The effect of mineral particle size on the bioleaching of uranium from Saghand mine (anomaly 1&2) by acidophilic mesophile Acidithiobacillus ferrooxidans was investigated in a shake flask. The findings are indicating that this strain is suitable for the uranium recovery from the mentioned ore. In the range of our studies the uranium recovery is faster in the case of d80=108 micron from anomaly 1, while, a comminution level of d80=160 micron was obtained as an appropriate size for the anomaly 2. The results showed that the particle size distribution of the mineral in this range did not considerably influence the microbial activity. Also, based on the results of bacterial oxidation, the negative effects and toxicity due to the presence of solid and solute components do not put a limit on the microbial activity, and at the tested parameters range, the grown microbial population is performing the desired process excelently.

In this paper, a process for solid-liquid separation was investigated by thickening method on the slurry obtained from leaching process under optimum conditions (Saghand Anomaly 1 soil). In mineral processing industries, the correct selection of the type and amount of flocculant can reduce the diameter of thickener, leading to an increase in the efficiency of the separation process and reducing the costs. Thus, in the present work, the experimental thickening was carried out by varying the amount of flocculant K-300 for solid-liquid separation process. By comparing the sedimentation rate of each experiment, the optimal value of flocculant for solid-liquid separation process (Saghand Anomaly 1 soil) was 80 g/tonore.

Khoshoumi Anomaly 6 is a significant uranium deposit located in the Bafq-Saghand metallogenic belt within the Central Iran zone. The gneiss serves as the primary host for uranium mineralization in block 1 of Khoshoumi Anomaly 6. Field emission electron microscopy studies have identified two stages of uranium mineralization within the area: primary mineralization (hypogene) and uranyl silicate (supergene). Primary uranium minerals found in the hypogene zone include uraninite, with minor amounts of thorouraninite, brannerite, and uranothorite. Uranyl silicate mineralization is observed along fractures in the form of boltwoodite and soddyite. Over time, boltwoodite undergoes alteration into sodium-boltwoodite and uranophane. Field evidence and mineralogical studies suggest that meteoric fluids, with a neutral to alkaline pH and low temperature, played a role in leaching uranium, silicon, potassium, sodium, and calcium from the gneiss. These elements were then deposited along fractures as uranyl silicate minerals, accompanied by calcite, clay, and chlorite. The presence of calcite alongside uranyl silicates indicates the transport of uranium in the form of uranyl carbonate complexes within the fluid.

Microbial leaching of uranium from Saghand low grade ore deposit by the acidiophilic mesophile acidithiobacillus ferrooxidants was investigated by changing the parameters such as pulp density, ferrous ions concentration as the resource of energy, initial pH of leaching solution and shaking speeds. The findings indicated that this strain is suitable for uranium recovery from the mentioned ore. About 60% of uranium could be recoverd in 50 hours by a pulp density of 2.5%(W/V). In the absence of microbial activity only about 5% of uranium was recoverd, and by the sulfuric acid leaching, only about 8.5% of uranium was extracted.

Extraction of ytterbium from anomaly No.5 of Saghand leach solution using DEHPA as extractant, kerosene as a diluent, and optimization of the effective parameters were investigated. In addition to uranium and thorium, rare earths elements also exist in Saghand ore. The effect of pH on the extraction of Yb and other existing elements shows that their extractions increase by increasing pH. The extraction of Yb, U, La, Y, Ce and Fe in pH= were 99.9, 8, .5, 99.8, 8.5 and 7.%, respectively. The increasing of the A/O ratio decreases the extraction of other elements more than Yb where it resulted in the increasing of the Yb separation. The theoretical number of extraction stages were determined in pH= and A/O=9 using McCabe-Thiele diagram. Stripping of the organic phase was also carried out by different concentrations of nitric acid.

The present work deals with successive uranium and thorium recovery from the sulfate leach liquor of the ore deposit of the 5th Anomaly of Saghand using liquid-liquid extraction technique, where trioctylamine (TOA) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) were used. The solvent extraction of uranium by trioctylamine in kerosene was investigated using Taguchi method. The extraction parameters were pH, extractant concentration, contact time and aqueous/organic volume ratio. The optimum conditions were determined as the extractant concentration of 5%, aqueous/organic volume ratio of 1, pH=1.6 and the contact time of 3 minutes. Under these conditions, the uranium extraction percent was 98.7% in a single step extraction process. For a deeper investigation of the achieved results by Taguchi method, the effect of different parameters such as contact time, temperature, concentration of extractant, and pH were considered. Thorium extraction from uranium extraction raffinate was performed by D2EHPA 4% in kerosene at pH=1.5-2 in a three step extraction process. The kinetic studies showed that the extraction follows a second order  kinetics. The optimium conditions for the selective stripping (back extraction) of uranium and thorium from the loaded organic phases were obtained when 5.0 M nitric acid and 1 M sulfuric acide were used, respectively.

This paper deals with the study of digestion processes effectiveness in processing metasomatite deposit of the Saghand anomaly No.5. To accomplish the task, the samples from metasomatite rocks of the Saghand anomaly No.5 were studied in laboratory. The sample containing minerals such as calcite, quartz, albite, actinolite, ilmenite, rutil, chevkenide, bastnasite, monazite, and sphen were first concentrated using the method of pre-concentration (electrostatic, magnetic and gravitation) which led to an increase in the rate of their heavy mineral from 10% to 50%. The purpose was to eliminate or reduce, calcite and other obtrusive minerals, and consequently have a better dissolution and a less consumption of acid. At this stage of study, and by using the produced concentrate, the effectiveness of the digesting process, the effect of different parameters such as temperature, digestion time, sulfuric acid concentration, solid-to-liquid ratio and oxidant concentration, with the aim of determining their optimum values, were studied which resulted in the following values for the above-mentioned parameters: temperature: 200°C, digestion time: 2h, sulfuric acid concentration: 10.8M, solid-to-liquid ratio: 0.33 (w/v), and oxidant (nitric acide) concentration: 5.3M. Under these conditions, the recovery extents of uranium, thorium and REE were found to be 85%, 83%, and 42%, respectively.

To study microbial oxidation of ferrous ions through the uranium bioleaching process, experiments were carried out in the internal loop air-lift reactor by Acidithiobacillus ferrooxidans. The microbial oxidation kinetics was evaluated with the Monod correlation and modified models for the substrate and product inhibition. The maximum recovery of uranium in the biological and control tests were 97.1% and 21%, respectively. Evaluation of the experimental data with the mentioned models showed that the modified model for the substrate inhibition gave a good fitting for all aeration rates. The R2-values were found to be 0.98, 0.97, 0.94 and 0.94 for the air superficial velocity of 0.0065, 0.0085, 0.01 and 0.015 m/s, respectively.

Narigan area in the southern part of the Bafq-Saghand metallogenic zone in Central Iran is a host of davidite-bearing quartz veins. Davidite is an important key mineral for exploration of not only uranium but also REE's in Central Iran. Narigan granite in the Narigan area is characterized by high-K calc-alkaline nature and its parental magma was partially contaminated by the Precambrian crust. The REE pattern of quartz veins is brought about by REE contents in davidite. The homogenization temperatures of vapor-liquid-solid (V-L-S) fluid inclusions in quartzes are >500˚C in quartz veins. Furthermore, the ∑REE contents (71910 to 90292 ppm) and U/Th ratios (<1000) in the studied davidites indicate upper 450˚C temperature for the generation of them. Based on the similarity of REE pattern of davidite to REE pattern of oxide-uranium minerals in the vein-type ores (characterized by negative Eu anomaly and high LREE/HREE ratio) as well as achievement of the homogenization temperatures for fluid inclusions and davidite formation; mineralization of this mineral can be related to granite related vein-type uranium deposits.

The electrical method as a geophysical survey can show the geological parameters including fragmentation, rock mass alteration index, saturation percentage and groundwater quality. These parameters play an important role in rock mass engineering classification by affecting the rock mass quality design (RQD) and geological strength index (GSI), mineralization of elements and drilling method. In this paper, using the vertical electrical sounding method in subsurface layers, the determination of these parameters and subsequently two mentioned indicators in anomalous III pyroclastic rock masses of Narigan deposit was investigated. The results showed that the interpreted electrical resistivity (using IPI2win software) has an acceptable correlation betweem the degree of alteration index and GSI in the rock mass. However, accurate determination of GSI and RQD using this geophysical method is not very reliable. In other words, using a mathematical equation, it is not possible to estimate the amount of GSI and the alteration index with the electrical resistivity.