36 results about "Nuclear graphite" patented technology

The invention discloses a nuclear graphite material preparation method including the following steps: (1) mixing and kneading; (2) grinding; (3) isostatic compaction; (4) roasting, to be more specific, baking treatment of the product obtained by the step (3) in an atmosphere furnace introduced with halogen or halogenated hydrocarbon at the treatment temperature of 800 to 1100 DEG C; (5) dipping; and (6) roasting; according to the method, in the roasting process, a halogen or halogenated hydrocarbon purified gas is introduced, a purification procedure is inserted in without reduction of the common preparation step, the cost of purification can be greatly reduced, in the roasting process, asphalt volatile components may cause many holes in graphite blocks, the holes greatly facilitate the purified gas to enter into the graphite blocks for purification so as to facilitate further purification of nuclear graphite blocks and great reduction of impurities and boron equivalent; the nuclear graphite material preparation method has the advantages of simple process, convenient operation, less production equipment, can further reduce the cost, and is convenient in popularization and application, and suitable for mass production.

The invention discloses a nuclear graphite material composition and a preprocessing method. The nuclear graphite material composition comprises 10 to 20 parts of petroleum coke powder, 70 to 80 parts of tar coke powder, 10 to 15 parts of graphite powder, 40 to 45 parts of coal tar and 1 to 3 parts of surfactant. The nuclear graphite material is prepared by the steps of kneading the raw materials, secondarily crushing the raw materials, isostatically pressing the raw materials, roasting the raw materials and the like. In the invention, the raw materials are made in China, an alkali metal catalyst is not used, isostatic technology is adopted, the prepared nuclear graphite material is low in cost, the uniformity of isotropy is high; and the antioxidant performance is high.

The invention discloses a method for preparing a SiC/C ceramic composite material through hot pressing sintering. The method comprises the following steps: forming a base material by using 87-91% of submicron beta-SiC micro-powder, 8-12% of aluminum nitride powder and 0.5-1% of a dispersant, adding the base material to an organic solvent, uniformly stirring the base material and the organic solvent, sequentially alcohol-soluble resin, a binder, a lubricant and highly-pure nuclear graphite powder, and uniformly stirring above materials to obtain a mixture; drying the mixture, scattering the dried mixture, and carrying out sealed ageing; and sequentially carrying out green body compacting, drying, pre-burning, vehicle working and high-temperature hot press sintering on the obtained aged powder to obtain the SiC/C ceramic composite material.

The invention relates to the technical field of microcrystalline graphite production and discloses nuclear graphite based on microcrystalline graphite as a raw material and a preparation method thereof. The nuclear graphite prepared from cryptocrystalline graphite has ultrahigh heat conductivity, high graphitization, low isotropic ratio and higher bending strength; compared with various cokes in the prior art, the nuclear graphite has the advantages that isotropic graphite at isotropic ratio of 1.1-1.15 is easily acquired in the manner of isostatic pressing and the thermal diffusivity of greenware of microcrystalline graphite is far higher than that of green ware of coke powder, so that the microcrystalline graphite is more beneficial to baking; the equivalent weight of ash content and boron in the nuclear graphite prepared according to the invention can meet the impurity requirement of nuclear graphite.

The invention discloses a preparation method for a graphite surface SiC coating used for a molten salt reactor. The preparation method comprises the following steps: adding polycarbosilane or modifiedpolycarbosilane into solvent to be dissolved to obtain polycarbosilane or modified polycarbosilane impregnant; vacuumizing a nuclear graphite construction member in impregnation equipment; adding impregnation liquid into the impregnation equipment for impregnation and drying under high-pressure inert atmosphere; carrying out roasting processing on the dried impregnation nuclear graphite construction member in a high-temperature furnace under the inert atmosphere to obtain the nuclear graphite construction member coated with the SiC coating. The preparation method has the advantages of simpletechnology and low cost and can be produced on a large scale.

The invention belongs to the technical field of nuclear graphite material production, and provides a preparation method of a nuclear graphite material. Adopted preparation raw materials comprise asphalt coke, needle coke, graphite powder and asphalt. In the preparation raw materials, the mass ratio of the asphalt coke to the needle coke to the graphite powder is 40:40:20, and the mass of the asphalt accounts for 45% of the total mass of the asphalt coke, the needle coke and the graphite powder. The preparation method comprises the following steps: (1) carrying out grinding: respectively grinding the asphalt coke, the needle coke and the graphite powder into powder with a particle size of 5000 meshes; (2) carrying out mixing and kneading; (3) carrying out crushing and grinding: carrying outcrushing by using a jaw crusher, and carrying out spiral extruding, milling treatment and grinding until the particle size is 4000 meshes and the purity is higher than 85%; (4) carrying out forming and pressing; (5) carrying out roasting, wherein the roasting temperature is 850 DEG C, and the temperature is kept for 48 hours; and (6) carrying out graphitizing: carrying out graphitizing treatmenton fired roasted products at a temperature of 2800-3200 DEG C. The preparation method disclosed by the invention is simple in raw material preparation and low in cost, and can be widely applied to thefield of nuclear graphite material production.

The invention provides a spherical graphite corpuscle compound carbon material, which is a compound graphite composed of spherical graphite with a clad sheet of nonferrous metal; the graphite that is almost the nuclear pure grade is adopted as the raw material, then a PCS system is utilized to collide, curl, knead, compact, conglobate and clad the graphite corpuscle for surface treatment, the rhombus crystal structure of the natural graphite is improved from 20 percent to about 80 percent, then nonferrous elements is clad or inserted into the interlamination of the spherical graphite crystal, the direction of the clad compound material is changed from uniform direction to random direction and the clad compound material has low specific area and high stacking density. The beneficial effect is that: the clad spherical graphite completely changes the crystal structure and microstructure of the natural graphite, and has large electrochemical capacity, good chemical and thermo-stability and high charge-discharge efficiency; meanwhile, the clad spherical graphite can not only be used as the cathode material of the lithium ionization cell but also can be used as the raw materials for isotropic high-end graphite products such as nuclear graphite; In addition, the production technology is simple, the cost is low and the performance is reliable.

A highly isotropic graphite useful for, inter alia, nuclear applications is disclosed, which has a ash content of less than 300 ppm and a boron equivalence of less than about 2 ppm without requiring a post graphitization purification step.

The invention discloses a high-temperature self-propagating solidifying method for radioactive graphite, which includes: firstly analyzing components and contents of the components of the radioactive graphite; designing formula of a solidified body by utilizing graphite, aluminum, titanium dioxide and the radioactive graphite as raw materials; mixing, refining and prepressing the raw materials; igniting formed samples at the temperature ranging from 1500 DEG C to 3000 DEG C and finally obtaining the radioactive graphite solidified body to realize solidifying after the samples are burned automatically. The high-temperature self-propagating solidifying method is simple in operation, high in production efficiency, fine in repeatability and capable of massively disposing radioactive graphite discharged from the relevant fields, such as nuclear power plants and the like.

The invention discloses a high-temperature self-propagating curing method for strontium-containing radioactive graphite. The method comprises the following steps of: firstly, analyzing compositions and content of the strontium-containing radioactive graphite; secondly, designing a cured body formulation by using graphite, titanium and the strontium-containing radioactive graphite as raw materials; thirdly, mixing, refining and pre-pressing the raw materials; fourthly, igniting a molded sample at the temperature of between 1,500 and 3,000DEG C; and finally, obtaining a strontium-containing radioactive graphite cured body to realize the curing. The high-temperature self-propagating curing method is simple in operation, high in working efficiency and high in repeatability, and can be widely applied to large-scale disposal of strontium-containing radioactive nuclear graphite discharged by nuclear power plants and the like.

The invention discloses a preparation method of high-purity nuclear graphite, and provides graphite, wherein the ash content of the graphite is less than about 300 ppm; the boron equivalent of the graphite is less than about 5.0 ppm; and the isotropous ratio of the graphite is about 0.85-1.5, which is calculated by dividing the CTE (Coefficient of Thermal Expansion) in the crosscutting texture direction by the CTE in the texture direction. The preparation method disclosed by the invention comprises the following steps of: grinding uncalcined needle coke into fine powder, mixing the fine coke powder with an adhesion agent, namely asphalt, then, grinding the mixture to form moulding powder, uniformly moulding the powder to form an expected shape of a graphite part, and roasting, densifying and graphitizing the blank product so as to obtain high-purity graphite having high isotropy. The high-purity nuclear graphite prepared by the invention is free from impurities and still has improved isotropy and controllable average density and bending strength; and thus, the high-purity nuclear graphite can be applied to a new generation of nuclear fission and ultra-high-temperature reactors.

The invention discloses a preparation method of a graphite surface pyrolytic carbon coating for a molten salt reactor. The preparation method comprises the steps: adding thermosetting resin into a solvent to be dissolved to prepare a thermosetting resin dispersion liquid; vacuumizing a nuclear graphite member in impregnation equipment; adding the thermosetting resin dispersion liquid into the impregnation equipment, and carrying out impregnation and drying in the existence of high-pressure inert gases; and after drying, carrying out solidification under pressure and roasting treatment on the impregnated nuclear graphite member at an inert atmosphere to obtain a nuclear graphite member coated by a pyrolytic carbon coating. The preparation method has the advantages of simple process, low cost and large-scale production.

The invention discloses a preparation method of a bismuth oxychloride graphite composite electrode material. The preparation method comprises the following steps: firstly, putting a graphite plate into an etching solution for chemical etching; then cleaning and drying; dissolving bismuth nitrate pentahydrate, potassium chloride and a dispersing agent into ethylene glycol at room temperature, stirring, and transferring into a container to serve as a bismuth oxychloride loading agent for later use; putting the dried graphite plate into a reaction kettle, transferring the bismuth oxychloride loading agent for later use into the reaction kettle, putting the reaction kettle into a drying box for water bath heating, promoting bismuth ions to hydrolyze under the participation of chloride ions at high temperature, and forming bismuth oxychloride crystal nucleuses on the surface of the graphite plate; taking out the reaction kettle, cooling, and washing the graphite plate loaded with the bismuth oxychloride crystal nucleus until only one layer of firmly loaded bismuth oxychloride is left; and drying in a drying oven to obtain the bismuth oxychloride graphite electrode composite material. According to the preparation method, the bismuth oxychloride powder which is difficult to load originally is uniformly and completely loaded on the graphite plate by utilizing a hydrothermal method, and the chemical adsorption activity of the loaded material is maintained to the greatest extent.