GB2271767A - Pure-colored iron oxide direct red pigments and a process for their production - Google Patents
Pure-colored iron oxide direct red pigments and a process for their production Download PDFInfo
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- GB2271767A GB2271767A GB9321765A GB9321765A GB2271767A GB 2271767 A GB2271767 A GB 2271767A GB 9321765 A GB9321765 A GB 9321765A GB 9321765 A GB9321765 A GB 9321765A GB 2271767 A GB2271767 A GB 2271767A
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- iron
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- iron oxide
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- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 239000001054 red pigment Substances 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims description 38
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000000725 suspension Substances 0.000 claims abstract description 72
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000000243 solution Substances 0.000 claims abstract description 20
- 229910052742 iron Inorganic materials 0.000 claims abstract description 18
- 239000004922 lacquer Substances 0.000 claims abstract description 14
- 239000012266 salt solution Substances 0.000 claims abstract description 13
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical class [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000012360 testing method Methods 0.000 claims abstract description 12
- 239000002245 particle Substances 0.000 claims abstract description 10
- 239000003513 alkali Substances 0.000 claims abstract description 8
- 230000001590 oxidative effect Effects 0.000 claims abstract description 3
- 239000000049 pigment Substances 0.000 claims description 21
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 10
- 239000007789 gas Substances 0.000 claims description 9
- 230000003647 oxidation Effects 0.000 claims description 9
- 238000007254 oxidation reaction Methods 0.000 claims description 9
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 229910052598 goethite Inorganic materials 0.000 claims description 7
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 238000001556 precipitation Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 6
- 238000003786 synthesis reaction Methods 0.000 claims description 6
- 239000004277 Ferrous carbonate Substances 0.000 claims description 4
- RAQDACVRFCEPDA-UHFFFAOYSA-L ferrous carbonate Chemical compound [Fe+2].[O-]C([O-])=O RAQDACVRFCEPDA-UHFFFAOYSA-L 0.000 claims description 4
- 235000019268 ferrous carbonate Nutrition 0.000 claims description 4
- 229910000015 iron(II) carbonate Inorganic materials 0.000 claims description 4
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 claims description 3
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 2
- YPJCVYYCWSFGRM-UHFFFAOYSA-H iron(3+);tricarbonate Chemical compound [Fe+3].[Fe+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O YPJCVYYCWSFGRM-UHFFFAOYSA-H 0.000 claims 1
- 239000000126 substance Substances 0.000 claims 1
- 235000019646 color tone Nutrition 0.000 abstract description 6
- 235000013980 iron oxide Nutrition 0.000 description 18
- 241000231392 Gymnosiphon Species 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 239000001034 iron oxide pigment Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 4
- 238000001354 calcination Methods 0.000 description 3
- 150000002505 iron Chemical class 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000004408 titanium dioxide Substances 0.000 description 3
- 239000001052 yellow pigment Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- 229910002588 FeOOH Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910000358 iron sulfate Inorganic materials 0.000 description 2
- 230000000485 pigmenting effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical class [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005189 flocculation Methods 0.000 description 1
- 230000016615 flocculation Effects 0.000 description 1
- WTFXARWRTYJXII-UHFFFAOYSA-N iron(2+);iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[Fe+2].[Fe+3].[Fe+3] WTFXARWRTYJXII-UHFFFAOYSA-N 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- YOBAEOGBNPPUQV-UHFFFAOYSA-N iron;trihydrate Chemical compound O.O.O.[Fe].[Fe] YOBAEOGBNPPUQV-UHFFFAOYSA-N 0.000 description 1
- 235000021388 linseed oil Nutrition 0.000 description 1
- 239000000944 linseed oil Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910006540 α-FeOOH Inorganic materials 0.000 description 1
Classifications
-
- 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
- C09C1/22—Compounds of iron
- C09C1/24—Oxides of iron
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/06—Ferric oxide [Fe2O3]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- 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
- C01P2006/12—Surface area
-
- 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)
-
- 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
- C01P2006/65—Chroma (C*)
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Iron (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Paints Or Removers (AREA)
Abstract
Pure-coloured iron oxide direct red pigments, having a colour saturation in the lacquer test of more than 37.5 CIELAB units are prepared by adding either (a) iron (II) salt solution and metallic iron or (b) iron (II) salt solution and an alkali solution to a seed suspension and then oxidizing with an O2-containing gas until the required colour tone is obtained wherein the seed suspension consists essentially of star-shaped particles of specific surface greater than 100 m<2>/g and an average particle size of less than 0.2 mu m. <IMAGE>
Description
2271767 PURE-COLORED IRON OXIDE DIRECT RED PIGMENTS, A PROCESS FOR THEIR
PRODUCTION AND THEIR USE This invention relates to new pure-colored iron oxide direct red pigments, to a process for their production and to their use for pigmenting lacquers and plastics.
There are four known processes for the production of red iron oxide pigments (T.C. Patton, Pigment Handbook, Vol. 1, New York 1988, page 288). One of these methods is the direct precipitation of red iron oxides which is described in US-A 2,716,595. In this method, an iron(II) salt solution and an alkali solution are mixed in substantially equivalent quantities and air is passed through the iron(H) hydroxide or carbonate suspension obtained. The iron(HI) oxide hydroxide seed suspension thus formed is made up into the red pigment in the presence of iron(II) salt by addition of metallic iron, heating and oxidation with oxygen- containing gases.
It is known from DE-B 1 084 405 that red pigments can only be produced from red seed suspensions and yellow pigments from yellow seed suspensions. Accordingly, the color of the end product is clearly determined by the seeds used.
Nfixtures of yellow and red iron oxide pigments only give brown and unattractive color tones. US-A 3,946,103 discloses a process using seed modifiers which enables pure red seed suspensions consisting of fine delta-FeOOH particles to be produced.
By virtue of their softness, the pigments produced by this method show improved properties in regard to dispersibility, gloss and flocculation behavior, particularly when used in lacquer systems, by comparison with the pigments produced by calcination of yellow and black iron oxides. In lacquer applications, however, the color purity of the iron oxide red pigments produced by direct precipitation in accordance with US-A-3,946, 103 does not approach that of the red pigments produced by calcination of black and yellow iron oxides.
Accordingly, the problem addressed by the present invention was to provide improved iron oxide direct red pigments which would have the outstanding performance properties described above, but not the disadvantage of inadequate color purity.
it has now surprisingly been found that these requirements are satisfied by new iron oxide direct red pigments which are not produced in the usual way from red seed suspensions, but instead from yellow seed suspensions, and which have a color saturation (C) of more than 37.5 CIELAB units in the lacquer test.
Accordingly the present invention relates to iron oxide direct red pigments, characterized in that they have a color saturation (C) in the lacquer test of more than 37.5 and preferably more than 38.9 CIELAB units.
In the lacquer test, the pigments according to the invention have higher color saturations than the hitherto known direct red pigments (Bayferrox 5108 produced in accordance with US-A 3,946,103 or Pfizer Croma Red RO 30970) and the red pigments obtained by calcination of black pigments (produced, for example, in accordance with DE-A 2 826 941) (Bayferrox 105M(D).
Particularly high red components (a) were obtained in the lacquer test, leading to an aesthetically impressive pure color impression.
In one particularly preferred embodiment, the iron oxide direct red pigments according to the invention are characterized in that, in the lacquer test, the red component (a) is more than 27.5 and the yellow component (b) more than 23 CIELAB units.
The iron oxide direct red pigments according to the invention are obtainable by preparation of a yellow goethite seed suspension (alphaFeOOH), addition of iron(II) salt solution and metallic iron or addition of iron(III) salt solution and alkali solution, heating and oxidation with oxygen-containing gases.
It must be regarded as surprising that pure-colored iron oxide red pigments can be obtained by this process because, according to the prior art, only yellow iron oxide pigments can be produced from yellow seed suspensions.
Accordingly, the present invention relates to a process for the production of pure-colored saturated iron oxide direct red pigments by precipitation of iron(][I) salts with an alkali solution and oxidation with oxygen-containing gases, addition of iron(II) salt solution and metallic iron or iron(][I) salt solution and an alkali solution to a seed suspension and oxidation with oxygen-containing gases until the required color tone is obtained, wherein a yellow goethite seed suspension consisting essentially of stellately branched particles having a specific surface of greater than 100 m2/g and an average particle size of less than 0.2 gm is used as the seed C) - suspension for synthesis of the pigment.
The BET surface is determined by the nitrogen one-point method (DIN 66 13 1) while particle size is determined from electron micrographs.
It is possible in the process according to the invention either directly to prepare the seed suspension in the suspension by establishing suitable conditions or to use separately prepared seeds.
The particles of the seed suspensions used in the process according to the invention differ totally in shape from the conventional seeds used for the production of iron oxide yellow pigments.
Figure I shows the typical stellate branches of the goethite seeds used in the process according to the invention. For comparison, Fig. 2 shows a conventional yellow seed which consists of unbranched acicular individual particles and, in the pigment synthesis process, leads to a yellow iron oxide pigment.
The yellow geothite seed suspension (alpha-FeOOH) is prepared by precipitation of iron (II) salts with an alkali solution followed by oxidation with oxygen-containing gases.
In one preferred embodiment of the process according to the invention, the seed suspension is prepared by a) b) c) forming an aqueous iron(II) sulfate solution having a concentration of from about 10 to 80 g/1 and preferably 20 to 40 g/l, adding about 0.8 to 1.0 and preferably 0.85 to 0.95 equivalent of an alkaline precipitant to said aqueous iron (11) sulfate solution to precipitate a suspension of iron (11) hydroxide or iron (II) carbonate, and oxidizing the iron (II) hydroxide or iron (II) carbonate by intensively aerating said suspension with an oxygen-containing gas to form a suspension of iron (111) oxide hydroxide of the cc-FeOOH modification.
Iron(II) salts from steel pickling plants and/or from the production of titanium dioxide may be used with particular advantage for the preparation of the iron(II) sulfate solution.
The temperature prevailing during seed formation is preferably in the range from 15 to 40C and, more preferably, in the range from 20 to 35'C.
A suspension of iron(]E[) hydroxide or carbonate is precipitated by addition of 0.8 to 1.0 equivalent and preferably 0.85- to 0.95 equivalent, NaOK Na,C03, NH3, MgO and/or MgC03 preferably being used.
Precipitation is followed by oxidation preferably using air as the oxidizing agent. To this end, 20 to 300 liters air per hour and per liter suspension are introduced.
The seed suspension thus obtained may then be advantageously subjected to ripening for I to 4 hours at 70 to 100'C.
A yellow seed suspension is obtained which, according to radiographic phase analysis (Siemens D-500), consists solely of goethite (alpha-FeOOII) (ASTM No. 29.0713).
A quantity of seeds of 4 to 30 g/l, calculated as Fe203, is preferably used for pigment formation, a quantity of 7 to 20 g/I being particularly preferred.
Pigment formation may advantageously be carried out by two methods.
In the first method, metallic iron and iron (11) salt solution are added to the seed suspension which is then heated to 70 to 100"C and preferably to 75 to 90"C and oxidized by aerating the suspension with 0.2 to 50 1 air per hour and per liter suspension until from about the required color tone is obtained. This is the case after seed multiplication by a factor of 3 to 15 and preferably 4 to 10.
In the second method, the seed suspension is heated to 70 to 100"C and preferably to 75 to 90'C, iron([I) salt solution and an allWi sohition are then added and the suspension is oxidized by aerating the suspension with from about I to 400 1 air per hour and per liter suspension until the required color tone is obtained, the pH value being in the range from 4 to 5. The required color tone is again obtained after seed multiplication by a factor of 3 to 15 and preferably 4 to 10.
The salt liquor can be removed by filtration and washing or by sedimentation. The red paste may be processed to slurries or dried and ground to c 1 form a powder-form pigment.
Soft pure-colored iron oxide pigments are obtained. a-FeO, is detected by x-ray phase analysis (ASTM No. 3) 1.0664).
The color testing of the pigments for applications in the paint field was carried out in Alkydal L64 (a product of Bayer AG, an alkyd resin containing 63% linseed oil and 23% phthalic anhydride to which 5% Luvotix HT (a product of Lehmann & Voss) is added to increase viscosity). The pigment volume concentration is 10%.
The CIELAB data (DIN 6174) were determined using a color measuring instrument with an Ulbricht ball (lighting conditions d/8', standard light type C/2"); the surface reflection was included.
Table I shows.the colorimetric data of a few pigments according to the invention and, for comparison, the corresponding data of a few commercial products.
The color saturation (C) is a measure of the color purity of the pigments.
The present invention also relates to the use of the iron oxide red pigments produced in accordance with the invention for pigmenting lacquers and plas tics both as powder-forni pigments and in the form of pastes or slurries.
Figure I shows an iron oxide seed (goethite) produced by the process according to the invention which, in the pigment synthesis process, leads to a pure colored red pigment. For comparison, Fig. 2 shows a conventional yellow iron oxide seed (goethite) which leads to a yellow pigment in the pigment synthesis process.
Figure 3 shows the CIELAB data of some iron oxide red pigments in the building materials test (plotted in the a-b plane).
The following Examples, which are intended to illustrate the invention without limiting it in any way, describe the formation of the yellow seed suspension and the synthesis of the red pigment according to the invention.
Example 1
22.3 1 of an iron sulfate solution from the production of titanium dioxide (concentration 25 g/I FeS04) are initially introduced. The temperature is 31'C.
1.325 1 of a 4.75 N NaOH solution are added and the suspension is subsequently - 5 oxidized for 28 minutes with 52 1 air per hour and per liter suspension. The yellow seed suspension obtained is heated to 80'C and stirred for 2 hours.
Example 2
44 m3 of an iron sulfate solution from the production of titanium dioxide (concentration 24.6 g/l FeS04) are initially introduced. The temperature is 29C. 2.95 m3 of a 4.5 N NaOH solution are added and the suspension is subsequently oxidized for 30 minutes with 215 1 air per hour and per liter suspension. The yellow seed suspension obtained is heated to 80'C and stirred for 2 hours.
Example 3
126 ml iron(II) sulfate solution (200 g/I FeS04). 1603 ml water and 450 g metallic iron are added to 3271 nil of the seed suspension produced in accordance with Example 1. After heating to 85'C, the suspension is oxidized with 20 1 air per hour and per liter suspension. After 40 hours, the yellow seed suspension has been converted into a pure-colored red pigment. The multiplication factor is 11.5. The suspension is filtered, washed free from salts, dried at 85"C and the pigment obtained is ground.
Example 4
3_36 ml iron(II) sulfate solution (200 g/l FeS04), 6664 ml water and 1600 g metallic iron are added to 14,000 ml of the seed suspension prepared in accordance with Example 2. After heating to 85'C, the suspension is oxidizecL-with 0. 5 1 air per hour and per liter suspension.
After 22 hours, the yellow seed suspension has been converted into a pure-colored red pigment. The multiplication factor is 4.4. The suspension is fil tered, washed free from salts, dried at 85T and the pigment obtained is ground.
1 1, Table 1 Colorimetric data of iron oxide red pigments 11 Pure tone testing in Alkydal@ L64 (lacquer applications) Pigment L a b C Remarks A Pfizer Croma Red RO 309701) 39.6 28.5 22.2 36.1 Direct red Bayferrox 5 10@2) 40.9 28.5 23.9 37.2 Direct red acc. to US-A-3,946,103 Bayferrox 105M@2) 41.3 29.1 24.4 38 Calcined black iron oxide I 00 Example 3 41.6 29.6 25.2 38.9 1 Example 4 42.3 29.6 26 39.4 1) A product of Pfizer 2) A product of Bayer AG i
Claims (19)
- WHAT IS CLAIMED IS:Iron oxide direct red pigments having a color saturation in the lacquer test of more than 37.5 CEELAB units,
- 2. Iron oxide direct red pigments as claimed in claim 1, wherein, in the lacquer test, the red components (a) is more than 27.5 CIELAB units and the yellow component (b) more than 23 CIELAB units.
- 3. A process for the production of pure-colored iron oxide red pigments comprising addition of iron (II) salt solution and metallic iron or iron (II) salt solution and an alkali solution to a seed suspension and oxidation with oxygen- containing gases until the required color tone is obtained, wherein a yellow goethite seed suspension consisting essentially of stellately branched particles having a specific surface of greatex than 100 m2/g and an average particle size of less than 0.2 gm is used as the seed suspension for synthesis of the pigment.
- 4. A process as claimed in claim 3, wherein the seed suspension is prepared by a) b)
- 5.forming an aqueous iron(II) sulfate solution having a concentration of from about 10 to 80 g1l; adding about 0.8 to 1.0 equivalent of an alkaline precipitant to said aqueous iron(H) sulfate solution to precipitate a suspension of iron(II) hydroxide or iron(II) carbonate; and oxidizing said iron(H) hydroxide or iron (III) carbonate by intensively aerating said suspension with an oxygen-containing gas to form said seed suspension.A process as claimed in claim 4, wherein the precipitation and oxidation steps are carried out at a temperature of from about 15 to 40C.
- 6. A process as claimed in claim 4, wherein the precipitant comprises at least one substance selected from the group consisting of NaOK NaC03, NH3, MgO and MgC03.
- 7. A process as claimed in claim 4, wherein the seed suspension is ripened for I to 4 hours at a temperature of from about 70 to 100'C.
- 8. A process as claimed in claim 3, wherein the concentration of seeds in the seed suspension is from about 4 to 30 g/I.
- 9. A process as claimed in claim 3, wherein metallic iron and iron(II) salt solution are added to the seed suspension, the suspension is then heated to a temperature of from about 70 to 100'C and is then oxidized W aerating the suspension with from about 0.2 to 50 1 air per hour and per liter suspension until the required color tone is obtained.
- 10. A process as claimed in claim 3, wherein the seed suspension is heated to a temperature of from about 70 to 100C, iron(II) salt solution and alkali solution are then added and the suspension is then oxidized by aerating the suspension with from about 1 to 400 1 air per hour and per liter suspension until the required color tone is obtained.
- 11. Iron oxide direct red pigments as claimed in claim 1, having a colour saturation in the lacquer test of more than 38.9 CEELAB units.
- 12. A process as claimed in claim 4, wherein the aqueous iron(II) sulfate solution has a concentration of from about 20 to 40 g/l.
- 13. A process as claimed in claim 4, wherein about 0.85 to 0.95 equivalent of the alkaline precipitant is added in steb b).
- 14. A process as claimed in claim 5, wherein the precipitation and oxidation steps are carried out at a temperature of from about 20 to 35"C.
- 15. A process as claimed in claim 8, wherein the concentration of seeds in the seed suspension is from about 7 to 20 g/l.
- 16. A process as claimed in claim 9, wherein the suspension is heated to a temperature of from about 75 to 90"C.
- 17. A process as claimed in claim 10, wherein the suspension is heated to a temperature of from about 75 to 90"C.
- 18. A process as claimed in claim 4, wherein the oxygen-containing gas in air.
- 19. A process as claimed in claim 18, wherein said air is introduced to said suspension or iron (II) hydroxide or iron(II) carbonate in a quantity of from about 20 to 300 liters of air per hour and per liter of said suspension.-1
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4235947A DE4235947A1 (en) | 1992-10-23 | 1992-10-23 | Color-pure iron oxide direct red pigments, process for their preparation and their use |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9321765D0 GB9321765D0 (en) | 1993-12-15 |
| GB2271767A true GB2271767A (en) | 1994-04-27 |
| GB2271767B GB2271767B (en) | 1995-09-13 |
Family
ID=6471262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9321765A Expired - Fee Related GB2271767B (en) | 1992-10-23 | 1993-10-21 | Pure-colored iron oxide direct red pigments,a process for their production and their use |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP3651919B2 (en) |
| DE (1) | DE4235947A1 (en) |
| GB (1) | GB2271767B (en) |
| IT (1) | IT1270902B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0645437A1 (en) * | 1993-09-23 | 1995-03-29 | Bayer Ag | Pure-colored iron oxide direct red pigments, process for their manufacture and their use |
| CN101913656A (en) * | 2010-08-09 | 2010-12-15 | 铜陵瑞莱科技有限公司 | Method for preparing iron oxide yellow pigment by using titanium white by-product of ferrous sulfate |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10232069A1 (en) * | 2002-07-16 | 2004-02-05 | Sachtleben Chemie Gmbh | Process for the production of iron hydroxide, iron oxide hydrate or iron oxide from filter salts of thin acid recovery |
| ES2642962T3 (en) * | 2011-09-30 | 2017-11-20 | Lanxess Deutschland Gmbh | Improved procedure for the preparation of finely divided hematite and red iron oxide pigments |
| MX2017003203A (en) | 2014-09-11 | 2017-07-20 | Lanxess Deutschland Gmbh | Red iron-oxide pigments with improved colour values. |
| PL3219763T3 (en) | 2016-03-16 | 2019-05-31 | Lanxess Deutschland Gmbh | Use of iron oxide red pigments in aqueous preparations |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1554456A (en) * | 1975-12-15 | 1979-10-24 | Bayer Ag | Process for the continuous production of iron oxide hydroxide |
| US4676838A (en) * | 1984-11-09 | 1987-06-30 | Bayer Aktiengesellschaft | Lamellar iron oxide pigments, a process for the production thereof and the use thereof |
| US4753680A (en) * | 1985-01-09 | 1988-06-28 | Bayer Aktiengesellschaft | Process for the preparation of bright, color-pure iron oxide red pigments |
-
1992
- 1992-10-23 DE DE4235947A patent/DE4235947A1/en not_active Withdrawn
-
1993
- 1993-10-13 IT ITMI932170A patent/IT1270902B/en active IP Right Grant
- 1993-10-18 JP JP28212093A patent/JP3651919B2/en not_active Expired - Fee Related
- 1993-10-21 GB GB9321765A patent/GB2271767B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1554456A (en) * | 1975-12-15 | 1979-10-24 | Bayer Ag | Process for the continuous production of iron oxide hydroxide |
| US4676838A (en) * | 1984-11-09 | 1987-06-30 | Bayer Aktiengesellschaft | Lamellar iron oxide pigments, a process for the production thereof and the use thereof |
| US4753680A (en) * | 1985-01-09 | 1988-06-28 | Bayer Aktiengesellschaft | Process for the preparation of bright, color-pure iron oxide red pigments |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0645437A1 (en) * | 1993-09-23 | 1995-03-29 | Bayer Ag | Pure-colored iron oxide direct red pigments, process for their manufacture and their use |
| AU675161B2 (en) * | 1993-09-23 | 1997-01-23 | Bayer Aktiengesellschaft | Pure-coloured iron oxide direct red pigments and a process for their production as well as their use |
| CN101913656A (en) * | 2010-08-09 | 2010-12-15 | 铜陵瑞莱科技有限公司 | Method for preparing iron oxide yellow pigment by using titanium white by-product of ferrous sulfate |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2271767B (en) | 1995-09-13 |
| IT1270902B (en) | 1997-05-13 |
| GB9321765D0 (en) | 1993-12-15 |
| ITMI932170A1 (en) | 1995-04-13 |
| JPH06211524A (en) | 1994-08-02 |
| DE4235947A1 (en) | 1994-04-28 |
| ITMI932170A0 (en) | 1993-10-13 |
| JP3651919B2 (en) | 2005-05-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20081021 |