Classifications

• • 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
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/45—Phosphates containing plural metal, or metal and ammonium
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/51—Particles with a specific particle size distribution
  • C01P2004/52—Particles with a specific particle size distribution highly monodisperse size distribution
• • 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
  • C01P2006/80—Compositional purity
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]

Definitions

• the present invention relates to a process for the preparation of barium sulfate and lithium metal phosphates.
• Barium sulfate is used in particular for the production of photographic papers, paints and plastics and in medical diagnostics and in medical plastics.
• Barium sulphate is a high-quality, pure white inert, acid and alkali-resistant filler that is extremely weather-resistant.
• Barium sulfate with a high so-called “whiteness”, with a small specific surface area and low oil absorption coefficient and good dispersibility is called “Blanc Fixe” and serves as white pigment and filler.
• Blanc Fixe Particularly high-quality and fine-particle "Blanc Fixe” types are also used in particular in cosmetics and sunscreen creams (WO 01/92157) Further details on “Blanc Fixe” are, for example, by J. Hocken in Euro Coat, Lyon 9/97 pages 1 to 14 discussed.
• Blanc Fixe types with an average particle size of 0.5 to 1 ⁇ m and a narrow grain band, ie in particular with a monomodal len particle size distribution have maximum light scattering effect and are therefore particularly well suited as white pigment or replacement material for titanium white. (Machunsky, E. Winkler, J., Polymers Paint Color Journal (1990) 180, 350-354).
• Blanc Fixe is usually produced industrially from the reaction of sodium hydroxide solution and sulfuric acid or sodium sulfate solutions with aqueous solutions of barium chloride or barium sulfide.
• the particle morphology is adjusted by adjusting the reaction conditions such as temperature, concentration, pH, mixing and stirring rates, addition of seed crystals or organic additives.
• organic additives have recently been used to improve the particle morphology of barium sulfate (WO 01/58809).
• barium sulfate can also be prepared from dissolved barium hydroxide with sulfuric acid, which, in addition to high raw material costs, is not economically very attractive, not least because of the poor solubility of barium hydroxide.
• Lithium metal phosphate compounds in particular lithium transition metal phosphate compounds, have recently found widespread use as cathode and anode materials in batteries (US Pat. No. 5,910,382, WO 02/099913).
• wet-chemical methods for the preparation of such compounds are also used, as they are exemplified in DE-10353266 or in WO02 / 083555.
• the particle morphology of the lithium transition metal phosphate produced can be controlled particularly advantageously.
• Lithium hydroxide is often used as raw material in these processes, which is brought together in one of the synthesis steps with an acidic solution containing phosphoric acid and at least one transition metal sulfate.
• the barium sulfate thus obtained has the particle size distribution required for "blanc fixe” and a low specific surface area, without having to resort to crystallization aids, such as seed crystals, or the addition of organic additives.
• crystallization aids such as seed crystals, or the addition of organic additives.
• the precipitated barium sulfate can be used economically as a white pigment.
• the solid precipitate is separated off from the mother liquor, for example by filtration or centrifugation or other suitable methods, and optionally washed to give a concentrated lithium hydroxide solution as the mother liquor, which can then be reused in the subsequent wet-chemical synthesis of lithium transition metal phosphates.
• the addition of solid barium hydroxide has the advantage over the barium hydroxide solutions used in the prior art that the lithium hydroxide solution obtained by the precipitation of the barium sulfate is not unnecessarily diluted, so that usually no additional energy-intensive concentration of the lithium hydroxide solution before its reuse is necessary.
• the dilute washing solution which is optionally obtained in the process according to the invention when washing the separated barium sulfate, is free of interfering foreign ions and can be used, for example.
• B. also be added to the mother liquor after an additional concentration step again.
• the barium sulfate obtained in the process according to the invention is very phase pure and almost free of interfering iron ions, which cause a yellowing and can be used directly as a "blanc fixe" quality.
• the addition of the solid barium hydroxide is carried out at a temperature of more than 50 ° C., more preferably above 75-80 ° C. Below 50 ° C., particle morphologies and particle distributions of the barium obtained sulphates, which allow use as "Blanc Fixe".
• barium hydroxide be completed in less than 15 minutes, preferably less than 5 minutes, more preferably within one minute for the precipitation to be rapid, which also positively affects the desired particle morphology.
• the mixture is stirred to prevent sedimentation of the barium hydroxide or precipitate used.
• the barium sulfate obtainable by the process according to the invention has a very high whiteness of greater than 95, preferably greater than 97 and particularly preferably greater than 99, and a low specific surface area of less than 15 m 2 / g, very particularly preferably less than 10 m 2 / G.
• the barium sulfate obtained is alkali-free and also free of chloride and sulfide, so that the purity of the barium sulfate obtained by the process according to the invention is particularly high.
• the barium sulfate obtained has a particle size in the range of 0.5 to 1 .mu.m, wherein the particle distribution is particularly preferably monomodal and the D 50 value preferably between 0.4-0.8 microns, most preferably at 0.6 microns.
• the solution containing lithium hydroxide is again fed to a wet-chemical production process of lithium iron phosphate, as described, for example, in US Pat. in DE 10353266 or in WO02 / 083555.
• lithium iron phosphate any other lithium transition metal phosphate can be prepared as well.
• Preferred transition metals in addition to iron, which are preferably used in the form of their sulfates are Mn, Co, Ni, and V and any combinations thereof. Particularly preferred combinations are those of Fe and Mn, or Co.
• the process according to the invention optionally also comprises a pretreatment of the wastewater containing lithium sulfate prior to the precipitation of barium sulfate.
• the wastewater is brought by the addition of lithium hydroxide to a pH between 8 and 2, preferably between 7 and 4, in order to reduce the phosphate content by precipitation of lithium phosphate and to precipitate any foreign metal ions as hydroxides.
• the precipitate is separated from the lithium sulfate-containing mother liquor, for example by filtration, centrifugation or other methods which appear to be suitable for a person skilled in the art.
• the basic adjusted mother liquor can also be fed to a concentration by reverse osmosis.
• the separated precipitate is disposed of in a suitable manner or, in the case of lithium phosphate, used again as a raw material for the preparation of, for example, lithium transition metal phosphates.
• it is preferably reacted by acidification, preferably with phosphoric acid, to give readily soluble lithium hydrogenphosphate.
• the residual content of sulfate ions or barium ions of the lithium hydroxide solution obtained in the barium sulfate precipitation is determined by the stoichiometric ratio of the barium hydroxide used to the lithium sulfate contained in the solution and by the completeness of the precipitation reaction. This requires close control of the levels and amounts of reactants used. Since barium hydroxide can occur in the form of different hydrates with varying water content and, depending on the aging state, with varying carbonate content, the process according to the invention also provides a simple operator-feasible procedure for direct control of the precipitation result.
• a sample of the suspension is removed from the reaction vessel and filtered off on a microfiltration membrane in a paint chute.
• the filtrate is neutralized with hydrochloric acid and distributed on two test tubes A and B.
• To test tube A a few drops of a saturated barium chloride solution are added, while to test tube B, a few drops of a saturated solution of lithium sulfate are added. If test tube A shows strong debris tion, there is a high residual content of sulfate and it must be corrected by adding more barium hydroxide to the reaction vessel. If test tube B shows severe turbidity, then there is a high residual content of barium and it must be corrected by adding further lithium sulfate solution.
• the procedure may be repeated iteratively until both tubes show no or only slight turbidity, and a lithium hydroxide solution of good purity is present. As a rule, a low barium content will be preferred and more likely to accept a slight turbidity in test tube A.
• test procedure can also be used to check the completeness of the precipitation reaction.
• the filter cake is removed from the filter and stirred in demineralized water and stirred for at least 10 min further.
• This suspension is again filtered off in the previously cleaned filter and the filtrate examined as above. If test tube B shows turbidity, the suspension contains unreacted solid barium hydroxide and the mixture in the reaction vessel must be stirred further.
• lithium hydroxide containing mother liquor in a process for the preparation of lithium transition metal phosphates for example according to DE-10353266 or WO02 / 083555 be used by contacting with an acidic solution containing phosphoric acid and at least one Transition metal sulfate is mixed.
• the process according to the invention thus provides a cyclic process which at the same time permits the production of pure phase barium sulphate and of lithium transition metal phosphates, so that a closed sewage system or a waste water cycle is obtained, which is particularly extensive. friendly and economically efficient.
• Figure Ia a SEM image of barium sulfate particles which have been precipitated at 40 0 C
• Figure 2a a SEM image of the precipitated at a temperature of 80 0 C barium sulfate
• Figure 2b a diagram of the particle size distribution of the product
• a lithium sulfate-containing wastewater from a wet-chemical production process for lithium iron phosphate according to DE 10353266 is adjusted to pH 10 by addition of lithium hydroxide, filtered off on a paper filter, acidified to pH 5 with sulfuric acid and evaporated in a laboratory flask to a concentration of 148 g / l lithium sulfate.
• the X-ray diffraction spectrum of the filtered precipitate shows lithium phosphate.
• 105 ml of the concentrated lithium sulfate solution are stirred in a 200 ml beaker on a magnetic stirrer with the heating plate not activated. It will be 26.78g finely powdered technical barium hydroxide monohydrate added within 10 sec.
• the result is a white suspension whose viscosity initially rises rapidly and then falls slowly again.
• the suspension is further stirred for 20 minutes and filtered off on a paper filter.
• the filtrate is separated and the filter cake washed with demineralized water to a conductivity of less than 150 ⁇ S / cm.
• the particle size distribution of the still wet filter cake is measured in a Malvern Mastersizer in ethanol with ultrasonic fingers.
• the filter cake is at
• test tube A shows a slight haze and test tube B no haze.
• composition of the obtained lithium hydroxide solution determined by ICP analysis was:

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 2007
  • 2007-07-18 DE DE102007033460A patent/DE102007033460A1/de not_active Withdrawn
• 2008
  • 2008-07-14 JP JP2010516412A patent/JP5246890B2/ja not_active Expired - Fee Related
  • 2008-07-14 US US12/668,562 patent/US8420215B2/en not_active Expired - Fee Related
  • 2008-07-14 CN CN200880025029.8A patent/CN101754932B/zh not_active Expired - Fee Related
  • 2008-07-14 KR KR1020107003223A patent/KR20100074105A/ko active IP Right Grant
  • 2008-07-14 WO PCT/EP2008/005738 patent/WO2009010263A2/de active Application Filing
  • 2008-07-14 CA CA2693607A patent/CA2693607A1/en not_active Abandoned
  • 2008-07-14 EP EP08773988A patent/EP2173661A2/de not_active Withdrawn
  • 2008-07-18 TW TW097127281A patent/TW200909347A/zh unknown
• 2010
  • 2010-07-29 HK HK10107272.2A patent/HK1140747A1/xx not_active IP Right Cessation

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