CN107845433B - A kind of MOX powder forming agent and lubricant adding method - Google Patents

Abstract

A method for adding MOX powder forming agent and lubricant, comprising the following steps: step 1: selecting zinc stearate; step 2: drying zinc stearate particles at 15-40°C and vacuum degree of 0.01-0.5Pa Dry for 0.5-3 hours to remove the volatile impurity elements and avoid the abnormal growth and melting of particles caused by excessive temperature; Step 3: Use a 20-100 mesh screen to screen the zinc hardate particles treated in step 2 Screening treatment; Step 4: Calculate the required MOX particle amount with a filling rate of 15% to 35% and add it to the ball mill tank, and add the zinc stearate particles processed in step 3 to the In MOX granules, feed cooling water at 15-38°C at a speed of 5-15L/min to avoid agglomeration and melting caused by material heating. Step 5: Mix at a speed of 1-10r/min for 5-45min to make the hard Preliminarily mix zinc phosphate and MOX particles evenly, then gradually increase the speed of the mixer at a speed of 1-20r/min, and mix at a speed of 10-100r/min for 15-600min to avoid MOX particles caused by violent mixing broken.

Description

A kind of MOX powder forming agent and lubricant adding method

technical field

The technology belongs to the field of forming agent and lubricant addition, and specifically relates to a method for adding MOX powder forming agent and lubricant.

Background technique

The MOX powder is fine and has poor fluidity. At the same time, the MOX pellets are small in size and contain a central hole and a chamfer structure. Therefore, in order to reduce the friction between the powder particles and the mold wall and the grinding punch during molding, and improve the density distribution of the green body, To reduce die wear and facilitate demoulding, forming agents and lubricants should be added.

At present, there are five major deficiencies in the powder forming agent and lubricant adding technology in the traditional industry. First, MOX materials will spontaneously generate heat, while traditional forming agents are easy to melt when heated; second, MOX materials have poor fluidity. Forming agent will easily lead to obvious deterioration of bulk density and fluidity of the material, which will have an adverse effect on the characteristics of the sintered body; third, the nuclear characteristics of MOX materials do not allow the addition of forming agent in a solution state; fourth, the traditional lubricant addition technology is Apply lubricant to the inner wall of the mold and the pressure head. Considering the radiation characteristics of MOX powder, this method of manually applying lubricant will not only increase the irradiation time of personnel, but also reduce production efficiency; fifth, the parameters are not set properly. Reasonably lead to the occurrence of MOX particle breakage and other phenomena, affecting the fluidity and compressibility of materials.

Contents of the invention

The object of the present invention is to design a method for adding MOX powder forming agent and lubricant. By selecting a suitable forming agent and adopting powder lubrication, the strength of the green compact can be improved, and the reliability of pellet manufacturing can be improved.

The technical scheme of the present invention is as follows: a method for adding MOX powder forming agent and lubricant, comprising the following steps:

Step 1: Select zinc stearate, wherein the metal zinc content in zinc stearate is 10-11.2%, the free fatty acid is less than 0.5%, the water content is less than 0.5%, the particle size is 20-200 mesh, and MOX particles are selected, the particle size is 185-500 μm , the specific surface area is 3~18m ² /g, the impurity content is 250~2600μg/g, the bulk density is 15~20%TD, the filling rate is 78~80%, the Carr fluidity index is 51~65, and the molding density is 41~ 48%TD;

Step 2: Dry the zinc stearate particles at 15-40°C and a vacuum of 0.01-0.5Pa for 0.5-3 hours to remove volatile impurity elements and avoid abnormal particle growth caused by excessive temperature and melting;

Step 3: Screening the zinc hardate particles treated in step 2 with a 20-100 mesh screen;

Step 4: Calculate the required amount of MOX particles with a filling rate of 15-35% and add them to the ball mill tank, and add the zinc stearate particles treated in step 3 to the MOX particles at a weight ratio of 0.02-5.0%, Inject cooling water at 15-38°C at a rate of 5-15L/min to avoid agglomeration and melting caused by heat generation of materials

Step 5: Mix at a speed of 1 to 10r/min for 5 to 45 minutes to initially mix the zinc stearate particles and MOX particles evenly, and then gradually increase the speed of the mixer at a speed of 1 to 20r/min, at 10 to 100r Mix at a speed of 15-600min for 15-600min to avoid breakage of MOX particles caused by vigorous mixing.

Step 6 is also included: gradually reduce the speed of the mixer at a speed of 1 to 10 r/min until it stops, and after stopping mixing for 5 to 30 minutes, turn off the cooling water.

In said step one, zinc stearate can be replaced by calcium stearate or lithium stearate.

The remarkable effects of the present invention are: good cohesiveness and lubricity, easy to disperse evenly in the mixed powder, and no chemical change; high softening point temperature, difficult to melt due to temperature rise during mixing; The bulk density and fluidity will not be significantly deteriorated due to the addition of these substances, and the properties of the sintered body will not be adversely affected; when heated, it is easy to discharge gas from the compact, and this gas does not affect the sintering furnace life.

Detailed ways

A method for adding MOX powder forming agent and lubricant, comprising the following steps:

Step 1: Select zinc stearate, wherein the metal zinc content in zinc stearate is 10-11.2%, the free fatty acid is less than 0.5%, the water content is less than 0.5%, the particle size is 20-200 mesh, and MOX particles are selected, the particle size is 185-500 μm , the specific surface area is 3~18m ² /g, the impurity content is 250~2600μg/g, the bulk density is 15~20%TD, the filling rate is 78~80%, the Carr fluidity index is 51~65, and the molding density is 41~ 48% TD; Zinc stearate can be replaced by calcium stearate or lithium stearate;

Step 2: Dry the zinc stearate particles at 15-40°C and a vacuum of 0.01-0.5Pa for 0.5-3 hours to remove volatile impurity elements and avoid abnormal particle growth caused by excessive temperature and melting;

Step 3: Screening the zinc hardate particles treated in step 2 with a 20-100 mesh screen;

Step 4: Calculate the required amount of MOX particles with a filling rate of 15-35% and add them to the ball mill tank, and add the zinc stearate particles treated in step 3 to the MOX particles at a weight ratio of 0.02-5.0%, Cooling water at 15-38°C is introduced at a speed of 5-15L/min to avoid agglomeration and melting caused by heating of materials

Step 5: Mix at a speed of 1 to 10r/min for 5 to 45 minutes to initially mix the zinc stearate particles and MOX particles evenly, and then gradually increase the speed of the mixer at a speed of 1 to 20r/min, at 10 to 100r Mix at a speed of 15-600 minutes per minute to avoid broken MOX particles caused by vigorous mixing

Step 6: Gradually reduce the speed of the mixer at a speed of 1 to 10 r/min until it stops. After stopping mixing for 5 to 30 minutes, turn off the cooling water.

Claims (3)

1. a kind of MOX powder forming agent and lubricant adding method, it is characterised in that: the following steps are included:

Step 1: zinc stearate is chosen, wherein metal Zn content 10~11.2% in zinc stearate, free fatty acid is less than 0.5%, water content is less than 0.5%, 20~200 mesh of granularity, chooses MOX particle, and granularity is 185~500 μm, specific surface area 3 ~18m²/ g, impurity content are 250~2600 μ g/g, and apparent density is 15~20%TD, and filling rate is 78~80%, Carr stream Dynamic sex index 51~65,41~48%TD of compact density；

Step 2: drying 0.5~3h for zinc stearate particle under conditions of 15~40 DEG C, 0.01~0.5Pa of vacuum degree, removal Volatile impurity element therein, and the excessively high caused particle of temperature is avoided to increase phenomenon and fusing extremely；

Step 3: screening process is carried out to the zinc stearate particle handled through step 2 with the sieve of 20~100 mesh；

Step 4: with 15~35% filling rate calculate needed for MOX grain amount simultaneously be added in ball grinder, will be through step 3 at The zinc stearate particle of reason is added in MOX particle with 0.02~5.0% weight ratio, is passed through 15 with the speed of 5~15L/min ~38 DEG C of cooling water avoids reunion and melting phenomenon caused by generating heat because of material；

Step 5: 5~45min is mixed with the speed of 1~10r/min, mixes zinc stearate particle and MOX particle tentatively It is even, batch mixer revolving speed is then incrementally increased with the speed of 1~20r/min, the mixed processing 15 under the speed of 10~100r/min ~600min avoids MOX Particle Breakage caused by being vigorously mixed.

2. a kind of MOX powder forming agent according to claim 1 and lubricant adding method, it is characterised in that: further include Step 6: gradually reducing batch mixer revolving speed with the speed of 1~10r/min until stopping, and after stopping 5~30min of mixing, closes cold But water.

3. a kind of MOX powder forming agent according to claim 1 and lubricant adding method, it is characterised in that: the step In rapid one, zinc stearate can be replaced with calcium stearate or stearic acid lithium.