JPH06507206A - Desiliconization method for inorganic aqueous solution - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Desiliconization method for inorganic aqueous solution The present invention provides a method for desiliconizing inorganic aqueous solutions, especially aqueous solutions for pickling, and reducing the silica content. The present invention relates to a method for producing iron oxide, in particular a method for producing ferrite.

In the technical field of regenerating the consumed pickling solution, we are developing spray roasting technology. known to be used. In this method, especially the precursors of the electronic industry It is possible to recover iron oxide I[1 (Fe20s), which serves as a ferrite structure. It is possible. The electronic (electromagnetic) properties of these iron oxide ceramics are mainly depends on the silica content of the material. Therefore, at present, soft ferrite For application, the silica content (Sin2) in iron oxide must not exceed 0.01%. is required by the electronics industry, but on the other hand, a few years ago this limit was 0.02%. was within the range. Developments in the field of iron oxides will further reduce this limit. make it possible. Therefore, very pure iron oxide powder (up to 0.01% S The price of iO□) is thought to be approximately 4,900 Austrian sinks per ton. has a content of approximately 0.05% SiO□, as produced in a conventional plant. Iron oxides range from about 700 Au sinks to about 950 Au sinks per ton. This is the price of the Tria sink.

Apparatus and method for treating water containing silica are disclosed in Japanese Patent Publication No. 59-90688. is known, according to which raw water containing silica is passed through two filtration stages; The first filtration stage is equipped with a microporous membrane or ultrafiltration membrane, and the second filtration stage is a reverse filtration stage. Equipped with a permeable membrane. This method removes microscopic particles with a maximum particle size of 1 micron or more in water. Silicic acid in its normal form, which can be trapped, has a particle size of less than 0.02 microns. cannot be separated. In addition, pickling water with a high content of additional components Nor is there any suggestion that this method be applied to solution desiliconization.

Therefore, some time ago, a method for desiliconization of pickling solutions was proposed and used in industrial bran l-. They were first adopted and tested respectively. These methods are described, for example, in Austria Patent No. No. 80675, this method uses Bickling acid (pickl- A part of the iron chloride (approximately 1 to 2%), which is rare in ing acid), is converted into iron hydroxide form. It is based on the fact that colloidal silicic acid is precipitated (precipitated) at the same time as colloidal silicic acid is co-precipitated by absorptive co-precipitation. I'm there. However, this method requires expensive equipment and technical costs, and However, the disadvantage is that a large amount of sludge must be collected and disposed of. Ru. Furthermore, the consumption of chemical products (e.g. ammonia flocculants) is relatively high, so , the plant for implementing this method is relatively expensive and not particularly economical. do not have. Therefore, the investment ratio of spray roasting equipment to the total brand cost is approximately 2 It reaches 0-30%.

The object of the present invention is therefore to extract from any inorganic aqueous solution the silicic acid contained therein. Allows separation to be performed relatively cheaply while avoiding chemicals and labor costs The purpose is to provide a method. Yet another objective is to provide a simple method for producing iron oxides. In a simple way, this iron oxide can meet the warping force limits required by the electronics industry. It is an object of the present invention to provide a simple method for producing iron oxide, which is characterized by not exceeding the above. child The method involves regenerating the spent pickling solution (preferably iron oxidation It is intended to be suitable for integration into existing methods for the recovery of materials.

In order to achieve the first objective, the present invention provides a cross flow (cross flow) solution to be treated. s-f low) far from the filter, temperature of 60-90°C, preferably 70-80° Pass through the filter at a temperature of C.

Silicic acid present in aqueous solutions is mainly supported under the conditions prevailing in cross-flow filters. It is converted into a micellar structure under moderate temperature. These poly The mer tissue exists in a hydrated form and is kept in suspension by electrostatic charges. these The diameter reaches tens to hundreds of microns.

Thanks to the size of the micellar structure of silicic acid, micro filtration can be easily achieved. The range for fine filtration, which is also available for microfiltration, is 0.02 micron and 10 micron. Contains separable particle sizes between chlorine and chlorine. The membranes of such filters are currently For biochemical applications, cellulose derivatives or cellulose derivatives are used. However, for cross-flow filtration techniques such as those employed in accordance with the present invention, the main Therefore, a synthetic resin membrane made of polypropylene, polyethylene or polysulfone is adopted. used. Hollow fibers, foam glass or porous ceramic materials are also used. be able to.

The principle of cross-flow filtration is also applicable for the treatment of liquids containing suspended or emulsified components. itself known. The coating on the filter cake of the filter element is Under conditions, the flow rate of the filtrate is constantly increased or decreased, but in cross-flow filtration, the equilibrium condition is The force exerted by the voltage gradient transverse to the filtration direction beyond be hindered. This allows filtration to be performed at high filtrate flow rates for long periods of time. Becomes Noh. Additionally, periodic backflow or short-term reversal of the filtration process can remove this coating. can be substantially released and removed from the surface of the filter element, thereby filtration ability can be restored. However, the silicic acid contained in the aqueous solution , converting it into a structure that allows separation by a cross-flow filter is initially I couldn't have predicted it. However, under the conditions described above, the diameter of the straw The formation of a micellar structure that exceeds that of the conventional 0.2 micron polyplast occurs. Virtually complete separation of the silicic acid is possible using a lopyrene membrane hose.

The method according to the invention can be particularly advantageously incorporated into the regeneration process of the spent pickling solution. The iron oxide recovered from the pickling solution contains almost no silica. It has the advantage of being extremely suitable for purposes in the electronics industry. of that purpose Therefore, the present invention is suitable for aqueous inorganic solutions, in particular those containing significantly dissolved iron and silicic acid. The used pickling solution is heated to 60-90°C, preferably 70-80°C, through a cross-flow filter. Contains 0.01% or less of silicic acid by passing through a filter and then using a spray roasting method. is converted into the corresponding oxide.

In both steps, it is preferred to recirculate the concentrate into the cross-flow filter. . This further enhances the separation effect of the filter and improves the purity of the filtrate. can.

In the following description, a preferred method for producing iron oxide from used pickling acid will be presented. New embodiments will be further described with reference to the accompanying drawings.

Figure 1 is a schematic diagram of a plant for regenerating pink phosphoric acid by combining desiliconization. It is.

Figure 2 shows details of a desiliconization plant with two filter units connected in series. It is a line diagram.

The filtration solution to be processed is collected in a hand-made shrinking machine 2 and a pre-collection container 3 that constitutes a tank of the hand-made shrinking machine. After passing through, it is spray roasted in the spray roast 1-reactor 1. that The solid reaction product, i.e. metal oxide, formed by the extraction device! ■ taken by On the other hand, the gaseous reaction products are preferably passed through an electrostatic filter 12 and then manually removed. It is returned to the shrinking machine 2. Hand-made shrinking machine (this is a Lurji type or Hentsch type) The conduit passes through two droplet separators 4. From there it is led to an absorption column 5.6 in which the bicking acid is recovered.

The waste gas from these absorption towers 5.6 eventually passes through two droplet separators 7 to the outer ring. discharged to the border.

However, the homemade condensation solution from the pre-collection container 3 can alternatively be pumped by the pump 31. You can also pass it through cross-flow filter 8. stomach.

In this case, the pump 81 repeatedly circulates the concentrate through the cross-flow filter 8. useful for.

As shown diagrammatically in Figure 2, two (or more) filter units (8a and and 8b) may be installed in series.

Example In a Bickling acid regeneration plant configured according to the diagram in Figure 1, the composition ( and the theoretical oxide composition obtained after the spray torrefaction process). The phosphoric acid was treated.

1. ICP analysis: The resulting theoretical oxide composition Fe: 87 g/l Fears 99.16% Cr: 0.03 Cr 2 (is 352 ppm Ni: 0.02 Ni0 204 Al: 0.05 AI. 01 760S+Ot 0.036 5102 28 9Mn: 0.27 Mn0 2800Ca: 0.08 Ca0 900 Zn: 0.06 Zn0 598 Mg: 0.16 Mg0 2315 pb・o, oo pbo o.

Cu: 0.025 Cu0 221 Total HCI: 197 g/I (approx. 20% ) Theoretical maximum CF value: 0.15% bound cross-fi filter (cross-fi lter) was integrated directly into the concentrate circuit.

The throughput capacity of the concentrate circuit reaches 28001V/h, and the throughput of the filter The ability reached 20001/h. After 13 and 17 hours of driving time respectively. , the following values were obtained for each of the iron concentration and silica concentration.

a)=Fe(2+)in g/1. b=Fe(3+)in g/1. c) =SiOz in mg/l concentrate permeate a) b) c) a) b) c) -----110,217,542 13h 108.2 22.3 25 106.6 20.8 22.5 (+2 24-148pp/oxide) 17h 111.3 23.3 27.6 117 ．． 3 23.9 22.9 (114-137 ppm/oxide) in the following experiment , Bickling acid was treated, and the concentration values were as follows: Fe(2 +)79.9 g/1. Fe(3+) 5.6 g/1. Si0□38m g/I (which corresponds to the theoretical maximum of 337 ppm in the oxide). orthogonal Using flow filtration, the following values were obtained within 1 hour and after 4 hours, respectively. : Concentrate, permeate a) b) c’) a) b) c) Ih 113.0 24.6 27.0 1!7.5 25.8 15.5 (7 6-92ppm/oxide) 4h 117.5 27.2 37.5 +18.3 27.6 22.8 (109-135 ppm/oxide) Then cross-flow filter The meter was switched off and after a further 4 hours the following values were obtained.

Concentrated liquid Permeated liquid a) b) c) a) b) c) 4h 113.8 32.4 56.2 (1) 39 (350ppm/oxide) In the table above, in the data for silica in the total oxide drawn , the oxide was silicified by extrapolation from solution. Therefore, regarding spray roasted oxide The analysis results are shown below.

Fe: Fe*O*: 99.2% Mn: 3093 ppm MnO: 0.399% SiOx: 100 5i02: 0.010% (maximum value) V : 141 V2O5: 0.025Ti: 95 Ti0z: 0.0+ 6Cr: 338 Crz02: 0.050Cu: +74 Cub: 0.021Ni, 166 Nip+ 0.021Co: 23 Cod: 0.029Pb: 26PbO: o, 003Zn: 246ZnO : 0.031Al: 749 Al2O2: 0.139Ca: 766 Cao: 0.108Mg: 692 Mg0 0.128P: 30 PzOs　O,007 l□□-’PCT/＾T　92100069Continuation of front page (72) Inventor: Gumsligra, Manfred Austria, Vienna et al. E-1220゜Lugierstrasse 28/3/12 (72) Inventor Ku Radnig, Austria, St. Georgen A-422 2, Luftenberg 65

Claims (3)

[Claims] 1. In the desiliconization method for inorganic aqueous solutions, especially pickling solutions, the solution to be treated is Pass through a cross-flow filter at a temperature of 60-90°C, preferably at a temperature of 70-80°C. A desiliconization method characterized by passing the filter through the filter. 2. In the production method of iron oxide with low silica content, especially ferrite, inorganic Aqueous solutions, especially spent pickling solutions containing predominantly dissolved iron and silicic acid , passed through a cross-flow filter at a temperature of 60-90°C, preferably at a temperature of 70-80°C. Then, the permeate was treated with a maximum silica content of 0.01% by spray incubation method. of iron oxides with low silica content, characterized by the ability to convert them into two corresponding oxides. Production method. 3. Claims characterized in that the concentrate is recirculated into the cross-flow filter. The method according to item 1 or 2.