Method for producing abrasive grains, method for producing slurry, and method for producing polishing liquid
View Patent ↗In the production method for abrasive grains according to the invention, an aqueous solution of a salt of a tetravalent metal element is mixed with an alkali solution, under conditions such that a prescribed parameter is 5.00 or greater, to obtain abrasive grains including a hydroxide of the tetravalent metal element.
1. A production method for abrasive grains, comprising mixing a first liquid, which is an aqueous solution of at least one tetravalent metal element salt, and a second liquid which is a solution of at least one alkali, so as to form a liquid mixture, under conditions such that parameter Z in the following formula (1) is 5.00 or greater, to yield abrasive grains including a hydroxide of the tetravalent metal element, wherein during the mixing the liquid mixture is stirred using a stirring blade, wherein the tetravalent metal element is at least one kind selected from the group consisting of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, and wherein the alkali is selected from the group consisting of ammonia, triethylamine, pyridine, piperidino, pyrrolidine, imidazole, chitosan, potassium hydroxide and sodium hydroxide:
Z =(1/(ΔpH× k )) ×( N/M )/1000 (1),
wherein in formula (1), ΔpH represents a variation in pH per minute in a reaction system of the liquid mixture, k represents a reaction temperature coefficient represented by the following formula (2), N represents a cycle count (min −1 ) represented by the following formula (3), and M represents a substitution count (min −1 ) represented by the following formula (5);
k=2 ((T−20)/10) (2),
wherein in formula (2), T represents a temperature (° C.) of the reaction system;
N =( u ×S )/ Q (3),
wherein in formula (3), u represents a linear speed (m/min) represented by the following formula (4), for the stirring blade stirring the liquid mixture obtained by mixing the first liquid and the second liquid, S represents an area (m 2 ) of the stirring blade, and Q represents a liquid volume (m 3 ) of the liquid mixture;
u= 2 π×R×r (4),
wherein in formula (4), R represents a rotational speed (min −1 ) of the stirring blade, and r represents a radius of rotation (m) of the stirring blade; and
M=v/Q (5),
wherein in formula (5), v represents a mixing rate (m 3 /min) of the first liquid and second liquid, and Q represents a liquid volume (m 3 ) of the liquid mixture, and
wherein:
the ΔpH is in the range of 0.001 to 5.00,
the cycle count N is in the range of 1.00 min −1 to 200.00 min −1 ,
the substitution count M is in the range of 1.0 ×10 −5 min -1 to 1.0 min −1 ,
the linear speed u is in the range of 5.00 m/min to 200.00 m/min,
the mixing rate v is in the range of 1.00 ×10 −7 m 3 /min to 1.00 ×10 −2 m 3 /min, and
the rotational speed R is in the range of 30 min −1 to 1000 min −1 .
2. The production method according to claim 1 , wherein a concentration of the at least one tetravalent metal element salt in the first liquid is 0.01 mol/L or greater.
3. The production method according to claim 1 , wherein an alkaline concentration of the second liquid is not greater than 15.0 mol/L.
4. The production method according to claim 1 , wherein a pH of the liquid mixture, after mixing the first liquid and the second liquid, is 2.0 to 7.0.
5. The production method according to claim 1 , wherein the tetravalent metal element of the at least one tetravalent metal element salt is tetravalent cerium.
6. A production method for a slurry, wherein abrasive grains obtained by the production method according to claim 1 are mixed with water to obtain a slurry.
7. A production method for a polishing liquid, wherein a slurry obtained by the production method according to claim 6 is mixed with an additive to obtain a polishing liquid.
8. A production method for a polishing liquid, wherein abrasive grains obtained by the production method according to claim 1 , an additive and water are mixed to obtain a polishing liquid.
9. A production method for a slurry, wherein abrasive grains obtained by the production method according to claim 5 are mixed with water to obtain a slurry.
10. A production method for a polishing liquid, wherein a slurry obtained by the production method according to claim 9 is mixed with an additive to obtain a polishing liquid.
11. A production method for a polishing liquid, wherein abrasive grains obtained by the production method according to claim 5 , an additive and water are mixed to obtain a polishing liquid.
12. The production method according to claim 1 , wherein the temperature T is in the range of 0° C. to 60° C.
13. The production method for abrasive grains according to claim 1 , wherein said first liquid is an aqueous solution of a tetravalent metal element salt, and said second liquid is a solution of an alkali.
14. The production method for abrasive grains according to claim 1 , wherein the mixing is conducted so as to react the at least one tetravalent metal element salt with the at least one alkali to obtain the tetravalent metal element hydroxide.
15. The production method according to claim 12 , wherein the liquid volume Q is 0.001 to 10.00 m 3 , and the radius of rotation r of the stirring blade is in the range of 0.001 m to 10 m.
16. The production method according to claim 15 , wherein the area S of the stirring blade is 0.0005 to 0.0340 m.
17. The production method according to claim 1 , wherein the mean particle size of the abrasive grains formed is 1-200 nm.
18. The production method according to claim 1 , wherein ΔpH is in the range of 0.001 to 1.00.
19. The production method according to claim 1 , wherein the tetravalent metal element is cerium, and the alkali is selected from the group consisting of ammonia and imidazole.