Classifications

• • 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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/007—Mixed salts
• • 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
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/10—Magnesium; Oxides or hydroxides thereof
• • 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
  • C01F7/78—Compounds containing aluminium, with or without oxygen or hydrogen, and containing two or more other elements
  • C01F7/784—Layered double hydroxide, e.g. comprising nitrate, sulfate or carbonate ions as intercalating anions
  • C01F7/785—Hydrotalcite
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/40—Compounds of aluminium
  • C09C1/42—Clays
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/20—Two-dimensional structures
  • C01P2002/22—Two-dimensional structures layered hydroxide-type, e.g. of the hydrotalcite-type
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
• • 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
  • C01P2006/12—Surface area

Definitions

• the invention relates to a process for the preparation of hydrotalcites from compounds of divalent and trivalent metals.
• hydrotalcite is derived from the mineral brucite and satisfies the following ideal formula:
• magnesium ions are replaced by aluminum ions, which gives the single layer a positive charge. This is compensated for by carbonate anions, which are found in the intermediate layers together with water of crystallization.
• the magnesium can be wholly or partly by zinc, calcium, iron (II), cobalt, copper, cadmium, nickel and / or manganese and the aluminum can be wholly or partly by iron (III), boron, manganese, bismuth and / or Cer be replaced.
• soluble salts such as sodium chloride
• soluble salts are formed as by-products, which have to be washed out either from the precipitate of the preliminary product or from the end product, which requires larger amounts of wash water and increases the salt load of the waste water.
• the most common and cheapest soluble salts are the chlorides of metals. Chlorides lead to severe corrosion in the system parts. Plant parts that come into contact with these raw materials must be designed for this. In general, only titanium equipment or coatings are suitable. This leads to high costs for equipping the system.
• the salt-oxide method describes the reaction of a metal salt with the oxide or hydroxide of the other metal.
• the pH is finally adjusted to an optimal value with acids or alkalis. As a rule, this value lies in the neutral to weakly basic range.
• MgO can be converted to hydrotalcite with A1C1 3 .
• a clever choice of raw materials results in a cost advantage compared to coprecipitation, since the oxides are generally cheaper than the soluble salts.
• Waste water also contains fewer salts.
• One of the disadvantages of this method is the problem that the production of phase-pure products is difficult.
• the third method involves the conversion of oxides, hydroxides or carbonates of the di- and trivalent metals. Examples of this method can be found in the patent literature, such as DE 20 61 114, US 5,399,329 and US 5,578,286. In addition to comparatively low raw material costs, there are relatively few salts in the wastewater.
• WO 01/12570 describes, inter alia, the production of an abrasion-resistant molded body containing crystalline anionic clay by mixing MgO with gibbsite or amorphous aluminum gel. An optional homogenization of the slurry is described. This is followed by calcination, resuspension and aging of the molded articles.
• the goal when planning new plants is, among other things, the careful use of resources and the environment.
• salt solutions the transport costs are disproportionately high due to the relatively low active substance content.
• the anions that are not incorporated in the product end up in the wastewater.
• raw materials that are as active as possible are used, in particular if suspensions of solids are to be used.
• the shelf life of active raw materials is limited.
• the active raw materials are more difficult to handle in a plant.
• the processing of these active raw materials is also problematic because the reactivities change considerably due to different idle times in the plant. This leads to strong quality fluctuations in the end product (hydrotalcite).
• hydrotalcite hydroxide
• MgO sets in water with strong heat development.
• An aqueous MgO suspension poses a safety risk in the event of too long a standstill or when system malfunctions occur.
• MgO in particular is difficult to handle as an active raw material.
• the active species should be used as low solids suspensions. If the Thin suspensions, however, increase the costs in the area of the batches because larger volumes have to be treated (boiler size, pumping units, stirring elements).
• the object of the invention was to provide a process for the preparation of hydrotalcites which enables the advantageous use of inexpensive and environmentally safe starting materials in the production of hydrotalcites, avoids the above disadvantages of the prior art and nevertheless provides high-quality hydrotalcites.
• the D 90 value (ie 90% of the particles present are smaller than the specified particle size) after intensive grinding is preferably 1 to 5 ⁇ m, in particular 1.5 to 4 ⁇ m, particularly preferably 1.5 to 3.5 ⁇ m.
• hydrotalcite is understood to mean a double-layer hydroxide compound of the general formula below:
• A is a divalent metal cation
• B is a trivalent metal cation
• C is a mono- or polyvalent anion and the following conditions apply to w, x, y, z and n: 0 ⁇ z ⁇ x ⁇ 4 ⁇ w ⁇ y and 12>n> 0.
• Preferred embodiments of the invention relate to the compounds mentioned at the outset derived from the ideal formula [Mg 6 Al 2 (OH) 16 ] C0 3 • n H 2 O.
• hydrotalcite some magnesium ions have been replaced by aluminum ions compared to brucite, which gives the single layer a positive charge. This is compensated for by carbonate anions, which are found in the intermediate layers together with water of crystallization.
• the magnesium can be wholly or partly by zinc, calcium, iron (II), cobalt, copper, cadmium, nickel and / or manganese and the aluminum can be wholly or partly by iron (III), boron, manganese, bismuth and / or cerium can be replaced.
• the carbonate primarily present in the intermediate layers can subsequently be completely or partially replaced by one or more of the above anions, including anions with organic residues.
• hydrotalcites produced according to the invention in particular have a phase purity of> 90%, in particular> 95%, particularly preferably> 98%, determined by the ASTM C method 1365-98.
• the process runs safely and pollutes the environment (especially the wastewater) only very slightly.
• the process according to the invention enables the production of finely divided, powdery hydrotalcites, in particular with an average particle size (D 50 ) in the range from 0.1 to 2 ⁇ m, in particular 0.1 to 1 ⁇ m, particularly preferably 0.5 to 1 ⁇ m.
• D 50 average particle size
• Inactive raw materials are those which are insoluble, ie a solubility in the reaction medium or solvent used, preferably water, at 25 degrees Celsius and pH 6 to 7 of less than 5 x 10 "8 , in particular less than 1 x 10 "9 , preferably less than 5 x 10 " 10.
• the BET surface area (DIN 66132) of such materials is generally below 30 m / g, preferably below 10 m 2 / g, in particular below about 6 m / g.
• Such products can surprisingly be activated inexpensively with the intensive milling according to the method of the invention and converted to a high quality hydrotalcite.
• inactive raw materials examples include the oxides, hydroxides and carbonates of the two and trivalent metals, preferably of magnesium and zinc, the term "carbonates” meaning both the neutral carbona te (eg MgC0 3 ) as well as the basic carbonates (eg Magnesia alba or the bicarbonates (eg Mg (HC0 3 ) 2 ) should be understood.
• the oxides of zinc and the oxides of aluminum are also particularly preferred.
• insoluble (inactive) raw materials are preferably used as suspensions.
• at least one source of a divalent metal and at least one source of a trivalent metal are used.
• one or more than one compound can be used, it being possible for different divalent or trivalent metals to be present.
• divalent metals are: Mg + , Ca 2+ , Zn 2+ , Mn 2+ , Co 2+ , Ni 2+ , Fe 2+ , Sr 2 ⁇ Ba + and / or Cu 2+ .
• trivalent metals are: Al 3+ , Mn 3+ , Co 3+ , Ni 3+ , Cr 3+ , Fe 3+ , Ga 3+ , Sc 3+ , B 3+ and / or trivalent Cations of rare earth metals.
• Intensive grinding increases the reactivity of the compounds of the di- and trivalent metals that are not used as a solution, in particular the above-mentioned inactive raw materials, such as the insoluble carbonates, oxides and / or hydroxides of the divalent metals or the oxides and hydroxides of the trivalent metals and enables surprisingly good hydrotalcite conversions and qualities. It was surprisingly found that in order to achieve particularly good results, intensive grinding should be carried out in such a way that an average particle size (D 50 ) of between about 0.1 to 5 ⁇ m, in particular 0.4 to 2 ⁇ m, particularly preferably 0.4 to 1, l ⁇ m, results.
• D 50 average particle size
• the preferred D 90 values are 1 to 10 ⁇ m, in particular 1 to 5 ⁇ m, particularly preferably 1.5 to 2.5 ⁇ m. Since inactive raw materials with a substantially higher average particle size than after intensive grinding are generally assumed, the intensive grinding according to the invention results in a significant comminution of the particles, usually by at least about 30%, not just homogenization or mixing of the suspension. It is assumed that the intensely ground particles have a particularly advantageous surface / volume ratio, which favors the subsequent conversion to high-quality hydrotalcite. Ultimately, a high-quality and finely divided hydrotalcite is obtained, which is particularly well suited for use as a plastic additive, for example. For this application, hydrotalcites with an average particle size (D 50 ) of less than about 1 ⁇ m and a D 90 of at most 2 to 3 ⁇ m are preferred.
• D 50 average particle size
• Intensive grinding can generally be carried out using any suitable grinding device, as long as the parameters according to the invention are observed. Intensive grinding is preferably carried out in a wet mill, in particular in a bead mill or annular gap mill.
• a high amount of energy (about 0.5 to 10 kW / liter, preferably about 1 to 10 kW / liter) is introduced into the system via the mechanical energy, and this high amount of energy leads not only to grinding / mixing but also to a chemical one Reaction, ie to a solid-state reaction because ions are likely to detach from the activated surface.
• the amount of energy can be reduced, e.g. to 2 to 5 KW / liter.
• the intensive grinding is preferably carried out at a pH in the range from about 7 to 13.5 and at temperatures in the range from about 20 to 100 ° C. A temperature increase takes place during grinding.
• At least one of the starting components ie a compound of the divalent or trivalent metal and / or the mixture of the compounds of the divalent and trivalent metals, is subjected to the above intensive grinding.
• the Intensive milling provided for by the method and the starting components for hydrotalcite production have already been sufficiently activated, in many cases an additional intensive milling is no longer necessary during or after the mixing of the compounds of the di- and trivalent metals.
• the same can apply if only one of the above components A and B is used as an inactive raw material, in particular as a suspension, while the other component is used in the form of a solution.
• inactive magnesium oxide is used as the compound of the divalent metal (component A) and is subjected to the intensive grinding according to the invention.
• Aluminum hydroxide can then be used as the compound of the trivalent metal (component B), which is converted to sodium aluminate by adding sodium hydroxide solution. Intensive grinding of the sodium aluminate solution is therefore not necessary.
• the initially inactive magnesium oxide is at least partially converted into the hydroxide during intensive grinding (wet grinding).
• carbon dioxide is preferably already supplied as the carbonate source.
• the mixture is then mixed with the compound of the trivalent metal, preferably the sodium aluminate solution mentioned above.
• the intensive grinding takes place during or after the mixing of the compounds of the di- and trivalent metals, it can advantageously be continued until an amorphous or crystalline hydrotalcite phase is formed.
• Such intensive grinding of the mixed suspension which is carried out for 1 to 3 minutes at 7 kW / liter or about 10 to 20 minutes at 5 kW / liter, leads to new phases. forms, namely initially an amorphous hydrotalcite phase and only to a lesser extent (eg 3 to 4%) a crystalline hydrotalcite phase.
• the amorphous hydrotalcite precursor phase is in a small grain size.
• an excess of carbonate must be added to achieve good results in the process according to the invention.
• An excess of> 0.5 mol of CO 2 or carbonate per mol of AI (or trivalent metals used) is regarded as an excess.
• Preferred ranges are:> 0.5 to 3 mol, in particular 0.8 to 2.5 mol, particularly preferably 1.0 to 2.0 mol of CO 2 or carbonate / mol AI or trivalent metals used).
• the addition is carried out before or during the mixing of the compounds of the di- and trivalent metal, but in any case before any. performed hydrothermal post-treatment of the approach.
• the addition of carbon dioxide as a carbonate source gives particularly advantageous results.
• the carbonate can also be obtained by using a corresponding carbonate-containing compound of the di- or trivalent metal or by additionally adding carbonate-containing salts.
• the addition of CO 2 is clearly preferred. By adding C0 2 , the pH of the suspension of the raw materials or the mixed suspension can be adjusted to the desired value or kept there.
• At least one of components A or B is activated separately by intensive grinding, this takes place according to the invention shortly before further implementation in the inventive method. This is to ensure that the activation achieved by the intensive grinding is not lost through undesired reactions before the implementation in the method according to the invention. As a rule, therefore, the intensive grinding is carried out a maximum of 5 hours before further implementation in accordance with the method according to the invention. It is assumed that the active particle surfaces formed during intensive grinding can play a role.
• the solids content of the suspension (s) used or of the mixed suspension with the compounds of the di- and trivalent metals is preferably about 30 to 60% by weight. These limits have also proven to be practical with regard to the devices used for intensive grinding, but in individual cases lower or higher solids contents may also be preferable.
• a preferred method for the preparation of hydrotalcites from compounds of divalent and trivalent metals is characterized in that (a) separate suspensions of the insoluble carbonates, oxides and / or hydroxides of the divalent metals and the oxides or hydroxides of the trivalent metals, or (b) subjecting a mixed suspension of these components to intensive grinding until an average particle size (D 50 ) of about 1 to 5 ⁇ m is reached, a carbonate source being added before, during or after intensive grinding when using the oxides or hydroxides of the divalent and trivalent metals ; in case (a) the separate suspensions are mixed together; in both cases, intensive grinding is carried out until an amorphous hydrotalcite phase or a hydrotalcite phase characterized by a sharp X-ray diffraction pattern occurs; and separates the product obtained, dries and optionally calcined.
• D 50 average particle size
• Components A and B are preferably mixed together at a temperature of about 40 to 100 ° C., in particular at about 80 to 90 ° C.
• reaction of the mixture of the compounds of the di- and trivalent metals begins immediately. This means that reaction times between 0 and 48 hours before thermal or hydrothermal processing are usually sufficient.
• the carbonates, oxides and / or hydroxides of the trivalent metals can be replaced in whole or in part by soluble salts (e.g. sodium aluminate).
• soluble salts e.g. sodium aluminate
• Aluminum hydroxide, active forms of aluminum oxide and / or sodium aluminate are preferably used as compounds of the trivalent metals.
• the latter hydrolyzes in the suspension, so that as a result a reaction takes place between the aluminum hydroxide formed and the carbonate of the divalent metal.
• the NaOH formed in this way is used to adjust the pH.
• insoluble carbonates of the divalent metals can be generated in situ by reacting the corresponding oxides and / or hydroxides with soluble carbonates.
• at least one of the suspensions in particular a mixed suspension of the oxides or hydroxides of the divalent or trivalent metals, sodium bicarbonate and / or sodium carbonate is added as the carbonate source. This allows the pH of the suspension to be adjusted to the desired value.
• The- ser is preferably in the range of about 6 to 13.5.
• the amorphous hydrotalcite phase or the partially crystalline hydrotalcite phase can be subjected to a hydrothermal aftertreatment and / or thermal aging, whereupon the product obtained is separated from the suspension, dried and optionally calcined.
• the hydrothermal aftertreatment is generally carried out at a temperature of> 100 to 200 ° C. over a period of about 1 to 20 hours, this period being divided into a heating phase, a holding phase and a cooling phase.
• the individual phases depend on the size of the system.
• the hydrothermal aftertreatment increases the proportion of the crystalline hydrotalcite phase characterized by a sharp X-ray diffraction diagram, while the proportion of the amorphous hydrotalcite precursor phase decreases accordingly.
• a suspension (stillage) with a solids content of about 30 to 60% by weight is pumped from the raw materials through the grinding chamber of the mill used with a longer residence time.
• the grinding chamber was filled to a high degree (up to about 70%) with grinding media (A1 2 0 3 , Zr0 2 , glass balls).
• the temperature of the stillage is between about 20 and 100 ° C, the pH between about 7 and 14.
• the viscosity of the stillage increases in the course of the grinding process.
• a grain size of approximately 0.5 to 1 ⁇ m (D 50 value, ie 50% of the particles present have a smaller grain size than the specified grain size) is generally achieved.
• the energy introduced leads directly to the formation of a mixed phase from an X-ray amorphous and a crystalline hydrotalcite.
• the latter provides the crystallization nuclei in the optional further processing by means of a hydrothermal aftertreatment.
• this process step proceeds significantly better (higher crystallinity, higher yield, shorter synthesis time and better quality).
• the overall process can be optimized with regard to greater flexibility in the selection of raw materials (cheaper raw materials) and shorter synthesis times.
• an aging treatment in the temperature range from about 90 to 135 ° C. can also be carried out over a period of 0.1 to 10 hours.
• Another aspect of the present invention relates to the hydrotalcites obtainable by the process according to the invention, which, particularly when used as plastic additives, show unexpected advantages over known hydrotalcites.
• Fig. 1 is a process diagram of a first embodiment of the invention.
• Fig. 2 shows a process diagram of a second embodiment of the invention.
• a stillage is first produced from the raw materials (metal oxides, hydroxides, carbonates) and from soda or bicarbonate and water at a pH of 7 to 14, which at about 20 to 100 ° C. in an annular gap mill (FRYMA MS32) is processed.
• FRYMA MS32 annular gap mill
• either an amorphous hydrotalcite phase with a low proportion of crystalline hydrotalcite phase (left branch of the process scheme) or predominantly the crystalline hydrotalcite phase with a lower proportion of amorphous hydrotalcite phase (right branch of the process scheme) is obtained.
• No hydrothermal aftertreatment is carried out in the right branch, and the product is immediately isolated, dried and calcined.
• the amorphous hydrotalcite phase is subjected to a hydrothermal aftertreatment in the left branch, the low proportion of crystalline hydrotalcite phase germs supplies.
• the hydrothermal aftertreatment is generally carried out at temperatures in the range from about 100 to 200 ° C. and reaction times from about 1 to 20 hours.
• the product obtained is filtered, dried and optionally calcined.
• a sodium aluminate solution is first prepared from aluminum hydroxide and sodium hydroxide solution at elevated temperature (approx. 100 ° C.).
• Magnesium oxide is suspended in cold water (max. 20 ° C) in a separate container.
• the intensive grinding according to the invention then takes place as wet grinding.
• An at least partial conversion to magnesium hydride also takes place.
• carbon dioxide is added, whereby on the one hand the pH value can be lowered and the desired range between pH 9 and pH 11 can be adjusted. At the same time, the excess of carbon dioxide provides the carbonate required for the hydrotalcite intermediate layers.
• hydrotalcites obtainable by the process according to the invention can in particular be used either (a) as catalysts or catalyst supports or (b) as fillers and co-stabilizers for polymers.
• Particularly suitable for the first application (a) are the largely amorphous hydrotalcites, which are determined by high surfaces (approx. 60 to 80 m a / g) in accordance with BET (DIN 66132), a pronounced fine-particle structure and good deformation properties. Mark shafts.
• the products obtained in the hydrothermal aftertreatment are also suitable for this application if catalysts or catalyst supports with a smaller surface area and larger crystallites are desired.
• catalysts can be used for all reactions in which hydrotalcite catalysts have been used. Examples are the synthesis of glycol ethers from olefin oxides (US-A-5, 110, 992) and the epoxidation of olefins (US-A-5,260,495). Further reactions are in Chem. Commun. , 1998, pages 295 to 296.
• the hydrotalcites according to the invention can be coated with activation components, such as nickel and noble metals.
• the catalysts are suitable for hydrogenations, dehydrogenations, alkylations, etc.
• the crystalline hydrotalcites obtainable according to the invention are particularly well suited for use as fillers, since they can be produced completely white, which makes it possible to produce completely white or translucent polymeric composite materials. Furthermore, surprisingly, it was found that the hydrotalcites obtainable by the process according to the invention can be incorporated perfectly into plastics. However, depending on the requirements, the amorphous hydrotalcite precursor phase can also be used for this purpose.
• the composite materials are produced from the polymer matrix and the finely dispersed nanocomposite fillers by processes known per se. Generally, these methods include the following steps.
• Suitable polymers are e.g. Polyolefins, polyhalohydrocarbons (e.g. PVC), epoxies, polyesters, acrylates, methacrylates, polyurethanes, polyureas, polyamides, polycarbonates and rubber.
• High-shear dispersing units are high-speed agitators, colloid mills, kneaders, extruders and other dispersing units.
• the dispersion can take place at room temperature or at elevated temperature.
• the hydrotalcites according to the invention are also suitable as co-stabilizers for polymers, in particular for polyhalohydrocarbons and olefins. In the first case, they trap the HCl generated during the decomposition. In the latter case, they prevent the discoloration resulting from chain degradation caused by residues of the catalysts used in the production of the polyolefins.
• the invention is illustrated by the examples below.
• Example 1 Intensive grinding of the mixed suspension with the compounds of the divalent and trivalent metals
• a laser diffraction particle size analyzer from Malvern (Mastersizer) was used, with the aid of which the particle size distribution in the range from 0.05 to 900 ⁇ m can be determined.
• the device works on the principle of light diffraction on small particles.
• a sample of about 50 mg in a 20 ml beaker was mixed with about 10 ml of ethanol and 5 min. treated with an ultrasonic finger.
• the suspension was transferred to the dispersion unit of the device and ethanol was added until the correct concentration of the samples was set on the measuring device. At the end of the measurement, the results were both saved and printed out.
• test results (grain sizes D 50 and D 90 before the hydrothermal aftertreatment) are summarized in Table II.
• Example 2 Intensive grinding of the inactive raw material MgO
• the magnesium oxide suspension thus obtained was carried out via an agitator ball mill (bead mill; type: Drais PM-1 RL-V) under the following conditions: 1 passage; Flow: 125g / min; Degree of filling of the grinding chamber: 70% with Al 2 0 3 balls (diameter 1 to 1.5 mm); final washing with 1 liter of washing water; Power consumption of the mill: 0.8 kW; Power input: 2.7 kW / liter.
• an agitator ball mill bead mill; type: Drais PM-1 RL-V
• the mean particle size was about 0.7 ⁇ m (D 50 ).
• the suspension is heated, it is at least partially converted to Mg (OH) 2 .
• the solids content of the suspension is about 30%.
• the product so obtained can be filtered, washed and dried in a conventional manner, e.g. by spray drying.
• a conventional hydrothermal treatment can also follow.
• the X-ray diffractogram of this product shows a pure hydrotalcite phase.
• the grain size distributions (as stated above) and the specific surfaces (according to BET; DIN 66131) and the degree of crystallinity were expressed as the ratio between amorphous and crystalline hydrotalcite phase according to the X-ray diffraction method analogous to ASTM D 396/85.
• the degree of crystallinity K determined in this way is shown in Table III along with other properties of the products obtained.
• a solution of 406.6 g MgCl 2 '6 H 2 0 and 121.2 g A1C1 3 in 1 liter of water was prepared. This solution was subsequently pumped into the autoclave within 2 hours after the carbon dioxide metering.
• the hydrotalcite synthesis including the hydrothermal aftertreatment was carried out in accordance with Example 2, with the exception that no intensive grinding was carried out. Furthermore, a corresponding MgO was used as in Example 2, but with an average particle size of about 0.7 ⁇ m.
• Example 3 Use of the hydrotalcites produced as a plastic additive
• This dry blend is used for further tests after a rest period of 24 hours.
• 110 g of the dry blend and 0.73 g of the hydrotalcite are processed at 180 ° C for 5 minutes on a roller calender to a rolled skin.
• the front roller is operated at 15 rpm, the rear roller at 11 rpm.
• the distance between the rollers is set to 0.4 mm.
• 50 mg of the rolled skin obtained in this way are cut out and placed in a glass tube.
• a litmus paper is positioned at the top of the tube to detect the first traces of HCl that are split out of the PVC.
• the glass tube is stored in a thermoblock at 200 ° C. The time until the first appearance of HCl traces, recognizable by the red color of the indicator paper, is determined. The value is called the VDE value.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Dispersion Chemistry (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Catalysts (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=7681997

Family Applications (1)

Country Status (9)

Cited By (8)

Families Citing this family (32)

Citations (4)

Family Cites Families (30)

• 2001
  • 2001-04-19 DE DE10119233A patent/DE10119233A1/de not_active Ceased
• 2002
  • 2002-04-18 AT AT02737973T patent/ATE395305T1/de not_active IP Right Cessation
  • 2002-04-18 ES ES02737973T patent/ES2305254T3/es not_active Expired - Lifetime
  • 2002-04-18 CA CA002444574A patent/CA2444574A1/en not_active Abandoned
  • 2002-04-18 DE DE50212271T patent/DE50212271D1/de not_active Expired - Lifetime
  • 2002-04-18 PT PT02737973T patent/PT1381567E/pt unknown
  • 2002-04-18 WO PCT/EP2002/004352 patent/WO2002085787A1/de not_active Ceased
  • 2002-04-18 US US10/475,243 patent/US7211235B2/en not_active Expired - Lifetime
  • 2002-04-18 EP EP02737973.4A patent/EP1381567B2/de not_active Expired - Lifetime
  • 2002-04-18 JP JP2002583325A patent/JP4105954B2/ja not_active Expired - Lifetime
• 2007
  • 2007-04-30 US US11/741,847 patent/US7897136B2/en not_active Expired - Fee Related

Patent Citations (4)

Also Published As

Similar Documents

Legal Events