DE3315851A1 - Process for the preparation of yellow bismuth vanadate pigment - Google Patents

Abstract

The present invention relates to a process for the preparation of yellow single-phase bismuth vanadate pigment starting from metallic bismuth or one or more vanadium(V) components, and the use of this pigment.

Description

Process for making yellow bismuth vanadate

Pigment The present invention relates to a method of manufacture of yellow phase-pure bismuth vanadate pigment and its use.

Bismuth vanadate (BiVO4) occurs naturally as the mineral pucherite yellow-brown color (Frenzel 1871) and crystallizes in an orthorhombic distorted scheelite structure (M.M. Quirashi, W.H. Barnes; Am. Min.

38, 1953, p. 489). Synthetic BiV04 is isotype with zirconium (ZrSi04) and changes irreversibly into a monoclinic distorted one above 400-5000C Scheelite structure (ß-ferqusonite type) around (R.S. Roth, J.L. Waring; Am. Min.

48, 1963, p. 1348).

DE-OS 2 727 863 teaches the production of bright yellow monoclinic Bismuth vanadate pigment by precipitation from bismuth nitrate and an alkali vanadate solution. The precipitation is converted into monoclinic BiVO4 by tempering.

The synthesis of BiVO4 mixed phases is achieved by annealing the respective Mixed phase of corresponding amounts of the individual components at higher temperatures. For example, DE-OS 2 727 865 describes the production of mixed phases with the composition BiV04 x Al203 y y SiO2 on the subject.

The color quality of the pigments is determined by intermediate grinding Improved. Without the addition of Al203 and Si02 it is obtained after annealing at 850 ° C in air (without intermediate grinding and renewed calcination) a product of inadequate quality.

According to DE-OS 2 933 778 BiVO4 / BiPO4 / AlPO4 mixed phases are made by annealing the corresponding amounts of the BiPO4, vanadium (V) and aluminum components Maintain temperatures between 700 and 11000C. Depending on the Al2 0 and P2 0 5 content as well as depending on the annealing temperature, products with green-yellow to yellow-orange hues preserved.

Pure bismuth vanadate pigments with good color qualities can be used so only produce in a complex two-stage process (precipitation, calcination). With bismuth nitrate an expensive bi-raw material is also used, through him and the nitric acid used are these processes with a high accumulation of nitrates afflicted.

The mixed phases naturally only have a lower content of coloring component BiVO4, which is detrimental to its coloristic properties affects (Table 4). The production of these mixed phases takes place at temperatures of more than 7000C and sometimes requires a second annealing after an intermediate grinding.

The object of the present invention is to provide a method to provide that does not have the disadvantages of the above-mentioned method and the Production of yellow bismuth vanadate pigment in a technically simpler and more economical way Way allowed.

Surprisingly, it has now been found that one is phase and color pure yellow bismuth vanadate pigments (BiVO4) are obtained when stoichiometric mixtures of metallic bismuth and one or more vanadium (V) components in oxidizing Atmosphere at temperatures of 3500C to 7500C and the reaction products comminuted to pigment size.

Stoichiometric in the context of this application is intended to mean that the actual Mixing ratios around + 5% by weight of the calculated stoichiometric ratios may differ. It is advantageous that the metallic bismuth is finely divided Form. It should be made up by mechanical crushing and intense grinding Grain sizes of less than 0.1 mm are crushed.

Sources of vanadium can be ammonium metavanate (NH4VO3), vanadium pentoxide (V205) and / or alkali metavanadates ((Na, K) VO3) can be used, with vanadium pentoxide with BET surface areas between 5 and 20 m2 / g is preferred (determined by N2 adsorption according to DIN 66 1131).

The oxidizing atmosphere during the reaction is released Oxygen-containing gases and / or the addition of oxidizing substances in at least Equimolar quantities generated. Such substances are ammonium nitrate, nitric acid, nitrates, Peroxydisulphates and / or peroxides of alkali and / or alkaline earth metals.

Combinations of potassium nitrate / nitric acid have proven advantageous as well as potassium peroxodisulfate / nitric acid in the molar ratios from 4: 1 to 1: 100 and in amounts of up to 2.5 moles per mole of BiVO4.

The addition of nitric acid is also suitable (up to 2 moles per mole BiV04) and gassing with air / oxygen mixtures (3: 1 to 1: 3) during the Annealing.

It must be regarded as surprising that metallic bismuth convert to yellow phase-pure bismuth vanadate by the process according to the invention leaves. It is also noteworthy that the method according to the invention at relatively low temperatures of 350 to 7500C and only one annealing too qualitative high quality products.

Mixing the finely powdered bismuth metal, the vanadium component and the oxidizing additives are best done dry in intensive mixers or mills (ball mills, hammer mills, mortar mills).

The annealing of the homogeneous raw material mixture should preferably be under Product movement in rotary kilns or rotary drum furnaces with direct or indirect heating in air or under gassing with air / oxygen mixtures take place. But it can also be implemented in a fluidized bed. Temperatures from 350 to 7500C and 0.5 to 12 hours, preferably 1 to 4 hours, reaction time is sufficient to a complete conversion to single-phase monoclinic BiVO4. A heating up the raw material mixture from room temperature to the final temperature is compared to the direct annealing at temperatures between 350 and 7500C with regard to the color purity of the BiVO4 formed is advantageous (examples 11a-d).

The color strengths of those produced by the process according to the invention Bismuth vanadate pigments are using the more uneconomical precipitation process (DE-OS 27 27 863) comparable. Products made without oxidizing additives are of poor color quality.

They have pale, sometimes even dirty tones.

The oxidizing additives must be at least in the process according to the invention be made available in the amount that is sufficient to remove the bismuth in the trivalent To transfer oxidation state. Prohibit large excesses of oxidizing agents from economic economic weight points, but are in general not of harm to product quality.

The pigments obtained by the process according to the invention are suitable excellent for coloring paints, plastics and emulsion paints.

The invention is explained below with the aid of examples.

After annealing, the products were pre-shredded (depending on Product quantity in a mortar or in a mill) as well as a wet grinding in a pearl mill (Netzsch-Molinex) at 150 rpm. The grinding time was varied between 10 and 120 minutes. It was then filtered and salt-dried.

The phase purity test was carried out radiographically, with all raw material mixtures both without (example 1) and with the additives (examples 2-22) at temperatures between 400 and 7000C completely for monoclinic high-temperature modification of the BiVO4 had implemented.

Comparative Example A (Precipitation Process) Corresponding to Example 1 of DE-OS 2 727 863 15.16 g of Na3VO4 in 250 ml of 1N NaOH were hot-melted and within of 2 min while stirring in a solution of 40 g Bi (NO3) 3 5H2O in 250 ml 1N HNO3 given. The mixture was stirred vigorously at RT and the pH was adjusted to 3.5 and the yellow-orange precipitate was stirred for a further 30 minutes. After filtration and Washing was carried out by annealing the moist filter cake at 4000C for one hour Air in a porcelain crucible. The calcine was crushed in a mortar. the Table 1 shows the characterization of the product.

Comparative Example B According to Example 6 of DE-OS 2,727,865, 25.83 g Bi203 (99.5%), 13.23 g NH4V03 (97.5%) and 29.34 g SiO2 (85.2%) intensive mixed and annealed in air in a porcelain crucible at 9000C for 1/2 hour. The calcine After cooling, it was comminuted and calcined again in air for 1 h at 11000C. After pre-comminuting in a mortar, wet grinding (30 min) took place in a Netzsch-Molinex mill at 1500 rpm, filtration, washing step and drying at 1050C. The characterization of the product can be found in Table 1.

Comparative Example C As in Example 8 of DOS 2,933,778 40.94 g BiP04 (97.7%), 20.94 g A12 (SO4) 3 18H2O and 7.34 g NH4VO3 pasted with a little water and mixed intensively in a mortar. After drying the Paste at 1050C, the mixture was homogenized well and placed in a porcelain crucible for 1 hour annealed in air at 11000C. The annealing product was cooled to RT in the furnace over a period of approx. 20 h. Then, according to Comparative Example B worked up. Table 1 shows the characterization of the product.

Comparative examples B and C are mixed phases of the BiVO4 with SiO2 or BiPO4 / AlPO4, their relative color strengths due to the lower BiVO4 content are significantly lower (Table 4).

Example 1 83.6 g of powdered metallic bismuth (99.9%) and 36.82 g V205 (98.8%) were mixed intensively in an agate mill for 20 minutes and each half the amount of this mixture from room temperature to 4250C (within 4 h) or to 6000C (within 5 1/2 h) with rotary motion in air in a rotary kiln heated up and annealed for 2 h at the respective final temperature. The implementation happened without oxidizing additives.

The products were pre-ground dry in a mortar and then Milled wet for 30 minutes in a Netzsch-Molinex mill at 1500 rpm. According to the usual Work-up (filtration, washing, drying), the deagglomeration took place in one Mill.

The product, which had been calcined at 4250C, had a dirty yellow-olive color Product annealed at 6000C had a dirty yellow hue and consisted of pure Vivo4.

Example 2 41.8 g of finely powdered metallic bismuth (99.99%) 18.41 g V205 (98.8%) and 10.11 g KNO3 (0.5 mol, based on 1 mol BiVO4) Mix intensively for 20 minutes in an agate mill, this homogeneous mixture while rotating in a rotary kiln in air from room temperature to 4000C (within of 4 h) and annealed for 2 h at the final temperature.

The glow product was worked up according to Example 1 and used as The final product is yellow-green BiVO4.

Example 3 The amounts of bismuth metal used in Example 2 and V205 were treated with 20.22 g of KN03 (1 mol based on 1 mol of BiVO4) in an agate mill for 20 minutes intensively mixed and this mixture is calcined and worked up according to Example 2.

Yellow BiVO4 was obtained as the end product.

Example 4 The amounts of bismuth metal used in Example 2 and V205 were treated with 40.44 g of KN03 (2 mol based on 1 mol of BiVO4) in an agate mill for 20 minutes intensively mixed and this mixture is calcined and worked up according to Example 2.

Yellow BiVO4 was obtained as the end product.

Example 5 The amounts of bismuth metal used in Example 2 and V205 were treated with 60.67 g of KNO3 (3 mol based on 1 mol of Vivo4) for 20 minutes in an agate mill intensely mixed and this mixture is calcined according to example 2 as well as worked up.

The final product (BiV04) was yellow in color.

Example 6 The amounts of bismuth metal used in Example 2 and V205 were with 101.11 g KNO3 (5 mol based on 1 mol BiVO4) for 20 minutes in an agate mill intensively mixed and this mixture is calcined and worked up according to Example 2.

Yellow BiVO4 was obtained as the end product.

Example 7 41.80 g of finely powdered metallic bismuth (99.99 figs) and 18.41 g of V205 (98.8%) were mixed intensively in an agate mill for 20 minutes and this mixture with 9.76 g of HNO3 (approx. 65%); 0.5 mol based on 1 mol BiVO4) and 20 ml of water processed into a homogeneous paste. After drying and pulverizing the mixture was annealed in a rotary kiln with product agitation Air, with the raw material mixture heated up from RT to approx. 4000C (4 h) and 2 h was annealed at this temperature.

The work-up was carried out according to Example 1 and yellow BiV04 received.

Example 8 The amounts of bismuth metal used in Example 7 and V205 were mixed in an agate mill for 20 minutes and this mixture at 19.52 g HNO3 (approx. 65%, 1 mol based on BiVO4) and with 20 ml water to a homogeneous Processed paste. Annealing and work-up were carried out according to Example 7.

The bismuth vanadate obtained was green-yellow in color.

Example 9 The amounts of bismuth metal used in Example 7 and V 205 were mixed intensively for 20 minutes in an agate mill and this mixture with 39.03 g of HN03 (approx. 65%, 2 mol based on 1 mol of BiVO4) and with 20 ml of water processed into a homogeneous paste. Annealing and work-up were carried out accordingly Example 7. The BiVO4 obtained was colored golden yellow.

Example 10 41.8 g of powdered metallic bismuth (99.99%) 18.41 g V205 (98.8%) and 5.06 g KNO3 (0.25 mol based on 1 mol BiVO4) were in a Agate mill mixed for 20 min and this mixture with the addition of 4.88 g ENO3 (approx. 65 cig; 0.25 mol based on 1 mol of Vivo4) and 20 ml of water to a homogeneous one Paste is working. After drying and pulverizing the raw material mixture the annealing was carried out with product movement in a rotary kiln according to the example 7th

After the usual work-up, bright golden yellow BiVO4 was obtained.

Example 11 167.20 g of powdered metallic bismuth (99.99%), 73.63 g V205 (98.8%) and 40.44 g KNO3 (0.5 mol based on 1 mol BiVO4) Mix intensively for 20 min in an agate mill and this mixture with the addition of 39.04 g of HNO3 (approx. 65%, 0.5 mol based on 1 mol of BiV04) and 80 ml of water are added processed into a homogeneous paste. After drying and crushing the raw material mixture a quarter of each batch was annealed in air while rotating as follows: a. 2 h at 4000C, heated from RT to 4000C within 4 h b. 4 h at 4000C, filled directly into the hot oven c. 4 h at 5009C, filled directly into the hot oven d. 4 h at 6000C, filled directly into the hot oven. After the usual work-up Canary to golden yellow bismuth vanadates were obtained, with brilliance and color purity from sample a. are greatest.

Example 12 41.80 g of powdered bismuth (99.99%), 18.41 g of V209 (98.8 Fig) and 20.22 g KNO3 (1 mol based on BiVO4) were 20 min in an agate mill mixed and this mixture with the addition of 19.52 g HNO3 (approx. 65%, 1 mol to 1 mole of BiVO4) and 20 ml of water processed into a homogeneous paste.

After drying and pulverizing the raw material mixture, the Annealing as described in Example 7.

The work-up was carried out as in Example 1 and was luminous golden yellow BiVO4 received.

Example 13 As in Example 12, a homogeneous raw material mixture was obtained with 0.5 mol of KNO3 (10.11 g) and 1.5 mol of HNO3 (29.28 g; approx. 65%), based on 1 Mol BiVO4 produced and calcined as in Example 7.

After the usual work-up, bright golden yellow BiVO4 was obtained.

Example 14 As in Example 12, a homogeneous raw material mixture was produced with 1.5 mol of KN03 (30.33 g) and 0.5 mol of HNO3 (9.76 g; approx. 65%), based on 1 mole of BiVO4 and calcined as in Example 7.

After the usual work-up, a greenish-tinged golden yellow BiV04 obtain.

Example 15 627.00 g of powdered metallic bismuth (99.99 Zig; HEK-GmbH), 276.12 g V205 (98.8%; G.f.E.) and 151.67 g KNO3 (0.5 mol based on 1 mol BiVO4) were intensively mixed for 20 min in a ball mill and this mixture in a kneader with 146.39 g of SNO3 (approx. 65%, 0.5 mol based on 1 mol of BiVO4) and 250 ml of water made into a homogeneous paste.

After drying (residual moisture approx. 1%) and pulverization (pin mill) the raw material mixture was annealed in a rotary kiln according to the example 7th

The glow product was pre-crushed dry (pin mill) and each one Quarter of this batch 10, 30, 60 and 120 minutes wet in a Netzsch-Molinex-Mthle ground at 1500 rpm.

Depending on the grinding intensity, the bismuth vanadates are after filtration and Drying bright golden yellow (10 min grinding time) to lemon yellow (120 min grinding time) colored.

Example 16 As in Example 15, a homogeneous raw material mixture was obtained prepared and a quarter each of the dried and powdered mixture Annealed in air while rotating as follows: a. from RT to 4500C within Heated for 4 1/2 hours, 1 hour at 4500C b. heated from RT to 4500C within 4 1/2 h, 3 h at 4500C c. heated from RT to 4500C within 4 1/2 h, 6 h at 4500C d. heated from RT to 4500C within 4 1/2 h, 12 h at 4500C according to the usual Work-up (Example 1) were phase-pure golden yellow bismuth vanadates of high Preserved brilliance.

Example 17 41.80 g of powdered metallic bismuth (99.99%, HEK-GmbH), 18.41 g V205 (98.8%; G.f.E.) and 5.41 g R2S208 (0.1 mol based on 1 mol BiV04) were mixed and this mixture with the addition of water how 1 g Na202 adjusted to a pH value of approx. 4.5.

The wet paste was dried at 1050C and after pulverizing Annealed in air in a rotary kiln for 4 hours at 6000C.

After the usual work-up (Example 1), it turned greenish-yellow BiVO4 received.

Example 18 As in Example 17, 41.80 g of metallic bismuth, 18.41 g V205, 10.81 g K2S208 (0.2 mol based on 1 mol BiVO4) and 2.14 g Na202 processed into a homogeneous mixture of raw materials (pH value approx. 5).

Annealing and work-up were carried out as in Example 1.

The BiVO4 obtained had a canary yellow color.

Example 19 According to Example 17, 41.80 g of metallic bismuth, 18.41 g of V205, 27.04 g of K2S208 (0.5 mol based on 1 mol of BåVO4) and 1.67 g of Na2Oz Eu processed from a homogeneous mixture of raw materials (pH value approx. 5).

After annealing (4 h at 6000C in a rotary kiln in air) and the usual A canary yellow BiVO4 was obtained.

Example 20 a. 41.80 g metallic bismuth (99.99%), 18.41 g V205 (98.8%) and 5.41 g of K2S208 (0.1 mol based on 1 mol of Vivo4) were in intensively mixed in a ball mill and this mixture at RT with 14.64 g HN03 (approx. 65%, 0.75 mol based on 1 mol BiVO4) and 25 ml of water pasted at 1050C dried and powdered.

The raw material mixture was heated from RT to 6000C while rotating and annealed for 2 h at this temperature (air, rotary kiln). The calcine was in Pre-crushed dry in a mortar, wet for 30 minutes in a Netzsch-Molinex mill Ground at 150 rpm and further worked up as usual.

The bismuth vanadate obtained was colored lemon yellow.

b. 41.80 g of metallic bismuth (99.99%), 18.41 g (98.8%) and 1.3 g of K25208 (0.024 mol) based on 1 mol of BiVO4 were in a ball mill for 20 minutes mixed and this mixture at RT with 14.64 g of HNO3 (approx. 65%; 0.75 mol to 1 mole of BiVO4) and 25 ml of water.

The further processing of the raw material mixture took place accordingly Example a. After the usual work-up, canary-yellow BiVO4 was obtained.

c. 41.80 g of metallic bismuth (99.99%), 18.41 g (98.8%) and 10.81 g of K2S208 (0.2 mol based on 1 mol of BiVO4) were in a ball mill for 20 minutes mixed and this mixture at RT with 9.76 g of HNO3 (approx. 65%; 0.5 mol based to 1 mole of BiV04) and 25 ml of water.

The further processing of the raw material mixture took place accordingly Example a. After the usual work-up, lemon-yellow BiVO4 was obtained.

Example 21 83.6 g of finely ground metallic bismuth (99.99% zig) and 36.82 g of V205 (98.8%) were processed into a homogeneous paste with 50 ml of water (Mortar), dried at 1050C and this raw material mixture into a finely divided Ground powder.

Half of the mixture was placed in a rotary kiln Air / oxygen gassing (1: 1; 20 l / h) annealed for 2 h at 600 or 7000C. The heating up took place from RT with rotary motion and gassing.

After working up (120 min wet grinding), canary yellow bismuth vanadates became obtain.

Example 22 41.8 g of metallic bismuth (99.99%) and 18.41 g of V205 (98.8 Zig) were 20 min in a ball mill mixes and with 14.64 g of H03 (approx. 65%; 0.75 mol based on 1 mol of BiVO4) and 25 ml of water RT processed into a homogeneous paste, dried at 1050C and homogenized in a mortar.

The mixture was annealed in a rotary kiln while gassing with air / oxygen (1: 1; 20 l / h) at 6000C (2 h), heated from room temperature with rotary movement and gassing became.

After the usual work-up (120 min wet grinding) it turned lemon yellow BiVO4 received.

The characterization of some products (Examples 10 to 22) is in given in Tables 2 and 3. The analytically determined contents of Bi203 and V205 were 71.8 + 0.4% (theory 71.93%) and 27.0 + 1% (theory 28.07%).

Table 1 Characterization of the reworked BiVO4 mixed phases Comparative Phase Chemical Composition Specific Visual Color Sample Surface assessment found calculated according to BET (m2 / g) A monoclinic BiVO4% Bi2O3: 70.9 71.93 5.7 lemon yellow% V2O5: 28.5 28.08 B BiVO4 # xSiO2% Bi2O3: 41.8 42.31 8.7 pale canary yellow% V2O5: 16.4 16.54% SiO2: 41.2 41.15 C xBiVO4 # yBiPO4 # zAlPO4 % Bi2O3: 62.3 62.67 7.6 greenish% V2O5: 11.4 11.69 pale yellow% P2O5: 19.1 19.09 % Al2O3: 6.7 6.55 Table 2 Production and characterization of the Examples 10-15 Example production conditions grinding specific upper color in Sand area according to BET mühle (m2 / g) 10 0.5 mol HNO3 / KNO3 (1: 1); from RT to 400 ° C, 30 min 6.2 bright golden yellow 2 h at 400 ° C., rotary tube 11 a 1 mol HNO3 / KNO3 (1: 1); from RT to 400 ° C, 30 min 6.0 bright golden yellow 2 h at 400 ° C, rotary tube b 1 mol HNO3 / KNO3 (1: 1); 4 h directly at 400 ° C, 30 min 5.8 canary yellow rotary barrel c 1 mol HNO3 / KNO3 (1: 1); 4 h directly at 500 ° C, 30 min 5.5 golden yellow rotary tube d 1 mol HNO3 / KNO3 (1: 1); 4 h directly at 600 ° C, 30 min 5.0 pale golden yellow rotary tube 12 2 mol HNO3 / KNO3 (1: 1); from RT to 400 ° C, 30 min 6.8 bright golden yellow 2 h at 400 ° C, rotary tube 13 2 moles of HNO3 / KNO3 (3: 1); from RT to 400 ° C, 30 min 6.6 bright golden yellow 2 h at 400 ° C, Rotary kiln 14 2 mol HNO3 / KNO3 (1: 3); from RT to 400 ° C, 30 min 6.7 golden yellow, slightly 2 h at 400 ° C., rotary tube greenish 15 1 mol HNO3 / KNO3 (1: 1); from RT to 400 ° C, 10 min 4.8 bright golden yellow 2 h at 400 ° C, rotary kiln 30 min 7.4 canary yellow 60 min 8.7 canary yellow 120 min 12.5 lemon yellow Table 3 Manufacture and characterization of Examples 16-22 Example, production conditions, milling Specific upper color in sandy areas according to BET mühle (m2 / g) 16 a 2 mol HNO3 / KNO3 (1: 1); from RT to 450 ° C, 30 min 5.2 bright golden yellow 1 h at 450 ° C, rotary tube b 1 mole of HNO3 / KNO3 (1: 1); from RT to 450 ° C, 30 min 5.9 bright golden yellow 3 h at 450 ° C, Rotary tube c 1 mol HNO3 / KNO3 (1: 1); from RT to 450 ° C, 30 min 5.8 bright golden yellow 6 h at 450 ° C., rotary kiln d 1 mol HNO3 / KNO3 (1: 1); from RT to 450 ° C, 30 min 5.9 glowing golden yellow 12 h at 450 ° C., rotary kiln 17 0.1 mol K2S2O8 / Na2O2; from RT to 600 ° C, 30 min 5.7 greenish yellow 4 h at 600 ° C, rotary kiln 18 0.2 mol K2S2O8 / Na2O2; from RT to 600 ° C, 30 min 5.9 canary yellow 4 h at 600 ° C, rotary kiln 19 0.5 mol K2S2O8 / Na2O2; from RT to 600 ° C, 30 min 5.9 canary yellow 4 h at 600 ° C, rotary tube 20 a 0.85 mol K2S2O8 / HNO3 (1: 7.5); from RT to 600 ° C. 30 min 6.5 lemon yellow 2 h at 600 ° C., rotary kiln b 0.75 mol K2S2O8 / HNO3 (1:31); from RT to 600 ° C, 30 min 6.7 canary yellow 2 h at 600 ° C, rotary kiln Table 3 (continued) Manufacture and characterization of Examples 16-22 Example production conditions Grinding specific upper color shade in a sand area according to BET mill (m2 / g) 20 c 0.7 mol K2S2O8 / HNO3 (1: 2.5); from RT to 600 ° C, 30 min 6.4 lemon yellow 2 h at 600 ° C, rotary kiln 21 from RT to 600 ° C, 2 h at 600 ° C under air / acid 120 min 15.0 canary yellow substance fumigation (1: 1); Rotary kiln from RT to 700 ° C, 2 h at 700 ° C under air / acid 120 min 13.5 canary yellow substance fumigation (1: 1); Rotary tube 22 0.75 mol HNO3; from RT to 600 ° C, 2 h at 600 ° C 120 min 16.3 lemon yellow with air / oxygen gassing (1: 1); rotary kiln Table 4 comparison of color strengths Example specific upper rel. Color strength in Alkydal R area after BET F 48 ** compared to example (m2 / g) game A *) (%) A 5.2 100 15 7.4 85 8.7 86 12.5 107 21 13.5 108 22 16.3 102 B 8.7 42 C 7.6 40 *) Determination of the color strength in the white cut with Ti02 (5: 1) at 10% PVC via Rz ** sales product from BAYER AG

Claims (9)

Claims 1. A process for the production of phase-pure yellow Bismuth vanadate pigment, characterized in that stoichiometric mixtures of metallic bismuth and one or more vanadium (V) components in oxidizing Atmosphere at temperatures of 35O0C to 75O0C and the reaction products comminuted to pigment size. 2. The method according to claim 1, characterized in that the metallic Bismuth is in finely divided form. 3. The method according to any one of claims 1 or 2, characterized in that that the vanadium (V) component is NH4V03, V205 and / or alkali metavanadates. 4. The method according to any one of claims 1 to 3, characterized in that that the oxidizing atmosphere by introducing oxygen-containing gases and / or Addition of oxidizing substances is generated in at least equimolar amounts. 5t method according to claim 4, characterized in that the oxidizing active substances NH4N03, HN03, nitrates, peroxodisulphates and / or peroxides of alkali and / or alkaline earth metals. 6. The method according to any one of claims 1 to 5, characterized in, that the implementation takes place with rotary motion. 7. The method according to any one of claims 1 to 5, characterized in, that the reaction takes place in a fluidized bed. 8. The method according to any one of claims 1 to 7, characterized in that that the reaction takes between 0.5 and 12 hours, preferably between 1 and 4 hours take. 9. Use of the yellow prepared according to claims 1 to 8 Bismuth vanadate pigments for coloring paints, plastics and emulsion paints.