For the salicylic acid chelating resin, the specific surface area and pore size were determined using low temperature nitrogen adsorption-desorption method; and its thermodynamic stability was examined. The effects of solution pH and ρ(Cl^-) on its uranium adsorption performance were studied, and its adsorption isotherms, adsorption kinetics, and desorption performance were also investigated. The results show that the specific surface area of salicylic acid chelating resin is 32.34 m²/g, and the pore size is 32.08 nm, The salicylic acid chelated resin has good thermal stability when the temperature is below 180 ℃. When the pH is in the range of 7~9, the resin has good adsorption performance, and the uranium adsorption capacity can reach 14.1 mg/g dry resin. The presence of Cl^- can reduce the adsorption capacity for uranium. When the ρ(Cl^-) is 3.0 g/L, the uranium adsorption capacity decrease by about 9.2%. When the equilibrium ρ(U) in solution is 400 mg/L, the uranium adsorption capacity of the resin reach its maximum, at 153 mg/g dry resin. After 20 h adsorption, the adsorption process reach equilibrium. Both acidic and alkaline desorption agents show good desorption performance for resins, with desorption rates both above 94%. For the real uranium leaching solution with ρ(U) of 21.2 mg/L and ρ(Cl^-) of 3.36 g/L, the uranium adsorption capacity of the salicylic acid chelating resin can reach 14.7 mg/g dry resin after 24 h adsorption, indicating good uranium adsorption performance.

In the fine filtration production of filter liquor of monazite alkali decomposition, the use of iron plate and frame filter had problems such as poor filtration effect, low automation level, and significant temperature drop after filtration. Improvements were made to the existing fine filtration process, and the applicability of surface filter as fine filtration equipment for filter liquor of monazite alkali decomposition was studied. The results show that the surface filter with PP and PTFE membrane materials has a filtration retention rate of 93% after one hour, which is higher than the retention rate of the iron plate and frame filter. Compared with the iron plate and frame filtration, the surface filter has better filtration efficiency, higher automation level, and better solution insulation effect, which can be well applied in the fine filtration of filter liquor of monazite alkali decomposition.

A method for simultaneous determination of As and Hg in uranium ore by hydride generation atomic fluorescence spectrometer was established, and the effects of digestion temperature, digestion time, medium system, KBH₄ concentration, and uranium content on the detection results were investigated. The results show that the optimal conditions for this method are to dissolve uranium ore with (1+1) aqua regia for 60 minutes at 125 ℃, (5+95)HCl as the medium and 2.0% KBH₄ solution as the reducing agent. The detection limits of this method are 0.006 μg/g (for As) and 0.001 μg/g (for Hg), with relative standard deviations of 2.46% (for As) and 4.22% (for Hg), and recovery rates of 98%~103%(for As) and 97%~106% (for Hg). This method has high accuracy and precision, and can meet the requirements for the determination of As and Hg in uranium ore.

Acid concentration and uranium concentration in raffinate phase generally need to be measured separately, which is cumbersome and requires a large amount of work. A new method for continuous measurement of acid concentration and uranium concentration in raffinate phase was developed. A strong base was used as titration agent, the color change of the indicator was selected to indicate the titration endpoint. After completing the acid concentration detection, the sulfuric acid and arsenazo III solutions with a certain amount and concentration were added to the above solution to make the solution color, and the absorbance of the color solution was measured at 650 nm. The results show that the precision of measuring acid concentration and uranium concentration is 1.53% and 1.13% respectively, the indication error for measuring acid concentration and uranium concentration is 1.69% and 1.52% respectively. For the measurement of actual water samples, the measurement data of this method is basically consistent with that of the laboratory current methods, the recovery rate of acid concentration measurement is between 97.0% and 102.5%, and the recovery rate of uranium concentration measurement is between 97.0% and 102.0%. The method is suitable for continuous monitoring of acid concentration and uranium concentration in raffinate phase and has accurate and fast characteristics.

The detection method of ²¹⁰Po in the surface water around the decommissioned uranium mine was studied, and the activity level of ²¹⁰Po in the surface water around the uranium mine was investigated. Using iron(III) hydroxide as the carrier, ²¹⁰Po in the water sample was adsorbed and allowed to self-deposit on a copper plate in a hydrochloric acid-sodium chloride system, and then measured on an alpha spectrograph. The detection limit of the method is 0.001 Bq/L,the precision is better than 10%, and the recovery is between 93.4% and 106.6%. The results show that the activity concentration of ²¹⁰Po in the surface water around the decommissioned uranium mine is between 0.001 and 0.223 Bq/L, indicating a certain level of pollution. There is a risk of transferring to humans through drinking water and food chain, resulting in an increase in internal exposure dose to residents. It is necessary to strengthen monitoring of surface water around the uranium mine and evaluation of public exposure.

Spectinomycin is an alkaline water-soluble aminoglycoside antibiotic, produced by the fermentation of actinospectacin. The prewashing process of D152 resin with EDTA-2Na was studied, by selecting the proper concentration, pH and flow rate of the prewashing solution, the extraction of high purity macromycin hydrochloride was realized, and the recovery process of EDTA-2Na was determined. The optimal prewashing parameters were obtained: the concentration of EDTA-2Na solution is 0.015 mol/L, the pH of prewashing solution is 7.5~8.0, and the flow rate is 1.0~2.0 BV/h. The prewashing process is simple, low cost and high recovery, which ensures the adsorption yield of D152 resin and realizes the green extraction.

Uranium is an important strategic resource as well as a heavy metal element with chemical and radioactive toxicity. Currently, the efficient remediation of uranium in groundwater from uranium mines remains a huge challenge for environmental protection and ecological security. In this study, sodium tripolyphosphate was used to modify nano zero-valent iron (nZVI), successfully preparing STPP-nZVI. The effects of solution pH, STPP-nZVI dosage, temperature, time, U(VI) concentration, and interfering ions on the STPP-nZVI-mediated remediation of U(VI) in groundwater were investigated. FTIR, SEM-Mapping, and XPS were employed to explore the mechanism underlying STPP-nZVI’s remediation of uranium-contaminated groundwater. The results indicate that STPP-nZVI is suitable for treating weakly acidic and alkaline uranium-contaminated groundwater. At a pH of 5.0, the maximum adsorption capacity of STPP-nZVI for U(VI) reached 102.72 mg/g, with U(VI) adsorption occurring as a spontaneous endothermic process. The removal of uranium by STPP-nZVI is primarily attributed to adsorption and reduction. STPP-nZVI materials demonstrate promising application prospects for treating weakly acidic and alkaline uranium-contaminated groundwater.

Since the independent path with so many applications in the ventilation network, it’s significant to search a quick algorithm in the complex network, which can optimize the regulation of ventilation network effect. However, the traditional algorithm of independent path can’t deal with special network search problem, the paths tending to be long, which can’t assure the independence and completeness simultaneously. To solve the problems of traditional independent path search algorithms, the key search theory of independent path was studied systematically and thoroughly. Based on the analysis about the limitation of traditional algorithms, an improved algorithm of independent path was presented. The problem of cut edge and cut vertex in the network were handled to avoid the infinite loop or abortion. The failure cause of the search of independent path completeness was analyzed. And this algorithm can solve the problems of ventilation network that includes unidirectional circuit by modifying the memory search strategy. An adaptive method is proposed according to the improved independent path algorithm, which can get a regulation tree with optimized position and get a set of optimal solutions of the air quantity regulation through increasing resistance.

Investigation on release characteristics of radon concentration, radon release amount, migration and diffusion trend of radon of an acid in-situ leaching uranium mine was carried out on the basis of data collection and field investigation. This study monitored radon concentration of source items and surrounding environment on uranium milling plant vents, leaching tanks, evaporation ponds and recovery wells with adoption of E-Perm electret detector, solid track detector and RAD7 radon detector. The results show radon concentration level is highest at top opening of leaching tanks, nevertheless affected area is no more than 500 m. Lowest radon concentration appeare at point of recovery wells. The annual total radon release of the acid in-situ leaching uranium mine is about 1.75 TBq/a, milling plant and leaching tanks are important radon release source items, which accounte for 58% and 39% of the total radon release respectively, additionally radon release of recovery wells and evaporation ponds account for 3% of the total radon release. In summary, the normalized annual radon release amount of the acid leaching uranium mine is much smaller than that of underground mine exhaust shaft.

The main causes of tailings dam failure include seepage damage, slope instability, seismic liquefaction, and ultra-high dam height. The high seepage line inside the tailings dam may cause seepage damage, and in severe cases, it may lead to slope instability, damage, and even dam failure. The common methods for reducing the seepage line of dam bodies have problems such as high construction difficulty, high manual maintenance cost, and complex equipment maintenance management. The horizontal drainage method is used to install horizontal filter pipes in the drainage blind ditch close to the horizontal level to reduce the seepage line. This project adopts the method of drilling horizontal holes inside the dam body and installing seepage pipes inside the holes to form a horizontal drainage body. The seepage pipes form a drainage network through the main collection pipe outside the dam body. The water inside the dam seeps into the drainage pipes, then converges to the main water collection pipe, and finally flows out of the dam by gravity. This method has the advantages of low cost, low energy consumption, and easy management, and is a practical and feasible method to reduce the seepage line of tailings pond。