CN115650270A - Preparation method of micron-sized spherical aluminum hydroxide - Google Patents
Preparation method of micron-sized spherical aluminum hydroxide Download PDFInfo
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- CN115650270A CN115650270A CN202210816191.3A CN202210816191A CN115650270A CN 115650270 A CN115650270 A CN 115650270A CN 202210816191 A CN202210816191 A CN 202210816191A CN 115650270 A CN115650270 A CN 115650270A
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- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 title claims abstract description 114
- 238000002360 preparation method Methods 0.000 title abstract description 18
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims abstract description 48
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- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims abstract description 42
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 claims abstract description 35
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- 239000000843 powder Substances 0.000 description 4
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 3
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
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- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a preparation method of micron-sized spherical aluminum hydroxide, which comprises the following steps: dissolving industrial-grade sodium aluminate in water to obtain a sodium aluminate solution with the concentration of 3-10 mol/L; adding analytically pure magnesium oxide into distilled water, and performing ultrasonic treatment, wherein a magnesium oxide solution is used as an initiation seed crystal; heating the sodium aluminate solution, adding the magnesium oxide solution, decomposing the sodium aluminate under the induction of magnesium oxide seed crystals, and stopping heating and stirring to obtain an aluminum hydroxide suspension after the decomposition by stirring is completed; and filtering, washing and drying the aluminum hydroxide suspension to obtain the aluminum hydroxide, wherein the aluminum hydroxide is in a smooth spherical shape with the particle size of 1-3 mu m and is uniformly distributed. The invention adopts the preparation method of the micron-sized spherical aluminum hydroxide, obtains the micron-sized spherical aluminum hydroxide with a smooth surface by controlling the concentration of the sodium aluminate solution and using the magnesium oxide seed crystal, can meet the requirements of high-end industries on the aluminum hydroxide, and has simple preparation process flow and convenient industrialization.
Description
Technical Field
The invention relates to the technical field of preparation and synthesis of aluminum hydroxide, in particular to a preparation method of micron-sized spherical aluminum hydroxide.
Background
The aluminum hydroxide has the functions of flame retardance, smoke abatement, filling and the like, is nontoxic and pollution-free in use, can generate synergistic flame retardance with various substances such as phosphorus and the like, and is often used as a flame retardant additive to be widely applied to the fields of electric power equipment, thermoplastic materials, rubber and the like. In addition, with the high development of electronic technology and electronic devices, aluminum hydroxide is also applied to the fields of display panel interlayers, high-end lubricating paste, high-thermal conductive paste and the like, but the fields require that the aluminum hydroxide has good fluidity and high filling rate, so that the synthesis and preparation method of spherical aluminum hydroxide with uniform micron-sized particle size distribution is very important.
Chinese patent (CN 108341422B) discloses a rod-shaped beta-aluminum hydroxide and a preparation method and application thereof, the D50 of the rod-shaped beta-aluminum hydroxide prepared by the method is 1.5-15 mu m, the aggregate of the rod-shaped beta-aluminum hydroxide is in a sphere-like shape, the size of the sphere-like body is about 30 mu m, and the rod-shaped beta-aluminum hydroxide does not meet the application requirements of the current high-end field. Chinese patent (CN 111807392A) discloses a method for preparing submicron-grade superfine aluminum hydroxide and a product and application thereof, wherein the submicron-grade superfine aluminum hydroxide is obtained by controlling the concentration and temperature of sodium aluminate and adding a blocking agent, the blocking agent used in the patent is aluminum hydroxide micropowder or aluminum hydroxide finished product slurry, the submicron-grade aluminum hydroxide which grows in a non-oriented way can be obtained under the condition of strictly controlling decomposition conditions, but the micro-morphology of the particles is still irregular particles, and a scanning electron microscope picture shows that the submicron-grade superfine aluminum hydroxide still has the characteristic of sheet cleavage. Chinese patent (CN 112028095A) discloses 'superfine aluminum hydroxide seed crystal and a preparation method thereof, submicron aluminum hydroxide and a preparation method and application thereof', the method still uses the superfine aluminum hydroxide as the seed crystal to prepare submicron-grade aluminum hydroxide particles, but the microstructure of the aluminum hydroxide prepared by the method is still irregular particles, and the method is only suitable for the fields of wire and cable flame retardance, silicone rubber flame retardance, paint and the like.
The Wang Jianli of the university of zhongnan mentions the shape control technology of ultrafine aluminum hydroxide powder particles in his doctor's paper "the preparation of ultrafine aluminum hydroxide and the research on the technology for improving the thermal stability of ultrafine aluminum hydroxide". A microemulsion method is adopted to ensure that aluminum hydroxide crystals grow directionally under the action of a template agent to prepare spherical micron-sized aluminum hydroxide, but the method needs to consume a large amount of hexane, OP emulsifier, n-octanol and other reagents to organically modify the surface of the aluminum hydroxide, and the obtained spherical particles have poor shapes, are easy to aggregate and adhere, have complex process and are not suitable for mass production. Zhang Youfei of university of continental transportation in his master's thesis "preparation and characterization of monodisperse spherical aluminum hydroxide" adopts alkoxide hydrolysis to prepare high purity monodisperse spherical aluminum hydroxide with particle size of about 400nm, and this method can prepare submicron spherical aluminum hydroxide with diameter of less than 1 μm, and the size uniformity is very good, but this method for preparing aluminum hydroxide's aluminum source comes from alkoxide, and the price is expensive, the production cost is too high, and in the course of adopting this method to prepare spherical aluminum hydroxide, it needs to use many surfactants and adjuvants to strictly control parameters such as isoelectric point, etc., it requires strict, easy to fail to lead to the product yields low, these two characteristics greatly increase the production cost, make it lack competitiveness in the market.
In summary, no method exists at present for preparing micron-sized spherical aluminum hydroxide with uniform particle size distribution and low production cost and simple process flow.
Disclosure of Invention
The invention aims to provide a preparation method of micron-sized spherical aluminum hydroxide, which aims to solve the problems of high cost, complex process flow and low yield of the method for producing the spherical aluminum hydroxide.
In order to achieve the above object, the present invention provides a method for preparing micron-sized spherical aluminum hydroxide, comprising the steps of:
(1) Dissolving industrial-grade sodium aluminate in water to obtain a sodium aluminate solution with the concentration of 3-10 mol/L;
(2) Adding analytically pure magnesium oxide into distilled water, and performing ultrasonic treatment to ensure that the magnesium oxide is completely and uniformly distributed in the distilled water to obtain a magnesium oxide solution, wherein the magnesium oxide solution is used as an initiation seed crystal;
(3) Heating the sodium aluminate solution, adding the magnesium oxide solution, decomposing the sodium aluminate under the induction of magnesium oxide seed crystals, and stopping heating and stirring to obtain an aluminum hydroxide suspension after the decomposition by stirring is completed;
(4) And filtering, washing and drying the aluminum hydroxide suspension to obtain the aluminum hydroxide, wherein the aluminum hydroxide is in a smooth spherical shape with the particle size of 1-3 mu m and is uniformly distributed.
Preferably, the concentration of the sodium aluminate solution in the step (1) is 7mol/L.
Preferably, the ultrasonic time in the step (2) is 3-5min, and the dispersion concentration of the magnesium oxide solution is 0.01-0.125g/mL.
Preferably, the volume of the magnesium oxide solution added in step (3) is 1-2% of the volume of the sodium aluminate solution.
Preferably, the decomposition temperature in the step (3) is 65-70 ℃, and the decomposition time is 8-12 hours.
Preferably, the step (1) further comprises the pretreatment of the sodium aluminate solution, wherein the pretreatment process specifically comprises the steps of carrying out primary filtration on the sodium aluminate solution to obtain a primary filtrate, then adding distilled water into the primary filtrate for dilution, and carrying out secondary filtration to obtain a secondary filtrate, wherein the volume ratio of the primary filtrate to the distilled water is 11 (9-11).
Preferably, the washing in step (4) is two to three times washed with distilled water at a drying temperature of 60 ℃.
Therefore, the preparation method of the micron-sized spherical aluminum hydroxide with the structure has the following beneficial effects:
1. the used raw materials (sodium aluminate and aluminum oxide) are low-price and easily-purchased raw materials, so that the cost for preparing the aluminum hydroxide is reduced;
2. in the process of decomposing sodium aluminate to generate aluminum hydroxide, the prepared aluminum hydroxide is in a micron size and has a better spherical micro-morphology, a smooth surface, uniform particle size distribution, good fluidity and high filling rate by the induction effect of taking magnesium oxide as a seed crystal, and can be widely applied to high-end fields such as display panel interlayers, high-end lubricating paste and high-heat-conducting paste;
3. the process flow is simple, easy to operate and implement, and convenient for industrial production of aluminum hydroxide.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is an XRD pattern of aluminum hydroxide obtained in example 1;
FIG. 2 is an SEM image of a magnesium oxide seed crystal;
FIG. 3 is an SEM photograph (scale bar 30 μm) of aluminum hydroxide obtained in example 1;
FIG. 4 is an SEM photograph (scale 5 μm) of aluminum hydroxide obtained in example 1;
FIG. 5 is an SEM photograph (scale: 3 μm) of aluminum hydroxide obtained in example 1;
FIG. 6 is an SEM photograph of the aluminum hydroxide obtained in comparative example 1;
FIG. 7 is an SEM photograph of the aluminum hydroxide obtained in comparative example 2.
Detailed Description
The present invention will be further described below, and it should be noted that the present embodiment is based on the technical solution, and a detailed implementation manner and a specific operation process are provided, but the present invention is not limited to the present embodiment.
Example 1
The invention provides a preparation method of micron-sized spherical aluminum hydroxide, which comprises the following steps:
(1) Adding water into industrial-grade sodium aluminate to dissolve the industrial-grade sodium aluminate to obtain a sodium aluminate solution with the concentration of 7 mol/L;
taking 165mL of sodium aluminate solution, adopting medium-speed filter paper to connect a suction filter for filtering, removing filtered residues to obtain primary filtrate, accurately measuring 165mL of primary filtrate by using a measuring cylinder, filling the primary filtrate by using a 500mL beaker, measuring 135mL of distilled water, adding the distilled water into the primary filtrate, uniformly stirring, diluting the primary filtrate, and then carrying out suction filtration to obtain secondary filtrate, wherein the ratio of the primary filtrate to the distilled water is 11:9;
(2) Adding 4.00g (0.1 mol) of analytically pure magnesium oxide into 32mL of distilled water, carrying out ultrasonic treatment for 3-5 minutes until the magnesium oxide is completely and uniformly distributed in the distilled water to obtain a magnesium oxide solution, and taking the magnesium oxide solution as an initiating seed crystal;
(3) Adding the secondary filtrate into a three-neck flask, mechanically stirring and heating to 67 ℃, adding 2.5mL of magnesium oxide solution after heating, decomposing sodium aluminate under the induction of magnesium oxide seed crystals, stirring and decomposing for 12 hours, and stopping heating and stirring to obtain an aluminum hydroxide suspension;
(4) Filtering the aluminum hydroxide suspension by adopting medium-speed filter paper and a suction filter, washing for 2-3 times by using distilled water, and drying in an oven at 60 ℃ to obtain the aluminum hydroxide.
Fig. 1 is an XRD chart of this example, from which it can be seen that the XRD spectrum of the prepared aluminum hydroxide microsphere sample is compared with those of aluminum hydroxide standard card PDF #33-0018 and aluminum oxide standard card PDF #37-1462, and the prepared aluminum hydroxide microsphere contains some aluminum oxide components, but from the number of peaks that can be matched, only the strongest three peaks of the aluminum oxide peaks on the standard card can be matched, and most of the weaker diffraction peaks of the aluminum hydroxide can be matched, which indicates that the ratio of the aluminum oxide in the sample is relatively small.
FIG. 2 shows the microscopic morphology of the magnesia seed crystal, and the magnesia crystal can be uniformly and stably dispersed in water by the ultrasonic process, and the magnesia crystal is rice grains with the length of 1 micron after ultrasonic treatment and is not spherical.
Fig. 3 to 5 show the morphology of the aluminum hydroxide prepared in this example, and SEM shows that the aluminum hydroxide is spherical and widely exists, has a size of 1 to 3 μm, and is spherical with a smooth surface, and the aluminum hydroxide with this morphology has good fluidity and high filling rate, and can be widely applied to high-end fields such as display panel interlayers, high-end lubricating pastes and high thermal conductive pastes.
Example 2
The invention provides a preparation method of micron-sized spherical aluminum hydroxide, which comprises the following steps:
(1) Adding water into industrial-grade sodium aluminate to dissolve the industrial-grade sodium aluminate to obtain a sodium aluminate solution with the concentration of 7 mol/L;
taking 150mL of sodium aluminate solution, connecting a suction filter with medium-speed filter paper for filtering, removing filtered residues to obtain primary filtrate, accurately measuring 150mL of primary filtrate by using a measuring cylinder, filling the primary filtrate in a 500mL beaker, measuring 150mL of distilled water, adding the distilled water into the primary filtrate, uniformly stirring, diluting the primary filtrate, and then carrying out suction filtration to obtain secondary filtrate, wherein the ratio of the primary filtrate to the distilled water is 1:1;
(2) Adding 4.00g (0.1 mol) of analytically pure magnesium oxide into 40mL of distilled water, carrying out ultrasonic treatment for 3-5 minutes until the magnesium oxide is completely and uniformly distributed in the distilled water to obtain a magnesium oxide solution, wherein the magnesium oxide solution is used as an initiation seed crystal;
(3) Adding the secondary filtrate into a three-neck flask, mechanically stirring and heating to 69 ℃, adding 2.5mL of magnesium oxide solution after heating, decomposing sodium aluminate under the induction of magnesium oxide seed crystals, stirring and decomposing for 8 hours, and stopping heating and stirring to obtain an aluminum hydroxide suspension;
(4) Filtering the aluminum hydroxide suspension by adopting medium-speed filter paper and a suction filter, washing for 2-3 times by using distilled water, and drying in an oven at 60 ℃ to obtain the aluminum hydroxide.
Comparative example 1
Comparative example 1 is different from example 1 in that a magnesium oxide solution is not added in step (3). It can be seen from fig. 6 that the aluminum hydroxide prepared without adding the magnesium oxide seed crystal is mainly flaky, which is determined by the crystallization property of the aluminum hydroxide itself, and this is also the reason that most of the aluminum hydroxides in the prior art still have flaky morphology on the surface even though they are agglomerated into spheres, and the aluminum hydroxide prepared in the present invention does not need to be agglomerated into spheres and has a smooth surface.
Comparative example 2
Comparative example 2 is different from example 1 in that ultra fine iron oxide is used as a seed crystal instead of magnesium oxide, and the other steps are the same as example 1. It can be seen from fig. 7 that the aluminum hydroxide prepared by using iron oxide instead of magnesium oxide as a seed crystal has a particle size significantly larger than that of the present invention and a flaky morphology on the surface, although it is spherical as a whole, which is significantly different from the smooth morphology of the present invention, and the magnesium oxide as a seed crystal in the present invention has a very important influence on the morphology of the aluminum hydroxide.
Comparative example 3
Comparative example 3 is different from example 1 in that nickel oxide is used as a seed crystal instead of magnesium oxide and the other steps are the same as example 1. The aluminum hydroxide produced in comparative example 3 also had a different morphology from that produced in the present invention.
Application example
(1) As flame retardants
The aluminum hydroxide powder is used as an inorganic non-metallic filler, has good flame retardant matching property with various polymers such as plastics, rubber, epoxy resin and the like, is decomposed after being heated to 200 ℃, absorbs heat and dehydrates to delay the combustion of the polymers, is equivalent to a radiator, slows down the combustion speed, and simultaneously dilutes various combustible gases generated by the decomposition of the polymers by the released water vapor, so that the ignition is more difficult; meanwhile, a protective layer consisting of alumina and carbonized products can be formed on the surface of the polymer, so that the combustion is further inhibited, and the smoke density is reduced by adsorbing soot particles. Due to the unique material characteristics, the flame retardant and smoke abatement functions of the aluminum hydroxide are achieved, and the aluminum hydroxide becomes one of the most used flame retardants in the world.
(2) As a filler
The morphology of the aluminum hydroxide can influence the filling performance and the application performance of the product, and spherical and spheroidal aluminum hydroxide has the advantages of small specific surface area, good particle dispersibility, low mixed viscosity of aluminum hydroxide/organic matrix polymer under the same addition amount, good processability and high elongation of the finished polymer product under the condition of the same particle size. Aluminum hydroxide used in most filling industries requires a smooth surfaced, highly spherical product to increase the amount and uniform dispersion of the added organic polymer. The advantages of spherical aluminum hydroxide over conventional aluminum hydroxide are illustrated by the following two indicators:
a. oil absorption number
The oil absorption value, also known as the resin adsorption, represents an index of the powder to resin adsorption, the minimum amount of linseed oil required to achieve complete wetting for 100g of powder. Factors affecting oil absorption value: compactness, surface morphology, particle size distribution and the like of the powder structure. The oil absorption value is a major factor affecting the viscosity of the aluminum hydroxide/organic substrate mixture when used, with higher oil absorption values for aluminum hydroxide providing greater polymer viscosity, and in the same case, greater polymer viscosity means less aluminum hydroxide being added. Conversely, the lower the oil absorption value of aluminum hydroxide, the lower the viscosity of the polymer when used, and the greater the amount of aluminum hydroxide added in the same case. The larger the added part of the aluminum hydroxide is, the lower the cost of the product is, and more importantly, the product has excellent performance, such as higher surface hardness, lower curing shrinkage and thermal expansion coefficient, higher thermal conductivity, and the advantages of reducing curing heat release, preventing cracking of the product, improving flame retardance and the like. The oil absorption value of the aluminum hydroxide with the particle size of 1.3 mu m is 26mL/100g, which is about 20 percent lower than that of common aluminum hydroxide. The aluminum hydroxide prepared by the invention can increase the adding parts, so that the performance of the aluminum hydroxide/organic base material product is excellent.
b. Workability
Generally, the better the flowability of the powder, the faster the mixing process proceeds. The higher the fused finger is after the aluminum hydroxide and the organic high polymer are mixed, the more convenient the molding processing is, which is beneficial to the improvement of the single-day output and the elongation of the product of the downstream customers. Compared with common aluminum hydroxide, the spherical aluminum hydroxide does not obviously increase the viscosity of the high polymer after the organic high polymer is added due to the unique spherical structure, and is very friendly to the processes of mixing, extrusion molding and the like. In addition, the high polymer added with spherical aluminum hydroxide has better elongation, smaller Shore hardness, namely better processing characteristics, which is very important for high-end manufacturing industry.
Therefore, the method for preparing the micron-sized spherical aluminum hydroxide with the structure can meet the requirements of high-end industries on aluminum hydroxide by controlling the concentration of the sodium aluminate solution and using the magnesium oxide seed crystal to prepare the micron-sized spherical aluminum hydroxide with the smooth surface, and has the advantages of simple preparation process flow and convenience for industrialization.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the invention without departing from the spirit and scope of the invention.
Claims (7)
1. A method for preparing micron-sized spherical aluminum hydroxide is characterized by comprising the following steps:
(1) Dissolving industrial-grade sodium aluminate in water to obtain a sodium aluminate solution with the concentration of 3-10 mol/L;
(2) Adding analytically pure magnesium oxide into distilled water, and performing ultrasonic treatment to ensure that the magnesium oxide is completely and uniformly distributed in the distilled water to obtain a magnesium oxide solution, wherein the magnesium oxide solution is used as an initiation seed crystal;
(3) Heating the sodium aluminate solution, adding the magnesium oxide solution, decomposing the sodium aluminate under the induction of magnesium oxide seed crystals, stirring and decomposing, and stopping heating and stirring to obtain an aluminum hydroxide suspension;
(4) And filtering, washing and drying the aluminum hydroxide suspension to obtain the aluminum hydroxide, wherein the aluminum hydroxide is in a smooth spherical shape with the particle size of 1-3 mu m and is uniformly distributed.
2. The method for preparing micron-sized spherical aluminum hydroxide according to claim 1, wherein the concentration of the sodium aluminate solution in the step (1) is 7mol/L.
3. The method for preparing micron-sized spherical aluminum hydroxide according to claim 1, wherein the ultrasonic time in the step (2) is 3-5min, and the dispersion concentration of the magnesium oxide solution is 0.01-0.125g/mL.
4. The method for preparing micron sized spherical aluminum hydroxide according to claim 1, wherein the volume of the magnesium oxide solution added in the step (3) is 1-2% of the volume of the sodium aluminate solution.
5. The method for preparing micron-sized spherical aluminum hydroxide according to claim 1, wherein the decomposition temperature in the step (3) is 65 to 70 ℃ and the decomposition time is 8 to 12 hours.
6. The method for preparing micron-sized spherical aluminum hydroxide according to claim 1, wherein the step (1) further comprises a pretreatment of the sodium aluminate solution, wherein the pretreatment comprises a step of carrying out primary filtration on the sodium aluminate solution to obtain a primary filtrate, and then adding distilled water into the primary filtrate to dilute the primary filtrate and carrying out secondary filtration to obtain a secondary filtrate, wherein the volume ratio of the primary filtrate to the distilled water is 11 (9-11).
7. The method for preparing micron-sized spherical aluminum hydroxide according to claim 1, wherein the washing in the step (4) is performed two to three times by using distilled water, and the drying temperature is 60 ℃.
Priority Applications (1)
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5304526A (en) * | 1991-10-18 | 1994-04-19 | W. R. Grace & Co.-Conn. | Silica bayerite/eta alumina |
| US5492542A (en) * | 1992-09-23 | 1996-02-20 | Martinswerk G.m.b.H. fur Chemische Und Metallurgische Produktion | Process for the production of an aluminum hydroxy Al(OH)3 having rounded grain surfaces |
| TW200609180A (en) * | 2004-09-02 | 2006-03-16 | Beaming Co Ltd | Method of producing aluminum hydroxide fine powder |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5304526A (en) * | 1991-10-18 | 1994-04-19 | W. R. Grace & Co.-Conn. | Silica bayerite/eta alumina |
| US5492542A (en) * | 1992-09-23 | 1996-02-20 | Martinswerk G.m.b.H. fur Chemische Und Metallurgische Produktion | Process for the production of an aluminum hydroxy Al(OH)3 having rounded grain surfaces |
| TW200609180A (en) * | 2004-09-02 | 2006-03-16 | Beaming Co Ltd | Method of producing aluminum hydroxide fine powder |
Non-Patent Citations (2)
| Title |
|---|
| 童志权等: "炼油催化剂制造技术基础（中级）", vol. 1, 31 January 1989, 化学工业出版社, pages: 335 - 336 * |
| 赵通林: "浮选", vol. 1, 31 August 2018, 冶金工业出版社, pages: 50 * |
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