فهرست مطالب محمدرضا رضوانیان زاده

The study area is located at east of Bam city and southeast of Kerman province. This area is located at 45 km from the Bam-Zahedan Road. From the main asphalt road of Bam - Zahedan it has 15 km of dirt and car accessible road. It is part of the NW-SE trending volcanic belt east of Bam.

This study aims to geochemically investigate the behavioral pattern of hydrothermal mineralization elements in the region in order to determine local and regional uranium enrichment at 1: 5000 scale. For this purpose 616 lithogeochemical samples were collected and analyzed. The study area is located southwest of Allahabad 1: 250000 Map. The Eocene outcrops are divided into two classes of pyroclastic and lava based on 1: 5000 scale studies. These deposits are cut by numerous dykes with an approximate northwest-southeast trend. These basaltic-diabase dykes can actually be attributed to the Eocene. The most important statistical parameters used in interpretation of area data are mean, median, mode, variance, standard deviation, coefficient of variation, skewness and kurtosis which were calculated for all data.

After normalizing and eliminating outlier values data, the data were analyzed using Pearson correlation matrix method to identify the correlation coefficients of the elements that accordingly, the highest correlation of uranium was observed with Be, Cd, Co, Cu, Mn, Mo, Na, Ni, Sc, Se, Tl, V, Y, Zn, Zr, Ga, Ge, and Hf. It indicates the paragenetic relationship of these elements with each other.Based on data clustering, four groups of chemical elements can be of particular interest due to their strong association with uranium, which include:Rare earth elements: Y, La, Ce Polymetallic elements: As,Sb, Ba, Cu, Pb, Zn, Mn, Fe, Se, Sr Related to acidic volcanism: Be, Mo, W, Zr Related to basic magmatic activities: Co, Cr, Ni, V The pattern of uranium paragenesis element groups in this diagram is roughly consistent with previous studies in the field of uranium volcanogenic deposits. Based on factor analysis, an 8-factor model with 78.6% variance was obtained for 43 elements. The second factor with a variance coverage of about 12.5% contains As, Mo, Sb elements with high factor loadings and Ag, Be, Ce, La, Pb, Tl, U, W, Y elements with average factor loadings. This factor is related to uranium mineralization in the region. Based on the results of the statistical analysis and interpretation of the geochemical map of the uranium element, the enrichment limit for this element is considered to be 5.67 ppm and background and threshold values were 2.39 ppm and 4.3 ppm, respectively.

The impact of hydrothermal solutions is strongly observed on the volcanics of the area, resulting in geochemical imbalances. Mo in the region forms large lithogeochemical haloes that are highly consistent with U elemental haloes and are generally concentrated at high U concentrations. Due to the Mo mineralization in the deeper regions, probability of U mineralization also exists in the deeper parts of the region and it is anticipated that subsurface studies will show significant results in terms of the occurrence of U compounds. Much of the southern half of the region, except for abnormal areas, is consistent with fault trends and concentrated along fault lines. There is widespread argillic alteration in the Eocene units of the region, with enrichment of the REEs, especially associated with lanthanum. Increasing the intensity of alteration and increasing joints and fractures allow the fluid to move, thereby increasing the fluid / rock ratio and facilitating migration of anomalies. The trend of uranium anomalies is often consistent with the cerium, yttrium, and lanthanum anomalies, and is usually in the margins of the basic dykes which indicates the convection of these elements from a mineralized fluid. This indicates the mobility of rare earth elements during alteration processes and their concentration by geochemical dams, including basic dykes. By comparing the obtained paragenesis for the uranium element in the region and the geochemical pattern observed with different types of known uranium deposits in the world, the most likely option for the type of mineralization in the region, is volcanogene uranium type.

In uranium mines, the excavated waste has a lower grade than the threshold grade and is dumped on the surface as waste material. Due to erosion and rainfall over time, it is very likely that part of the uranium content is washed out of waste dump and leaked into surface and subsurface water resources and cause severe environmental hazards. The excavated waste during mining, as well as water collected during the drainage process of underground excavations, can be reused in the preparation of concrete fillers. In this study, samples of concrete backfill material were prepared by using waste material excavated from Saghand open pit and underground mines. Based on conducted testing and analyses, it was found that a large proportion of deposed waste and drained water can be used to prepare concrete fillers to fill stopes in Saghand underground mine. This process leads to a major reduction in mining costs, increased safety of mining operations, and significant improvements in reducing environmental pollutions.

The study zone is a part of 1:100000 Anarak map which is located in the east of Isfahan province, at 10 km North of Anarak town. The Structures of this Zone is formed in Anarak-Khor region and are affected by the movement toward the north of Arabian plate, and activation of two strike-slip faults (Dorouneh and Biabanak) as a result of the mentioned movement. There is thrust fault in Chahshoureh with the east-west direction. This fault is not only a thrust but also it has during the different duration, dextral component, and then instal components. Polymetal mineralization is restricted to the hanging wall and into vein and veinlet of the listwanites of the study zone. Litswanites are uncommon carbonated rocks that forms from the alteration of ultramafic units and are abundant in silicic-carbonated threads. Ophiolites of this area belong to the ring ophiolites of central Iran. In this study, the direction of an effective paleo-stress field is reconstructed with the collecting data from slickenlines of faults and processing them by using inversion method. Trend and position of principle paleo stress axes are calculated from analysis of slickenlines by using T-tecto3 software, and it is found a that listwanites has formed in  a tear fault. As the tectonic regime of the study zone show an iterative model it could be listwanites are forming is the similar way and restricting U- mineralization to their veins and veinlets. Also, according to the same forming, it could be concluded that in the west listwanites we have a poly-metal and U-mineralization.

Mineralogical examination of the gangue and ore parts of the Se-Chahun magnetite-apatite ore deposit revealed the existence of Th and REE bearing minerals with paragenetic relationships with amphiboles, magnetite and calcite. Trace and REE host minerals are found in both of the gangue and the magnetite-apatite ore showing remarkable concentration in a phase referred to as the brecciated phase. This zone (phase) is characterized by high amounts of trace (Th) and light rare earth elements including La, Ce, Pr and Nd that were revealed in geochemical analysis. Mineralization of these elements is related to fluids appeared after magnetite mineralization in the region and resulted in metasomatism of the host rocks and a part of the ore and also concentration of the REE and trace elements as phosphates and silicates, respectively. There is not a clear key concerning the origin of these fluids but based on the geochemical evidence, the probable provenance is thought to be related to the magmas derived from the arc related subvolcanic bodies injected in subduction zones. Based on the paragenetic and geochemical evidence, a part of these elements is transported by carbonate complexes and accumulated in the brecciated rocks.

Examination of geochemical distribution pattern of trace and rare earth elements in the rocks affected by metasomatic processes revealed a magmatic origin for Th-REE mineralization at the Se-Chahun ore deposit. Chondrite and primitive mantle-normalized patterns of REE and trace elements for the rhyolitic host rocks (which formed in a subduction setting) compared with the patterns of the Th-REE mineralization zone also provides evidence that the origin of the Th-REE mineralization zone is similar with rhyolitic magma or a magmatic chamber from which the rhyolitic magma was originated. This is also supported by oxygen and hydrogen isotopic data in actinolite paragenetically associated with Th-REE bearing minerals. Thorium minerals at the Se Chahun ore deposit include huttonite and thorite. O and H isotopic data for actinolite paragenetically associated with Th-silicates revealed a magmatic source for Th-REE mineralizing fluids in the ore deposit δD and δ18O for actinolite paragenetically associated with Th silicates are calculated between -73.29 to -42.04 and 6.65 to 7.71, respectively, which lie within the field of magmatic fluids.

The Bafq region hosts the most important magnetite-apatite deposits of Iran. The geology of this region has been studied by many researchers (e.g., Haghipour, 1977). The ore deposits are mainly hosted by a volcano-sedimentary unit. The presence of a brecciated unit at the margin of the magnetite -apatite ore deposits is discussed by several authors. This unit contains remarkable concentration of Th and REE minerals paragenetically associated with magnetite, actinolite, calcite and albite. Mineralogical properties of the brecciated unit as one of the most important geological events in the magnetite-apatite ore deposits of the Bafq region, and Th-REE mineralization hosted by this zone at the Se-Chahun ore deposit is discussed. The present study has been carried out in four stages including: field work, microscopic studies, ICP-MS and ICP-OEA analysis as well as EPMA analysis. The field work included observations, investigations, radiometry, spectrometry and sampling from different lithologies in both open pits and drilled cores. The microscopic studies were carried out in order to identify the minerals and examine the textural properties of these minerals found in the brecciated unit. The ICP-MS and ICP-OEA analysis were carried out on the samples taken from the ore bodies and the radioactive parts of the mine. The EPMA analysis was also carried out to achieve a more precise hint at the occurrences of the Th and REE minrals and also to investigate the paragenetic relationships between the minerals probed. The brecciated unit is generally formed at the margin of or within the ore deposits mentioned. The matrix of the brecciated unit at the Se-Chahun ore deposit is composed of different minerals including magnetite, titanomagnetite, actinolite, albite, apatite, titanite, calcite, epidote, chlorite and Th silicates. The coarse rock fragments are mainly of the rhyolitic rocks and metasomatic fragments. Based on the mineralogical studies, the brecciated unit is the host of Th-REE minerals. The Th-silicates are formed in two crystallized forms including monoclinic (huttonite) and tetragonal (thorite). Thorium occurrence is found in three types: granular, massive and veinlet. The geological investigations indicate the role of solutions derived from magmatic arc originated in calc-alkaline magmas as a source for Th(-REE) in the brecciated unit. Based on the field, mineralogical and geochemical evidence, a remarkable part of Th has been transported by carbonate complexes in basic and reduced solutions. Apatite and monazite show a notable concentration within the brecciated unit. Monazites are found mostly as single crystals not always hosted by apatite crystals. Two types of actinolite are recognized, 1. Older than Th mineralization within the magnetite ore and 2. A younger generation paragenetically associated with Th silicate. Two types of albites are recognized: an early (white) albite found within the magnetite ore; a late (red) albite also found within the brecciated zone in association with Th occurrences.
Metals such as Th and REE, at the Se-Chahun magnetite-apatite ore deposit are thought to be predominantly derived from the associated magmas, via magmatic–hydrothermal fluids exsolved upon emplacement into the crust. Two main sources exist for the origin of the metals (Th and REE): 1: sediments on the downgoing slab subducted into the mantle wedge (located between the downgoing slab and the overriding plate); 2: assimilation of crustal rocks within the magma chamber and also during ascending of the magmas. Th-REE have been transported mainly by carbonate complexes in alkaline and reduced environments. The presence of a reduced environment during Th-REE mineralization is evidenced by paragenetic association of magnetite and pyrite (and minor chalcopyrite) supported by negative Eu anomaly. Presence of an alkaline environment is also supported by the presence of calcite crystals, veins and veinlets paragenetically associated with Th-REE minerals. A limited number of models have been suggested to explain the provenance of the brecciated unit. Mohseni and Aftabi (2012), among others, suggested that this zone is a proximal zone of magnetite-bearing keratophyres formed in submarine environments. By contrast, no clear source for thorium silicate is suggested. Recently, Khoshnoodi (2016) discussed the subject in one of the largest iron-apatite ore deposits in the region, the Choghart. According to his suggestions, the solutions derived from the calc-alkaline magmas are the source of thorium.
According to our suggestions, the lower continental crust and also the continental derived sediments on the sea floor adjacent to the subduction zones can be proposed as one of the most important sources for limited amounts of thorium found within the magmatic arc magmas. It is proposed that these magmas and associated mineralization are not limited to the margin of the magnetite-apatite ore deposits. Until now, the importance of the Bafq mining district has been due to its discovered magnetite-apatite resources. Further exploration programs supported by mineralogical and geochemical studies may lead to opening new ways in exploration of uncovered ore deposits in the Bafq district containing more economical resources.

Uranium playa type is limited reserves which are formed in special conditions. The Dagh-e-Sorkh playa is located at 30 km north-norgh east of Ardestan which is located in the Central part of Iran. The two main facies type of basin, including pediment and playa type were determined, and by drilling 77 pit, sampling and analysis with the Induced Coupled Plasma - Mass Spectroscopy (CP-MS), the uranium anomaly was identified in a layer with the thickness of 10 cm - 15 cm, where the maximum activity and uranium grade were 250 cps and 15 mg kg-1, respectively. The results showed the uranium mineralization potential of the basin is low.

The Saghand mining district is a part of Bafq- Saghand metallogenic zone in the Central Iranian geostructural zone which is located in northeast of city of Yazd. This area is known to be more susceptible to mineralization of U and Th radioactive elements, but in fact is that its main importance is for relatively large iron deposits. However, in this region similar to some of the ore deposits within the Bafq area, rare earth elements have a high anomaly. Alkali-metasomatism occurs in a large variety of environments and geological periods. It can be spatially associated with ore deposits, as for some IOCG deposits or exists in barren systems such as metasomatism within the ocean crust (Johnson and Harlow, 1999). Although average U and REEs contents of the ore bodies associated with alkalimetasomatism are not high, they represent a promising exploration target because the resources of such deposits are relatively large (Cuney et al., 2012). The alkali-metasomatism could take place in all kinds of rocks. In addition to wide distribution in granite and granodiorite, it could be also identified in all kinds of metamorphic rocks, pegmatites, subvolcanic and volcanic rocks, and they all have mineralization (Zhao, 2005). After field studies, host rocks and metasomatites were sampled from outcrops, trenches, and core drillings. Since the rare earth elements and radioactive elements are present within the same mineralogy (Samani, 1985), surface spectrometry measurements were used in the selection of appropriate samples. For microscopic studies, 210 samples were prepared and studied. Ore minerals were investigated in polished and polished thin sections using optical microscope and Scanning Electron Microscopy (SEM) analysis was done in the Iranian Mineral Processing Research Center. An LEO-1400 SEM with energy dispersive X-ray spectrometry and back-scatter electron (BSE) imaging capabilities was used (accelerating voltage, 17-19 kV, and beam current of 20 nA). The 16 samples were analyzed by the ICP-MS method at Zarazma Mineral Studies Company, Iran, for major and trace elements at the various radiations and lithological ranges. The detection limit and precision for determination of REE, U and Th concentration were 0.2 to 1 ppm and 1 to 0.1 ppm, respectively. Discussion and results: Based on field evidence and microscopic studies, four main stage of metasomatism with continuous evolution have been distinguished in the Saghand area, including: 1) Na-metasomatism, 2) Ca-Mg metasomatism, 3) K-metasomatism, and 4) Epidote±chlorite±calcite±quartz vein and veinlets. All metasomatic zones are generally enriched in U and REE and compared with the host rocks but economic grades are less widespread and limited to Ca-Mg metasomatite zones near pinkish to red color albitites. The major Ti-REE-U(Th) minerals are davidite and brannerite, which have mainly crystallized during the Ca-Mg metasomatic stage. Ti or Tibearing minerals as paragenesis with davidite and brannerite are also deposited in amphibole-albite metasomatic zones. All these minerals are usually fractured and along fractures and its margin is replaced by titanite, leucoxene and rutile. In this study, geochemical analysis results of igneous rocks in the Saghand ore deposit, confirm the active continental margin arc setting and the nature of calc-alkaline magmatism in the region. The good adaptation of the REEs patterns in granites with the quartzdiorite-diorite rocks, can be a strong reason for their common tectonomagmatic origin. This Geodynamic environment had been the appropriate background in terms of protolith, heat engine for metasomatism cycle and supply hydrothermal solution and controlling structural pathways. The proximity of mineralized metasomatic rocks with the granitic rocks and intrusion of the granite apophysises into the metasomatic rocks, mobility of REE elements in the metasomatic environments, adaptation of geochemical properties of REE, U and Th elements in the mineralized metasomatitic rocks with the granitic rocks and finally, there was no evidence of intrusion of unusual magmas such as the carbonatite or alkaline magmas at the current level of ore deposit outcrops. Thesesuggest a close relationship between mineralization and metasomatic events with the granite intrusion. Fluids differentiated from the Douzakh-Darreh granite have entered the fault and crushed zones in a tectonically active regime of marginal continental arc. Due to reaction of the high temperature fluid with the protolith rocks, the ratios of Na+/K+ and Na+/H+ in fluid in equilibrated to feldspars of protolith rock elevated (Cuney et al., 2012). A basically alkaline medium to low temperature hydrothermal fluid is a suitable environment for the activation and transfer of U and REE in the form of hydroxyl complex (Romberger, 1984). Conversely, Th remained essentially immobile during the metasomatic processes (Cuney et al., 2012) and therefore, cannot be in abundance carried by this fluid. Hematite pigmentation of albite and transfer of U shows that oxygen fugacity in the early hydrothermal fluid has been quite high. These geochemical conditions simply allow U, and REEs enter from wall rocks to fluids and form hydroxyl complex of these elements, which are sustainable and are portable. Titanium bearing minerals within the quartzdiorite-diorite rocks and Douzakh Dareh granite easily decompose under hydrothermal activity and form titanium hydroxides, which is a very strong absorbent for U. After mineralization of albite and hematite, oxidation degree of fluid quickly drops and as a result, conditions for instability of complexes containing Ti, REE and U are provided. Acknowledgements: This paper is based on a part of the first author's Ph.D thesis at Shahid Beheshti University. This research was also supported by Skam Company and Iranian Mines & Mining Industries Development & Renovation Organization.

Special measures must be taken to maximize the recovery of uranium deposits, reduce the absorption rate of radiation for personnel working, reduce environmental pollution and reduce mining costs in underground uranium mining. One of these measures is to fill the extracted spaces, in particular, in the tunnel cut and fill mining method. In this research, it has been tried to select the most suitable concrete filler mixing plan with the above-mentioned attitudes. To carry out this research, in a laboratory scale, concrete mixing designs were implemented for hydraulic concrete with four types of rock materials from waste of uranium mines, river sand, washed sand and barite sand. Samples of these mixing designs for testing of resistance One-axial pressure was taken. Also, in addition to calculating the cost of making any mixing plan, hydraulic concrete was constructed in different thicknesses adjacent to the uranium ore was poured to measure the amount of radiation. Radiation experiments and measurements were carried out for concrete mixing designs in different thicknesses. The results indicate a sharp decrease in the radiation and absorption dose of radiation by increasing the thickness of the filler concrete. It has also been proven that mining waste and drainage water from uranium mines that are contaminated with radioactive substances can be mixed with hydraulic concrete fillers to fill uranium underground mines in order to reduce environmental pollution and Filling costs.

The studied area is located in the central Iran micro-continent, in the southern part of Lut block, 45 kilometers east of Bam Township. The main units of the area are mostly intercalation of pyroclastic rocks and lava layers in the age of Eocane, with the general trend of southwest- northeast and include high potassium calc- alkaline magma that their formation are related to the tectonic environments of magmatic arc and subduction zone. Argillic, silica, hematite, zeolite and chlorite alteration are observed in the area in relationship with uranium mineralization. The geochemical complexes related to uranium presence were identified in the study area. They are: complexes in relation with acidic and moderate rocks, including U-W-As-Mo-S-Cu-Ag, and complexes related to the basic igneous rocks, including U-Ni-V-Ag-Co-W-Mo-Cr-Cu-S. The main observed structures and textures in this area involve stock work, vein veinlet, corrosion, radial, release and peripheral membrane. The main mineralization in the area includes uranium secondary minerals contains Boltwoodite, Phosphuranylite and carnotite, manganese oxides, iron oxides and hydroxides, a few sulfide, zeolite mineral group and other minerals groups which mostly are formed under the influence of hydrothermal and late supergene processes. Based on a comparison pattern of mineralization in the area and its adjustment with the geological, alteration and geochemical conditions in uranium deposits, the most possible choice for mineralization type in the area has been introduced as volcanogenic uranium mineralization.

In order to achieve maximum recovery and minimum absorption level of radiation in underground uranium mines specific measures must be taken. One way to achieve this goal is to employ the backfilling method using hydraulic concrete fills, in particular in the tunnel cut and fill method. The backfill is a material which is used to fill the excavated underground stopes to provide support and safety for the mining operations. In this research various mixes of hydraulic concrete fillers were prepared at the laboratory scale. The underground mine waste rock, open pit waste rock, natural river sand, and barite sand were used as backfilling main ingredients and representative samples of each mix design were prepared for the laboratory tests. Moreover, large scale samples of concrete hydraulic fills were cast at varying thicknesses in in the vicinity of uranium ore to enable examining the radiation level. The test results demonstrate that the use of hydraulic concrete fills can provide safety and stability to mining activities.

The accuracy of isotopic compositions measurement is affected by all the ICP-MS instruments because of the phenomenon known as mass bias, where it is defined as difference between the measured and true values in an isotopic analysis. This research has introduced mass bias and also evaluated the effective parameters including concentration of uranium, electrical field behind the second or skimmer cone, detector voltage, plasma power and nebulizer flow. The least mass bias with a relative error -0.3% for the isotopic analysis of uranium results in aqueous media without interference of the matrix with 1.2% RSD of 0.3 mg/L concentration, while the voltages of ion lens 1 and 2 in the ICP-TOF-MS were -700V and -550V, respectively. The instrument was set in the plasma power of 1000 watts, nebulizer flow of 0.78 ml/min, and the detector voltage of -2450V.

In this paper, the effect of crystallographic texture on hydride orientation in the inner and outer layers of Zr-(1%)Nb clad was investigated. (0002) pole figures were measured by transmission and reflection X-ray diffraction method. Volume fraction, Vr of grains having their basal poles in a specified orientation region with respect to the radial direction and effective fraction of basal poles aligned with a circumferential direction, fr, were calculated from the data pole figures. The results of the analyses showed that there was a texture gradient in the clad thickness from the inner to the outer layers. fr and Vr(φ:0-30°( had inverse relationship to hydride fraction (F). In the inner layer fr, Vr(φ:0-30°( and F were 0.53, 0.57 and 0.25, respectively. In the outer layer, those were shown to be 0.41, 0.33 and 0.61, respectively.

Replacement of four individual, time-consuming and expensive ASTM standard methods for determination of Mo, As, Th and K in samples having uranium matrix with one new proficient method is considered. The main advantages of this method are overcoming the mentioned shortages and preserving the precision and accuracy of the analysis results for the desired technical specification of materials and nuclear industries. In the new method, the interfering uranium matrix was removed by extraction with a mixture of tri (2- ethylhexyl) phosphate (TEHP): n-Heptane. The elements were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) simultaneously. The effective parameters on the extraction including: pH, the remained uranium and temperature were studied. The dynamic range of calibration curve related to the element type was linear (R2>0.999) at 10-500 μg/g U. The method detection limits (MDL) of 0.51, 0.66, 1.1 and 0.55 μg/g U were obtained for Mo, As, Th and K, respectively. The obtained quantity of En for all elements was less than 0.26. The analytical precision and bias of current method at two different concentration levels were determined and compared with the available standard methods denoting an evidence of the method verification. The decreased analysis of time duration from ~24 hr to <2 hr and the remarkably reduced instrumental and material charges are some of the joined industrial and applied properties of the present method.

In this study, a simple method for the AUC powder preparation from uranyl fluoride solution, which is more effective for uranium recovery from AUC effluent is presented. At first, the uranium was precipitated in the form of ADU with more than 99.99 percent efficiency by ammonia solution. Then, through overflowing the solution, most of the fluoride ions were removed from the precipitated uranium. By adding ammonium carbonate solution to the ADU slurry, the AUC with stochiometry formula with high efficiency was prepared. The remained uranium in the AUC liquid waste was recovered by ADU precipitation in 99.99 percent. In this step, the uranium concentration in the final waste solution was decreased to less than 1ppm, where it is an important factor for enriched uranium. The ADU slurry was recycled to the next cycle of the AUC production. In this study, the NH4+ concentration, CO32-/UO22+ molar ratio and temperature effects were studied on the properties of the AUC powder and the precipitation efficiency. The results show that the NH4+ concentration is only effective on the fluoride separation and precipitation efficiency. The AUC precipitation efficiency depends on the uranium concentration in the ADU slurry. Also, the uranium recovery depends on the uranium concentration in the AUC waste. Decreasing the CO32-/UO22+ ratio to a minimum value caused the maximum particle size of the AUC crystals to be on an average value of 121 microns. The results of the XRD and SEM for the AUC powder are also presented.

NaF disks are used for the adsorption of UF6 in low concentration. In this paper a wet chemical method is presented for recovery of uranium from NaF disks. In this method the adsorbed uranium on the disks is dissolved in sodium carbonate solution and converted to UO2(CO3)34- and this complex is adsorbed on the ionic exchange resin amberlit-110. By using sodium nitrate solution, UO2(CO3)34- is desorbed from resin. The uranium on the resulting solution can be used in production process of UF6. The proposed method introduced in this paper shown to have high efficiency and convenient operational procedure.

In this research, separation of fluoride and uranyl ions from high content nitrate and fluoride solution, by γ-Alumina in moving and fixed bed methods, has been studied. In this investigation, the effect of some principal parameters such as, alumina weight, its particle size, and pH on the efficiency of separation of these ions from uranium solution, has been optimized. In the moving bed process, in fact, for decreasing pH, the best and economical condition for uranium extraction by solvent extraction process with TBP has been made available, and therefore it leads to save 800m3 HNO3 as a good advantage. In addition, in the fixed bed process, at an optimum pH, the concentration of uranyl and fluoride ions in the final raffinate decreased for uranium in a range of 50 ppb to 1.3 mg/L, and 170 ppb for fluoride. The effect of adsorption parameters on desorption of these ions was investigated and optimized by sodium carbonate solution. Uranium desorption from the column by sulfuric and nitric acid and sodium carbonate solution was carried out easily, and by sulfuric and sodium carbonate solution 99% recovery was obtained.

In this research work, the recovery and separation of La(III), Ce(III), Sm(III), Dy(III) and Nd(III) from Saghand uranium ore have been studied by precipitation and ion-exchange chromatography methods using Dowex 50W-X8 cation exchanger. At first, some preliminary and preconcentration experiments such as comminution, sieve analysis, gravity table and electrostatic in preconcentration of lanthanides were performed. Then, acidic digesting and leaching procedure were used. The results of experiments showed that rare earth elements, along with interfering ions such as Al(III), Fe(III), Mg(II) and Mn(II) present in the leach liquor solution. The investigation of separation process by precipitation method revealed that precipitation and then fast separation using centrifugal technique had the best results in the elimination of interference elements. In order to separate the lanthanides and to obtain their elution curves, the chromatographic column containing Dowex 50W-X8 resin was employed. For efficient separation of lanthanides from interference elements the hydrochloric acid with concentration of two and six molar was used respectively. Recovery of lanthanides from the leach liquor solution was achieved more than 85%.