CN101049966A - Method for producing powder in micron order of bismuth oxide - Google Patents

Abstract

This invention discloses a method for preparing high-purity bismuth oxide micropowder. The method comprises: dissolving bismuth in nitric acid to obtain bismuth nitrate, filtering, adding ammonia solution into the bismuth nitrate solution to synthesize bismuth subnitrate, hydrolyzing, centrifuging, and dry-filtering, heating and pulverizing by a gas flow pulverizer to obtain high-purity bismuth oxide micropowder. During bismuth subnitrate synthesis, uniform particle sizes of bismuth subnitrate can be realized by controlling the concentration and flow rate of ammonia solution, as well as the concentration and synthesis temperature of bismuth nitrate solution. The method has such advantages as no need for dispersant, simple process, low requirement for apparatus, and low energy consumption.

Description

The production method of powder in micron order of bismuth oxide

Technical field

The invention belongs to used in electronic industry bismuth oxide field, particularly a kind of production method of powder in micron order of bismuth oxide.

Background technology

Micron order of bismuth oxide (Bi ₂O ₃) micro mist is as a kind of electric function powder dopant material, be widely used in the production of display element device, sensitive components, dielectric ceramic electronic devices and components etc., and can be used as organic catalyst compound, special glass, chemical fabrics fire retardant etc.

The traditional technology of preparation bismuth oxide is bismuth metal to be dissolved in concentrated nitric acid generate bismuth nitrate solution, generates Vikaline through hydrolysis again, and Vikaline is converted into bismuth oxide through alkali, bismuth oxide through washing, dry product.Its shortcoming is that processing condition need accurately control, and the bismuth oxide powder particle diameter of production is bigger, and granularity is about 6 μ m, if conduct heat bad during calcining even can be unwell to the dopant material of making electronic devices and components greater than 6 μ m.

Chinese patent 94113621.3 provides " a kind of processing method of producing superfine bismuth oxide ", this method is dispersion agent with glycerine, utilize Bismuth trinitrate and alkaline reaction to generate superfine bismuth oxide, obtain product granularity less than 10 microns, owing to used alkali lye in the production process, inevitably brought basic metal or alkaline-earth metal ions into, influenced the foreign matter content and the granularity of bismuth oxide, so the composition of the selection of alkali lye, dispersion agent has just become the difficult point of controlled oxidation bismuth granule footpath with size-grade distribution with concentration.

In addition, patent related to the present invention has:

Chinese invention patent application 200310110558.7 disclosed " preparation technology of nano bismuth oxide "; With hydrochloric acid to chlorine oxygen bismuth concentrate leach, removal of impurities; Immersion liquid is carried out removal of impurities with hydrolysis method; With sodium hydroxide solution chlorine oxygen bismuth is converted into Bi ₂O ₃Carry out removal of impurities; With nitric acid with Bi ₂O ₃The dissolving removal of impurities; Precipitate bismuth nitrate solution with sodium hydroxide solution; The bismuth oxide that generates spends the ionic activity water washing, and is dry in vacuum drying oven after the filtration, promptly gets the nano bismuth oxide product.

Chinese invention patent application 200310121804.9 disclosed " preparation method of bismuth oxide micro-powder " will contain Bi ³⁺Bismuth nitrate solution join in the ammonium bicarbonate soln, the ammonium bismuth weight ratio that control adds and the add-on of dispersion agent under normal temperature and stirring state, generate the Bismuth Subcarbonate precipitation; Filtration washing; Filter cake is heat-treated under 100～700 ℃, obtains the bismuth oxide product.

Chinese invention patent application 200410026454.2 disclosed " a kind of electron grade bismuth oxide micropowder preparing process ", this method comprise the steps: the 1. preparation KOH aqueous solution; 2. preparation bismuth nitrate solution; 3. the bismuth nitrate solution that makes is joined in the reactor, splash into prepared KOH solution; The temperature of control reaction system is 20～50 ℃, and the add-on of KOH is 1～1.02 of a theory measurement; 4. filter, washing, oven dry promptly obtains the superfine bismuth oxide micro mist.

These methods or environmental pollution are serious, perhaps complex process, and perhaps foreign matter content height, perhaps productive rate is low, all has certain problem in commercial process.

Summary of the invention

Technical problem to be solved by this invention is: overcome the deficiencies in the prior art part, provide a kind of foreign matter content low, the production method of the powder in micron order of bismuth oxide of controllable granularity.

Technological principle of the present invention is: bismuth metal is dissolved in generates Bismuth trinitrate in the nitric acid, bismuth nitrate solution ammonification hydration after the filtration becomes bismuth subnitrate, in synthetic bismuth subnitrate process, control ammonia concn and flow velocity, control the concentration and the synthesis temperature of bismuth nitrate solution, can get the bismuth subnitrate of uniform particles unanimity.Be ground into powder in micron order of bismuth oxide through hydrolysis, centrifugal dried filter, heating and stepless speed regulation micronizer mill.

The present invention deal with problems technical scheme be: the production method of powder in micron order of bismuth oxide, its processing step is as follows:

It is 1.6 gram/cm that a, nitric acid deposite metal bismuth obtain density ³Bismuth nitrate solution;

B, the bismuth nitrate solution after will filtering import in the reactor and add 8～10% ammoniacal liquor, the flow velocity of control ammoniacal liquor, and the concentration of control bismuth nitrate solution is 1.6 gram/cm ³, synthetic bismuth subnitrate under 40～50 ℃ temperature condition;

C, control synthetic end point pH value are 2.0～2.2, and the hydrolysis bismuth ion is used the deionized water wash bismuth subnitrate, and reacted mother liquor recycles; With the centrifugal dried filter of gained bismuth subnitrate,, wash appropriate amount of deionized water again in dried bismuth subnitrate process;

D, bismuth subnitrate is heated from dryed product, be converted into the bismuth oxide of particle diameter about 12 μ m under 500～600 ℃ of temperature, pulverize through the stepless speed regulation micronizer mill again, promptly obtain particle diameter and be the powder in micron order of bismuth oxide about 1.5 ± 0.3 μ m.

Compared with the prior art, technique effect of the present invention is:

1, be equipped with the stepless speed regulation micronizer mill, adjustable grain, fine size and narrower particle size distribution can satisfy the customer demand of different class, different levels.Not only be easy to control the purity of product but also be beneficial to the granularity of controlling product.

2, the present invention prepares in the powder in micron order of bismuth oxide process, does not need to add dispersion agent, can not introduce other impurity; Technology is simple, less demanding to equipment, and energy consumption is low, can effectively reduce production cost.

3, adopt ammoniacal liquor directly synthetic,, save precipitation " transition " operation with ammoniacal liquor replace sodium hydroxide solution or potassium hydroxide solution, ammoniacal liquor alkalescence than sodium hydroxide or potassium hydroxide a little less than, can prevent to cause other positively charged ion such as Fe because of stirring inequality ³⁺Local hydrolysis and bringing in the product.Also avoided bringing in the product Na that is difficult to clean ⁺, Na ⁺Remainingly be reduced to below 0.001% by 0.1%.

4, the quality product of utilizing the present invention and being produced: standard purity height (〉=99.5%), the impurity zwitterion is few, fine size and narrower particle size distribution.Can satisfy the demand of users at home and abroad fully.

So far, domestic do not have bismuth oxide quality ministerial standard as yet, has only the company standard of each enterprise oneself.

The quality standard of the ultra micro electron grade bismuth oxide of my company is as follows:

Bi 2O 3Content	≥99.5％	Calcination loss	≤0.5％
				Chromium (Cr)	≤10ppm	Aluminium (Al)	≤30ppm
Arsenic (As)	≤10ppm	Tin (Sn)	≤50ppm
				Sodium (Na)	≤10ppm	Potassium (K)	≤10ppm
Iron (Fe)	≤20ppm	Copper (Cu)	≤20ppm
				Plumbous (Pb)	≤10ppm	Calcium (Ca)	≤30ppm
Cadmium (Cd)	≤5ppm	Silver (Ag)	≤10ppm
				Lithium (Li)	≤10ppm	Chlorine (Cl)	≤10ppm
Nitrate (NO 3)	≤300ppm	Alkalies and alkaline earth	≤0.1％
				Particle diameter	1.5±0.3μm

Embodiment

Come the present invention is further described below in conjunction with specific embodiment, but the present invention's scope required for protection is not limited to the described scope of embodiment.

The production method of powder in micron order of bismuth oxide, technical process is:

Smart bismuth+nitric acid → bismuth nitrate solution → bismuth subnitrate → bismuth oxide → ultra micro electron grade bismuth oxide → check → packing → warehouse-in.

Its processing step is as follows:

A, bismuth nitrate solution preparation

It is 1.6 gram/cm that nitric acid deposite metal bismuth obtains density ³Bismuth nitrate solution;

Synthesizing of b, bismuth subnitrate

Bismuth nitrate solution after filtering imported add 8～10% ammoniacal liquor in 316 stainless steel cauldrons, by the flow velocity of spinner-type flowmeter control ammoniacal liquor, the concentration of control bismuth nitrate solution is 1.6cm ³, synthesis temperature is controlled between 40～50 ℃, synthetic bismuth subnitrate;

C, bismuth ion hydrolysis

Control synthetic end point pH value is 2.0～2.2, only allows the bismuth ion hydrolysis come out, and other metal ion major part is stayed in the mother liquor;

The then hydrolysis of following salt, its pH value is:

Oxyhydroxide	Concentration and constant (Ksp)	Positively charged ion begins sedimentary pH value
			Ca(OH) 2	5.5*10 -6	11.9
Mg(OH) 2	1.2*10 -11	9
			Mn(OH) 2	4.0*10 -14	7.8
Fe(OH) 2	1.6*10 -14	7.6
			Cd(OH) 2	1.2*10 -14	7.5
Ni(OH) 2	4.8*10 -16	6.8
			Pb(OH) 2	2.5*10 -16	6.7
Co(OH) 2	2.0*10 -18	6.65
			Zn(OH) 2	1.0*10 -17	6
Cu(OH) 2	5.5*10 -20	4.9
			Cr(OH) 2	7.1*10 -31	4.3
Hg(OH) 2	4.2*10 -22	3.3
			Al(OH) 3	2.0*10 -33	3.4
Fe(OH) 3	1.1*10 -36	2.3

As seen, control terminal point PH=2.2-2.2, bismuth ion almost completely hydrolysis is intact, and other positively charged ion still is present in the mother liquor with ionic condition, drains mother liquor, can obtain containing other cationic high purity product of trace.

Use deionized water, promptly the distilled water wash bismuth subnitrate is further removed the zwitterion that is adsorbed on the bismuth subnitrate surface, and the mother liquor that the reaction back is produced is by the recycling of raffinate absorption unit; With the centrifugal dried filter of gained bismuth subnitrate, in dried bismuth subnitrate process, wash appropriate amount of deionized water again, further remove foreign ion;

Deionized water is self-produced, adopts secondary to produce deionized water, and one-level master is reverse osmosis, and secondary is ion-exchange, and resistivity can reach more than the 17-18M Ω .m.

D, make the micron order bismuth oxide

Bismuth subnitrate is converted into bismuth oxide from the dryed product heating under 500～600 ℃ of temperature, gained bismuth oxide particle diameter is pulverized through the stepless speed regulation micronizer mill about 12 μ m again, and particle diameter is generally about 1～3 μ m.This stepless speed regulation micronizer mill, adjustable grain can satisfy the customer demand of different class, different levels.

E, equipment scheme

Produce and be equipped with the key equipment table

Device name	The place of production
		The 316L stainless steel cauldron	Jiangsu
Negative pressure raffinate absorption equipment	Self-produced
		In 304 stainless steels and still	Jiangsu
Hot air circulation drying oven	Jiangsu
		The intelligence incinerator	The Hunan
The stepless speed regulation micronizer mill	Jiangsu
		Testing instruments equipment	Shanghai, Beijing, Germany
Boiler	The Hunan
		Purified water equipment	Guangdong

Claims (1)

1, the production method of powder in micron order of bismuth oxide is characterized in that by following processing step production:

It is 1.6 gram/cm that a, nitric acid deposite metal bismuth obtain density ³Bismuth nitrate solution;

B, the bismuth nitrate solution after will filtering import in the reactor and add 8～10% ammoniacal liquor, the flow velocity of control ammoniacal liquor, and the concentration of control bismuth nitrate solution is 1.6 gram/cm ³, synthetic bismuth subnitrate under 40～50 ℃ temperature condition;

C, control synthetic end point pH value are 2.0～2.2, and the hydrolysis bismuth ion is used the deionized water wash bismuth subnitrate, and reacted mother liquor recycles; With the centrifugal dried filter of gained bismuth subnitrate,, wash appropriate amount of deionized water again in dried bismuth subnitrate process;

D, bismuth subnitrate is heated from dryed product, be converted into the bismuth oxide of particle diameter about 12 μ m under 500～600 ℃ of temperature, pulverize through the stepless speed regulation micronizer mill again, promptly obtain particle diameter and be the powder in micron order of bismuth oxide about 1.5 ± 0.3 μ m.