DE2017240A1 - Process for the production of ferrous sulphate - Google Patents

Description

nappe 22226 ~ Dr, Β / Π. CASE 757

BESC II RDIBU Il G. for the patent application of the '.

Company H & T CHEHICALS INO ₀ , liew York, 1T, Y "/ V"> St _o of America,

concerning:

"Process for the production of iron (H) sulfate"

PRIORITY: April 10, 1969 - V.Öt _o of America «

The invention relates to a method of manufacture of iron (II) sulfate from Sohrotteieen · The invention relates I particularly focus on a process for the production of Isen (II) < Sulphate monohydrate from Sohrotteieen, whereby SiBen (IX) ~ 8ulfate "heptabydrate is not formed" in between

As is generally known, iron (II) eulphate is a particularly useful source material for the production of

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pure iron oxide, which in turn is used in the manufacture of perrites " If one realizes that only a little more than 61 kg of iron (II) sulfate iaonohydrate contains the same amount of iron sulfate as 100 kg of egg (II) heptahydrate, then the economic advantage of using ilonohydrate in the production of egg oxide becomes clear, even if one just looks at the difference in weights. This difference is of course due to the fact that there is much more water in heptabydrate, which must be driven off in order to obtain a satisfactory one and economic-scientific ~ starting material for the production of pure iron oxide to create _o

Other advantages of the conohydrate over the heptahydrate reside in the fact that it is more easily calcined to ferric oxide and that it does not melt nearly as easily when heated as the heptahydrate. Finally, the llonohydrate is much more stable when stored and does not oxidize itself as easily in air and also does not absorb moisture as easily as the heptahydrate produce sulfuric acid, "However, this reaction results in the less desirable heptahydrate, as it is commonly known · There have been attempts to cope with this problem, especially in processes for the recovery of iron salts from spent Abbeizflüssigkeiten ₀ However, other problems occur in these processes as in the production of llonohydrate from very high iron, since in this process iron salts are separated from solutions and elevated temperatures and / or bridges are required in order to produce an intermediate product from these stripping liquids »

Thus, there is a problem that one in the production of bisene sulfate directly from iron, such as β, Β. Steel scrap »that

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20172A0

unwanted iron (II) sulfate heptahydrate is obtained, which is difficult to convert into other products, and that undesirable processes are necessary in the production of the more suitable end product iron (II) sulfate = - * monohydrate, in which, for example, expensive evaporation and / or high pressure technology must be used to direct the reaction in such a way that the cheaper honohydrate is formed ₀

In contrast, it was unexpectedly found that an iron (II) hydrate monohydrate precipitate is formed which can easily be separated from the reaction medium under conditions which require no pressure and very little temperature, when iron such "B _e scrap steel, treated with a sulfuric acid solution of a Konsentration between about 10 and 90 # for a time sufficient that the acid concentration is reduced considerably, separating any precipitates and / or impurities from the acid solution of reduced concentration and sufficient sulfuric acid is added in an amount such that the free acid concentration is within a certain range. Little or no control is necessary in the reaction and the end product is separated off after a period of time, the only requirement being that the reaction be started at a certain content of free acid runs to the end »

The resulting precipitate can easily be separated from the reaction solution by filtration, and if a batch procedure is used as described below, any unreacted iron in the filter cake can easily be separated from it magnetically such operation of the reaction little attention must be paid ₀ cost is AUOH so low because the temperature and / or pressure during OCE reaction not be controlled

009850/1822 BAD OR ₁ GINAL

It has been found in accordance with the invention that an essentially pure form of iron (II) sulfate monohydrate is achieved ₀

Furthermore, the method according to the invention is easy in con * to be carried out continuously with sulfuric acid and iron, the sulfuric acid with a certain concentration is added and continuously through a container from scrap iron in a circle * This continuous * - liche omission is continued until the concentrate tion of the free acid is reduced to a certain fourth j, whereupon the acid solution is drawn off and filtered to to separate any impurities and / or precipitates β Concentrated sulfuric acid is then added to the piltrate in order to bring the content of free sulfuric acid to a certain concentration, with pure iron (II) sulfate monohydrate The product is then filtered off and the piltrate is again passed through the scrap iron container returned, in which further amounts of scrap iron are continuously entered to the to maintain initial reaction conditions »

The aim of the invention is therefore the production of iron (II) sulfate monohydrate from iron, such as ZoB. Eisensohrott * Another aim of the invention is the production of such a ferrous (lI) "sulfate" monohydrateB in practically pure form, whereby iron sulfate fceptahydrate is not formed in between

It is a further object of the invention to produce an eolchee Eiaen (II) sulfate monohydrate by reacting iron with sulfuric acid, the reaction requiring little control. A further aim of the invention is to provide a process for the production of iron (II) sulfate nionohydrate directly from sohrate without the application of pressure and with only a moderately elevated temperature.

009850/1822 _{BATHROOM 0R1QINAL}

It is a further aim of the invention to create a substantially pure Elsen (II) sulfate monohydrate which can easily be separated from the reaction medium, the product in turn being slightly clay unused iron can be freed of the reaction «

Before the invention is described in more detail, it should be pointed out that the method according to the invention can be applied to a large number of iron sources, such as ζ „Β · scrap iron that remains in detinning processes. Eb is well known that tin-containing scrap is treated in such a manner that it recovers the valuable tin, wherein the steel is left _o Examples following were obtained satis "tory results under commercially attractive conditions in large-scale operations with an iron" scrap that remains in EntZinnungsoperationen wherein the scrap iron is introduced into the reaction zone together with a sulfuric acid having "a concentration between about 10 and 90 i", and wherein the mixture is a except calibrating time maintained at a temperature between room temperature and 10O ⁰ C, that the free acid concentration up drops to about 2 to 35 5 », whereupon the resulting solution is separated from unreacted iron, the Ϊ & eung is filtered to remove any precipitates and impurities, concentrated sulfuric acid is added to the solution, bringing the free acid content back to about 35 to 45 Bring #, 2U to precipitate pure Bieen (II) eulphate monohydrate, and the pure Bieen (II) eulphate monobydrate is separated from the filtrate *

Besides, as already mentioned »on that diuo no pressure and / or no vacuum can be applied to achieve satisfactory results «, the reaction produces egg (II) sulfate monohydrate with practically no pressure control

000850/1822 ORIGINAL BATHROOM

Ie ₁ and the precipitated iron sulfate monohydrate can easily be separated from the reaction zone. In certain cases, the resulting separated precipitate can only be separated from the unconverted bis-scrap by the use of magnets ",

When the general conditions of the invention If the process is considered, which will be dealt with in more detail below, "then you will find" that iron (II) sulfate " monohydrate is formed in a cyclical manner, ™ in which after the separation of the product from the acid and after the separation of unreacted iron from the product additional Kengen iron and sulfuric acid in the Reaction zone for the formation of further amounts of iron (II) »sulfate · = monohydrate can be introduced, with only on it Care must be taken to maintain the concentration of free acid in the. Reaction zone within the specified ranges keep"

A preferred cycle of operation according to the invention for the production of iron (II) sulfate ^ monohydrate is that _p that iron, such as z, B. Scrap of any detinning, P and Sohwefölsäure with a concentration of about 10 to 90 i> free sulfuric acid, preferably 40 # free sulfuric acid in a reaction zone mischtο The temperature of the Hlsohung is between room temperature and TOO ⁰ C and preferably 5O ⁰ G gehaltenο The reacting mixture is maintained as long as is until the free acid concentration between about> 2 to 35 ^c / and preferably between about 20 and 30 # are separated from the solution after which any contaminants and off »precipitations. Mused concentrated sulfuric acid is added to the solution to adjust the concentration of the free acid again to between about 45 and i * t to bring preferably 40 Section 4, "the pure Eiöen (II sulphate monohydrate product to precipitate. The precipitate is

BAD ORIGINAL 009850 / Ϊ822 ^v

of the acid solution, preferably separated by a centrifuge, wherein a substantially pure iron (II) - is obtained "monohydrate sulfate" The remaining Piltrat is recycled to the first reaction zone ₅ wherein a further reaction with further amounts of iron takes place,

As already mentioned, the method according to the invention provides the desired iron (II) sulfate monohydrate directly from a Reaction between iron and sulfuric acid, not in between the undesired intermediate product iron (II) ~> sulfate- g heptahydrate is formed and with only a slight or no control of the reaction medium at all is necessary "by which means expensive evaporation or the expensive application of pressure and / or vacuum is avoided «, In addition, iron (H) - sulfate = monohydrate a much larger amount of what is desired ten ferrous sulfate and can easily last for long periods be stored without care having to be taken to prevent oxidation and / or water absorption,

The invention is illustrated in more detail by means of the following examples.

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example 1

This example shows a continuous way of working «

A 40 #ige sulfuric acid, which was heated to 5O ⁰ C, was passed through a glass column in a circle, which was filled with steel scrap · The size of the column and the amount of iron may be different, and it is only important that the amount of iron sufficient and that the acid concentration is within * "within the above-mentioned limits".

"After the concentration of the circulating acid had fallen to 30, the solution was withdrawn and filtered.

009850/1822 BADORLGiNAL

The filter cake contained some carbon and some iron (H) -SuIfat "monohydratο FiItrat to this solution was added sufficient concentrated sulfuric acid, to bring back to # 40 to determine the concentration of the free acid _P wherein the iron (II) sulfate monohydrate were to fail, this ~ was separated from the acid by filtration. Experiments showed that the filter cake consisted of pure iron (II) ulfate monohydrate. The filtrate from the last filtration was returned to the glass column and circulated, with further scrap and further acid were exposed to maintain the acid concentration mentioned above «

example

In this example, a semi-industrial plant was prepared with a glass column, 3 »9 kg of steel scrap was introduced into the column, and 129? 2 1 4-0 #ige sulfuric acid was conducted at 5O ⁰ C through the column in the circuit, the circulation has been interrupted, when the free acid of the solution had fallen ^{to 30 c} ß> _e During this time a further 5 _S 4 kg of scrap were added in order to bring the amount of scrap back to the original Yfert ₀ The 30 # solution was filtered. It contained impurities such as Carbon, 2.5 kg FeSO ₄ ^ H ₂ O. The clear filtrate was brought back to an acid concentration of 40 ^{° C.} by adding 27.2 kg of concentrated sulfuric acid. FeSO ₄₀ H ₂ O precipitated out and was filtered off separated «The yield was 10.4 kg of pure PeSO..H ₂ Oo. The filtrate was then circulated through the scrap column, further sulfuric acid being added as required to reduce the concentration of free acid on the ob to keep the given value «,

Although in these examples the circulation through the scrap column was interrupted between each cycle,

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But it is pointed out that it is also possible to ^{draw off the acid solution with a concentration of 30 $ and to add more acid with a concentration of 40 c} ß> to the circulating flow through the scrap column _{9 in} order to maintain continuous operation the piltration and the precipitation would be carried out in a separate plant outside of the main circulation stream of the acid that flows through the scrap _P In addition, the filter cake that is obtained during the first filtration and impure 3? eSO. oHpO contains, be fed back into the system « g As an alternative, the impure product could be used for certain purposes where the presence of the impurities during reuse is not harmful

Thus, the invention provides a method for the production of pure iron (II) ~ oulfat- * monohydrate directly by reaction of iron and sulfuric acid, with no in between the unwanted ferrous sulfate heptahydrate ₀ Furthermore, it is formed, the method does not require continuous or expensive controls, "ISS can only be desirable to use a slightly elevated temperature »

Dae can easily be separated from Beaktionemedium i from dent inventive process resulting product, the product will turn easily freed from non-umgeoetζten parts of Roaktanten kamu The obtained by the erfindungsge * "Permitted process products are cheaper than those known at the date Process can be obtained, which according to the application process was very economical * ^! .

PATENTAH3PRÜ0HE:

1022 ^BAD ORIGINAL

Claims (2)

20172A0 to - YES! EAHSP RÜOHE; Process for the production of iron (II) sulfate bionohydrate, characterized in that iron and sulfuric acid are mixed in a reaction zone, the sulfuric acid having a concentration in the range between approximately 10 and 90 $ and the reaction zone at a temperature between £ about room temperature and about 100 ⁰ O, the iron reacts with the sulfuric acid until the concentration of the free acid is within a range between 2 and 35 ^c ß> , whereby a first acid solution is formed, the resulting acid solution from the Removes the reaction zone and in a first separation stage separates the impurities present in the first solution. To produce a second solution, add concentrated sulfuric acid to the first solution in an amount sufficient to bring ^{the free acid concentration to a range between 35 and 45 C} A ^ to precipitate pure iron (H) sulphate monohydrate and in a second separation stage that Separates product from the second solution « 2. The method according to claim 1, characterized in that & 1q iron steel scrap is used « 3 »The method according to claim 1, characterized in that the concentration of the free acid in the reaction Bzone is approximately 40 i» ο 4. Method according to claim 1, characterized in that you learn
haiton will Hie Tomparatur in the reaction time to ungofä / ir 50 ^c 'C Ι «» «/» »'BA _D0RIQ , NAL 5. Method according to claim 3, characterized in that the concentration of the free sturgeon in the first acid solution is approximately $ 30 o "':> ■ 6 * Method according to claim 5 _S, characterized in that the concentration of the free acid in the second acid solution is approximately 40 % « 7o. Process according to claim 1, characterized in that both separation stages are carried out by filtration _o 8ο method of claim 1 _S thus marked that the second acid solution after the second separation step is recycled to the reaction zone and that further amounts of sulfuric acid and iron are supplied to the reaction zone to the acid concentration to 10 to 90% to bring again _s wherein these additional steps after the second separation stage to produce an additional amount of precipitated iron (III) sulfate monohydrate product ₀ 9o method according to claim 6 _f, characterized in that the temperature in the reaction zone is ^{kept at about 50 0} C o 10c Process according to Claim 9 _9, characterized in that both separation stages are carried out by filtration « 11 ο method according to claim 8, characterized in that that the precipitate of the first separation stage is added to the recycled second acid solution. MTENTANWXtn & .M. FINCKt DIPL-ING. DIPL.-1NG S. STAEGER 00 9 8 50/1822 BATH