فهرست مطالب عباس سام

The purpose of this study was to introduce and investigate a new combination of collectors and their effect on flotation efficiency of Sarcheshmeh Copper Complex. In this study, the chemical composition of 2, 5-dimercapto-1, 3 and 4-thiadiazole (DMT ) as a new collector at pH values between 10 and 11.8 was tested. A review of scientific references and research records showed that DMT has not been used as a collector or in combination with other collectors in the flotation process so far. Nine experiments were performed to determine the collector performance as well as 6 additional experiments to determine the effect of different collector values. Based on the results, using DMT collector at pH 11.2, the recovery percentage and copper grade were achieved 88.2 and 11.9, respectively, which was 2.1 and 3.9% higher than the plant conditions, respectively. In this case, the separation efficiency was increased by 17%. Also, the recovery and grade of iron concentrate decreased by 17.1% and 4.8%, respectively. FTIR analysis was showed that during the adsorption process, the DMT form was changed from the tion-thiol form before chemical adsorption to the dithiol form after chemical adsorption. Also, the adsorption behavior of DMT on the chalcopyrite surface was limited in the chemical equilibrium between the extra-ring sulfur atoms and the metallic copper.

Deralu Copper Mine in 120 Km of south of city Kerman and 35 Km of north Eastern Baft in mountain area, are rested between Hezar with high of 4465 meters and Lalehzar by high 4351 m mountains. Tailings dam for the processing plant, is a required facility for mining operation. Site selection of tailings dams has a great impact on the initial and final investment of the mining operations. The dam site selection process was based on economic issues and of ease of operation criteria in the past, but for now, due to the importance of the environmental issues, tailings dam site selection is a complicated process. In this study, determination of location of the copper mine tailings dam Deralu using GIS software as a decision support software is used. Many parameters affect the localization of tailings dam, which these parameters cause complexity in choice of localization of tailings dam. In this research, the Analytic Hierarchy Process (AHP) - based on weighting parameters by the experts, will attempt to locate - is used. The opinions of experts, consisting of five layers of geological, environmental, hydrological, and economic and morphology was classified. Then, paired comparisons were performed between the layers to weight. Simultaneously the weighted sets analyzes were inconsistent judgments. Finally, By field control operations, the four proposed areas for further research were identified. The four regions were compared using TOPSIS method and preferred option was chosen.

Summary :The dominant mechanism in the High Pressure Grinding Rolls (HPGR) is compressive breakage. A laboratory scale experiment could be implemented to study the compressive mechanism. In the present research, for the first time in Iran, the piston and die device consists of controllable hydraulic press (P&D test) were utilized at Golgohar complex to study the compression breakage. This test was applied to investigate the edge recycle effect on the HPGR performance.
The usage of HPGR in the iron mineral processing plants is extending in Iran. Edge product of the HPGR is coarser than the central product that is not favorable for downstream processes. It is imaginable that the HPGR performance could be controlled by separating and circulating the edge materials. Before any mechanical changes in the industrial HPGR machine at the 4th train of iron concentrate plant in Golgohar, it was necessary to investigate the edge recycle effect fundamentally. From operational point of view, the HPGR in pilot scale is required for feasibility study, investigating the variables and predicting the associated operational advantages of any changes. The pilot plant scale of HPGR is not available at Golgohar complex. Also, conducting the pilot scale experiment requires a significant amount of samples, which is costly and time-consuming.
In both cases, fundamental and operational researches, the simple, available and knowledge-based laboratory tests are required. In addition, the laboratory tests play an important role in understanding and prediction of variable behaviors in industrial scales.
Methodology and Approaches : A laboratory method was developed to study the effect of the edge product recycling. After designing and constructing of the piston and die system, compressive breakage tests were conducted at the pressure of 1730 bars using samples taken from the feed of the 4th train of the concentrate plant. For separating the central product from the edge product of the experiments, a punch system was designed and constructed. To obtain the effect of edge product circulation, this material was mixed with the fresh feed at the ratio of 0.8. The sample was compressed at the same pressure. The D50 of the product was reduced by 25% with the edge product recycle. Particles from test product were studied using optic microscope and scanning electron microscope (SEM). Also a numerical method (trapezoid formula) was implemented to calculate the compressive breakage specific energy.
Results and Study of piston and die test cake product particles using optic microscope and scanning electron microscope (SEM) showed that just a few numbers of particles have surface micro cracks. Therefore, circulating the edge product will increase probability of particle breakage or crack creation. Finally a flowsheet was proposed which allows circulating the edge product of the industrial HPGR at the 4th train of the concentrate production of the Golgohar complex.
Also the compressive breakage specific energy was obtained by a numerical method named trapezoid formula using force-displacement graph. This graph was attained from piston and die test data.

Sulphur is one of the waste elements in coal material which is in two forms, organic and inorganic. The amount of sulphur more than acceptable quantity in coal concentration affects the environment and coke characteristics. The quality of steel is depended on the quantity of sulphur in coke. High sulphur in entering materials to the steel furnace causes inferior steel. Also, sulphur in heat coal makes SO2 gas which has negative environmental effects. Different chemical, physical and biological techniques are investigated for removing sulphur from coal. In recent years, new method for desulfurization from coal is expressed with improving biotechnology and microbial mining. In this research, feasibility study of depyritization from Tabas coal using bioflotation method in laboratory scale was considered. In these tests, Pyrite in coal pulp depressed with desulfurization bacteria. To carry out bioflotation tests, a sample from C1 seam (Tabas, Parvadeh Mine, no. 2) was used. After comminuting and screening, the coal material less than 500 micron was used as flotation feed. A Thiobacillus ferrooxidans bacterium was obtained from the biotechnology laboratory at Sarcheshme Copper Mine. Thiobacillus ferrooxidans was cultured in 9K medium. Bioflotation tests were carrying out in Denver flotation cell and the important parameters such as pulp density, particle size, bacterial density and interaction time were optimized. Final results indicated that by using the mentioned method, the pyritic and total sulphur were decreased about %62 and %35, respectively.

The present study was performed on propose of assessment and comparison of stress, depression and emotional intelligence among medical students and engineering students This cross-sectional study was done on 383 student in 1st to 3rd year students of medicine, dentistry, nursing, computer science, electronics, and materials, 60 members of each subject were selected and classified randomly. The emotional intelligence questionnaire (SSEIT-33), the obtained stress (PSS-10) and the Beck Depression Inventory (BDI-21) were used to assess the significance of the data which was examined and analized utilizing Pearson's correlation coefficient, chi-square, and t are independent groups, were analyzed. The mean score of emotional intelligence in the general population was121.4±13.4, the mean score of experienced strees score was 17.5±6.8, and the mean score of Beck depression test was 10.28±8.7. In addition, a significant negative correlation was observed between emotional intelligence and stress (r = - 0.417, p = 0.01) and between emotional intelligence and depression(r = -0.372, p = 0.01). There was no significant difference between students of different disciplines in terms of emotional intelligence, stress and depression(p> 0.05); moreover, the relationship between age, gender, marital status and education level of emotional intelligence, stress and depression was not significant (p> 0.05). In concultion, the results showed that emotional intelligence was effective to lessen stress and depression, and the difference regarding to these technical components was not noticed between medical students and engineering students.. Therefore, the promotion of emotional intelligence in medical and engineering students appears to be necessary.

Determination of chemical elements assay plays an important role in mineral processing operations. This factor is used to control process accuracy، recovery calculation and plant profitability. The new assaying methods including chemical methods، X-Ray fluorescence and atomic absorption spectrometry are advanced and accurate. However، in some applications، such as on-line assaying process، high accuracy is required. In this paper، an algorithm based on optimal estimator is presented to predict and correction on-line XRF errors. This research is based on the industrial real data collection for evaluating the performance of the presented algorithm. The quality of the obtained results was very satisfied; so that the RMS errors of Cu and Mo grades in rougher feed reduce to less than 0. 19 and 0. 006 and in final flotation concentration to less than 2. 48 and 0. 274، respectively. The results indicate that the mentioned method is quite accurate to reduce the on-line XRF errors measurement.

Zirconium and hafnium are the two most important elements in the nuclear industries. Zirconium is used in fuel rods due to its low neutron absorption cross section. On the contrary, hafnium has a very high neutron absorption cross section, therefore it must be separated from zirconium. The extractive separation of zirconium and hafnium have been investigated using Taguchi method. The separartion parameters were acid type (Sulfuric, Nitric, Hydrochloric) and their concentrations (10-2, 1, 5M) and extractant type (D2EHPA, Cyanex 301, Cyanex 302). The optimum conditions were determined as 5M nitric acid in addition with 5×10-3 M Cyanex 302 in the kerosene. Under these conditions, the zirconium the extraction percent and the separation factor were 99.5% and 8.7, respectively. For detailed investigation from the achieved results by Taguchi method, the effects of different parameters such as agitation time, nitric acid concentration, extractant concentration, sodium nitrate concentration and diluent type were considered.

Application of flotation in ilmenite fine particles recovery was not proved promising in previous studies, due to very limited active sites on ilmenite which is responsible for poor flotability of the mineral. In this work, surface activation and acidic pretreatment were examined to improve ilmenite floatability. Experiments were conducted on samples collected from the feed to line 3, containing 6.36% TiO2. The samples were ground to minus 106µm. Taguchi method was used to design experiments leading to optimal operational conditions, which found to be 700 g/t Clarient Flotinor SM 15 and Flotinor FS mixture with ratio 1/1 as collectors, 15 minutes as conditioning time and pH at 8.5. It is shown that using Pb(NO3)2 as surface activation with dosages up to 150 g/t, resulted in about 50% increase in recovery with a corresponding 9% increase in separation efficiency. Additionally, the concentrate grade was increased about 14% by using acidic pretreatment before conditioning.

This paper deals a with the study of an innovative method for processing the Oman placer ores by alkaline leaching in ball mill autoclaves¡ where grinding and leaching of the refractory minerals take place simultaneously. This was followed by the selective separation of thorium and uranium from lanthanides by autoclave leaching of the hydroxide cake with ammonium carbonate-bicarbonate solutions. The introduced method is based on the fact that thorium and uranium form soluble carbonate complexes with ammonium carbonate¡ while lanthanides form sparingly soluble double carbonates. It was found that a complete alkaline leaching of Oman placer ores (98.0%) was attained at 150 and 175C within 2.5 and 2h¡ respectively. Oman placer ores leaching was intensified and accelerated in a ball mill autoclaves as a result of the grinding action of steel balls¡ removal of the hydroxide layer covering ores grains and the continuous contact of fresh ore grains with alkaline solution. The study of selective carbonate processing of hydroxide cake with ammonium carbonate-bicarbonate solutions on autoclave under pressure revealed that the complete thorium recovery (97.5%) with uranium recovery (90.8%) and their separation from the lanthanides were attained at 70-80C during 1-2h. The extraction of lanthanides in carbonate solution was low and did not exceed 4.6%.

A hydrocyclone unit in a mineral processing circuit can be selected based on different procedures. Because of the coal nature, selecting a hydrocyclone in the coal washing circuit is a complicated process. The third correction factor (particle density) plays an important role in this area. In the present research, the underflow of Zarand Coal washing thickeners as hydrocyclone feed was monitored. Then the third correction factor of hydrocyclone was modified. Finally, the hydrocyclone diameter was calculated as 37 cm.

Because of low grade of thorium and uranium in the Zarigan mineral deposit, the
pre-concentration operation prior to leaching is necessary. From X-ray diffraction analysis results, it was clear that this ore has large amount of other minerals such as Feldespat, Quartz, Hematite, Titanomagnetite, and rare earths. In this paper the thorium enhancement grade in Zarigan deposit by using gravity, magnetic and electrical separations methods is reported. The output of a Jaw crusher was ground to 85 micron by using ball mill. Then about 95% of SiO2 was separated by using shaking table separation. The heavy concentrate of shaking table was processed by a high intensity magnetic separator and then the magnetic concentrate separated by a low intensity magnetic separator. Finally, the non magnetic concentrate of low magnetic separator was processed with the electrical separation. The grades of thorium and uranium in the non magnetic concentrate of low magnetic separator were increased to 4000 and 5000 ppm, respectively where only 15% of the initial feed (ore) was transferred to this concentrate. Therefore, this resulted in a decrease of acid consumption in the leaching processes and the efficiency enhancement of the process. The pre-treatment circuit of this ore was designed as Jaw crusher/ball mill/shaking table/high-magnetic separator/low-magnetic separator/electrical separator, respectively.

For centuries, intelligence as an individual characteristic, has been accepted. One of the popular tests namely intelligence quotient is stated in the rational understanding. In many cases, a big part of the human experiences, including: human feelings and his motivation desires are completely ignored. In recent years, the spirit quotient factor has been considered. This factor includes: intelligence quotient which is more inherent and emotional quotient that is much more acquired. Study in the process of intelligence-training-evaluation, especially in the realm of engineering sciences and fundamental change, is a necessity. In the present paper, in addition to the theory of different practical solutions, the educational engineering system and the status of balance in the intelligence and emotional quotient of students are presented.

Engineering education is a two-phase system of tuition and manner, which any lack of attention to each leads to upbringing professionals inefficient in both material and mental points of view, respectively. The manner phase makes engineer capable of communicating, arguing, reasoning, and making decision in the most impressive manner. Hence, the education of engineering ethics at university might prepare students to face the professional life readily. This ability is possible if only they are educated in the light of an organized new curriculum program. The aim of the current paper is to support such a modified program. The proposed curriculum map includes four parts of scopes, topics, teaching methods, and outcomes, regulated at four levels. These parts would be upgraded from fundamentals of engineering profession up to moral evaluations and criticisms.

Loading and transportation are often the most expensive process in an opencast mining operation. Gohar Zamin, being an important reserve with some 600 Million tons of iron ore, is now in the planning stage and an optimum loading and transportation system would add considerably to the economics of its operations. In this paper, two main methods have been introduced. The first method is the conventional shovel and trucks system, whilst the second one is using belt conveyors. The appropriate crushing method decided and the optimum location of the crushers has been determined in both cases. These two methods have then been subject to economic comparison, using real data from field studies in Gohar Zamin mine. The paper concludes that the method of using an in pit crusher and belt conveyors, being technically advantageous, is also more economical than the conventional method