DD151144A1 - METHOD AND DEVICE FOR CONTINUOUS PRODUCTION OF ALUMINUM SULFATE - Google Patents

Abstract

The invention relates to a method and an apparatus for the continuous production of aluminum sulfate from aluminum hydroxide and sulfuric acid. Such aluminum sulfates are used in particular in the paper, textile, paint and building materials industry as well as in water treatment and tannery from different considerations. The aim and object of the invention are to eliminate the prior art adhering to the defects, which result in particular from the pressure side closed flow reactors, by principle changes in the Stroemungsreaktorsystems including the Nachreaktionsteils or park as far as possible. According to the invention, this is achieved by a method and a device according to which the reaction components are applied in non-equimolar amounts to a closed flow channel inclined up to 8 degrees C., passing through the tube cross-section of a maximum of 60% by gravity, in the downstream post-reaction section consisting of stirred tank with sulfuric acid re-dosing device and vertical reaction tube to undergo a post-reaction.

Description

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invention registration

Title of the invention - '

Process and apparatus for the continuous production of aluminum sulphate

Field of application of the invention

The invention relates to a method and an apparatus for the continuous production of aluminum sulfate from aluminum hydroxide and sulfuric acid. Such aluminum sulfates are mainly used in the paper industry for gluing, in the textile industry as a mordant and in the tannery for white tanning · In addition, they are used, inter alia, in the paint and building materials industry and water treatment as additives.

Characteristic of the known technical solutions

The production of aluminum sulfate in a continuous manner from aluminum hydroxide and sulfuric acid has been known for some time or has already been described many times be.

In this case, in particular, methods and devices have attained industrial significance whose continuity results from the use of open, heatable containers or the use of tubular reactors. While those taking place in open vessels

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Implementation of the reactants due to their decades of handling technologically mature in principle, give the younger, more modern manufacturing methods based on tubular reactors more or less still general technical-technological problems. Among the best known methods of the latter type is the solution described in DOS 24 58 955, which is characterized by a tubular reactor with a downstream retention zone. However, despite the subsequent retention zone, this technology does not eliminate the principal disadvantages of the tubular reactors; Due to the strong, highly exothermic reaction due to partial evaporation occurs in the flow reactor to a considerable pressure build-up, whereby the procedure is technologically complex. In addition, the reactor described in the DOS 24 58 955 does not allow correction of the raw material composition and thus the product quality, which, among other things, also result in adverse effects in terms of yield.

Object of the invention .

The aim of the invention is to eliminate the prior art inherent defects, which result in particular from the pressure side closed flow tube reactors, or largely shut down and produce aluminum sulfate with an advantageous product quality in technologically simple V / iron and high space-time yield.

Explanation of the essence of the invention

The object of the invention is to develop a process and a device for the continuous production of aluminum sulphate by basically changing the flow reactor system, including the post-reaction part, with which the aforementioned objective is met.

It was found that aluminum sulfate in a technologically simple manner and high space-time yield with

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can continuously produce advantageous product quality, when the reaction components aluminum hydroxide and sulfuric acid flow through a closed flow channel to then undergo afterreaction with sulfuric acid after-dosing in a downstream stirred tank and an associated ascending reaction tube.

Essential to the invention is that on the one hand the Reaktions.skomponenten be entered simultaneously and in non-equimolar proportions in the flow channel, while on the other hand, the flow, which takes place at a Aus¬ filling the pipe cross section of a maximum of 60%, preferably 4-0 - 50% , Is effected only by gravity, which eliminates additional energy input by means of pumps or similar funding. As has also been found advantageous to add aluminum hydroxide as an aqueous suspension having a temperature of about 90 ⁰ C, said composition above in a known manner in stirred vessels.

The addition amount of aluminum hydroxide suspension is expediently such that at the time of entry into the flow channel an excess of at most 0.3 mol, based on the sulfuric acid used, exists. This excess of aluminum hydroxide suspension is partially equalized in the stirred tank of Nachreaktionsteils due to sulfuric acid after-dosing, it being significant that the sulfuric acid is added with the simultaneous addition of Brüdenkondeüsat.

In addition, a device was found which is particularly suitable for carrying out the method according to the invention.

The relevant apparatus is composed of a closed horizontal or with an angle of inclination of at most 8 °, preferably 3 - 4.5 ° »arranged flow channel and a subsequent U-shaped post-reaction part, consisting of stirred tank with sulfuric acid dosing, downpipe and a vertical standing

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the reaction tube without additional internals for mixing ·

It should be emphasized in this context that the connection between the flow channel and the downstream stirred tank and the vertical reaction tube is produced without additional funding, such as pumps,

AusführungsbeispieIe

In Figure 1, the device of the invention is shown, from which at the same time the technological scheme is derivable.

Thereafter, 1 means an allocation device, via which the reaction components of the flow channel 2 are supplied to the flow channel 2 is followed by a heatable stirred tank 3, which is connected via the pipe 5 with a vertical, · heatable reaction tube 6. »In addition, the stirred tank 3rd The reaction tube 6 has a drain valve 7 and an outlet nozzle 8 ₀ Via the pipeline 9, the flow channel 2 is coupled to a condenser 10, which in turn is connected through the pipeline 11 communicating with a separator 12 between the separator 12 and the mixing vessel 3 and a dip 15, a connection is established via the pipeline 13 and 14.

The method according to the invention in the device shown in FIG. 1 proceeds as follows:

The flow channel 2 is concentrated via the metering device 249.7 IA concentrated sulfuric acid (96 %) and 335.8 l / h of an aqueous suspension of aluminum hydroxide having a solids content of 792.0 g / l, many previously in a stirred 'container' prepared and heated to 80 ° C, supplied.

The subsequent reaction takes place in the temperature range 110-130 ⁰ C, which is due to the mass flow rate and the slope of the flow channel

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of 4.5 a filling whose tube cross sections through the reaction mixture of about 50% results. After a mean residence time of about 15 minutes, the reaction mixture enters at a conversion rate of 83%, based on aluminum hydroxide, in the downstream stirred tank 3, in which sulfuric acid is metered in via the device 4 in accordance with the sales value determined by means of device 16. In the stirred tank 3, the condensate separated in the separator 12 simultaneously flows through the pipeline 13 and has been separated in the condenser 10 from the vapor emerging from the flow channel 2. The non-deposited inert gases, however, are discharged via the pipe 14 and the dive 15 from the system.

After a mean residence time of approx. ' 45 minutes in the stirred tank 3 at a temperature of 120-130 ° C, the reaction mixture flows through the pipe 5 in "the vertical reaction tube 6, in which after another residence time of about 30 minutes, the reaction at a temperature of 120 - Ü3O ° C. The reaction product is obtained via outlet 8 and processed further in a known manner.

O ^ 17.26%

₃ _39,9O %

Insoluble '0.20 %

2. The procedure is analogous to Example 1 and gives about the allocation device 1 of the flow channel 2 210 l / h kpnzentrierte sulfuric acid (96%) and with a solids content of 486 g / l 451 1 Aluminiumiuiahydroxidsuspension. At an inclination angle of the flow channel of 3 °, the tube cross-section is filled to about 40% by the reaction mixture, the average residence time is about 10 minutes. '

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The product obtained in 99.6% yield shows the following analytical values:

Al ₂ O ₃ 14.28%

SO ₃ . 33.02 %

Insoluble 0.10 %

Claims (2)

22 15 15 invention claims 1. A continuous process for the production of aluminum sulfate from aluminum hydroxide and sulfuric acid using tubular reactors with Nachreaktionsteil, characterized in that the reaction skompo η ent en be entered in non-equimolar proportions simultaneously in a closed flow channel of a reactor system, these at the filling the tube cross section of at most 60% _t preferably 40 - 50%, by flow by gravity and thereafter undergo a post-reaction under Schwefelsäurenachdosierung in a subsequent stirred tank, as well as in an associated rising reaction tube. 2, device for carrying out the method according to item 1, characterized in that the reactor system from a closed, horizontal or with an angle of inclination of a maximum of 8 °, preferably 3 - ^ i5 °> arranged flow channel and a subsequent U-shaped N- achreaktionsteil, consisting of stirred tank with means for sulfuric acid addition, downpipe and a vertical reaction tube without additional internals for mixing, is composed, wherein the connection between the flow channel and the downstream stirred tank and the vertical reaction tube without additional funding, such as pumps, is prepared and known Are connected downstream Abkühlaggregate, 3. The method according to item 1, characterized in that aluminum hydroxide is added as an aqueous suspension, which was previously prepared in a stirred vessel in a known manner, with a temperature of about 90 ⁰ C. 4, method according to item 1 and 3j, characterized in that the aluminum hydroxide suspension in an excess of not more than 0.3 mol, based on the sulfuric acid used, the flow channel is added. 22 15 15 Process according to items 1, 3 and 4, characterized in that the replenishment of the sulfuric acid takes place with simultaneous addition of vapor condensate. For this 1 page drawings