DE1592894B1 - Process for the production of barium potassium chromate pigment - Google Patents

Description

In accordance with the present invention, a pig- 40 Such a procedure is a preferred one

ment based on barium-potassium-chromate by Um- embodiment of the invention.
Settlement of stoichiometric proportions of in water

suspended barium hydroxide and potassium dichro- claims:

mat and subsequent evaporation of the water 1. Process for the production of a pigment A

Manufactured at elevated temperature by the fact that the 45 based on barium-potassium chromate by Um- ™

Aqueous suspension of the starting materials atomized and stoichiometric proportions of in water

exposure to suspended barium hydroxide and potassium bicarbonate heated to around 270 to 400 ° C

Air or an oxidizing or indifferent and subsequent evaporation of the

rent gas flow is exposed. Water at elevated temperature, thereby

Known atomizers are suitable for atomization, characterized in that the aqueous suspension dryer. It has been found that this sion of the starting materials is atomized and the one-way way directly receives a product that requires no further action of about 270 to 400 ° C heated comminution. The advantages of the air according to the invention or an oxidizing process or in accordance with the present invention are that one is exposed to the different gas stream,
fine pre-grinding, the mixing of dry and 55 2. The method according to claim 1, characterized in powder-form starting materials, the cumbersome characterizes that the dust obtained by drying the handling of the paste and the subsequent grinding atomized suspension in addition to the reaction product, ie the pigment, avoid. borrowed another 40 to 10 minutes at 400 to 500 ° C det. In place of the paste a liquid suspension is roasted.

Claims (1)

1 2 The present invention relates to a method applied that is easily poured over and pumped for the production of a barium-potassium-chromate can. Pigments, which are used as anti-corrosive pigments in the Position of paints is used. according to the method described by way of example. A well-known barium that is commercially available. Both starting materials are in the solid state in Potassium chromate pigment, see Kittel, "Pigments" stoichiometric amounts with the proviso in a (Stuttgart 1960), p. 172, that is entered by roasting a mixing vessel charged with water Mixture of potassium dichromate and barium carbon to about 66 parts by weight of H ₂ O 34 parts by weight of the nat produced at around 700 ° C. Both starting materials come dry mass of the starting materials. To must for this up to a grain size of about io the mixing one obtains a completely homogeneous 10 μπα are ground. The liquid suspension generated in this way. This suspension will held sintered product consists of grains with a continuously and passing heated Size of a few millimeters, which is why there is up to air or oxidizing or inert gases a grain size of less than 20 μΐη are ground at an inlet temperature of 350 ° C the atomization got to. The roasting of this pigment is supplied to the above-15 air dryer. The dryer becomes a given high temperature as well as twice the dust with a bulk density of about 1.2 g / cm ³ Fine grinding requires a cumbersome process and a grain size of 5 to 17 μπι obtained. Of the wise and high manufacturing cost. dust obtained in this way can be used directly as Barium potassium chromate pigment can also be used. by mixing aqueous potassium bromate and 20 The according to the process according to the invention Barium chloride solutions are produced. In the case of the retained pigment, the well-known, initially mentioned When the reaction occurs, a pigment is obtained that is superior in that it is made from spherical Precipitation, which exists after washing out and drying grains, whereby the distribution in the lacquer ^ nen must be ground to the required eased and the stability of the paint dispersion To bring about fine grain of the pigment. 25 is increased. A certain difference in the Barium-potassium-chromate pigment can also be used in the same way as the known pigment mentioned at the outset by grinding finely ground potassium dichro- forms a minimal, only by means of X-ray mat and barium hydroxide and, by subsequent diffraction, detectable content of isolated The paste obtained in this way is heated on lowing barium and potassium chromate. a temperature of more than 100 ° C produced 30 In those cases where one is on a complete will. When heated, the conversion of these chromates takes place in the barium-potassium between the two starting materials, whereby the product attaches value to chromate, it is recommended that the obtained is dried at the same time. The mass of pigment obtained in this way at temperatures of 400 to 500 ° C. must then also be ground. rend 40 to 10 minutes, e.g. B. at 450 ° C during The last two wet processes described last 35 minutes to roast. In doing so, the pigment will not sintered, however, are not used in industry today, but rather retains its original grain, because by roasting potassium dichromate with size. The same success is achieved through atomization Barium carbonate a product with better properties in which at a higher temperature, for example shafts will be obtained. achieved air or gas medium heated to 450 ° C.