DE1007907B - Process for the production of cadmium color pigments - Google Patents

Description

Process for the production of cadmium color pigments It is known that Caidrn, iu, msu, Ifid and Cadmiumsel, - n:, d # form mixed climate groups. Depending on the proportion of the cadmii, urnsiu, Ifi, dis and -s # elen # ids present in the Misich crystal, shades of orange to deep red, even to Bordb, are achieved. These colors, a-rbpiigme, nte, si, nid'unt, er generally known as "Cadmiiui-nrot" and, due to their clear, luminous hues and their excellent fastness properties, are among the most sought-after mineral colors JE because they are small due to the relatively high content of expensive selenium compared with other mineral dyes disproportionately expensive. Up to now it has not been possible to find a cheaper red color which corresponds to the cadmium colors in terms of luminosity and fastness properties.

Boi trying the expensive sel, en of the red cadmium color pigments through to replace another element has now surprisingly been found to be visible have these color pigments produced completely identical pigments, if the selenium used up to now is wholly or partly due to Telltir cr,; ets will.

It has also been found that there are already several quantities, for example Quantities below 31 / o of the total mass are sufficient for those according to the invention Process pigments produced to achieve a depth of color that is otherwise only possible with Use of a moderate amount of selenium is possible.

It has also been shown that the color strength, ei, e, white 1) ordo, # jh # n # li, cbi2 pigments here -., tellem lasoen, if tellurium is next to selenium and sulfur is used in the reaction mixture to form cadmitime red. It it results all so that -, 4-hon a te, ilm, "iser replacement of selenium by tellurium a -, - This represents a significant improvement compared to the higher 7, usarnmen- £ tz # and ng.

The pigments produced according to the invention are suitable wherever cadmium color pigments based on cadmium selenide and sulfide have been used for reasons of heat resistance, light and solvent fastness, etc. All these pigments 1: as, can be produced, for example, by the fact that the foreign element determined for de-, ii exchange of the sulfur in the Caidm, iiu, m ", ii, Ifi, d is divided into fine distribution in C, 2 , dmi, u # m # siu, Ifi # d is brought. The dry cadmium sulfide foreign, de, liemelite mixture or a mixture of cadmium sulphide carbonate, sulfur, tellurium and, if appropriate, souls is preferably subjected to heat treatment in an inert atmosphere.

The decisive advantage of the method according to the invention consists in the complete or partial wise replacement of the very expensive selenium; through the im Comparison herewith cheap-e and: sohon in comparative wise lower percentage of effective tellurium. Also the coloring power, especially with dark ones - Varieties, quite significantly increased. In the following there are some examples for the approach the process of the invention. Example 1 2500 parts Cadmi # u # mchl-orid solution (1), density = 1.30) are precipitated with 14.4% sodium sulphide. filtered, dried without washing and with 6 parts Tellurium curdled deeply, another 12 hours at 100 ' getroc -knet and 1/2 hour at a temperature of 500 ' exposed. The firing product is treated with water boiled, washed out to the point where it is free of EI-dl <trolyte. ge dries tin, d ,. ground. Example 2 2500 parts of Cadmi # umch-loridlös # mig (D = 1.30) are the one with 14.40 / aiiger sodium # um # suilfi-dn-ösung and 6 parts of tellurium added in finest distribution. the fine distribution of tellurium in the nat, rium - # ulfi., d- solution is achieved by using tellurium in concentrated t-rated sdhwe, dissolved rock acid and the necessary precipitation manoeuvrable amount of tellurium in the form of this Sch, # vefel.sätire- solution poured into cold water while stirring vigorously will. This weakly acidic solution becomes strong Stir Entered into the sodium sulfide solution, whereby the tellurine. finest distribution fails. These so- Siuspension prepared is now to the cases of the Cad- m, i, u # rilchlori # dlösiu! n, g are used. The precipitation will then, as in Example 1 , dried and fired.

Be; isp.iel 3 A mixture of 70.24 parts Cd C Ose 13.31 parts Se, 1.05 parts Te, 15.23 parts S is about. Ground for 3 hours and baked at temperatures of 500 Ne 650 ' for about 1 hour and boiled with water after cooling.

B e, is pi el 4 Pure calcium sulfide precipitated with sodium sulfide is mixed with 2 to 4% tellurium. This mixture is ground for 3 hours and burned at temperatures of 500 to 650 ' for about 1 hour and, after cooling, boiled with water. Example 5 6.30 parts of CdCO., 2 parts, 0.12 parts are nailed and burned at 500 to 600 ' for about 1 hour and cleaned by boiling with water, salt solution or dilute lye.

Claims (2)

PATENT CLAIMS: 1. Process for the production of cadmium color pigments, characterized in that the selenium required by the customary methods for the production of red C # dtni # colored pigments is wholly or partially replaced by tellurium. 2. The method according to claim 1, characterized in that the amount of tellurium added is less than 3%, based on the end product.