CN103708419A

CN103708419A - Method for preparing of high-activity LiH microspheres through wet process

Info

Publication number: CN103708419A
Application number: CN201310741088.8A
Authority: CN
Inventors: 张迎春; 向茂乔; 洪明; 刘志昂; 冷佳迅; 张云
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2013-12-27
Filing date: 2013-12-27
Publication date: 2014-04-09
Anticipated expiration: 2033-12-27
Also published as: CN103708419B

Abstract

The invention discloses a method for preparing of high-activity LiH microspheres through a wet process, which belongs to the field of ceramic materials. The method comprises the following steps: (1) preparing slurry: dissolving paraffin wax in a saturated solution of petroleum ether or ethyl ether to serve as a ball milling medium, and ball milling lithium hydride in an argon atmosphere to obtain stable and uniform slurry; (2) forming a microsphere blank: dropping the slurry into a circulating argon tower to form spheres; (3) sintering: introducing argon in an atmosphere furnace for sintering, heating at speed of 10 DEG C/h, maintaining the temperature in four stages, sintering for 4 hours at 450 DEG C, and cooling at speed of 30 DEG C/h; (4) carrying out microsphere coating: putting the sintered microspheres into paraffin wax and into a super-saturated solution of petroleum ether or ethyl ether, taking out the microspheres and drying the microspheres in argon. The lithium hydride microspheres prepared by the method provided by the invention have the advantages of uniform size, high sphericity, good mechanical properties, controllable microsphere diameters and the like; the method also avoids problems generated in preparation of lithium hydride microspheres through a melting method, for example, a large amount of cracks and difficult mold filling and demolding of hot pressure casting forming, and the like; moreover, the equipment and preparation process are simple, the efficiency is high and mass production is available.

Description

A kind of wet method is prepared the method for high reactivity LiH microballoon

Technical field

The invention belongs to stupalith field, relate to the preparation method of ceramic microsphere, particularly a kind of the preparation of high reactivity LiH microballoon wet method and method for coating for nuclear fusion stack tritium propagation ceramic microsphere and hydrogen storage material field.

Background technology

Lithium hydride (LiH) has in vacuum and inert atmosphere that ordination number is little, thermodynamics is relatively stable, mechanical property is excellent, fusing point high (688 ℃), the low (0.775g/cm of density ³), hydrogeneous and high by (5.82 * 10 containing lithium amount ²²atoms/cm ³) etc. excellent performance.This stupalith can be used as structure and function material and is widely used in new energy materials field.As nuclear energy field can be used as neutron shielding material, neutron moderator, ceramic tritium-breeding material, ICF target materials etc.; In hydrogen storage material field, because hydrogen density surpasses liquid hydrogen, can be used as the solid-state hydrogen storage material of excellent performance.Lithium hydride microballoon have handling easily, transportation is convenient, specific surface area is large, the diffusion of gas and release property is good, to be conducive to thermal stresses lax and prevent the excellent properties such as irradiation cracking.Therefore, generally all need lithium hydride to be prepared into microballoon.

Lithium hydride is because chemical property is very active, can with most substance reactions, produce hydrogen and corresponding lithium-containing compound.Powder lithium hydride can spontaneous combustion in damp atmosphere, the reaction of blasting in the nitrogen of heating.Therefore the preparation of the microballoon of lithium hydride is very difficult.In the 1950's, the U.S. and Soviet Union material supply section scholar using lithium hydride as Nuclear weapons and space power source done widely research, comprising the preparation of microballoon.Owing to relating to military secret, all Research Literatures are just open in decades recently.But all do not obtain and be satisfied with achievement through a lot of experiments.Document 1(H. Sheinberg, R.E. Riley and J.M. Taub, Los Alamos Scientific Laboratory Report no. LA-4905-MS (April 1972)) be reported in metal hydride simple substance lithium in oil bath, but only seldom part success, and efficiency is low, sphericity is bad.Document 2(C.E. Messer, A Survey on Lithium Hydride, US AEC Report no. NYO-9470 (Oct. 1970)) in, adopt molten atomizing legal system for lithium hydride microballoon, but because of have an appointment when solidifying 19% volumetric shrinkage of lithium hydride, there is a large amount of crackles on the inner and surface of the microballoon of preparing and failure.(Carstens D H W, Farnum E H, Fries R J, et al. Fabrication of LiD in document 3 _0.5t _0.5microspheres for use as laser fusion targets [J]. Journal of Nuclear Materials, 1975,57 (1): 1-10) adopt granulation scorification to prepare (40-125 μ m) microballoon performance and be relatively good, but spherome surface crackle is many, ultimate compression strength is little, and efficiency is low and involve great expense.

summary of the invention

The present invention will solve key issue, change scorification and prepare lithium hydride microballoon present situation, avoid cracking because comparatively large vol shrinks, also avoid the problem such as mold filling and demoulding difficulty in hot die-casting molding simultaneously, reduce and prepare lithium hydride microballoon cost of equipment, and can manufacture out good sphericity, mechanical property is excellent, the lithium hydride microballoon that density is high, and for convenience of storing and transporting, lithium hydride microballoon is coated to processing.

Technical scheme of the present invention is:

Wet method is prepared the method for high reactivity LiH microballoon:

(1) preparation of slurry: take solid paraffin and sherwood oil or ether as raw material, under room temperature, solid paraffin is dissolved in sherwood oil or ether, be made into the saturated solution of paraffin, again in the glove box of argon gas atmosphere lithium hydride block and paraffin saturated solution by volume 1:1 put into vacuum sphere grinding jar, add again appropriate steel ball, after vacuumizing, in an atmospheric argon gas, ball milling is 4 ~ 8 hours, forms stable, uniform lithium hydride slurry;

(2) moulding of microballoon: the slurry after ball milling in above-mentioned steps (1) is completed to moulding and dry in Fig. 1 device simultaneously.First closing switch 1 and material are managed switch 9, open tracheae switch 7, open vacuum pump 6, sealed vessel 3 is vacuumized, then from airway 5, be filled with argon gas, making sealed vessel 3 internal pressures is a normal atmosphere, realize argon shield slurry, then open switch 1, from feed-pipe 2, add the slurry after ball milling in above-mentioned steps (1), open the abundant mixed slurry of agitator 4, then open recovery catheter switch 21 and tunger tube switch 18 simultaneously and pass into argon gas, regulate argon gas pump 17, making argon flow amount in argon air tower 12 is 200 milliliters of per minutes, displace the air in argon air tower, open again material pipe switch 9, regulate pump and under meter 10, the speed that makes dropper 13 ooze microballoon 14 be 2 seconds each, the argon gas flowing out from gas mesh sieve 15 makes microballoon 14 slow decreasings, and the argon gas of circulation is taken away sherwood oil or the ether in microballoon 14, microballoon 14 is dried.Select different diameter dropper 13, the titratable microballoon that goes out different diameter;

(3) sintering: the dried microballoon that above-mentioned steps (2) is oozed, logical argon gas sintering in atmosphere furnace, temperature rise rate be 10 ℃ per hour, 55 ℃ of insulations 30 minutes, at 230 ℃, 350 ℃ and 410 ℃, be incubated respectively 60 minutes, 450 ℃ of sintering 4 hours, with 30 ℃, per hourly cool to 200 ℃ subsequently, then cool to room temperature with stove;

(4) microballoon is coated: the microballoon after above-mentioned steps (3) sintering is put into the sherwood oil of paraffin or the supersaturated solution of ether, then it is dry in argon gas atmosphere glove box to take out lithium hydride microballoon, and after sherwood oil or ether volatilization, the completely coated microballoon of paraffin.

The present invention compared with prior art had advantages of:

(1) technical process of the present invention is simple, easy to operate, efficiency is high, can manufacture, and has reduced the high cost of equipment that scorification is prepared lithium hydride microballoon;

(2) microballoon good sphericity, big or small homogeneous, good mechanical property, and surface and inside do not have crackle, avoided scorification to prepare the crackle of lithium hydride generation;

(3) after green microspheres is dried, paraffin is wrapping lithium hydride fine powder, has completely cut off lithium hydride and has contacted with external substance, has prevented the oxidation of lithium hydride;

(4) to the lithium hydride microballoon after sintering, carried out paraffin coated, facilitated transportation and the storage of lithium hydride microballoon, and coating layer easily removes, in sherwood oil that only need be after intensification or ether, washing just can be removed paraffin coating layer several times;

(5) compare with hot die-casting molding, only adopting sherwood oil or ether is that the paraffin saturated solution of solvent is as lithium hydride ball-milling medium, lithium hydride green microspheres paraffinicity is low, and lithium hydride solid content is high, has avoided the problems such as mold filling in hot die-casting molding, demoulding difficulty simultaneously.

Accompanying drawing explanation

Fig. 1 be the present invention design prepare the moulding of lithium hydride green microspheres and dry schematic diagram.

In figure: 1 switch, 2 feed conduits, 3 sealed vessels, 4 agitators, 5 airways, 6 vacuum pumps, 7 tracheae switches, 8 sealing baffles, 9 material pipe switches, 10 pumps and under meter, 11 material pipes, 12 argon air towers, 13 droppers, 14 microballoons, 15 gas mesh sieves, 16 tunger tubes, 17 argon gas pumps, 18 tunger tube switches, 19 argon gas, 20 reclaim conduit, 21 and reclaim catheter switch.

Fig. 2 is the X ray diffracting spectrum (XRD) that the embodiment of the present invention 1 is prepared lithium hydride microballoon.

Detected result shows, as technological invention content, the lithium hydride microballoon sphericity that wet method is prepared and density is high, surface and inside do not have crackle, and acquisition for microballoon be pure lithium hydride.

embodiment:

embodiment 1:

(1), under room temperature, 10 grams of paraffin are dissolved in the sherwood oil of 30 milliliters.After dissolution equilibrium, get supernatant liquid, obtain the saturated solution of paraffin;

(2) saturated solution of pressing in lithium hydride and above-mentioned steps (1) is long-pending than 1:1, takes 15 grams of lithium hydrides, 13.6 grams of paraffin saturated solutions, suitably grain size proportion steel ball, is positioned over vacuum sphere grinding jar, after vacuumizing, in ball grinder, be filled with an atmospheric argon gas, ball milling 6 hours;

(3) at argon gas gloves, take out the slurry after above-mentioned steps (2) ball milling in mutually, adopt the moulding of Fig. 1 device.First closing switch 1 and material are managed switch 9, open tracheae switch 7, open vacuum pump 6, sealed vessel 3 is vacuumized, then from airway 5, be filled with argon gas, making sealed vessel 3 internal pressures is a normal atmosphere, realize argon gas atmosphere protective paste, then open switch 1, from feed-pipe 2, add the slurry after ball milling in above-mentioned steps (2), open the abundant mixed slurry of agitator 4, then open simultaneously reclaim catheter switch 21 and tunger tube switch 18, regulate argon gas pump 17, making argon flow amount in argon air tower 12 is 200 milliliters of per minutes, displace the air in argon air tower, open again material pipe switch 9, regulate pump and under meter 10, the speed that makes dropper 13 ooze microballoon 14 be 2 seconds each, the argon gas flowing out from gas mesh sieve 15 makes microballoon 14 slow decreasings, and the argon gas of circulation is taken away the sherwood oil in microballoon 14, make microballoon 14 dry,

(4) collect dry rear microballoon in above-mentioned steps (3), in atmosphere furnace, logical argon gas sintering.Argon gas flow velocity is 80 milliliters of per minutes, temperature rise rate be 10 ℃ per hour, 55 ℃ of insulations 30 minutes, at 230 ℃, 350 ℃ and 410 ℃, be incubated respectively 60 minutes, 450 ℃ of sintering 4 hours, with 30 ℃, per hourly cool to 200 ℃ subsequently, with stove, cool to room temperature, obtaining the lithium hydride microballoon of 1 millimeter.Microballoon X-ray diffractogram (XRD) is as Fig. 2;

(5) the lithium hydride microballoon after above-mentioned steps (4) sintering is positioned in the paraffin supersaturated solution of 40 ℃, then homodisperse taking-up, is positioned over seasoning in argon gas, obtains the coated lithium hydride microballoon of paraffin.

embodiment 2:

Sherwood oil in embodiment 1 makes ether into, and all the other parameters are identical.

Claims

1. wet method is prepared a method for high reactivity LiH microballoon, it is characterized in that the step of preparation is:

(1), adopt the saturated solution of paraffin in sherwood oil or ether as lithium hydride the ball-milling medium in argon gas;

(2), only adopt in saturated solution paraffin as the forming skeleton material of lithium hydride green microspheres in argon air tower;

(3), adopt the supersaturated solution of paraffin as the coating material of lithium hydride microballoon.

2. wet method according to claim 1 is prepared the method for high reactivity LiH microballoon, it is characterized in that:

In described step (1), in argon gas atmosphere during ball milling, the volume ratio 1:1 of paraffin saturated solution and lithium hydride; Concrete grammar is as follows:

At room temperature configuring the saturated solution of paraffin in sherwood oil or ether, is that 1:1 takes raw material by the volume ratio of saturated solution and lithium hydride, puts into vacuum sphere grinding jar, and after vacuumizing, in an atmospheric argon gas atmosphere, ball milling is 4 ~ 8 hours.

3. wet method according to claim 1 is prepared the method for high reactivity LiH microballoon, it is characterized in that:

In described step (2), in argon air tower, paraffin is as the framework material of lithium hydride green microspheres, and wherein in argon air tower, the flow velocity of argon gas is 200 milliliters of per minutes; Concrete grammar is as follows:

First closing switch (1) and material are managed switch (9), open tracheae switch (7), open vacuum pump (6), sealed vessel (3) is vacuumized, then from airway (5), be filled with argon gas, sealed vessel (3) internal pressure is a normal atmosphere; Then open switch (1), from feed-pipe (2), add ball milling disposed slurry, open agitator (4) mixed slurry, then open recovery catheter switch (21) and tunger tube switch (18) simultaneously and pass into argon gas, regulate argon gas pump (17), in argon air tower (12), argon flow amount is 200 milliliters of per minutes, then opens material pipe switch (9), regulate pump and under meter (10), the speed that dropper (13) oozes microballoon (14) be 2 seconds each.

4. wet method according to claim 1 is prepared the method method of high reactivity LiH microballoon, it is characterized in that:

In described step (3), use the supersaturated solution of paraffin as the coated raw material of lithium hydride microballoon, concrete grammar is as follows:

Lithium hydride microballoon is put into the supersaturated solution of paraffin, then taken out the argon gas glove box seasoning that lithium hydride microballoon is put into room temperature.