The main uses of holmium oxide are :(1) yttrium aluminum garnet doped with holmium (Ho∶YAG) can emit 2μm laser, human tissues to 2μm laser absorption rate is high, almost 3 orders of magnitude higher than Hd∶YAG. Therefore, the Ho∶YAG laser can not only improve the efficiency and precision of surgery, but also reduce the thermal damage area to a smaller extent. (2) A small amount of holmium can also be added to the magnetostrictive alloy Terfenol-D to reduce the external field required for saturation magnetization of the alloy. (3) In addition, the holmium doped fiber can be used to produce fiber lasers, fiber amplifiers, fiber sensors and other optical communication devices, which will play a more important role in the rapid development of fiber communication today. Currently, nano-holmium oxide is used in press-free sintering to produce high-performance silicon nitride (Si3N4) ceramics for transparent ceramics of white LEDS, high-performance CPP films, permanent magnet materials and other higher technology products. At present, the preparation of holmium oxide mainly uses ammonia-based precipitant, which has some problems in environmental protection, and the product particles are not uniform, and the dispersion is not good.
The technical scheme to realize the invention is a preparation method of nano-holmium oxide; The following steps are included: first, holmium chloride with a concentration of 0.1mol/L-1mol/L prepared with pure water is added to the reaction kettle; The polyethylene glycol surfactant with 5%-15% holmium oxide mass as the final product was added into holmium chloride and stirred for 15-30min. Weigh the analytical pure sodium carbonate or sodium bicarbonate prepared by pure water with the concentration of 0.1mol/L-1mol/L as precipitator. The mass ratio of the final product holmium oxide to analytical pure sodium carbonate or sodium bicarbonate is 1:1-1:1.2. Then, the precipitator is evenly dropped and stirred for aging. The final product holmium oxide and the mass ratio of the n-butanol is 1:2000-1:400; Nano-holmium oxide with particle size of 50-70nm and specific surface area of more than 20m2/g was obtained after burning at 800-900℃ for 3-5h and holding for 1-2h.
The preferred temperature of holmium chloride is 15-25℃, and the precipitant is sodium carbonate or sodium bicarbonate and the temperature is 15-25℃.
The optimized extraction and filtration water is soaked in hot pure water above 95℃ in the extraction and filtration barrel, and the mass ratio of the amount of water washing and the final product holmium oxide is 500:1. The burning is a trolley type rare-earth roaster.
The optimal uniform dripping precipitant is controlled by a governor, and the stirring time is 0.5h and the aging time is 2h-4h.
The invention has positive effects:
(1) Nano-holmium oxide plays a great role in inhibiting oxygen vacancy and migration in nickel electrode ceramic capacitors. Holmium oxide prepared by this method has uniform particle size, large specific surface, good dispersity and simple process, which can be used in large-scale production.
(2) Polyethylene glycol surfactants are added to effectively inhibit grain growth and agglomeration, while n-butanol plays an indispensable role in its uniformity and is the key to determining particle size. In addition, the temperature and time of burning are also important, too high temperature, burning time and holding time will affect the size of specific surface area.
Specific implementation mode
Embodiment 1: The final product is 1kg nano-holmium oxide, which is prepared with 0.3mol/L concentration and 17.64L volume by adding pure water into the reaction kettle. The measured temperature is 15 degrees, and then 1kg analytical pure sodium carbonate is weighed. The concentration is 0.4mol/L volume and 23.58L volume are prepared with pure water and the temperature is 15 degrees. Weigh 100g of polyethylene glycol 20000 surfactant with 10% mass ratio of nano-holmium oxide as the final product, add 1L pure water, heat it to dissolve into liquid, add polyethylene glycol 20000 into the material liquid holmium chloride, mix and stir for 15min, and finally add sodium carbonate uniformly for 35min. Which can be calculated at the rate of 0.67 L/min to join and joined by governor to control the flow rate and speed, and after that, continue to stir 0.5 hours, then aged for 2 hours, with over 95 degrees in the suction filter barrels hot water immersion bath, water about 500 L, the final drain, add 200 ml n-butyl alcohol in filter cake, mix thoroughly, with fantastic costumes, Burn at 850 degrees for 3 hours and keep warm for 2 hours.
Embodiment 2: The final product nano-holmium oxide 5KG was added into the reaction kettle to prepare a holmium chloride solution with a concentration of 0.4mol/L and a volume of 66.16L prepared with pure water. The measured temperature was 17 degrees. Then, 5KG of analytical pure sodium carbonate was weighed and prepared with pure water with a concentration of 0.4mol/L and a volume of 117.92L and a temperature of 18 degrees. Add 4L pure water and heat it to dissolve into liquid. Put the polyethylene glycol 4000 into the holmium chloride solution and mix and stir for 15min. Finally, add sodium carbonate evenly for 107min. Which can be calculated at the rate of 1.1 L/min to join and joined by governor to control the flow rate and speed, and after that, continue to stir 0.5 hours, then aged 3 hours, with over 95 degrees in the suction filter barrels hot water immersion bath, water about 2500 L, the final drain, add 1 L n-butyl alcohol in filter cake, mix thoroughly, with fantastic costumes, Burn at 800 degrees for 5 hours and keep warm for 1 hour.