Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G49/00—Compounds of iron
  • C01G49/02—Oxides; Hydroxides
  • C01G49/06—Ferric oxide [Fe2O3]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J47/00—Ion-exchange processes in general; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J47/00—Ion-exchange processes in general; Apparatus therefor
  • B01J47/10—Ion-exchange processes in general; Apparatus therefor with moving ion-exchange material; with ion-exchange material in suspension or in fluidised-bed form
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F11/00—Compounds of calcium, strontium, or barium
  • C01F11/46—Sulfates
  • C01F11/462—Sulfates of Sr or Ba
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F5/00—Compounds of magnesium
  • C01F5/14—Magnesium hydroxide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F7/00—Compounds of aluminium
  • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
  • C01F7/34—Preparation of aluminium hydroxide by precipitation from solutions containing aluminium salts
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G1/00—Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G21/00—Compounds of lead
  • C01G21/20—Sulfates
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G3/00—Compounds of copper
  • C01G3/10—Sulfates
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G45/00—Compounds of manganese
  • C01G45/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/80—Compositional purity

Definitions

• the invention relates to a process for producing precipitates with an increased grain size, with improved sedimentation characteristics and a better filtrability and/or a higher grade of purity by using an ion-exchange auxiliary phase; the invention also relates to the equipment being suitable for performing said process.
• the essence of the chemical reactions resulting in precipitate formation lies in that after having mixed the solutions containing the anion forming the precipitate to be isolated and the cation, respectively, the solid product of reaction having been formed under the influence of the chemical reaction talcing place in the solution phase, precipitates from the solution being supersaturated in respect to the poorly soluble compound.
• the precipitate is formed from the reaction product in course of the nodule formation, nodule growth and agening; under agening the coagulation, as veil as the Ostwaldian agening is meant /see Nielsen, A. E : Kinetics of Precipitation, Pergamon Press, 1964/.
• the grain size distribution of the precipitate is determined by the enumerated partial processes, out of which the ratio of the velocity of nodule formation and nodule growth can be considered as the most important factor, when in general, the velocity of the nodule formation is considerably higher, than the velocity of nodule growth.
• the reactions resulting in the formation of precipitates serve namely for the production of compounds of poor solubility and it is a well-known fact, that the lower the solubility of the compound formed, the higher the velocity of nodule formation.
• the small grain size of the precipitate formed is to be considered as unfavourable and disadvantageous not only with regard to further processing, as sedimentation, filtration, drying, etc. but often it results in inconvenience in course of the final utilization.
• the accompanying ions getting into the process together with the reagents may deteriorate the purity of the product, by penetrating into the inclusions or infiltrating into the lattice or being adsorbed on the surface they are tending to contaminate the precipitate.
• the process according to the invention is based on the surprising recognition that if at least one ion out of the ions forming the precipitate, or at least one of the ions inducing the chemical reaction between the components contained in the solution resulting in the formation of the precipitate and promoting it, respectively, is introduced into the system bound to a ion-exchange material, precipitates of an increased grain size and/or tending to a spontaneous coagulation and/or of a greater purity can be obtained, furtheron, by the partial recirculation of the precipitate having been obtained in such a manner and/or by subjecting the suspension with a precipitate to a heat treatment, sedimentation and filtrability can be further improved.
• the essence of the process according to the invention lies in that crystalline substances and precipitates, respectively, are gained from a solution, by means of a chemical reaction in such a manner, that at least one ion out of the ions forming the precipitate to be produced or at least one ion inducing the chemical reaction between the components contained in the solution or promoting the same, is introduced into the system bound to an ion-exchange material and the ion-exchange material serving as an ion-exchange auxiliary phase is brought into contact with the solution containing the other ions forming the precipitate; it is also possible to bring together the ion-exchange materials containing individually the ions forming the precipitate in a suspension, while formation of the precipitates is taking place and in a given case, by the partial recirculation of the precipitate and/or by a repeated contact with the ion-exchange material and the solution, both the grain size can be increased and the filtrability improved.
• the ion-exchange auxiliary phase to be used in course of the process is either a natural or an artificial anion-changing or cation-changing substance being present in a solid granular and/or gel and/or liquid state.
• contact between the solution, the ion-exchange auxiliary phase and the precipitate is established in one or more stages; in case of more stages, the precipitate formed is advantageously recirculated between the single stages, i. e. it is brought repeatedly into contact with the ion-exchange auxiliary phase and the solution.
• the solution and the precipitate dissipation heat transfer or heat ex ⁇ raction is applied.
• the mixture containing the precipitate formed, the ion-exchange auxiliary phase and the solution are separated; the ion-exchange material is regenerated in a well-known manner, i. e. by bringing it repeatedly into contact with the solution, it is brought in a state being suitable for the formation of the precipitate and it is used in the system once again.
• the equipment being suitable for the realization of the process according to the invention is based on the recognition, that by forming individual spaces within an apparatus-body by inserting vertical partitions, the crystals of smaller grain size can be recirculated from the spaces having been already agitated into the preceding space through the apertures on the upper part of the partitions, whereas the ion-exchange auxiliary phase and the suspension containing the crystals of larger particle size are passing forwards through the apertures on the lower part of the partitions, from space to space, and in accordance with prevailing necessity, in the single spaces dissipation heat transfer or heat extraction may be applied.
• the ion-exchange material may be a granular solid matter or a gel or a material in a liquid state not intermixing with the solution.
• the ion-exchange material the following requirements are to be met: - the ion required for the precipitate formation should be bound with a satisfactory capacity;
• the ion-exchange material could be well isolated from the suspension containing the precipitate.
• the ion exchanging material functions as an auxiliary phase; first of all it is saturated with one of the ions needed for the format ion of the precipitate, thereafter it is brought into contact with the solution containing the other ion needed for the formation of the precipitate and after having been isolated, it is regenerated.
• the ion-exchange material can be evenly distributed in the entire volume of the solution, as a consequence, local supersaturation can be avoided.
• the possibility of local supersaturation is further reduced by the fact, in so far as the access of the reagent ions into the solution is delayed by the velocity of diffusion and ion-exchange reaction, which is less than the velocity of the chemical reaction, in such a manner the ion-exchange material is quasi slowly dosing the ions needed for the precipitate formation.
• the other essential characteristics of the precipitate formation with ion-exchange lie in, that the ion-exchange material is binding the "accomparing ion" being present in the solution, as a consequence, in the solution phase of the suspension containing the precipitate - with the proper proportions of dosage - the concentration of the cation accompanying the anion forming the precipitate and the concentration of the anion aceempaling the cation forming the precipitate can be reduced to the minimum.
• the electrolyte layer is formed to a slighter extent or there is no electrolyte at all; in such a manner
• the crystallization with precipitate formation is well suitable for producing compounds of a higher purity, since by using pure reagents the adhesion of the accompanying ions onto the surface of the precipitate grains can be avoided, thus the infiltration of the foreign ions into the lattice and/or into the inclusions does not take place.
• the precipitate formation with ion-exchange precipitates with a larger grain size and tending to spontaneous coagulation may be obtained - and compared to the precipitates produced by the usual precipitating processes -, they are showing improved sedimentation and filtration characteristics.
• the process according to the invention is more suitable for separating different materials by precipitate formation, than the traditional precipitating methods.
• the primary reason for this is, that partly due to the more uniform distribution of the ion-exchange reagent, partly owing to the velocity defining character of the ion-exchange, local supersaturation may be avoided, and the concentration of the reagent ion can be more accurately controlled.
• the process is yielding the possibility for the performance of precipitate forming isolations based on the pH-selective hydrolysis.
• figure 1 is showing the sectional front view of the equipment
• figure 2 the sectional top-view and figure 3 the side-elevation of the equipment
• figure 4 is showing the schematical flow diagram of the equipment and the ancillary units.
• the apparatus-body 1 is divided into two or more spaces 3 by means of one or more vertically arranged partitions 2.
• the pipe sbu 4 provided with the nozzle 5 and overhanging into the confining space 3 is connected to the aperture in the upper third of the vertical partition 2.
• the vertical partition 2 does not extend to the bottom of the apparatus-body 1, whereby the apertures 6 connecting the single spaces 3 are formed.
• the perforated air-distributing pipes 7 arranged, to which the air-conducts 8 have been connected.
• the apparatus-body 1 is shaped with the restricted cross-section 9.
• the bottom of the apparatus-body 1 is connected via the aperture 11 to the aerolift 10, at the bottom of which the air blower 12 is to be found.
• the space of the aerolift 10 is connected via the return aperture 13 to the last space 3; the aerolift 10 is provided with the material discharge pipe stud 14 and the air out-let-stud 15.
• the solution 16 containing one or more components of the precipitate to be isolated, as well as the ion-exchange auxiliary phase 17 containing the ion/s/ inducing or promoting the reaction resulting in precipitate formation, are led into the first space 3 of the apparatus-body 1.
• the solution having been introduced into the first space 3, the ion-exchange auxiliary phase, as well as the precipitate formed travel through the apertures 6 formed in the lower part of the vertical partitions 2, from space to space forwards , from the space marked with I to the space:3 marked with V.
• mixing is performed by the air stream introduced via the perforated pipes 7 /nozzles/ having been arranged in the spaces each, along the longitudinal axis of the apparatus-body 1.
• the air stream is delivered by the air conducts 8.
• a circulating stream may be obtained in the single compartments.
• selective recirculation of the small-sized grains from the last space 3, i. e. from the aperture 13 of the aerolift 10 up to the first space 3 can be realized.
• the isolated precipitate, the ion-exchange material and the solution are led away from the last space 3 through the passage opening 11 on the bottom of the apparatus-body 1, by the aid of the aerolift 10, which is receiving the delivery air through the nozzle 12.
• the constant level of the suspension in the apparatus-body 1 is controlled by means of the opening 13 of the aerolift 10.
• the solid matter and the materials in a liquid state are leaving the aerolift 10 through the stud 14, while delivery air is discharged via the stud 15.
• the quantity of the ion-exchange material and the precipitate, respectively, dwelling in the apparatus-body 1 can be advantageously controlled by changing the size of the opening 11 resp. 13 and the quantity of the air to be introduced via the nozzle 12.
• the suspension mixture consisting of the ion-exchange auxiliary phase, the isolated precipitate and the solution having been discharged through the stud 14 of the aerolift 10 arrives expediently at the vibroscreen 18, when a granular ion-exchange material is used; the granular material is thus separated and the solution with the precipitate is passing through the vibroscreen 18 and is led to the screen 19, where the precipitate is isolated from the mother lye solution 21.
• a part of the mother lye is recirculated to the vibroscreen 18 in order to be able to wash out the ion-exchange resin /indicated with a dashed line in figure 4/.
• the suspension mixture consisting of the ion-exchange material, the isolated precipitate and the solution is led firstly to the equipment separating the solid matter, e. g. to the screen 19 or the centrifuge, where the precipitate is isolated; thereafter the mixture consisting of the solution and the liquid ion-exchange material is separated in an equipment not illustrated here, e. g. in a liquid separator or a decanting apparatus.
• the equipment separating the solid matter e. g. to the screen 19 or the centrifuge, where the precipitate is isolated
• the mixture consisting of the solution and the liquid ion-exchange material is separated in an equipment not illustrated here, e. g. in a liquid separator or a decanting apparatus.
• the ion-exchange material to be regenerated is led into the ion-exchanger 22, which can be any type of the known ion-exchangers.
• the regenerating reagent is dissolved in the reservoir 24, from where it is delivered by means of the pump 25 into the ion-exchanger 22.
• the regenerated granular resin is washed on the vibroscreen 26 with the water having been used for preparing the regenerating solution, hereupon it can be repeatedly used as an ion-exchanger auxiliary phase for the process of precipitate formation.
• the spent regenerating solution 27 is drained and within the range of possibilities the useful components are recovered. In a given case, the mother lye can be also used for preparing the regenerative solution.
• the cross-section of the apparatus-body 1 lying perpendicularly to the material stream may be shaped as a trapezoidal crocs-section 9 or as an arched restricted part or as a rectangle in the full height of the apparatus-body, in addition to these, the bottom of the apparatus-body may be formed with a convex surface.
• the apparatus-body 1, showing expediently an oblong top-view, is divided into smaller parts with a square or oblong cross-section by means of the partitions 2.
• the partitions 2 are arranged normal to the streaming direction of the material and in a case of necessity they may be prepared as interchangeable parts.
• the partitions 2 are forming a continuous aperture at the bottom of the apparatus-body 1, which enables the advance of the ion-exchange auxiliary phase, the solution and the precipitate of larger grain-size from one compartment to the other.
• the stream of the materials is induced by the spontaneously formed hydrostatical differential pressure, in general, special means are not required, however, the use of such means for producing the stream is not excluded at all.
• one or more apertures are provided serving for the recirculation of the precipitate grains of smaller size being present in the upper part of the solution space into the preceding space. Recirculation is obtained in such a manner, that a stud - bent downwards expediently by
• 90o- is connected to said aperture/s/, into which a stream of air or gas is led through e. g. a nozzle, while the solution containing the precipitate is pneumatically circulated to the precedent space.
• the rate of recirculation may be controlled by the size of the stud and the quantity of the gas introduced.
• pneumatic agitation is performed e. g. in such a manner that on the bottom of the single spaces, in the direction of the material stream gas- or air-distributing pipes being closed on both ends are arranged and the gas stream needed for the agitating activity is led through the perforations on the mantle of the pipes into the solution space.
• Perforation may be formed in one or two rows. In so far as the perforations are formed along the length of the pipe, along a generatrix having been rotated by 30-60° in relation to the vertical plane, an internal circulation may be produced by means of the air stream in the apparatus-body with the trapezoidal cross-section.
• pneumatic agitation may be performed by using an internal casing pipe, or nozzles or any equivalent means, or in a given case mechanical agitation can be performed.
• the ion-exchange material and the solution/s/ needed for the precipitate formation are led into the first space falling into the direction of the material stream, however, it is possible to introduce the material into an other space or simultaneously into more spaces.
• the materials are discharged from the apparatus-body 1 through the last space by means of the aerolift, which is connected to the lower part of the space.
• the suspension is led into the aerolift through the opening on the bottom of the apparatus-body, simultaneously - for keeping a constant level - between the aerolift and the apparatus-body a further passage is formed in the height of the solution level.
• the last spaces of the apparatus may serve as sedimentation stages without agitation.
• the separated outlet of the isolated ion-exchange phase becomes possible, taking place - in dependence of specific weight conditions - in the upper or lower part of the apparatus-body.
• the process and the apparatus according to the invention may be used not only for producing inorganic compounds, but both can be successfully applied for the production of compounds, which are slightly soluble in water and one of the components is an organic, the other an inorganic substance.
• the most general form of the invention relates to a process for producing precipitates in a liquid solvent medium from organic and/or inorganic components, which are insoluble or slightly soluble in said solvent, in course of which one or more components dissolved in the solution are allowed to react with the component being present in the ion-exchange auxiliary phase in a bond ferm or with ion-exchange materials containing individually the precipitate forming components.
• a/ Por the sake of comparison precipitation is performed in the usual manner by adding 60 ml sodium hydroxide solution of the concentration of 5 mole/l, at a dosage rate of 2 ml/minute, to 200 ml ferric/III/chloride solution of the concentration of 0,5 mole/l, thereafter the suspension is allowed to stand for 50 minutes.
• c/ 100 ml suspension having been prepared according to b/ are mixed with 100 ml ferric/III/chloride solution of the concentration of 0,381 mole/l, thereafter - at a dosage rate of 4 ml/minute - 100 ml Varion-AD resin are added, which contain 21 g/l OH- ions. After having stirred the mixture for 30 minutes, the resin is isolated on a 0,6 mm screen.
• d/ 100 ml suspension having been prepared according to c/ are mixed with 100 ml ferric/III/chloride of the concentration of 0,381 mole/l, thereafter - at a dosage rate of 4 ml/minute - 100 ml Varion-AD resin are added, which contain 21 g/l 0H- ions. After having stirred the mixture for 30 minutes, the resin is isolated on a 0,6 mm screen.
• e/ 200 ml suspension haying been prepared according to a/ are mixed with 100 ml Varion-AD resin of a hydroxide form and 135 ml hydrogenous Varion-MKS resin. After having been stirred for 60 minutes, the resin is isolated on a 0,6 mm screen.
• the suspension contained solid matter in a quantity of 40 g/l.
• the suspension having been prepared in the previously described manner are filtered under a vacuum of 600 Torr in a nutsch-filter covered with a filter cloth ⁇ 6 cm and with a surface of 28,3 cm 2 ; the timely change of the filtrate volume Is measured.
• the following table is showing the average rates of filtrating for the filtering periods of 1 minute and 6 minutes, respectively, as well as the rates of filtrating related to the suspension a/.
• 40 ml Varion-AP resin containing 68 g sulfate ions/l are added at a dosage rate of 1,0 ml/minute. After having been stirred for 30 minutes, the resin is isolated on a 0,6 mm screen.
• d/ 100 ml suspension having been prepared according to c/ are mixed with 100 ml barium chloride solution of the concentration of 0,175 mole/l, thereafter 40 ml Varion-AP resin containing 68 g sulfate ions/l are added at a dosage rate of 1,0 ml/minute. After having been stirred for 30 minutes, the resin is isolated on the 0,6 mm screen.
• e/ 200 ml suspension having been prepared according to b/ are mixed with 107 ml Varion-A-D resin of the hydroxide form. After having been stirred for 60 minute the resin is isolated on a 0,6 mm screen.
• f/ 200 ml suspension having been prepared according to a/ are heated to 50 oC, thereafter the suspension is allowed to cool to 20 °C in 30 minutes.
• g/ 200 ml suspension having been prepared according to b/ are heated to 50 °C and allowed to cool to 20 °C in 30 minutes.
• Example 5 for producing a lead sulfate precipitate by using an anion-exchange material in a liquid state
• Example 4 for the production of anhydrous cupric sulfate in a non-aquaeous medium
• Example 5 for the selective preparation of aluminium hydroxyde, magnesium hydroxide and iron hydroxide precipitates Under steady stirring Varion-AB resin containing 18 g/l hydroxide ions is added to 200 ml aquaeous solution containing 0,1 mole/l aluminium sulfate, 0,1 mole/l iron/III/chloride and 0,1 mole/l magnesium sulfate, meanwhile the pH-value of the solution is continuously controlled.
• the mixture After having introduced the ion-exchange resin in a quantity of 62 ml, the mixture is separated. The ferric/III/hydroxide precipitate formed, weighing 2,1 g in a dried state, is to be analysed. The purity of the isolated ferric/III/hydroxide surpassed 99,8 %.
• the mixture After having admixed further 125 ml ion-exchange resin to the solution, the mixture is separated and the precipitate formed - aluminium hydroxide weighing 3,0 g in a dried state and contaminated by 0,21 % ferric/IIl/oxide and 0,03 % magnesium oxide - is isolated.
• magnesium hydroxide precipitate is isolated, weighing 1,1 g in a dried state, containing 0,005 % ferric/III/oxide and 0,012 % aluminium oxide as contaminations.
• the initial filtrating rate of the solution containing the precipitate amounts to 2,1 m 3 /m 2 /h.
• Example 7 for producing manganese-oxy-hydroxide precipitate in the apparatus as illustrated in the figures
• the petroleum phase was separated from the mixture having been discharged from the space III of the apparatus.
• the sedimentation and filtration characteristics of the aquaeous phase containing the pre cipitate were tested.
• the solid matter conten ⁇ Increased to 122 g/dm 3 .
• the initial rate of filtering amounted to 3,4 m 3 /m 2 /h.
• the advantages of the invention are as follows: - due to the more accurate dosage and more uniform distribution of the ion-exchange material local super saturations can be avoided;
• - sedimentation and filtrability characteristics may be further improved by using, flocculating agents, which are efficient even in lower concentrations, than usual;
• the ions needed for the precipitate formation can be gained from cheaper raw materials or waste;
• the accompanying ions being bound in the solution by the ion-exchange material may be utilized, when regenerating the ion-exchange material;

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 1981
  • 1981-04-23 JP JP50142481A patent/JPS57500635A/ja active Pending
  • 1981-04-23 WO PCT/HU1981/000015 patent/WO1981003016A1/fr not_active Application Discontinuation
  • 1981-04-23 EP EP19810901159 patent/EP0050640A4/fr not_active Withdrawn

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