H Khorrami; B Rezai; A Amini; F Mossavari
Abstract
Mineralogical and liberation studies are the most important parameters used in the selection of separation. An investigation was carried out to identify the various types of minerals present in fluorite ore and to determine the suitability of the methods for its preconcentration and final concentration. ...
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Mineralogical and liberation studies are the most important parameters used in the selection of separation. An investigation was carried out to identify the various types of minerals present in fluorite ore and to determine the suitability of the methods for its preconcentration and final concentration. The sample has been evaluated and characterized by ore microscopy, x-ray diffraction, chemical analysis and also approximate mineralogy based on chemical analysis and Microscopic studies and also the texture characteristics such as grain size, Situation of infor locked particle and their arrangement in the ore body were also investigated. According to surveys conducted this ore contains of fluorite (40.52%), calcite (24%), quartz (20%), smitsonite (8%), galena (2%), clay minerals (3%), barite (1%) and goethite (0.6%). Carbonate phases is two parts sparry calcite, micrite to microsparate piece has been observed. Quartz, in the form of microcrystalline with limonite and goethite oxide of stained has been observed. The liberation degrees of crushed ore in different size fractions was estimated by the Counting method of showed that for fluorite (1000 μm), Calcite (100 μm) and quartz (90 μm) of fluorite in size 100 mesh (150 μm) with quartz (36%) and calcite (23%) were determined. The size fraction of -600, +425, can be assessed for gravity concentration as a preconcentration process and for the size fraction -150,+75 μm for flotation.
S. Khoshjavan; B. Rezai; A. Amini
Abstract
In this research, processing of Dalir area phosphate ore was investigated for reduction of its gangue minerals such as carbonates (mainly calcite and poorly dolomite) and silicates minerals. According to characterization studies, phosphate mineral content of the ore was sedimentary collophane mineral ...
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In this research, processing of Dalir area phosphate ore was investigated for reduction of its gangue minerals such as carbonates (mainly calcite and poorly dolomite) and silicates minerals. According to characterization studies, phosphate mineral content of the ore was sedimentary collophane mineral and the predominant constituents of the gangues were calcite and quartz. Liberation degree of phosphate mineral determined by using microscopic and sink and float tests to be 140 µm. Primary flotation tests (un-pre-concentrated) results did not have desirable grade and recovery. So, at first step, phosphates samples was subjected to calcination and scrupping process. After scrupping and removing calcium and magnesium oxide, anionic and cationic flotation tests were done. By using a combination methods (calcining, scrupping and flotation) the grade and recovery of final concentrate reaches to 31% and 62% respectively. Finally a Lab-flowsheet of processing was suggested
S. Khoshjavan; B. Rezai; A. Amini
Abstract
In this research, characterization studies of sedimentary phosphate rock from Zanjan Dalir area with respect to processing are investigated. According to mineralogical studies, phosphate ore (Collophane 28.13%), sedimentary mineral and the predominant constituents of the gangues were Calcite (43.53%), ...
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In this research, characterization studies of sedimentary phosphate rock from Zanjan Dalir area with respect to processing are investigated. According to mineralogical studies, phosphate ore (Collophane 28.13%), sedimentary mineral and the predominant constituents of the gangues were Calcite (43.53%), Quartz and Dolomite (4.65%). Main composition of phosphate rock were P2O5 (11.9% wt), CaO (36.36% wt), SiO2 (24.49% wt) and MgO (1.01% wt). Microscopic studies showed that apatite pletts had inclusions of Calcite and Quartz (about 15-70 microns). Content of inclusions was considerable. Mineralogy texture is very complicated. Liberation degree determined by grain counting (with optic microscope) and sink and float test methods. From The results of liberation degree studies can be inferred that in dimension about 140 microns about 96% of phosphate particles librated. In desliming step about 8.2% of total phosphate was removed. Optimum grinding time to reaching liberation of phosphate particles was obtained about 10 min and 30 second. Organic material determined by heating method (about 1.66% wt). Scanning electron microscopy studies showed that inclusions and organic materials existed. Specific gravity of phosphate particles and gangues difference was low. Based on the mentioned studies, effective method for processing of phosphate minerals from carbonate and silicate impurities is suggested flotation method.
A. Amini; sh. Mehrabian
Abstract
All the earthquakes are transient and nonstationary. For lack of alternatives, in seismology as well as earthquake engineering, most data are still processed by using the Fourier analysis. The most difficulties in the Fourier spectral analysis are associated with nonlinearity and non-stationary nature ...
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All the earthquakes are transient and nonstationary. For lack of alternatives, in seismology as well as earthquake engineering, most data are still processed by using the Fourier analysis. The most difficulties in the Fourier spectral analysis are associated with nonlinearity and non-stationary nature of the data. Such methods cannot reveal the detailed information in the dispersion properties, the wave form deformation, and the energy-frequency distribution. In this study, a new technique based on the time-domain empirical mode decomposition has been explained, which enables us to analyze both short-term information and long-term structures in seismic waves. It provides insight into long term memory and local time behavior of seismic signals. Oscillation modes of Earthquakes and Explosions are compared to each others, relationships between each group of the same data and differences between different data are obtained based on the produced IMFs. With respect to the advanced methods such as discrete stochastic non-Markov process it has been shown that this technique gives better identification. Plotting the maximum frequency of different IMFs via position of them, gives an effective identification tool. In this study first the technique is explained and then the obtained results are illustrated and discussed.
M. Moazemi; B. Rezai; A. Amini
Abstract
In this research firstly ore characterization studies from ore dressing point of view have been conducted and then increase in module ratio i.e. ratio of Al2O3 to SiO2 of the bauxite samples from Boolboolieh area of Kerman province investigated by the means of ore dressing techniques. Obtained ...
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In this research firstly ore characterization studies from ore dressing point of view have been conducted and then increase in module ratio i.e. ratio of Al2O3 to SiO2 of the bauxite samples from Boolboolieh area of Kerman province investigated by the means of ore dressing techniques. Obtained results from ore characterization studies revealed diaspore and hematite were major mineral phases and Al2O3, Fe2O3 and SiO2 contents of head sample were 36.6, 27.02 and 20.32 % respectively and consequently module ratio was determined to be 1.8. Mineralogical studies on all prepared microscopic sections show clastic texture that contains pisolith and oolith particles inside microcrystalline matrix formed from hematite, clay minerals and fine bauxite particles. In ore dressing studies, physical separation methods, selective grinding, heavy media separation and tabling have been investigated. Obtained results from selective grinding revealed that alumina to silica ratio increases from 1.8 to 1.91 with alumina recovery about 69.3 %. Heavy Liquid separation tests proved that alumina to silica ratio increases to 3.32 with 64.02% alumina recovery by adjusting heavy liquid density to 3.22. Tabling tests approved increase in concentrate module ratio to 2.64 with reduction in alumina recovery to 21%.
M. Moazemi Goodarzi; B. Rezaei; A. Amini
Abstract
In this paper, iron removal studies on high iron diasporic bauxite by thermochemical treatment was investigated for the first time. For this purpose, bauxite samples were calcined in temperatures between 600 and 1100°C and then leached with hydrochloric acid. Obtained results revealed, in spit of ...
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In this paper, iron removal studies on high iron diasporic bauxite by thermochemical treatment was investigated for the first time. For this purpose, bauxite samples were calcined in temperatures between 600 and 1100°C and then leached with hydrochloric acid. Obtained results revealed, in spit of gradual decrease in both iron and aluminum extraction with rising calcination temperature, iron extraction to aluminum extraction is selective at calcination temperature above 900°C. Leaching studies of calcined sample at 900°C proved that leaching temperature is the most important parameter for iron dissolution in acid and rising leaching temperatures from 20 to 95°C increases iron extraction over 70%. The other optimum parameters are: leaching time120 minutes, acid concentration 50% V/V, grinding size of 210 µm, pulp density of 15% solid by weight. As a result of optimizing parameters, 96.5% of bauxite iron content removed successfully with 88.5% aluminum recovery and solid residue iron content, i.e., the obtained concentrate, decreased from 27.02 to 1.59%.
