The present invention relates to a procedure for processing liquids, such as for oxidizing, flotating, or processing in other ways, in which procedure

(a) a liquid to be processed is conducted as an in-flow into a first volume,

(b) a dispersion liquid and air / gas / liquid dissolved therein are conducted into said first volume or into a volume in the immediate adjacency therebelow for intermixing the liquid to be processed and the air / gas / liquid containing dispersion liquid, and

(c) the mixed, processed liquid mixture containing bubbles is made into an upward motion, whereby the impurities are rapidly accumulated into a suspen¬ sion surface.

The invention also relates to a means for treating, such as for oxidizing, flotating, or processing in some other desired way liquids, with which means

(a) a liquid to be processed is conducted as an in-flow into a first volume,

(b) a dispersion liquid and air / gas / liquid dissolved therein are conducted into said first volume or into a volume in the immediate adjacency therebelow for intermixing the liquid to be processed and the air / gas / liquid containing dispersion Hquid, and

(c) the mixed, treated liquid mixture containing bubbles is made into an upward motion, whereby the impurities are accumulated into a suspension surface.

In a variety of industrial applications, endeavours have been made to process

liquids chemically, to carry out chemical reactions, to circulate a liquid solution, to flotate solid components out of a liquid, to mix gases in a liquid into a homo¬ geneous mixture, and/or mix liquids with a liquid into a homogeneous mixture, as well as to carry out the above reactions at desired pressures.

Processing several liquids is, however, difficult and sometimes even impossible because in ordinary conditions, i.e. at a standard pressure they cannot be made to mix. One of such waste solutions is e.g. emulgated oil in water. Highly fine oil in an alkaline solution is near-impossible to separate without lowering the pH of the solution e.g. below 5. Hereby, the entire liquid mixture cannot usually be used any longer for the original purpose. As an example can be mentioned car washing liquid or water, into which oils are dissolved into an emulsion. Air can¬ not be mixed in such water because the air is not sufficiently dissolved therein. On the other hand, gas is known to be dissolved in a liquid directly in compari- son with the pressure. Thus, increasing the pressure in a gas and liquid mixture enables multiple gas dissolution in comparison with the normal atmospheric pressure.

In general, the hquids may contain difficult components and solid agents which should be separated therefrom, in particular if the hquids are pumped. The pumps will otherwise wear and may be blocked. Endeavours have usually been made to eliminate the problems like these using a filter on the suction side of the pump. It depends on the quality and quantity of the solid agents, how well said filter operates and how long it is kept open. Cleaning filters continuously is not sensible, either. Therre are instances also in industrial applications in which no method is available for pumping Hquids because the impurities contained in the Hquid block aU generaHy known and used filters.

Circulating a Hquid in a container into a reaction target and back causes in several cases great difficulties. One of the problems is e.g. how to get the Hquid quantity in the entire container mixed uniforrnly, how to bring the entire Hquid

into a reaction target and to get the entire Hquid amount mixed with a reacting component. In a continuous process, difficulties arise in how to ensure the homo¬ geneity of the discharging Hquid and as great purity as possible from e.g. soHd agents. Therefore, e.g. in the industry so-caUed batch processes exist for produc- ing a homogeneous product. Even in such cases it is customary to filter the product.

In a number of industrial applications adding a reacting agent into a Hquid in container has lead into a great number of difficulties because adding the reacting agent should be accompHshed as an addition of appropriate amount and suffi¬ ciently mixed.

An object of the invention is to provide an improvement in methods and means currently known in the art for processing Hquids.

A more detailed aim of the invention is to provide a method and a means which is particularly well appropriate e.g. for oxidizing, flotating or processing Hquid in another desired method.

The aims of the invention are achieved by means of a method which is charac terized in that in the method

(d) at least part of the Hquid to be processed is conducted as a suction flow int a pump,

(e) with said pump air / gas / Hquid is drawn as a flow into a suction flow whereby in the pressure generated by said pump the air / gas / Hquid is dis solved in said pump and on the discharge side thereof into a circulating flow possibly reacting with the reactable components in said circulation flow, and

(f) with said pump at least part of the circulating flow processed in step (e) i returned to the Hquid to be processed.

The means according to the invention is characterized in that the means is provided with a suction system for conducting at least part of the Hquid to be processed as a suction flow into a pump, that said pump has been arranged to draw air / gas / Hquid as a flow into a suction flow so that in the pressure caused by said pump the air / gas / Hquid is dissolved in said pump, and on the discharge side thereof, into a circulation flow, possibly reacting with the reactable components in said circulation flow, and that said pump has been arranged to return at least part of the processed circulating flow into the Hquid to be proc¬ essed.

According to the basic idea of the invention, the Hquid to be processed can be brought into tubular circulation from a container when the suction point is on the so-caUed clean side of the pump, into the suction opening whereof a re¬ quisite component is fed controUedly, in addition to the Hquid to be processed, such as reducing or oxidizing gas / Hquid, whereafter the components of the dis¬ charge side, entered in the pump, are aUowed to react / dissolve at a controUed pressure with themselves before being returned through a dispersing nozzle into a solution in the container to be reacted / circulated further whHe part of the solution is discharged from the circulation cycle e.g. in an amount equivalent to the feed out or for further reaction.

With the procedure and means of the invention a pluraHry of significant advan¬ tages are achieved. With the design of the invention extremely difficult solutions or Hquid mixtures can be processed and chemicaUy impure mixtures purified in a desired manner. In the design of the invention, purified solution enters the Hquid circulation and pressurization by which the operabiHty of the pump is guaranteed. In a preferred embodiment of the invention the free pressurization control and use of a dispersion nozzle yields great opportunities to accomplish chemical reactions in a drawn-in solution.

The invention is described in detail referring to some preferred embodiments of the invention presented in the figures of the drawings, whereto the invention is

not, however, intended to be exclusively confined.

Fig. 1 presents an advantageous embodiment of a means design used in the method of the invention as a schematical cross-section image.

Fig. 2 presents an embodiment of a second preferred means design used in the method of the invention as a schematical cross-section image.

In the embodiment of Fig. 1 the means used in the procedure of the invention is in general indicated by reference numeral 10. The means 10 is provided with a cover 11 through which a pipe 12 leads for conducting in a Hquid to be proc¬ essed in the form of an in-flow A. The upper surface a of the Hquid is usuaUy preferably in the proximity of the cover 11. The lower end of the pipe 12 is provided with a flange 13, from the outer edge of which rises a cone 14 and its extensions 14a so that the upper edge of the extension 14a of the cone 14 re¬ mains sufficiently below the Hquid surface a. In the embodiment of Fig. 1 the extension 14a of the cone 14 is preferably a cyHndrical surface. The pipe 12 is surrounded by a second pipe 15, this being preferably a concentric pipe. The pipe 15 extends lower than the upper edge of the extension 14a of the cone 14 into the Hquid. In the adjacency of the upper edge of the extension 14a of the cone 14 is placed a perforated ring 16, extending to the pipe 15. The perforated ring 16 is preferably a sheet metal ring. The perforated ring 16 has been sup¬ ported both to the extension 14a of the cone 14 and to the pipe 15. In the annular space defined by the pipe 12 and the flange 13 therebelow has been placed the suction part of the suction pipe 18 of the pump 17, being preferably a suction ring 18, in order to equalize the suction in the Hquid space. The Hquid flow flowing in the suction pipe 18 is indicated by K.

In the suction aperture of the pump 17, a second suction pipe 20 with control valves 20a has been connected so that the suction flow B entering along the pipe 20 can be controlled as desired. After the pump 17 is positioned a channel

21 which can be quite long. The channel 21 ends in an equalization chamber 22,

with which e.g. extra, non-dissolved gas can be removed if necessary or if desired. The Hquid flow continues its flow from the channel 21 along a pipe 23 either back into the circulation along the pipe 24 as a flow K or preferably con¬ troUed by a Hquid surface height monitor 25, through a control valve 24a into the discharge flow C. If desired, a control valve or a potential back pressure valve 29 can be inserted witiήn the suction pipe 18 with which a vacuum pressure of desired magnitude can be provided on the suction side of the pump 17 in order to produce a desired flow B.

The Hquid / solution flowing back in the pipe 24 is pressured / controUed to be appropriate in pressure with a dispersion nozzle 26, positioned preferably at the lower mouth of the pipe 12 either thereabove or therebelow. When new Hquid / solution to be processed is fed into the space provided by pipe 12 as a flow A, the solution / Hquid to be processed may contain desired mix compo- nents or additions so that the solution / dissolved gas discharging from the dispersion nozzle is immediately made to mix / react with the Hquid flow A to be processed. The pressure provided by the dispersion nozzle 26 can be control¬ led e.g. by counterpressure, in the present embodiment by means of compressed air b of the control valve 27.

In the design according to the invention, air / gas / Hquid can be thus drawn into the pump 17 through a suction connector provided with a control valve 20a as a flow B, from which e.g. the air is released in a volume after the dispersion nozzle 26 in an amount which is in proportion to the pressure as an extremely fine, nearly molecular, dispersion, usuaUy gathering into greater bubbles tending at the same time to adhere to the soHd matter particles in the Hquid and/or in the Hquid impurities. The impurities contained in the Hquid to be processed become thus flotated, i.e. they arise onto the surface of the Hquid to be pro¬ cessed. The truly heavy soHd matter components go downwards past the disper- sion nozzle 26. The gaseous bubbles and impurity components attached thereto rise towards the surface at their own speed. The impurity components rising to the surface form foam 28 on the surface of the Hquid, which is removed as a

flow D in a manner known in itseH in the art.

The embodiment in Fig. 2 is otherwise similar to that in Fig. 1, except that th cover 11 in the embodiment as shown in Fig. 2 is connected to a container 30 the size thereof being selected according to the cone 14 used therein. Hereby the truly heavy soHd matter components faU onto the bottom of the container 30 Circulation flow K discharging as uniformly as possible in aU directions from th dispersion nozzle 26 is extremely great in speed. Into the discharging circulatio flow K an inflow A is mixed after the dispersion nozzle 26. The flows K an A constitute a flow F which is directed upwards in the space between th container 30 and the extension 14a of the cone 14 at a desired speed. Said Hqui flow F is equalized with the aid of a perforated ring 16, whereby the magnitud of the flow G directed downwards through the perforated ring 16 is so sma that the solid matter within the air bubbles will not follow along with the flow Therethrough the Hquid entering the suction ring 19 can be purified from soli agents. The discharge point of the purified Hquid is indicated by E, and it i drawn from the space between the pipes 12 and 15.

In some instances, the flow C can be conducted into a further process such a into a wet washer, whereby the dissolved oxygen / chemicals contained in th flow C react to / wash gases and dusts as desired, returning into the circulatio water container 30 in the form of flow A or as part thereof, containing impur ities which are purified with the means design 10 according to the invention Hereby, Hquid may have to be removed from the circulation as a flow E, bein drawn from the annular space between the pipes 12 and 15, but said Hquid to b removed has, however, undergone a purification process simflar to the flow K of the Hquid entering the pump 17.

Also in the embodiment shown in Fig. 1, the flow C may similarly be conducte into a further process.

The design of the invention can be used for several purposes: for instance, fo

sulphur removal from flue gases, in which the flow C enters the washer, therein dissolving into itself e.g. SO ₂ gas, that is, sulphur dioxide. This kind of dissolved sulphur dioxide becomes oxidized with the oxygen prevailing in the flow B drawn into the pump 17 into sulphur trioxide SO ₃ , and further, into sulphuric acid because an aqueous solution is in question. Hereby, part of the flow C may be carried directly into further processing of sulphuric acid, where the sulphuric acid can, if needed, be processed or concentrated in a desired manner. Flow C, re-entering totaUy or partly the washer, contains no S0 ₂ gas in dissolved form and it is therefore prepared to dissolve again new sulphur dioxide in itself.

The design according to the invention can be used for flotation e.g. in paper industry in manufacttiring recycled paper in the flotation process of black printing ink. The residual waters contain syanides, phenols, humus, etc., which can be oxidized by appropriate chemical additions in the feed flow A. The iron in the drinking waters is in f erro form, which with the design of the invention can be eliminated easUy utilizing appropriately the pH range in the feeding A. The invention is in no way critical regarding the flow B, but How B can be any gas / chemical, because of which the design of the invention has a wide usage and appHcation range.

In the foregoing, only a few advantageous embodiments of the invention, and it is obvious to a person skiUed in the art that a pluraHty of modifications can be made therein within the scope of the inventive idea presented in the accompany¬ ing claims.