grade iron ore sample from Noamundi iron ore mines. The objective of this study was to examine the possibility of the physical beneficiation of low grade iron ore sample by physical methods for the blast furnace route of iron production. The present investigation relies on petrography and ore mineralogical characterization, ore textures (primary, secondary, metamorphic), liberation characters and its impact on the mineral beneficiation methods to produce quality concentrate. The geological characters, alteration mineralogy, morphometric variation, ore microscopy (using model microscope with transmitted and reflected light) and thereby understanding the genesis has given proper insight into the occurrence of various minerals. In addition to this, representative samples were employed for detailed investigation by using XRD, SEM-EDS and cathodoluminescence (CL) studies for confirmation of major as well as minor ore minerals and associated gangue minerals. Investigations suggest that lateritic iron ore samples obtained from the study area are composed of hematite (two generations), goethite (two generations) and limonitic material (younger generation) in association with major gangue minerals such as clay minerals (kaolinite, illite), bauxitic minerals(gibbsite, boehmite and diaspore), cryptocrystalline silica(japer, chert) and crystalline quartz as well as apatite and collophane. Fair liberation obtained below 74 micron size. It was interesting to find that inspite of the complex mineralogy of iron ore, beneficiation results using gravity separation like multi gravity separator (MGS), particularly in finer size ranges was encouraging. The result of ore-gangue mineralogical studies were found quite useful in evaluating the separation efficacy of gravity separation process. The process mineralogical data corroborated well with beneficiation results

Building human capital of small scale farmers: a Coalition approach

Small and marginal farmers benefited from the coalition approach in accessing some of the resources such as technology, credit and markets. Improvement in their livelihood through enhanced production and higher margins in bulking, storing and selling their produce solely depended on the strength of collective action