CA1303328C - Bismuth vanadate process - Google Patents
Bismuth vanadate processInfo
- Publication number
- CA1303328C CA1303328C CA000574927A CA574927A CA1303328C CA 1303328 C CA1303328 C CA 1303328C CA 000574927 A CA000574927 A CA 000574927A CA 574927 A CA574927 A CA 574927A CA 1303328 C CA1303328 C CA 1303328C
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- Prior art keywords
- bismuth
- process according
- bismuth vanadate
- alkaline
- cation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G31/00—Compounds of vanadium
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/04—Compounds of zinc
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/0006—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black containing bismuth and vanadium
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/02—Compounds of alkaline earth metals or magnesium
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
- C09C3/006—Combinations of treatments provided for in groups C09C3/04 - C09C3/12
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
- C01P2006/62—L* (lightness axis)
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
- C01P2006/63—Optical properties, e.g. expressed in CIELAB-values a* (red-green axis)
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
- C01P2006/64—Optical properties, e.g. expressed in CIELAB-values b* (yellow-blue axis)
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Catalysts (AREA)
Abstract
3-16646/=/CGC 1291 Bismuth Vanadate Process Abstract of the Disclosure An improved solid state process for the preparation of compounds based on bismuth vanadate wherein the improvement comprises subjecting the reaction product to wet grinding in alkaline solution or to sequential wet grinding and alkaline treatment, said process modification resulting in the preparation of bright yellow pigments with high tinting strength.
Description
~ ~3~33~
Bismuth Vanadate Process Bismuth vanadates have been identified as pigmentary, yellow compounds applicable for coloring plastics and paints (see U.S. Patents 4,115,141 and 4,115,142). A variety of precipitation and solid state reactions have also been disclosed for preparing such bismuth vanadates and related compounds. For example, prior to discovery of the indicated pigmentary properties, Gottlieb et al., Thermal Analysis, Proceedings Fourth ICTA, Budapest, 1, pp. 675-679 (l974) describe synthesis of bismuth vanadates by solid state preparations wherein lntimately mixed bismuth and vanadium oxides are heated at 800C for 16 hours, or by precipitation methods wherein solutions of sodium vanadate and bismuth nitrate are reacted at controlled concentrations, temperatures, time and pH. Correspondingly, Roth et al., American Mineral, vol. 48, pp. 1348-1356 (1~63~ disclose solid state approaches involving heating of the mixed oxides.
In addition, the approach of the above noted U.S. patents involves first preclpitating a gel-like precursor from soluble bismuth and vanadium compounds, and then converting the precursor into the crystalline, pigmentary form either by a heat treatment at 200-500C or by an aqueous aftertreatment carried out under specified conditions.
Alternate approaches are disclosed in German Offenlegungs-schriFt 3,315,580, German ~ffenlegungss-chrift 3,315,581, U.S.
Patent 3,843,554 and U.S. Patent 4,063,956. In addition, U.S.
Patent 4,316,746 describes bismuth vanadate/molybdate and bismuth vanadate/tungstenate pig~ents which consist, in the case of bismuth vanadatelmolybdate, of a crystalline phase having a scheelitsllke structure, while in the case of bismuth vanadate/tungstenate a two-phase product is present.
~3V3;~~
A bismuth vanadate/molybdate or bismuth vanadate/tungstenate was also proposed in ~.S. Patent 4,455,174 and German Offenlegungs-schrift 3,221,338 as a further alternative yellow pigment. These are multiphase products which consist of a bismuth vanadate phase and a bismuth/molybdate and/or a bismuth/tungstenate phase and which are prepared by a process in which a solution containing a bismuth salt, a vanadate and a molybdate is acidified, then treated with an alkaline solution optionally containing the tungsten compound, whereupon the solids are recovered, washed and optionally dried and heat treated at 300-800C.
Finally, greenish-yellow pigments based on BiVOI~ and containing Ca, Ba, Mg or Zn were also proposed in U.S. Patent 4,251,283. They are obtained by calcination, in the presence of air, of a mixture of BiPOI~, V20s and of a corresponding oxide Me~, in whlch Me is Ca, ~a, Mg or Zn, at a temperature of between 500 and 800C.
These diverse processes have, however, exhibited certain disadvantages. A
key disadvantage of the solid state processes is noted in the calcined mass wherein a dull yellow brown color or a dirty green color is fre~
quently encountered. Such a reduction ~n the desired bright yellow color has, in turn, a significant impact on the use of these materials in pigment-related applications. Although the use of oxidizing agen-ts in certain of the prior art processes has served to minimize this effect, many of the oxidizing agents produce noxious off-gases. A further disadvantage of certain of these processes :Ls the need for a mult:Lplicity of steps including precipitation, calcining, and the like.
Acco}dingly, it is the primary advantage of the invention to develop animproved solid state process for the preparation of pigmentary-quality bismuth vanadate compounds.
It is a further ob~ect to provide such a process which substantially eliminates the adverse color effects on the desired bright yellow color of these compounds.
~3~3~
Various other objects and advantages of this invention will become apparent from the following descriptive material.
It has now been surprisingly found that by subjecting the calcined bismuth vanadate compounds to a procedure where the compound is wet ground in the presence of an alkaline material or is treated with the alkaline material subsequent to wet grinding, the disadvantages of the prior art approaches have been substantially eliminated. Thus, the off-color is believed to be attributable to the presence of the excess vanadium frequently utilized in order to insure complete bismuth reaction and/or to the presence of lower valent vanadium, namely trivalent and quadrivalent vanaditlm. The instant process thus serves to convert these contaminants to the soluble and readily removable alkali vanadate form in order to obtain desired color. In addition, the process allows Eor the use of low cost raw materials and for relatively simple operation particularly in the combined alkaline-wet grinding procedure. Finally, the process is applicable to a wide variety of bismuth vanadate com-pounds, including bismuth vanadate and bismuth vanadates containing a broad range of bismuth and vanadium replacement ions. The key end result is the preparation of bright yellow plgmentary bismuth vanadate com-pounds.
Accordingly, the present invention relates to a process for the prepara-tion of bismuth vanadate and bismuth vanadate-containing compounds wherein the precursor materials are calcined at elevated temperatures, the improvement comprising the steps o~ wet grinding the calcined product, contacting the calcined product with suf~icien~ alkaline material to provide a pH level of 7.0-13.0 and recovering the treated product, said wet grinding of the calcined product being conducted either in the presence of said alkaline material or prior to said contacting with said alkaline material.
The bismuth vanadate compounds applicable for preparation according to the instant process comprise bismuth vanadate and single phased bismuth vanadate compounds resulting from the incorporatlon of various precursor materials or the solubilization o~ various ADO~ compounds therein. These compounds may be depicted by the general ~ormula ~3~333~
~, wherein A represents trivalent bismuth alone or cation combina-tions of bismuth and at least one other cation, and D represents pentavalent vanadium alone or cation combinations of vanadium and at least one other non-A cation, at least one of A
or D being a cation combination. The applicable cations are com-patible with the pigmentary properties of the resulting product.
Typical bismuth replacement cations include alkaline earth metals and ~inc, while typical vanadium replacement cations include molybdenum and tungsten.
A sub-group within the above noted formula corresponds to the formula (Bi,E)(v,G)o4 wherein E is an alkaline earth metal, zinc or mixtures thereof, and G is molybdenum, tungsten or mixtures thereof, the molar ratio oE E:Bi being between 0.1 and 0.4 and the molar ratio of G:V
between 0 and 0.4. Molar ratios of 0.1-0.3 for each are prefer-red. The (Bi,E) and (V,G) notations are to be understood as mean-ing that bismuth is partly replaced by one or more E cations and that vanadium can be partly replaced by one or more G cations.
The latter compounds are more fully described in the European Patent Applica-tion No. 0239,526.
The pre-calcining and calcining operations are well-known to those skilled in the art, as particularly identified in certain of the aforementioned publications. The applicable pro-cesses include solid state reactions at elevated temperatures starting from the corresponding metal oxides. As noted, the usual method is to calcine mixtures of oxides, or any salt which yields the corresponding oxide by thermal decomposition, e.g., carbon-ates, nitrates, oxalates, hydroxides, etc., in the proper ~3~3;~
ratios for the desired composition. Calcining temperatures vary from about 300 to about 950C. The optimum temperature depends upon the particular composition being prepared. Higher temperatures are preferred in order to facilitate reaction and to assure a homogeneous product. A
critical upper limit for calcining temperatures is imposed by the formatlon of a liquid phase.
The time of calcination is not crltical; times of 1 to 100 hours may beused, but from 4 to 48 hours are preferred. Longer times are required at lower temperatures. Calcining times may be shortened and homogeneity of the products improved by regrinding between periods of heatlng.
The improved process steps of the invention involve subjecting the calcined product to wet grinding in the presence of an alkallne material or wet grinding followed by alkallne treatment. Thus, subsequent to calcining, the product i5 discharged and cooled to room temperature. Wet milling will generally be conducted in a pebble, ball, microball or sand mill for a period of time sufficient to achieve pigmentary particle size.
The alkaline material is added as an aqueous solution to provlde the wet milling environment, The alkaline material will generally be introduced at the onset of the milling operation, although it may also be added in solution during milling such that it is in contact with the calcined material for sufficient time to form the alkali vanadate.
An operable but less preferred approach involves s~irring the milled material in an alkaline solution at room temperature for a sufficient period of time for salt formation.
Applicable alkaline materials lnclude alkali metal hydroxides and carbonates, preferably sodium and potassium materials, and alkaline earth metal hydroxides, carbonates and oxides, preferably magnesium materials.
The alkaline materials are added in sufficient amount to provide a pH
value of from about 7.0-13.0 to the pigment-containing slurry, and preferably a pH value of 9.5-12Ø
~3V33Z~
Finishing operations for the resulting material will include filtration, washing to remove soluble salts and drying, for example, at 100-110C.
Subsequent dry grinding may also be an option.
The resulting bismuth vanadate compounds exhibit quality pigmentary properties, particularly the desired bright yellow color and high tinting capability. They are highly suited for pigmenting a wide variety of high molecular weight organic materials, including resins, oils and organic polymers. They can be incorporated into lacquers, paints and printing inks.
To improve certain pigment properties, the prepared compounds can additionally by treated with texture-improving agents, for example with long-chain aliphatic alcohols, esters, acids or salts thereof, amines, amides, wa~es or resinous substances, such as abietic acid, hydrogenation products, esters or salts thereof, further with nonionic, anionic or cationic surface-active agents.
The following examples further illustrate the embodiments of the inven-tion. In these examples, all parts given are by weight unless otherwise indicated.
Example 1: Bismuth oxide (46.6 g) and vanadium pentoxide (18.2 g) are wet milled, dried and heated at 778C for four hours. The resulting calcined material is thereafter introduced into a pebble mill together with sufficient sodium hydroxide solution to provide a pH in the area oE 9.5 to the system and milling is conducted until pigmentary particle size is attained. The resulting product is then washed and dried. The product exhibits a bright yellow color.
Pigmentary qualities are determined utilizing rubout in an acrylic lacquer and subsequent color readings utilizing a colorimeter. In each case, 22.8 parts of dry pigment and 100 parts of above lacquer are prepared as an ink dispersion, referred to as the masstone ink, and drawn down. In order to assess color strength, 11.4 parts of pigment and 11.4 parts of pigmentary titanium dioxide are blended, a corresponding ink dispersion (referred to as tint) is prepared and drawn down. The results la~3~2~
noted below are obtained utili~ing L, a, b colorimeter measurements wherein "L" refers to lightness, "a" refers to red-green ratio with "+a"
denoting redness and "-a" denoting greeness, and "b" re~ers to yellow-blue ratio with "~b" denoting yellowness and "-b" denoting blueness.
Masstone Tint L 82.2 88.3 a - 8.6 -ll.0 b ~50.1 ~42.9 These data thus indicate the quality pigmentary properties of the resulting pigment.
Example 2: The following pigments are prepared according to the generalprocedure of Example 1.
Parts (in g) Ex. 2b Ex. 2c Ex. 2d . _ Bismuth subnitrate 40.15 (basic bismuth nitrate) Bismuth oxide - 46.6 46.6 Vanadium pentoxide 9.10 18.2 18.2 Molybdic oxide 3.7 7.5 3.75 Calcining temp. (C) 667 778 778 Calcinlng time (hours) 4 4 4 pH value 9.5 9.5 9.5 Color of the bright bright bright rssulting pigmentyellow yellow yeliow Summarizing, it is seen that this invention provides an improved process for preparing pigmentary bismuth vanadate compounds. Variations may be made in procedures, proportions and materials without departing from the scope of the invention as defined by the following claims.
Bismuth Vanadate Process Bismuth vanadates have been identified as pigmentary, yellow compounds applicable for coloring plastics and paints (see U.S. Patents 4,115,141 and 4,115,142). A variety of precipitation and solid state reactions have also been disclosed for preparing such bismuth vanadates and related compounds. For example, prior to discovery of the indicated pigmentary properties, Gottlieb et al., Thermal Analysis, Proceedings Fourth ICTA, Budapest, 1, pp. 675-679 (l974) describe synthesis of bismuth vanadates by solid state preparations wherein lntimately mixed bismuth and vanadium oxides are heated at 800C for 16 hours, or by precipitation methods wherein solutions of sodium vanadate and bismuth nitrate are reacted at controlled concentrations, temperatures, time and pH. Correspondingly, Roth et al., American Mineral, vol. 48, pp. 1348-1356 (1~63~ disclose solid state approaches involving heating of the mixed oxides.
In addition, the approach of the above noted U.S. patents involves first preclpitating a gel-like precursor from soluble bismuth and vanadium compounds, and then converting the precursor into the crystalline, pigmentary form either by a heat treatment at 200-500C or by an aqueous aftertreatment carried out under specified conditions.
Alternate approaches are disclosed in German Offenlegungs-schriFt 3,315,580, German ~ffenlegungss-chrift 3,315,581, U.S.
Patent 3,843,554 and U.S. Patent 4,063,956. In addition, U.S.
Patent 4,316,746 describes bismuth vanadate/molybdate and bismuth vanadate/tungstenate pig~ents which consist, in the case of bismuth vanadatelmolybdate, of a crystalline phase having a scheelitsllke structure, while in the case of bismuth vanadate/tungstenate a two-phase product is present.
~3V3;~~
A bismuth vanadate/molybdate or bismuth vanadate/tungstenate was also proposed in ~.S. Patent 4,455,174 and German Offenlegungs-schrift 3,221,338 as a further alternative yellow pigment. These are multiphase products which consist of a bismuth vanadate phase and a bismuth/molybdate and/or a bismuth/tungstenate phase and which are prepared by a process in which a solution containing a bismuth salt, a vanadate and a molybdate is acidified, then treated with an alkaline solution optionally containing the tungsten compound, whereupon the solids are recovered, washed and optionally dried and heat treated at 300-800C.
Finally, greenish-yellow pigments based on BiVOI~ and containing Ca, Ba, Mg or Zn were also proposed in U.S. Patent 4,251,283. They are obtained by calcination, in the presence of air, of a mixture of BiPOI~, V20s and of a corresponding oxide Me~, in whlch Me is Ca, ~a, Mg or Zn, at a temperature of between 500 and 800C.
These diverse processes have, however, exhibited certain disadvantages. A
key disadvantage of the solid state processes is noted in the calcined mass wherein a dull yellow brown color or a dirty green color is fre~
quently encountered. Such a reduction ~n the desired bright yellow color has, in turn, a significant impact on the use of these materials in pigment-related applications. Although the use of oxidizing agen-ts in certain of the prior art processes has served to minimize this effect, many of the oxidizing agents produce noxious off-gases. A further disadvantage of certain of these processes :Ls the need for a mult:Lplicity of steps including precipitation, calcining, and the like.
Acco}dingly, it is the primary advantage of the invention to develop animproved solid state process for the preparation of pigmentary-quality bismuth vanadate compounds.
It is a further ob~ect to provide such a process which substantially eliminates the adverse color effects on the desired bright yellow color of these compounds.
~3~3~
Various other objects and advantages of this invention will become apparent from the following descriptive material.
It has now been surprisingly found that by subjecting the calcined bismuth vanadate compounds to a procedure where the compound is wet ground in the presence of an alkaline material or is treated with the alkaline material subsequent to wet grinding, the disadvantages of the prior art approaches have been substantially eliminated. Thus, the off-color is believed to be attributable to the presence of the excess vanadium frequently utilized in order to insure complete bismuth reaction and/or to the presence of lower valent vanadium, namely trivalent and quadrivalent vanaditlm. The instant process thus serves to convert these contaminants to the soluble and readily removable alkali vanadate form in order to obtain desired color. In addition, the process allows Eor the use of low cost raw materials and for relatively simple operation particularly in the combined alkaline-wet grinding procedure. Finally, the process is applicable to a wide variety of bismuth vanadate com-pounds, including bismuth vanadate and bismuth vanadates containing a broad range of bismuth and vanadium replacement ions. The key end result is the preparation of bright yellow plgmentary bismuth vanadate com-pounds.
Accordingly, the present invention relates to a process for the prepara-tion of bismuth vanadate and bismuth vanadate-containing compounds wherein the precursor materials are calcined at elevated temperatures, the improvement comprising the steps o~ wet grinding the calcined product, contacting the calcined product with suf~icien~ alkaline material to provide a pH level of 7.0-13.0 and recovering the treated product, said wet grinding of the calcined product being conducted either in the presence of said alkaline material or prior to said contacting with said alkaline material.
The bismuth vanadate compounds applicable for preparation according to the instant process comprise bismuth vanadate and single phased bismuth vanadate compounds resulting from the incorporatlon of various precursor materials or the solubilization o~ various ADO~ compounds therein. These compounds may be depicted by the general ~ormula ~3~333~
~, wherein A represents trivalent bismuth alone or cation combina-tions of bismuth and at least one other cation, and D represents pentavalent vanadium alone or cation combinations of vanadium and at least one other non-A cation, at least one of A
or D being a cation combination. The applicable cations are com-patible with the pigmentary properties of the resulting product.
Typical bismuth replacement cations include alkaline earth metals and ~inc, while typical vanadium replacement cations include molybdenum and tungsten.
A sub-group within the above noted formula corresponds to the formula (Bi,E)(v,G)o4 wherein E is an alkaline earth metal, zinc or mixtures thereof, and G is molybdenum, tungsten or mixtures thereof, the molar ratio oE E:Bi being between 0.1 and 0.4 and the molar ratio of G:V
between 0 and 0.4. Molar ratios of 0.1-0.3 for each are prefer-red. The (Bi,E) and (V,G) notations are to be understood as mean-ing that bismuth is partly replaced by one or more E cations and that vanadium can be partly replaced by one or more G cations.
The latter compounds are more fully described in the European Patent Applica-tion No. 0239,526.
The pre-calcining and calcining operations are well-known to those skilled in the art, as particularly identified in certain of the aforementioned publications. The applicable pro-cesses include solid state reactions at elevated temperatures starting from the corresponding metal oxides. As noted, the usual method is to calcine mixtures of oxides, or any salt which yields the corresponding oxide by thermal decomposition, e.g., carbon-ates, nitrates, oxalates, hydroxides, etc., in the proper ~3~3;~
ratios for the desired composition. Calcining temperatures vary from about 300 to about 950C. The optimum temperature depends upon the particular composition being prepared. Higher temperatures are preferred in order to facilitate reaction and to assure a homogeneous product. A
critical upper limit for calcining temperatures is imposed by the formatlon of a liquid phase.
The time of calcination is not crltical; times of 1 to 100 hours may beused, but from 4 to 48 hours are preferred. Longer times are required at lower temperatures. Calcining times may be shortened and homogeneity of the products improved by regrinding between periods of heatlng.
The improved process steps of the invention involve subjecting the calcined product to wet grinding in the presence of an alkallne material or wet grinding followed by alkallne treatment. Thus, subsequent to calcining, the product i5 discharged and cooled to room temperature. Wet milling will generally be conducted in a pebble, ball, microball or sand mill for a period of time sufficient to achieve pigmentary particle size.
The alkaline material is added as an aqueous solution to provlde the wet milling environment, The alkaline material will generally be introduced at the onset of the milling operation, although it may also be added in solution during milling such that it is in contact with the calcined material for sufficient time to form the alkali vanadate.
An operable but less preferred approach involves s~irring the milled material in an alkaline solution at room temperature for a sufficient period of time for salt formation.
Applicable alkaline materials lnclude alkali metal hydroxides and carbonates, preferably sodium and potassium materials, and alkaline earth metal hydroxides, carbonates and oxides, preferably magnesium materials.
The alkaline materials are added in sufficient amount to provide a pH
value of from about 7.0-13.0 to the pigment-containing slurry, and preferably a pH value of 9.5-12Ø
~3V33Z~
Finishing operations for the resulting material will include filtration, washing to remove soluble salts and drying, for example, at 100-110C.
Subsequent dry grinding may also be an option.
The resulting bismuth vanadate compounds exhibit quality pigmentary properties, particularly the desired bright yellow color and high tinting capability. They are highly suited for pigmenting a wide variety of high molecular weight organic materials, including resins, oils and organic polymers. They can be incorporated into lacquers, paints and printing inks.
To improve certain pigment properties, the prepared compounds can additionally by treated with texture-improving agents, for example with long-chain aliphatic alcohols, esters, acids or salts thereof, amines, amides, wa~es or resinous substances, such as abietic acid, hydrogenation products, esters or salts thereof, further with nonionic, anionic or cationic surface-active agents.
The following examples further illustrate the embodiments of the inven-tion. In these examples, all parts given are by weight unless otherwise indicated.
Example 1: Bismuth oxide (46.6 g) and vanadium pentoxide (18.2 g) are wet milled, dried and heated at 778C for four hours. The resulting calcined material is thereafter introduced into a pebble mill together with sufficient sodium hydroxide solution to provide a pH in the area oE 9.5 to the system and milling is conducted until pigmentary particle size is attained. The resulting product is then washed and dried. The product exhibits a bright yellow color.
Pigmentary qualities are determined utilizing rubout in an acrylic lacquer and subsequent color readings utilizing a colorimeter. In each case, 22.8 parts of dry pigment and 100 parts of above lacquer are prepared as an ink dispersion, referred to as the masstone ink, and drawn down. In order to assess color strength, 11.4 parts of pigment and 11.4 parts of pigmentary titanium dioxide are blended, a corresponding ink dispersion (referred to as tint) is prepared and drawn down. The results la~3~2~
noted below are obtained utili~ing L, a, b colorimeter measurements wherein "L" refers to lightness, "a" refers to red-green ratio with "+a"
denoting redness and "-a" denoting greeness, and "b" re~ers to yellow-blue ratio with "~b" denoting yellowness and "-b" denoting blueness.
Masstone Tint L 82.2 88.3 a - 8.6 -ll.0 b ~50.1 ~42.9 These data thus indicate the quality pigmentary properties of the resulting pigment.
Example 2: The following pigments are prepared according to the generalprocedure of Example 1.
Parts (in g) Ex. 2b Ex. 2c Ex. 2d . _ Bismuth subnitrate 40.15 (basic bismuth nitrate) Bismuth oxide - 46.6 46.6 Vanadium pentoxide 9.10 18.2 18.2 Molybdic oxide 3.7 7.5 3.75 Calcining temp. (C) 667 778 778 Calcinlng time (hours) 4 4 4 pH value 9.5 9.5 9.5 Color of the bright bright bright rssulting pigmentyellow yellow yeliow Summarizing, it is seen that this invention provides an improved process for preparing pigmentary bismuth vanadate compounds. Variations may be made in procedures, proportions and materials without departing from the scope of the invention as defined by the following claims.
Claims (9)
1. A process for the preparation of bismuth vanadate and bismuth vanadate-containing compounds wherein the precursor materials are calcined at elevated temperatures, the improvement comprising the steps of wet grinding the calcined product, contacting the calcined product with sufficient alkaline material to provide a pH level of 7.0-13.0 and recovering the treated product, said wet grinding of the calcined product being conducted either in the presence of said alkaline material or prior to said contacting with said alkaline material.
2. A process according to claim 1, wherein bismuth vanadate is prepared.
3. A process according to claim 1, wherein bismuth vanadate-containing compounds are prepared, said compounds corresponding to the formula wherein A is trivalent bismuth or a cation combination of bismuth and at least one other cation, D is pentavalent vanadium or a cation combination of vanadium and at least one other non-A cation, at least one of A or D being a cation combination.
4. A process according to claim 3, wherein A is an alkaline earth metal and D is molybdenum or tungsten.
5. A process according to claim 3, wherein said compounds correspond to the formula (Bi,E)(V,G)O4 wherein E is an alkaline earth metal, zinc or mixtures thereof, and G is molybdenum, tungsten, or mixtures thereof; the molar ratio of E:Bi being between 0.1 and 0.4 and the molar ratio of G:V being between 0 and 0.4.
6. A process according to claim 1, wherein said calcined product is wet ground in the presence of the alkaline material.
7. A process according to claim 1, wherein said alkaline material is an alkali metal hydroxide, alkali metal carbonate, alkaline earth metal hydroxide, alkaline earth metal carbonate or alkaline earth metal oxide.
8. A process according to claim 7, wherein said alkaline material is an alkali metal hydroxide.
9. A process according to claim 1, wherein said pH level is 9.5-12Ø
FO 7.3/RU/cc*
FO 7.3/RU/cc*
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US8707787A | 1987-08-19 | 1987-08-19 | |
| US087,077 | 1987-08-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1303328C true CA1303328C (en) | 1992-06-16 |
Family
ID=22202984
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000574927A Expired - Lifetime CA1303328C (en) | 1987-08-19 | 1988-08-17 | Bismuth vanadate process |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0304399B1 (en) |
| JP (1) | JP2636894B2 (en) |
| KR (1) | KR960002624B1 (en) |
| BR (1) | BR8804192A (en) |
| CA (1) | CA1303328C (en) |
| DE (1) | DE3866634D1 (en) |
| ES (1) | ES2027797T3 (en) |
| MX (1) | MX168677B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR910014471A (en) * | 1990-01-25 | 1991-08-31 | 베르너 발데크 | Modified bismuth vanadate pigment in monoclinic crystalline form and preparation method thereof |
| DE4040849A1 (en) * | 1990-12-20 | 1992-06-25 | Bayer Ag | Bismuth Vanadate pigments, process for their preparation and their use |
| DE59708927D1 (en) * | 1996-06-17 | 2003-01-23 | Ciba Sc Holding Ag | Bismuth vanadate pigment powder mixtures |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1101010B (en) * | 1978-10-06 | 1985-09-28 | Montedison Spa | NEW INORGANIC PIGMENTS AND PROCESS TO PREPARE THEM |
-
1988
- 1988-08-10 DE DE8888810543T patent/DE3866634D1/en not_active Expired - Lifetime
- 1988-08-10 ES ES198888810543T patent/ES2027797T3/en not_active Expired - Lifetime
- 1988-08-10 EP EP88810543A patent/EP0304399B1/en not_active Expired - Lifetime
- 1988-08-16 MX MX012692A patent/MX168677B/en unknown
- 1988-08-17 CA CA000574927A patent/CA1303328C/en not_active Expired - Lifetime
- 1988-08-18 BR BR8804192A patent/BR8804192A/en not_active IP Right Cessation
- 1988-08-19 KR KR1019880010544A patent/KR960002624B1/en not_active IP Right Cessation
- 1988-08-19 JP JP63204898A patent/JP2636894B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| BR8804192A (en) | 1989-03-14 |
| EP0304399A1 (en) | 1989-02-22 |
| ES2027797T3 (en) | 1992-06-16 |
| KR960002624B1 (en) | 1996-02-24 |
| JP2636894B2 (en) | 1997-07-30 |
| EP0304399B1 (en) | 1991-12-04 |
| DE3866634D1 (en) | 1992-01-16 |
| KR890003925A (en) | 1989-04-18 |
| JPS6469521A (en) | 1989-03-15 |
| MX168677B (en) | 1993-06-03 |
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