Hamed Haghi | University of Tehran (original) (raw)

Papers by Hamed Haghi

This investigation was undertaken to assess the possibility of increasing the copper recovery by ... more This investigation was undertaken to assess the possibility of increasing the copper recovery by microbial action using mesophilic bacteria in Sarcheshmeh heap leaching. Mesophilic microorganisms are active in 30-45 ºC and have been used for oxidizing sulfide minerals. Feed samples were provided from Sarcheshmeh heap leaching located in Kerman province, Iran. Copper grade of feed samples were 0.23%. Leaching tests carried out by means of laboratory shake flask and mesophilic bacteria as leaching reagent. Mixture of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans were used with different ratios. Two levels full factorial design (FFD) with four variables (pH, medium type, bacteria ratio and Fe2+ concentration) were applied. The highest copper recovery (66.38%) was obtained during 25 days with addition of 1.5 g/l Fe2+ , Norris medium and at pH level of 1.6.

In this research the effect of fine particles (less than 10 µm) removal were investigated with st... more In this research the effect of fine particles (less than 10 µm) removal were investigated with statistical methods. Two types of sample (with and without fine particles) were provided from Esfordi Phosphate Plant, located in Yazd province, Iran. Two series of flotation tests were carried out based on L 9 orthogonal array Taguchi design (including 4 variables in 3 levels). Experiment variables were depressant and collector dosage, solid percent and pH. Also multivariate regression was used for data analysis. Regarding to flotation tests, the best product of samples containing fine particles had 31.48% P 2 O 5 with 83.67% P 2 O 5 recovery. These values for deslimed samples were 33.10% and 88.12% respectively. Considering maximizing P 2 O 5 grade and its recovery, predicted values of product for samples containing fine particles are 30.07% and 90.09% respectively. Optimized levels in this condition for depressant and collector dosage, solid percent and pH are 420 g/t and 560 g/t, 18% a...

Silica is the most important raw material in glass industry. In this paper, decreasing of iron co... more Silica is the most important raw material in glass industry. In this paper, decreasing of iron content (Fe2O3) using agitated and vat acidic leaching were investigated. Silica sample were provided from Shenin mine located in Qazvin province, Iran. Two levels full factorial design (FFD) and multivariate regression methods were applied. Silica and hematite grades of feed were 93.75% and 0.44%, respectively, that is not utilizable in glass industry. For vat leaching, experiment variables were leaching time (A), acid dosage (B) and dithionite dosage (C). BC, C and B factors had most effects on response (hematite grade of product) by having 38.06%, 27.50% and 24.36% respectively. The best result of vat leaching experiments was obtained with 24 kg/t acid and 10 kg/t dithionite. Hot agitated leaching tests were carried out by H2SO4 and HCl. For development of model, linear multivariate regression was applied. In this case, variables were feed type, acid type, acid concentration, temperatur...

This investigation was undertaken to assess the possibility of ash and sulfur removal by microbia... more This investigation was undertaken to assess the possibility of ash and sulfur removal by microbial action of high sulfur-content coal. Thiobacillus ferrooxidans and Thiobacillus thiooxidans have been used for biodesulfurization of coal. Feed samples were provided from Tabas coal mine located in Yazd province, Iran. The sample contained 28.80% ash and 2.30% sulfur. Flotation tests were implemented to optimize the effective parameters in these cells which were constant during bio-flotation tests. According to the results, obtained from various tests using Taguchi orthogonal array design (L 27), the values of optimized parameters were pH at 7, 1000 g/t gas oil as a collector, 10% solid content, 15 min conditioning time, 100 g/t MIBC as a frother and 800 rev/min rotor speed. Bio-flotation tests are carried out by means of laboratory double discharge cell and mesophilic bacteria as depressant reagent using above mentioned optimized parameters. The bio-flotation experiments were conducted...

Particulate Science and Technology

Minerals

Removal of iron impurities in silica is one of the most important issues in the glass industry. T... more Removal of iron impurities in silica is one of the most important issues in the glass industry. The most noted impurities are surface coating and staining on silica particles; additionally, some cases of inclusions are observed. The prepared silica sample, for this research work, mostly was in the size range of 106-425 µm. Mineralogical studies indicated the existence of goethite, hematite, limonite and pyrite as the major iron impurities. The poor liberation degree of silica particles from clays encouraged the use of ultrasound irradiation to improve the efficiency of reverse flotation. The head sample contained 96.98% SiO 2 , 0.143% Fe 2 O 3 , 1.52% Al 2 O 3 , and 0.088% TiO 2 ; Fe 2 O 3 had to be reduced to below 0.04%. The reverse flotation tests were carried out with and without indirect ultrasound irradiation. The lowest Fe 2 O 3 grade of the flotation yield was 0.058% and this was achieved using 2000 g/t of C 4 collector with 15 min conditioning at neutral pH. C 4 consisted of Aero 801, Aero 825, oleic acid and sodium oleate at equal dosage. As a result, a flowsheet was developed to include indirect ultrasound irradiation with reverse flotation and two stages of dry high intensity magnetic separation. In conclusion, the best product contained 98.43% SiO 2 , 0.034% Fe 2 O 3 , 0.90% Al 2 O 3 and 0.051% TiO 2 .

ÖZET Fosfat cevherlerinin zenginleştirilmesinde karşılaşılan çevresel problemler vardır. Fosfat c... more ÖZET Fosfat cevherlerinin zenginleştirilmesinde karşılaşılan çevresel problemler vardır. Fosfat cevherlerinin konsantrasyonunda kullanılan yöntemlerden ikisi flotasyon ve liç yöntemleridir. Bu yöntemlerden flotasyon yönteminin artıkları katı tanecikler, ağır metal iyonları ve kalıntı olarak flotasyon reaktifleri, liç yönteminin artıkları ise kalsiyumlu organik tuzların çökeltilerini içermektedirler. Bu artıklar özel olarak dikkat gerektiren, çevreye zarar verebilme potansiyeline sahiplerdir. Bu bildiride, söz konusu iki yöntem ve bu yöntemlerin artıklarının olası yeniden değerlendirilebilirlik-zenginleştirilebilirlikleri üzerinde durulmuştur. Günümüzde İran'da fosfat zenginleştirilmesi flotasyon yöntemi kullanılarak gerçekleştirilmektedir. Ancak diğer yöntemlerin de kullanılması yönünde oldukça büyük bir ihtiyaç vardır, ve bu durum yöntemlerin çevresel etkilerinin detaylı olarak araştırılması konusunun önemini vurgulamaktadır.

In this research work, it was investigated to reduce iron contents (Fe 2 O 3) of dry high intensi... more In this research work, it was investigated to reduce iron contents (Fe 2 O 3) of dry high intensity magnetic separation (DHIMS) mid product, silica sample from Shenin mine, with hot agitated leaching by means of sulfuric acid and oxalic acid. Leaching process feed sample contains 97.03% SiO 2 and 0.12% Fe 2 O 3. For comparison of this two acids (sulfuric and oxalic) dissolution ability, full factorial design (FFD) and multivariate regression methods were used. Experiment variables are acid type (A), temperature (B) and leaching time (C). A model from full factorial design were represented with over than 99% confidence interval and 0.42% noise probability. The best product of leaching with Oxalic and sulfuric acid were achieved at high level of Temperature and time. In this condition for oxalic acid silica and hematite grade were 98.1%, 0.048% respectively. Also for sulfuric acid, silica and hematite grade were 98.2%, 0.054% respectively.

The flotation performance (recovery and grade) of apatite particles in a Esfordi Phosphate Comple... more The flotation performance (recovery and grade) of apatite particles in a Esfordi Phosphate Complex was investigated as a function of collectors' ratio and dosage, pH, depressant dosage, depressant conditioning time, collectors conditioning time, frothing time and solid percent. The experiments were conducted according to a Taguchi orthogonal array design (L27). The collected data were analyzed by using DX7.0, Minitab 14.0 and WinRobust 1.02 softwares for evaluation the effect of each parameter on the optimization criterion. The highest P2O5 recovery and grade obtained with collectors' ratio and dosage of 10% and 630 g/ton, pH 9, depressant dosage of 440 g/ton, depressant conditioning time of 7 minutes, collectors conditioning time of 3 minutes, frothing time of 5 minutes and 22% solid percent.

In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample whic... more In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample which was provided from Shenin Silica Mine using conventional flotation. This silica contains 93.75% SiO2, 0.44% Fe2O3, 2.78% Al2O3, and 0.08% TiO2 and the Fe2O3 has to be reduced to about 0.1% or less than 0.02%. Mineralogical studies and XRD analysis indicated the presence of Hematite, Pyrite, and Goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections yielded that the degree of freedom of silica is more than 80% in -300+212 microns size fraction. Due to low weight content of gangue minerals (about 6%) reverse flotation were applied. Anionic collectors (Aero 800 series) were selected for these experiments. 23 experiments were carried out by means of conventional Denver flotation cell. Variables were feed type (wet rod mill product (with or without desliming and elimination of free iron) or scrubber product with de-sliming), pH, collector type and dos...

The removal of Copper from a dilute synthetic wastewater (10mg/l ) was studied by ion flotation a... more The removal of Copper from a dilute synthetic wastewater (10mg/l ) was studied by ion flotation at laboratory scale. Anionic sodium dodecyl sulfate (SDS) was used as a collector and ethanol as a frother. Different parameters such as pH, collector and frother concentrations, foam height and bubble size distribution were tested to determine the optimum flotation conditions. In order to check the effect of bubble size distribution, a micro bubble generator was designed. The bubbles that are generated in this way have a dimensional distribution ranging from 10 to 100 microns. Metal removed up to about 93% and water was recovered 13% by using an intermixing method of coalescence phenomena (combined flotation by micro-bubbles and normal size bubbles generated mechanically) in a Denver type flotation machine, at low pH. The flotation time fell considerably at 37.5% when the bubble coalescence phenomenon was used.

In this research work, it was attempted to reduce the iron contents (Fe2O3) in relatively low gra... more In this research work, it was attempted to reduce the iron contents (Fe2O3) in relatively low grade silica sample which was obtained from Shenin silica mine, using magnetic separation. The prepared sample contained 93.75%SiO2, 0.44%Fe2O3, 2.78%Al2O3, and 0.08%TiO2 and the Fe2O3 had to be reduced to less than 0.08%. Mineralogical studies and XRD analysis indicated the presence of Hematite, Pyrite, and Goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections demonstrated that the degree of freedom of silica is more than 80% in -300+212 m size fraction. After primary stages including crushing, milling, scrubbing and de-sliming, various methods such as low intensity magnetic separation (LIMS), high gradient magnetic separation (WHGMS) and dry high intensity magnetic separation (DHIMS) were applied to find out that which process would be appropriate for the elimination of iron impurities from this sample. Different experiments were carried out on t...

In lead-zinc sedimentary deposits presence of carbonaceous shales is detrimental to the concentra... more In lead-zinc sedimentary deposits presence of carbonaceous shales is detrimental to the concentration of zinc and lead in the flotation process. Koushk is one of the largest zinc and lead complexes in Iran. The most valuable minerals are galena and sphalerite and carbonaceous material is present among the gangue minerals. Flotation in the absence of collector and prior to galena flotation, called pre-flotation, is employed to remove some of the organic carbon, black shale, from the flotation feed. These contents are naturally hydrophobic. The main issue is low selectivity of carbonaceous against zinc causing 15% zinc and 16% lead loss during pre-flotation process. Reducing the loss during pre-flotation using chemical methods is the first reasonable solution. Vast variety of highly recommended reagents for the problem, were tested and the effective parameters were recognized by DX, data analysis software, using Design Of Experiment (DOE) methods to determine the least possible loss o...

In this research, optimization of effective parameters for increasing gold recovery in Cyanidatio... more In this research, optimization of effective parameters for increasing gold recovery in Cyanidation process was carried out on Hamzeh-Qarnein gold ore containing 0.8 ppm gold. Accordingly, the effect of parameters such as particle size (d80), pH, cyanide concentration, and leaching time on the gold recovery examined through agitation leaching tests. The results showed that gold recovery of 95.21% will be achieved if the test is carried out applying feed distribution size of d80=63µm, pH of 10.5, Cyanide concentration of 1500 ppm and 12 hour for leaching time. Consumption of cyanide and lime in optimum condition was also measured and were 1.23 kg/t and 2 kg/t, respectively. In addition, by increasing leaching time to 48 hour in the experiments gold recovery may reach up to 97.93%.

In this research, the operation of screen classifying in silica processing circuits was investiga... more In this research, the operation of screen classifying in silica processing circuits was investigated and the effect of replacement the other classifying methods on final concentrate, recovery and production rate was checked. Since the silica which is used in glass industry should have precise particle size distribution in the range of 100 to 600μm, the main problems that usually occur in screen classifying are as follows: - The target particle size distribution (according to silica standards) cannot be obtained with screens; - Application of trommel screen with casting mesh could impose high cost of repairing and maintenance; - Increasing the shut down time for maintenance and repairing causes the lower machinery availability and therefore lower annual capacity; - Fluctuation in particle size distribution because of corrosion and deterioration in casting mesh seems to be inevitable. Considering the problems of screens efficiency for achieving the certain particle size distribution, ...

Heap leaching is a simple, low-cost method of metal recovery in low grade ores, which is widely a... more Heap leaching is a simple, low-cost method of metal recovery in low grade ores, which is widely applied in the mining industry. The Hamze-Qarnein gold deposit is located in Kurdestan province with gold grade of 0.8 ppm. The mineralogical studies indicated that major gold particles characterized as native captured inside quartz particles. In the present work, the bottle roll and column leaching tests were carried out on the provided samples from the mentioned deposit in order to define related heap leaching parameters. Gold recovery, kinetic of gold dissolution, and consumption of reagent in heap leaching application were investigated. Accordingly, the parameters of particle size (d80), cyanide concentration, and duration of heap leaching on the gold recovery examined through experiments. The bottle role experiments showed that about 70% of the gold was recovered after 24 hours and the maximum recovery was 81.28% after 72 hours for the sample with aggregation size about 3.3 mm. The c...

In this research, the possibility of producing concentrate from a relatively low grade Scheelite ... more In this research, the possibility of producing concentrate from a relatively low grade Scheelite ore with total WO3 grade of 0.1% were investigated by application of shaking table. The mineralogical studies showed that Scheelite mineral was the main tungstate mineral of Nezam-Abad Ore and the appropriate liberation degree of Scheelite from waste minerals were in the range of 100-125 µm. The dominant gangue minerals were Silicate minerals. In order to optimize the effective parameters of shaking table on the grade and recovery of Scheelite, Box-Behnken design was used. The results of shaking table tests, showed that in size range of +125 -600µm with different ranges of feed sizes and two primary concentration, the product grade of 1.44% WO3 and the recovery of 70% can be achieved. Afterwards, two other concentration stages were designed and the product grade of 27.5% of WO3 with an overall recovery of 50.86% was obtained and proposed flow-sheet was developed accordingly. Keywords: Sc...

Heap leaching is one of the several alternatives for processing of precious metallic ores which i... more Heap leaching is one of the several alternatives for processing of precious metallic ores which is suitable for beneficiation of low grade ores and small deposits due to low capital and operating costs. Heap leaching of oxidized copper ore of the Meskani-Anarak deposit conducted with sulfuric acid in laboratory scale. Mineralogical studies indicated that samples are mainly composed of Malachite, Azurite and Cuprite and the Copper (Cu) grade was about 1.32%. At the first step, the bottle roll test was carried out at different particle sizes in order to determine the maximum Cu recovery and sulfuric acid consumption. The bottle roll tests showed at particle size finer than 9.51mm; the acid usage was 68.8kg/t and the maximum Cu recovery was 77.43% after 48 hours. At the second phase, the permeability test performed and irrigation rate was selected at the range of 5-7 l/h.m2. The column leaching tests consisted of columns with about 1 and 2 meter height and particle sizes ranging betwee...

Although a number of equations have been suggested for prediction of S-wave with-out direct measu... more Although a number of equations have been suggested for prediction of S-wave with-out direct measurement, but these prediction equations can be divided into three main groups. The main predicting equations define Vs from Vp which are usually used in rock mechanics and petroleum industry with limited number of Vs measurements. The correlation between such data points are used as a based for the other set in nearby geological sequences. The second group of estimations defines Vs based on other logging data such as resistivity logs, gamma ray, NPHI and etc. Sometimes a mixture of these logging data is used. This method is basically used in petroleum industry where sonic logging costs more than other logging operations and the reason for such predictions are economical concerns. The final series of predicting equations correlate Vp or Vs with some physical properties like porosity, density, quarts content, cementation degree and etc. The purpose of such equations is to identify effective...

The cores gathered from a gas storage field were selected and thin sections and XRD studies perfo... more The cores gathered from a gas storage field were selected and thin sections and XRD studies performed on the samples. Initial results showed that less than a third of the formation is composed of clay minerals and the percentage of troublesome clays (smectite group) is negligible. Using previous suggested equations for the kinetics of illite and montmorillonite, it was revealed that alkaline environment caused the gradual conversion of montmorillonite to illite during the time. Keywords: Montmorillonite, Illite, montmorillonite to illite conversion, kinetics,

This investigation was undertaken to assess the possibility of increasing the copper recovery by ... more This investigation was undertaken to assess the possibility of increasing the copper recovery by microbial action using mesophilic bacteria in Sarcheshmeh heap leaching. Mesophilic microorganisms are active in 30-45 ºC and have been used for oxidizing sulfide minerals. Feed samples were provided from Sarcheshmeh heap leaching located in Kerman province, Iran. Copper grade of feed samples were 0.23%. Leaching tests carried out by means of laboratory shake flask and mesophilic bacteria as leaching reagent. Mixture of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans were used with different ratios. Two levels full factorial design (FFD) with four variables (pH, medium type, bacteria ratio and Fe2+ concentration) were applied. The highest copper recovery (66.38%) was obtained during 25 days with addition of 1.5 g/l Fe2+ , Norris medium and at pH level of 1.6.

In this research the effect of fine particles (less than 10 µm) removal were investigated with st... more In this research the effect of fine particles (less than 10 µm) removal were investigated with statistical methods. Two types of sample (with and without fine particles) were provided from Esfordi Phosphate Plant, located in Yazd province, Iran. Two series of flotation tests were carried out based on L 9 orthogonal array Taguchi design (including 4 variables in 3 levels). Experiment variables were depressant and collector dosage, solid percent and pH. Also multivariate regression was used for data analysis. Regarding to flotation tests, the best product of samples containing fine particles had 31.48% P 2 O 5 with 83.67% P 2 O 5 recovery. These values for deslimed samples were 33.10% and 88.12% respectively. Considering maximizing P 2 O 5 grade and its recovery, predicted values of product for samples containing fine particles are 30.07% and 90.09% respectively. Optimized levels in this condition for depressant and collector dosage, solid percent and pH are 420 g/t and 560 g/t, 18% a...

Silica is the most important raw material in glass industry. In this paper, decreasing of iron co... more Silica is the most important raw material in glass industry. In this paper, decreasing of iron content (Fe2O3) using agitated and vat acidic leaching were investigated. Silica sample were provided from Shenin mine located in Qazvin province, Iran. Two levels full factorial design (FFD) and multivariate regression methods were applied. Silica and hematite grades of feed were 93.75% and 0.44%, respectively, that is not utilizable in glass industry. For vat leaching, experiment variables were leaching time (A), acid dosage (B) and dithionite dosage (C). BC, C and B factors had most effects on response (hematite grade of product) by having 38.06%, 27.50% and 24.36% respectively. The best result of vat leaching experiments was obtained with 24 kg/t acid and 10 kg/t dithionite. Hot agitated leaching tests were carried out by H2SO4 and HCl. For development of model, linear multivariate regression was applied. In this case, variables were feed type, acid type, acid concentration, temperatur...

This investigation was undertaken to assess the possibility of ash and sulfur removal by microbia... more This investigation was undertaken to assess the possibility of ash and sulfur removal by microbial action of high sulfur-content coal. Thiobacillus ferrooxidans and Thiobacillus thiooxidans have been used for biodesulfurization of coal. Feed samples were provided from Tabas coal mine located in Yazd province, Iran. The sample contained 28.80% ash and 2.30% sulfur. Flotation tests were implemented to optimize the effective parameters in these cells which were constant during bio-flotation tests. According to the results, obtained from various tests using Taguchi orthogonal array design (L 27), the values of optimized parameters were pH at 7, 1000 g/t gas oil as a collector, 10% solid content, 15 min conditioning time, 100 g/t MIBC as a frother and 800 rev/min rotor speed. Bio-flotation tests are carried out by means of laboratory double discharge cell and mesophilic bacteria as depressant reagent using above mentioned optimized parameters. The bio-flotation experiments were conducted...

Particulate Science and Technology

Minerals

Removal of iron impurities in silica is one of the most important issues in the glass industry. T... more Removal of iron impurities in silica is one of the most important issues in the glass industry. The most noted impurities are surface coating and staining on silica particles; additionally, some cases of inclusions are observed. The prepared silica sample, for this research work, mostly was in the size range of 106-425 µm. Mineralogical studies indicated the existence of goethite, hematite, limonite and pyrite as the major iron impurities. The poor liberation degree of silica particles from clays encouraged the use of ultrasound irradiation to improve the efficiency of reverse flotation. The head sample contained 96.98% SiO 2 , 0.143% Fe 2 O 3 , 1.52% Al 2 O 3 , and 0.088% TiO 2 ; Fe 2 O 3 had to be reduced to below 0.04%. The reverse flotation tests were carried out with and without indirect ultrasound irradiation. The lowest Fe 2 O 3 grade of the flotation yield was 0.058% and this was achieved using 2000 g/t of C 4 collector with 15 min conditioning at neutral pH. C 4 consisted of Aero 801, Aero 825, oleic acid and sodium oleate at equal dosage. As a result, a flowsheet was developed to include indirect ultrasound irradiation with reverse flotation and two stages of dry high intensity magnetic separation. In conclusion, the best product contained 98.43% SiO 2 , 0.034% Fe 2 O 3 , 0.90% Al 2 O 3 and 0.051% TiO 2 .

ÖZET Fosfat cevherlerinin zenginleştirilmesinde karşılaşılan çevresel problemler vardır. Fosfat c... more ÖZET Fosfat cevherlerinin zenginleştirilmesinde karşılaşılan çevresel problemler vardır. Fosfat cevherlerinin konsantrasyonunda kullanılan yöntemlerden ikisi flotasyon ve liç yöntemleridir. Bu yöntemlerden flotasyon yönteminin artıkları katı tanecikler, ağır metal iyonları ve kalıntı olarak flotasyon reaktifleri, liç yönteminin artıkları ise kalsiyumlu organik tuzların çökeltilerini içermektedirler. Bu artıklar özel olarak dikkat gerektiren, çevreye zarar verebilme potansiyeline sahiplerdir. Bu bildiride, söz konusu iki yöntem ve bu yöntemlerin artıklarının olası yeniden değerlendirilebilirlik-zenginleştirilebilirlikleri üzerinde durulmuştur. Günümüzde İran'da fosfat zenginleştirilmesi flotasyon yöntemi kullanılarak gerçekleştirilmektedir. Ancak diğer yöntemlerin de kullanılması yönünde oldukça büyük bir ihtiyaç vardır, ve bu durum yöntemlerin çevresel etkilerinin detaylı olarak araştırılması konusunun önemini vurgulamaktadır.

In this research work, it was investigated to reduce iron contents (Fe 2 O 3) of dry high intensi... more In this research work, it was investigated to reduce iron contents (Fe 2 O 3) of dry high intensity magnetic separation (DHIMS) mid product, silica sample from Shenin mine, with hot agitated leaching by means of sulfuric acid and oxalic acid. Leaching process feed sample contains 97.03% SiO 2 and 0.12% Fe 2 O 3. For comparison of this two acids (sulfuric and oxalic) dissolution ability, full factorial design (FFD) and multivariate regression methods were used. Experiment variables are acid type (A), temperature (B) and leaching time (C). A model from full factorial design were represented with over than 99% confidence interval and 0.42% noise probability. The best product of leaching with Oxalic and sulfuric acid were achieved at high level of Temperature and time. In this condition for oxalic acid silica and hematite grade were 98.1%, 0.048% respectively. Also for sulfuric acid, silica and hematite grade were 98.2%, 0.054% respectively.

The flotation performance (recovery and grade) of apatite particles in a Esfordi Phosphate Comple... more The flotation performance (recovery and grade) of apatite particles in a Esfordi Phosphate Complex was investigated as a function of collectors' ratio and dosage, pH, depressant dosage, depressant conditioning time, collectors conditioning time, frothing time and solid percent. The experiments were conducted according to a Taguchi orthogonal array design (L27). The collected data were analyzed by using DX7.0, Minitab 14.0 and WinRobust 1.02 softwares for evaluation the effect of each parameter on the optimization criterion. The highest P2O5 recovery and grade obtained with collectors' ratio and dosage of 10% and 630 g/ton, pH 9, depressant dosage of 440 g/ton, depressant conditioning time of 7 minutes, collectors conditioning time of 3 minutes, frothing time of 5 minutes and 22% solid percent.

In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample whic... more In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample which was provided from Shenin Silica Mine using conventional flotation. This silica contains 93.75% SiO2, 0.44% Fe2O3, 2.78% Al2O3, and 0.08% TiO2 and the Fe2O3 has to be reduced to about 0.1% or less than 0.02%. Mineralogical studies and XRD analysis indicated the presence of Hematite, Pyrite, and Goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections yielded that the degree of freedom of silica is more than 80% in -300+212 microns size fraction. Due to low weight content of gangue minerals (about 6%) reverse flotation were applied. Anionic collectors (Aero 800 series) were selected for these experiments. 23 experiments were carried out by means of conventional Denver flotation cell. Variables were feed type (wet rod mill product (with or without desliming and elimination of free iron) or scrubber product with de-sliming), pH, collector type and dos...

The removal of Copper from a dilute synthetic wastewater (10mg/l ) was studied by ion flotation a... more The removal of Copper from a dilute synthetic wastewater (10mg/l ) was studied by ion flotation at laboratory scale. Anionic sodium dodecyl sulfate (SDS) was used as a collector and ethanol as a frother. Different parameters such as pH, collector and frother concentrations, foam height and bubble size distribution were tested to determine the optimum flotation conditions. In order to check the effect of bubble size distribution, a micro bubble generator was designed. The bubbles that are generated in this way have a dimensional distribution ranging from 10 to 100 microns. Metal removed up to about 93% and water was recovered 13% by using an intermixing method of coalescence phenomena (combined flotation by micro-bubbles and normal size bubbles generated mechanically) in a Denver type flotation machine, at low pH. The flotation time fell considerably at 37.5% when the bubble coalescence phenomenon was used.

In this research work, it was attempted to reduce the iron contents (Fe2O3) in relatively low gra... more In this research work, it was attempted to reduce the iron contents (Fe2O3) in relatively low grade silica sample which was obtained from Shenin silica mine, using magnetic separation. The prepared sample contained 93.75%SiO2, 0.44%Fe2O3, 2.78%Al2O3, and 0.08%TiO2 and the Fe2O3 had to be reduced to less than 0.08%. Mineralogical studies and XRD analysis indicated the presence of Hematite, Pyrite, and Goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections demonstrated that the degree of freedom of silica is more than 80% in -300+212 m size fraction. After primary stages including crushing, milling, scrubbing and de-sliming, various methods such as low intensity magnetic separation (LIMS), high gradient magnetic separation (WHGMS) and dry high intensity magnetic separation (DHIMS) were applied to find out that which process would be appropriate for the elimination of iron impurities from this sample. Different experiments were carried out on t...

In lead-zinc sedimentary deposits presence of carbonaceous shales is detrimental to the concentra... more In lead-zinc sedimentary deposits presence of carbonaceous shales is detrimental to the concentration of zinc and lead in the flotation process. Koushk is one of the largest zinc and lead complexes in Iran. The most valuable minerals are galena and sphalerite and carbonaceous material is present among the gangue minerals. Flotation in the absence of collector and prior to galena flotation, called pre-flotation, is employed to remove some of the organic carbon, black shale, from the flotation feed. These contents are naturally hydrophobic. The main issue is low selectivity of carbonaceous against zinc causing 15% zinc and 16% lead loss during pre-flotation process. Reducing the loss during pre-flotation using chemical methods is the first reasonable solution. Vast variety of highly recommended reagents for the problem, were tested and the effective parameters were recognized by DX, data analysis software, using Design Of Experiment (DOE) methods to determine the least possible loss o...

In this research, optimization of effective parameters for increasing gold recovery in Cyanidatio... more In this research, optimization of effective parameters for increasing gold recovery in Cyanidation process was carried out on Hamzeh-Qarnein gold ore containing 0.8 ppm gold. Accordingly, the effect of parameters such as particle size (d80), pH, cyanide concentration, and leaching time on the gold recovery examined through agitation leaching tests. The results showed that gold recovery of 95.21% will be achieved if the test is carried out applying feed distribution size of d80=63µm, pH of 10.5, Cyanide concentration of 1500 ppm and 12 hour for leaching time. Consumption of cyanide and lime in optimum condition was also measured and were 1.23 kg/t and 2 kg/t, respectively. In addition, by increasing leaching time to 48 hour in the experiments gold recovery may reach up to 97.93%.

In this research, the operation of screen classifying in silica processing circuits was investiga... more In this research, the operation of screen classifying in silica processing circuits was investigated and the effect of replacement the other classifying methods on final concentrate, recovery and production rate was checked. Since the silica which is used in glass industry should have precise particle size distribution in the range of 100 to 600μm, the main problems that usually occur in screen classifying are as follows: - The target particle size distribution (according to silica standards) cannot be obtained with screens; - Application of trommel screen with casting mesh could impose high cost of repairing and maintenance; - Increasing the shut down time for maintenance and repairing causes the lower machinery availability and therefore lower annual capacity; - Fluctuation in particle size distribution because of corrosion and deterioration in casting mesh seems to be inevitable. Considering the problems of screens efficiency for achieving the certain particle size distribution, ...

Heap leaching is a simple, low-cost method of metal recovery in low grade ores, which is widely a... more Heap leaching is a simple, low-cost method of metal recovery in low grade ores, which is widely applied in the mining industry. The Hamze-Qarnein gold deposit is located in Kurdestan province with gold grade of 0.8 ppm. The mineralogical studies indicated that major gold particles characterized as native captured inside quartz particles. In the present work, the bottle roll and column leaching tests were carried out on the provided samples from the mentioned deposit in order to define related heap leaching parameters. Gold recovery, kinetic of gold dissolution, and consumption of reagent in heap leaching application were investigated. Accordingly, the parameters of particle size (d80), cyanide concentration, and duration of heap leaching on the gold recovery examined through experiments. The bottle role experiments showed that about 70% of the gold was recovered after 24 hours and the maximum recovery was 81.28% after 72 hours for the sample with aggregation size about 3.3 mm. The c...

In this research, the possibility of producing concentrate from a relatively low grade Scheelite ... more In this research, the possibility of producing concentrate from a relatively low grade Scheelite ore with total WO3 grade of 0.1% were investigated by application of shaking table. The mineralogical studies showed that Scheelite mineral was the main tungstate mineral of Nezam-Abad Ore and the appropriate liberation degree of Scheelite from waste minerals were in the range of 100-125 µm. The dominant gangue minerals were Silicate minerals. In order to optimize the effective parameters of shaking table on the grade and recovery of Scheelite, Box-Behnken design was used. The results of shaking table tests, showed that in size range of +125 -600µm with different ranges of feed sizes and two primary concentration, the product grade of 1.44% WO3 and the recovery of 70% can be achieved. Afterwards, two other concentration stages were designed and the product grade of 27.5% of WO3 with an overall recovery of 50.86% was obtained and proposed flow-sheet was developed accordingly. Keywords: Sc...

Heap leaching is one of the several alternatives for processing of precious metallic ores which i... more Heap leaching is one of the several alternatives for processing of precious metallic ores which is suitable for beneficiation of low grade ores and small deposits due to low capital and operating costs. Heap leaching of oxidized copper ore of the Meskani-Anarak deposit conducted with sulfuric acid in laboratory scale. Mineralogical studies indicated that samples are mainly composed of Malachite, Azurite and Cuprite and the Copper (Cu) grade was about 1.32%. At the first step, the bottle roll test was carried out at different particle sizes in order to determine the maximum Cu recovery and sulfuric acid consumption. The bottle roll tests showed at particle size finer than 9.51mm; the acid usage was 68.8kg/t and the maximum Cu recovery was 77.43% after 48 hours. At the second phase, the permeability test performed and irrigation rate was selected at the range of 5-7 l/h.m2. The column leaching tests consisted of columns with about 1 and 2 meter height and particle sizes ranging betwee...

Although a number of equations have been suggested for prediction of S-wave with-out direct measu... more Although a number of equations have been suggested for prediction of S-wave with-out direct measurement, but these prediction equations can be divided into three main groups. The main predicting equations define Vs from Vp which are usually used in rock mechanics and petroleum industry with limited number of Vs measurements. The correlation between such data points are used as a based for the other set in nearby geological sequences. The second group of estimations defines Vs based on other logging data such as resistivity logs, gamma ray, NPHI and etc. Sometimes a mixture of these logging data is used. This method is basically used in petroleum industry where sonic logging costs more than other logging operations and the reason for such predictions are economical concerns. The final series of predicting equations correlate Vp or Vs with some physical properties like porosity, density, quarts content, cementation degree and etc. The purpose of such equations is to identify effective...

The cores gathered from a gas storage field were selected and thin sections and XRD studies perfo... more The cores gathered from a gas storage field were selected and thin sections and XRD studies performed on the samples. Initial results showed that less than a third of the formation is composed of clay minerals and the percentage of troublesome clays (smectite group) is negligible. Using previous suggested equations for the kinetics of illite and montmorillonite, it was revealed that alkaline environment caused the gradual conversion of montmorillonite to illite during the time. Keywords: Montmorillonite, Illite, montmorillonite to illite conversion, kinetics,