DE2352845A1 - PROCESS FOR THE PRODUCTION OF CRYSTALLINE SULPHIDES AND SELENIDES OF CADMIUM, ZINC AND MERCURY - Google Patents

Description

HERCULES INCORPORATED, 910 Market Street, Wilmington, Delaware, OBR

Process for the production of crystalline sulphides and selenides of cadmium, zinc and mercury

The invention relates to a method for producing crystalline Compounds of group ÜB of the periodic table and sulfur and / or selenium and in particular one. Procedure for Conversion of crude precipitates containing cadmium sulfide or deposits on materials with pigment properties.

Various ways of working have been proposed in order to raw precipitates or deposits containing cadmium sulfide to convert into pigments. One known procedure involves heating the crude precipitate, usually in a non-oxidizing one Atmosphere, at elevated temperatures of about 400 ° to 700 ° C; d. H. a so-called calcination treatment, see FS Patent 2,504,147. Others known

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Procedures include heating the raw starting materials under pressure in aqueous medium in the presence of a small amount of an alkaline reacting salt at elevated temperatures and preferably at about 360 ^° C, see US Pat. No. 2,148,294. Other known procedures include heating an aqueous slurry of crude cadmium in the presence of 1000 to 2000% of an alkali metal hydroxides s and 50 to I50% of an alkali or Erdalkalimetallnitrates, -sulfates, -halogenides or -aluminates at '90 ° to 160 ⁰ C, see US Patent 3 54-2526. Furthermore, it has already been proposed to purify compounds of groups HB and VIA by heating the compounds in a water slurry of an alkaline earth metal ^{halide in a flow of inert gas in a furnace to about 1000 °} C. until the impurities have reacted with the halide and through the gas See U.S. Patent 3,385,656. These prior art treats Lungs require either high temperatures, high temperatures and pressures, or large amounts of alkali to promote crystal growth and particle size enlargement, which are required for a good pigment. Hence, any benefit to lower treatment conditions is offset by the high investment required in equipment, maintenance and chemical recovery. ·

The object of the invention is to create a method that does not have the disadvantages described above.

Surprisingly, it has been found that crude, amorphous precipitates or precipitation of sulfides, selenides or mixtures of sulfides and selenides of cadmium, zinc or mercury without the disadvantages of the prior art with the formation of crystalline products can be cleaned, which are of particular value as pigments for coloring materials in shades,

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which range from light yellow to orange tones to yellow tones. The inventive method for solving this problem is characterized in that a crude, essentially amorphous precipitate of at least one sulfide, selenide or mixture of sulfides and selenides of cadmium, zinc or mercury with a sufficient amount of an aqueous ammonium sulfide solution to form a weight ratio of solution treated to precipitate at least 1: Λ and a weight ratio of ammonium sulfide to precipitate of at least 0.02: 1 until the precipitate is converted into the ordered, hexagonal crystal state and then the crystalline product thus produced is obtained. .

It has been found that the inventive method on a any sulfide, selenide or mixture of sulfides and selenides of a metal from group HB of the periodic table can be used, and that it is of particular value when applied to precipitates containing cadmium sulfide. For example, the process according to the invention is particularly advantageous for processing or refining cadmium sulfide, Mixtures of cadmium sulfide and cadmium selenide, mixtures of Cadmium sulfide and zinc sulfide and mixtures of cadmium sulfide and mercury sulfide. The method of the invention is also for the aging of the pure cadmium pigments as well as the so-called stretched pigments, e.g. B. from the so-called lithopone * suitable. .

The raw, essentially amorphous precipitates or precipitates, which treated according to the invention can be by any of the known methods of preparation the desired, raw precipitations of cadmium, zinc or mercury sulfides, selenides or mixtures of sulfides and selenides, e.g. B. by implementing aqueous solutions or suspensions of salts of cadmium,

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Zinc and / or mercury with solutions of an alkali metal or alkaline earth metal sulfide and / or selenide. Advantageously is the cadmium, zinc or mercury saltζ a nitrate, Sulfate or halide. By properly selecting the raw materials such as cadmium, zinc, mercury, sulfur and selenium, a Series of crude products can be produced which give a wide range of colored pigments with shades which range from light yellows to oranges to reds and browns.

As already described, the process according to the invention is a wet conversion process "in which crude, amorphous precipitates of at least one sulfide, selenide or mixture of sulfides and selenides of cadmium, zinc or mercury are treated in the presence of aqueous ammonium sulfide until the precipitate forms the well-ordered The treatment can be carried out at any convenient temperature, but it is advantageously within the range of about 0 ^° C. to 300 ^° C., and preferably about 20 ^° C. to about 275 ^° C. for periods of time ranging from less than about 1 hour to several days or more. Longer periods of time are of course required for perfect crystallization at lower temperatures. In addition, by careful selection of the time conditions, Temperature conditions A range of products with varying levels of transparency, color strength and purity can be produced.

The amount of ammonium sulfide solution which is used in practicing the invention is an amount which is useful to create a weight ratio of solution to precipitate (dry, raw) of at least 1: 1 and a weight ratio of

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Ammonium sulfide, - (2SiII ^) 2S, is sufficient to precipitate at least 0.025%. The ratio of solution to precipitate preferably ranges from 1.5: 1 to 20: 1 and particularly preferably from 2: 1 to 10: A * and the ratio of ammonium sulfide to precipitation is preferably from 0.05 '· 1 to 15: 1 and particularly preferably from 0.1: 1 to 10 degrees. 1. The concentration of ammonium sulfide in the treatment solution may vary within relatively wide limits, advantageously it ranges from about 2 fo Ibis about 60% and preferably from about 5% to about 50% in villain the solution .. Other ammonium salts, and in particular such salts as The nitrates, sulfates or halides can also be present in the treatment solution in varying amounts, provided that they do not impair the advantages of the process according to the invention. The amount of such other, applied salts is usually from about 5 weight -% to about 25% of the S-ew.- · treatment solution.

The crude precipitate which is treated according to the invention may be a freshly formed precipitate in the aqueous medium be in which it was formed, a ■ filter cake or a Press cake of the precipitate, or precipitate which already filtered, washed and optionally 'dried and pulverized became.

The treatment according to the invention does not require holding or stirring, grinding, rubbing, etc. Such a treatment can, however, optionally be used to ensure intimate contact ensure and facilitate handling

The products produced by the process according to the invention are crystalline, strongly colored materials. The materials containing cadmium sulfide are characterized in particular by a wide range of properties, including maximum values of transparency, purity of hues and color strength

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Color range from lightgell) - over orange tones to the hot tones distinguish. They can be produced in all desired, guaranteed color shades for commercial pigment applications. ,. ;

The method according to the invention is illustrated below with reference to FIG Examples explained in more detail, here all data relate in parts and percentages by weight, unless otherwise specified.

example 1

There was prepared a crude Cadmiumsulfidausfällung by 600 parts of a 9% aqueous solution of sodium sulfide at 60 ⁰ C for a period of 10 minutes to 480 parts of a stirred, 34-, 1% aqueous solution of cadmium nitrate, which at 50 ⁰ C was kept, were added. Stirring was continued for one hour at 50 ^° C., after which time the slurry obtained was filtered off and the precipitate was washed, dried and pulverized to remove soluble salts. The dry crude product (100 parts) was combined next with 640 parts of a 9% aqueous solution of ammonium sulfide in a vessel, the vessel was closed and the contents were allowed to age 16 hours at 30 ⁰ C without Inbewegunghalten or stirring. After this time, the aged product was recovered from the ammonium sulfide liquid, washed, dried and pulverized. The product is a highly transparent, golden yellow pigment, which shows the hexagonal crystal structure of cadmium sulfide in X-ray diffraction. The product is a pigment with good coloring power and gives pure, intensely colored tints.

Example 2

The procedure of Example 1 was repeated with the exception that in this example the washed precipitate (400 parts

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of 100 parts of the boho product, on a dry basis, containing porridges) was not dried or pulverized, but with 34-0 parts of a 17% aqueous ammonium sulfide solution were put together in the boiler. The crystalline product of this example is a highly transparent, golden yellow Pigment, and it is practically identical to the product of Example 1.

Example 3

The procedure of Example 1 was repeated with the exception that the slurry containing the C admiumsulfidnieder strike of this example was ^{cooled to 30 0} C and transferred directly to the container without filtration, washing, drying and pulverizing, and that the slurry with 516 parts of a 24% aqueous ammonium sulfide solution was combined. The crystalline product is a transparent, golden yellow pigment which is practically identical to the product of Example 1.

Example 4

The procedure of Example 1 was repeated with the exception that the contents of the kettle aged for 6 hours at 70 ° C became. The product of this example is a golden yellow pigment with a similar hue but purer in reflected light and less transparent than the product of Example 1.

Example 5

The procedure of Example 1 was repeated with the exception that 100 parts of the dry crude product were combined with a solution which was obtained by dissolving 112 parts of ammonium sulfate and 66 parts of sodium sulfide in 462 parts of water had been. The crystalline product of this example is a highly transparent, golden yellow pigment, which practically with the product of Example 1 is identical.

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Example 6

A dry, crude cadmium sulfide precipitate was prepared as in Example 1, and the crude product (100 parts, dry weight) was ^{ground with 640 parts of an 18% aqueous solution of ammonium sulfide for 48 hours at 30 0} C in a ball mill, then the product was like obtained in example 1. The crystalline product is a golden yellow pigment, which is similar in color but more opaque than the product of the example. The product in this example is characterized by ■ unusually high color strength and purity.

Example 7

A crude precipitate of a mixture of cadmium sulfide and zinc sulfide was made by adding 48? Parts of an aqueous solution which contained 148 parts of cadmium nitrate and 18.6 parts of zinc nitrate were prepared at 25 ^° C. for 10 minutes to form 500 parts of a stirred, aqueous solution which contained 58 parts of sodium sulfide and was kept at 50 ^° C. Stirring was continued for one hour at 50.degree. C., after which time the resulting slurry was filtered off and the precipitate was recovered in the same manner as in Example 1. The dry crude product (100 parts) was combined next with 1140 parts of a 10.5% aqueous ammonium sulfide solution in a container, the container was closed and the contents were aged without stirring or Inbewegunghalten 16 hours at 70 ⁰ C, after which time the product obtained according to the procedure of Example 1. The product is a highly transparent, primrose yellow pigment, which has a high color strength and clarity. The product shows a hexagonal crystal structure in X-ray diffraction and is a solid solution of cadmium sulfide and zinc sulfide.

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Example 8

A crude precipitate from a mixture of cadmium sulfide and mercury sulfide was prepared by adding an aqueous solution prepared previously by combining 575 parts of a 9% sodium sulfide solution and 54- parts of a 30% QuecksiTber- (Il) nitrate solution prepared at 60 ⁰ C; had been prepared within 10 minutes to 1810 parts of a stirred, 8% strength aqueous' solution of gadmium nitrate, which was kept at 60 ° C. The Eühren was continued for one hour at 60 ⁰ C, then ^ the crude precipitate was recovered in the same manner as in Example. 1 The dry crude product (100 parts) was next combined with 400 parts of a 55% strength aqueous solution of ammonium sulfide in a container, the container was sealed and the container contents were ^{aged for 142 hours at 30 °} C., then the aged product was treated in the same way obtained as in example 1. The product is a highly transparent, deep orange pigment with high color strength. The product shows a hexagonal crystal structure in X-ray diffraction and is a solid solution of cadmium sulfide and mercury sulfide.

Example 9

A crude precipitate of a mixture of cadmium sulfide and cadmium selenide was made by adding a solution of sodium sulfide and sodium selenide (previously prepared by dissolving 14 parts of selenium in 425 parts of a 10.1% strength aqueous solution of sodium sulfide at 60 ⁰ C) for 10 minutes been obtained of a 35% aqueous solution of cadmium nitrate with 260 parts of a 3 »5% aqueous solution of sodium carbonate at 25 ⁰ C stirred slurry of cadmium carbonate, and cadmium nitrate, which was maintained at 50 ⁰ C", and wherein the slurry by reaction von430 parts Stirring was continued for one hour at 50 ° C., after which the precipitate was removed by filtration, the precipitate was washed to remove soluble salts, dried and pulverized, 100 parts of the pulverized crude precipitate

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was mixed with 500 parts of a 24% strength aqueous solution of ammonium sulfate in a pressure vessel equipped with a stirrer, the vessel was closed and the contents were ^{stirred for 4 hours at 250 °} C. under a pressure of about 70.3 kg / cm, then the pressure is reduced and the product obtained in the same way as in Example 1. The product is a medium red pigment which shows a hexagonal crystal structure on X-ray diffraction. It is a solid solution of cadmium sulfide and cadmium selenide.

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Claims (7)

• - 11 - patent claims 1. Process for the production of crystalline sulfides, selenides. or solid solutions of sulfides and selenides of cadmium, zinc or mercury, characterized in that a crude, essentially amorphous precipitate of at least one sulfide, selenide or mixture of sulfides and selenides of cadmium, zinc or mercury with a sufficient amount of an aqueous ammonium sulfide solution to form a solution to precipitate weight ratio of at least 1.1 and a weight ratio of
Ammonium sulfide to precipitate at least 0.02: 1 to treated to convert the precipitate into the ordered, hexagonal crystal state and then the so produced, crystalline product is obtained. 2. The method according to claim 1, characterized in that it is shown et that obtained as a crystalline product cadmium sulfide will. 3. The method according to claim 1, characterized gekennz eichn et that the crystalline product obtained is a solid
Solution of cadmium sulfide and cadmium selenide is. 4. The method according to claim 1, characterized in that the crystalline product obtained is a solid
Solution of cadmium sulfide and zinc sulfide is. 5. The method according to claim 1, characterized in that the crystalline product obtained is a solid
Solution of cadmium sulfide and mercury sulfide is. 409818/1171 6. The method according to claim 1, characterized in that that the weight ratio of solution to precipitate is at least 2: 1 and the weight ratio of Ammonium sulfide to precipitate is at least 0.1: 1. 7. The method according to claim 6, characterized in that the weight ratio of solution to precipitate from 2: 1 to 10: 1 and the weight ratio of ammonium sulfide to precipitate from 0.1: 1 to 10: 1 enough. 8 * Method according to claim 7 »characterized in that that an aqueous ammonium sulfide solution is used, which have an ammonium sulfide concentration of about 5 to about 50% by weight of the solution. 9 · Method according to claim 1, characterized in that it is marked e t that the product is a pigment. A O 98 1 8/1171