6 results about "Thorium nitrate" patented technology

The invention provides an ultra-pure thorium fluoride production process which comprises the following steps: preparing a nanoscale ThF4.xNH4F precursor through a gas-liquid-solid three-phase reaction, atomizing an ammonium fluoride solution into microdroplets by adopting ultrasonic atomization, and carrying out synergistic reaction with gaseous ammonium fluoride and a liquid-phase thorium nitrate solution; a microwave-plasma synergistic fluorination reaction is adopted, and the precursor is heated in a high-purity inert atmosphere to generate crude thorium fluoride; according to the ultra-pure thorium fluoride production process provided by the invention, the purity of thorium fluoride is remarkably improved through the technical means of preparation of a nanoscale precursor through a gas-liquid-solid three-phase reaction, microwave-plasma synergistic fluorination, multi-stage sublimation combined with graphene-based nano trapping membrane purification, intelligent process control, by-product closed-loop recovery and the like; the impurity content is low, and the requirements of nuclear reactor fuel substrates and high-end optical coatings on ultra-high purity are met. The method has the advantages of high yield, high process stability and small purity fluctuation among batches, and the production efficiency and the product consistency are obviously improved.

The invention relates to the technical field of chemical component analysis, in particular to a method for measuring fluorine in cryolite, and aims to solve the problems that when the fluorine content in the cryolite is measured by adopting a traditional distillation-thorium nitrate titration method or lead fluoride chloride precipitation-mercuric nitrate volumetric method and the like at present, the operation is time-consuming and labor-consuming, the reagent is relatively high in harmfulness and the detection precision is relatively low. The method comprises the following steps: decomposing a cryolite sample by using a sodium carbonate-sodium silicate mixed solvent to enable fluorine to become water-soluble fluoride, generating a lead fluorochloride precipitate by using hydrochloric acid and lead acetate as precipitants, filtering out the precipitate, dissolving the precipitate in nitric acid, precipitating chloride ions by using a silver nitrate standard solution, and measuring the concentration of the excessive silver nitrate by using ferric sulfate as an indicator. Compared with traditional fluorine content determination, the method has the advantages that the detection difficulty is reduced, the use of highly toxic reagents is effectively avoided, the test safety risk is greatly reduced, and the method is widely applicable to determination of fluorine in cryolite for factory inspection.

The invention relates to a method for solidifying an aqueous solution of thorium nitrate Th(NO3)4, which method comprises the steps of: a) concentrating the aqueous solution by circulating the aqueous solution in an evaporator comprising an inlet for feeding the aqueous solution into the evaporator and an outlet for discharging the aqueous solution from the evaporator, wherein a temperature gradient prevails from a temperature θ1 of between 50°C and 70°C at the inlet of the evaporator to a temperature θ2 of between 130°C and 160°C at the outlet of the evaporator, whereby a concentration gradient of the aqueous solution is established between the inlet and the outlet of the evaporator, the establishment of the concentration gradient leading to a concentrated aqueous solution of thorium nitrate pentahydrate of formula Th(NO3)4.5H2O at the outlet of the evaporator; then b) transferring the thus-concentrated aqueous solution from the outlet of the evaporator to a container in which the aqueous solution is left to cool, whereby the aqueous solution solidifies in the container by crystallization of thorium nitrate pentahydrate. The invention can be used for the storage of aqueous solutions of thorium nitrate in solid form pending subsequent recovery of these solutions.

The invention discloses a device and a method for measuring the solubility product of trace actinide colloids. The device comprises a nitrogen gas cylinder and a small plastic bottle. According to the device and the method for measuring the solubility product of the trace actinide colloid, a set of experimental device which can stably release ammonia gas, is used for generating An (OH) 4 (am) colloid through acid-base titration and can capture a colloid generation critical point in a system is designed, only the concentration of hydrogen ions in a solution is changed, and the concentration of An4 + is not changed, so that single-factor control is facilitated; the gas phase titration process is slower than the traditional liquid phase titration process, and the slow change and accurate control of the pH value of the solution to be titrated can be realized; the concentration of the ammonia gas introduced into the titration system can be adjusted in various modes, so that low-concentration ammonia gas sample introduction can be realized; ammonia molecules are blown into an acidic thorium nitrate (plutonium nitrate) system in the form of bubbles, and are stirred by a magnetic stirrer, so that the acid-base reaction is more sufficient; an asymmetric flow field separation instrument and a matched ultraviolet and visible absorption spectrometer are combined with a mass spectrometer under the extremely low colloid concentration to enrich and observe the colloid, and the critical point of actinide colloid generation is accurately obtained.

A method for extracting high-purity lead 212 based on a decay chain of thorium nitrate comprises the following steps: (1) a step of removing Pb by using a package: enabling a preliminarily filtered thorium nitrate solution to flow through a silica gel column A to adsorb and enrich Pb in the thorium nitrate solution so as to obtain a solution A; (2) preliminary purification: enabling the solution A to flow through a diatomite filter column, and adsorbing and enriching Th and Ra to obtain a solution B; (3) secondary purification: filling a DTPA modified silica gel column B with the solution flow B, and adsorbing and enriching 212Bi to obtain a solution C; (4) re-purification: taking a sulfydryl modified silica gel column C, enriching and intercepting 212Pb, and flowing out waste liquid; (5) elution and re-enrichment: eluting 212Pb on the silica gel column C by hydrochloric acid to obtain an eluent C, and enabling the eluent C to flow through a filling AG1-X8 resin column; and (6) leaching: leaching the enriched resin column by using a diammonium hydrogen citrate solution to obtain a final solution.

An apparatus and method for continuously preparing Pb-212 solution using thorium nitrate. The apparatus includes a thorium nitrate solution bottle, a first Pb-212 solution bottle, a second Pb-212 solution bottle, an air pump, a first electromagnetic three-way valve, a second electromagnetic three-way valve, a third electromagnetic three-way valve, a pressure relief valve, a spray head, a water pump, a dilute nitric acid solution bottle, and hoses. The thorium nitrate solution bottle is connected to the first and second Pb-212 solution bottles via hoses to form an airflow circulation loop under the action of the air pump, the first electromagnetic three-way valve, and the second electromagnetic three-way valve. The dilute nitric acid solution bottle is connected to the first and second Pb-212 solution bottles via hoses under the action of the water pump and the third electromagnetic three-way valve. The air pump and electromagnetic three-way valves are configured to deliver high-concentration Rn-220 from the thorium nitrate solution bottle into the first and second Pb-212 solution bottles at regular intervals, and the water pump is configured to continuously pump dilute nitric acid into the first and second Pb-212 solution bottles to continuously prepare the Pb-212 solution. The device of this invention has a simple structure and is easy to set up. It is inexpensive and environmentally friendly, and enables the continuous preparation of Pb-212 solution, which has great market application prospects.