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
  • C01F7/00—Compounds of aluminium
  • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
  • C01F7/44—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water
  • C01F7/447—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water by wet processes
  • C01F7/448—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water by wet processes using superatmospheric pressure, e.g. hydrothermal conversion of gibbsite into boehmite
• • 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
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
  • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
• • 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

Definitions

• This invention relates to a process for manufacturing of Boehmite particulate material from aluminum hydroxide recovered from waste containing Aluminium chloride, Aluminium sulfate, Aluminium carbide or any other Aluminium salt etc.
• this invention relates to a process for manufacturing of Boehmite particulate material from aluminum hydroxide recovered from waste containing Aluminium chloride.
• This invention also relates to Boehmite particulate material comprising 80 to 84 % of Boehmite, 3 to 10 % silica and 3 to 10 % silane; for use as flatting agent.
• Various fillers or additives are used to enhance the properties of Paints, Plastic, Papers, Rubbers, Polymers, or other similar materials.
• One of such additives is a flatting agent which is also called as matting agent /additive. It is conventionally incorporated into paint systems in order to produce a coating with a reduced gloss level.
• the. final appearance of the coating can range from satin to matt finish. Low gloss or matt surfaces are sought after for their anti-glare properties, visual appearance or simply to meet fashion requirements.
• Many of the mineral fillers and pigments used as flatting agents also find utility in plastic film applications as anti-block agents.
• Flatting agents includes but not limited to silica, waxes or filler pigments which once added to paint create a micro-rough surface after the coating has dried. It is this rough surface that scatters incoming light to produce the desired matt effect.
• Boehmite is one such filler pigments used as flatting agent.
• CA 2,323,289 (Equivalent: US 6,413,308) discloses the use of Boehmite as a flatting agent and the process for the preparation of Boehmite.
• Boehmite is an aluminium oxide hydroxide ( ⁇ - ⁇ ( ⁇ )) mineral, a component of aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit. It is white with tints of yellow, green, brown or red due to impurities. It has a vitreous to pearly luster, a Mohs hardness of 3 to 3.5 and a specific gravity of 3.00 to 3.07.
• US 4, 1 17, 105 discloses the method for the preparation of dispersible, colloidal sized particles of Boehmite alumina (alpha-alumina monohydrate).
• Alumina trihydrate is calcined for the partial dehydration and further mixed with water to form slurry.
• the slurry is autoclaved to crystallize and rehydrate the alumina followed by spray drying or tray drying for dewatering the aqueous slurry.
• Amorphous aluminum hydroxycarbonate is prepared by carbonating an alkali metal aluminate and further admixed with carbon dioxide.
• the precipitated product is then filtered and washed with a solution of an acid, a base, a salt, or mixture thereof, with the pH of the resulting reaction medium being maintained at a value of less than 1 1.
• the reaction medium is heated at a temperature of less than 90°C and subsequently the medium is heated at a temperature ranging from 90°C to 250°C.
• GB 1 ,328,052 discloses the method for producing Colloidal fibrous Boehmite.
• the active aluminium oxide having a residual water content of 2 to 15 % is obtained by the incomplete dehydration of hydrated alumina, by reacting in an aqueous slurry with a monobasic organic acid to give the corresponding basic Al salt which is subsequently subjected to hydrothermal treatment at 120°C to 200°C and 2 to 15 atmospheres in an aqueous suspension have a concentration equivalent to 2 to 20 % by weight of A1 2 0 3 until a colloidal fibrous Boehmite solution has been formed.
• the active aluminium oxide is also obtained by rapid dehydration of the hydrated alumina in a turbulent stream of gas at 400°C to 800°C. Further, it may be converted by heating with the organic acid on the boil until constant viscosity is reached.
• EP 1 ,888,463 discloses a method for preparing Boehmite and [gammaj-alumina with high surface area. This method comprised of the steps of hydrolysis of aluminum alkoxides to produce Boehmite which is further calcined to produce [gammaj-alumina. In this method, an alcohol is used as a reaction solvent with a small amount of water.
• KR 101 178397 discloses a low soda Boehmite having average particle size of 0.5 to 50 ⁇ , soda (Na 2 G) content of 0.12 wt. % or less, and a specific surface area (BET) of 1 to 5 m 2 /g. It discloses hydrothermal synthesis in which oxalic acid is added in Aluminium hydroxide aqueous solution to control the pH as 3.0 to 8.0. This solution is processed for hydrothermal synthesis reaction to obtain Boehmite.
• US 2007148083 and US 200803 1808 disclose a method of forming Boehmite particulate material.
• the method comprised of hydrothermal treatment of the aqueous suspension of Boehmite precursor and Boehmite seeds.
• EP 0,278,469 discloses a process for preparing Boehmite.
• the ground aluminium trihydroxide in water is digested at elevated temperatures and pressure in the presence of mineral acid.
• the Aluminium hydroxide particles are first heated at a temperature of at least 300°C so as to embed Boehmite into a matrix of chi-aluminate.
• the Boehmite product is then separated by dissolving the chi-aluminate to obtain Boehmite particles of a specific surface area.
• CN 101920978 discloses a method for producing Boehmite by using washing liquor from the production of washing red mud by alumina. This method used washing liquor obtained from the production of the washing red mud.
• the red mud and lime is added to desilicication tank.
• the desilicication is carried out till desilicication index is more than or equal to 400.
• the precipitated product is filtered and transferred to a diluting tank for cooling and is subjected to carbonation gelatinizing by using 20 to 60 volume percent C0 2 gas obtained by concentrating and enriching C0 2 waste gas generated in the production of alumina as a precipitator.
• the gelatinized slurry is heated to 70°C to 100°C and kept aging.
• the aged slurry is filtered and dried to obtain powdery Boehmite.
• US 2010040536 discloses a method for producing Boehmite particles where powder of aluminum hydroxide is subjected to hydrothermal reaction in presence of a nucleation agent, metal salt or sol. of metal oxide, at a pH 8 or lower.
• US 5,306,680 discloses a process for preparing fine Boehmite particles.
• the aluminum hydroxide or hydrated alumina having a particle size of the order of submicron is subjected to hydrothermal treatment in essentially pure water or a solution consisting essentially of an aqueous caustic soda solution or an aqueous sodium carbonate solution at a temperature from 150°C to 350°C and at pressure between 10 to 100 atm.
• CN 102139204 discloses a method for the preparation of pseudo-Boehmite containing amorphous silica alumina.
• Pseudo-Boehmite containing the amorphous silica alumina is obtained according to the conventional ageing, filtering and washing methods after amorphous silica alumina slurry and pseudo-Boehmite slurry are mixed.
• Pseudo-Boehmite contains 5 to 40 wt.
• Pseudo- Boehmite containing the amorphous silica alumina is mainly applied to hydrogenation treatment, particularly preparation of an intermediate distillate hydrogenation catalyst carrier. This material may not be suitable for Flatting agent. This reported process consumes high energy and thereby makes the process costly.
• R 20080044307 discloses a method for producing high porosity Boehmite alumina.
• an aqueous Boehmite slurry is mixed with an effective amount of a modifier comprising a hydroxide or oxide of an element of group IIIA-VIA on the Periodic Table of Elements and having a p sp of greater than 1 1 to produce a precursor mixture and hydrothermally aging the precursor mixture at an elevated temperature under agitation with an effective consumptive power of greater than 1 kW/m 3 .
• a modifier comprising a hydroxide or oxide of an element of group IIIA-VIA on the Periodic Table of Elements and having a p sp of greater than 1 1
• IP 2007223836 discloses a method for producing Boehmite with a new shape suitable for use as filler for a resin or the like without adding elements such as calcium, barium, strontium or cerium, and to provide Boehmite.
• This Boehmite contains ⁇ 100 ppm for each of calcium content, barium content, strontium content and cerium content.
• Boehmite particles have been known and examples of such processes as described above include one which comprises conducting pyrolysis of aluminum hydroxide as a starting material in the atmosphere to remove part of the water of crystallization, thereby forming a Boehmite phase, and one which comprises conducting hydrothermal treatment of aluminum hydroxide in a hermetically sealed vessel to form a Boehmite phase.
• Boehmite particles prepared by some of above processes can be finely ground mechanically by the use of, e.g., a ball mill, into fine particles having a size of the order of submicron, these processes are problematic in that obtained particles tend to become globular and fine flaky particles are difficult to obtain.
• the pyrolysis process has another problem in that when aluminum hydroxide to be used as the starting material is contaminated with fine particles, no Boehmite phase is formed, but chi- alumina (.chi.-Al 2 03), which is a transitional alumina, is formed to lower the yield of Boehmite particles.
• the hydrothermal treatment process has another problem in that the formed Boehmite particles are in the form of a tight aggregate of rhombic prisms and cannot form fine flaky particles, even when they are finely ground.
• CPC Green and CPC Blue Copper Phthalo Cyanine Green and Blue
• the raw materials for CPC Green Plant are Aluminium chloride, cupric chloride, crude CPC Blue, chlorine, caustic soda.
• This mother liquor of the CPC Green mainly contains Aluminium chloride, Copper etc. and is treated with sodium sulphide to get copper as Copper sulphide.
• the resultant clear mother liquor which is free from copper and other impurities is neutralized with soda ash solution to get Aluminium hydroxide slurry. This slurry is filtered in filer press, washed and dried to get Aluminium hydroxide powder.
• An object of the invention is to provide a process for manufacturing of Boehmite particulate material from aluminum hydroxide; which is recovered from mother liquor of CPC Green; which contains Aluminium chloride, Aluminium sulfate, Aluminium carbide or any other Aluminium salt etc; thereby making the process cost-effective.
• Another object of the invention is to provide a process for manufacturing of Boehmite particulate material wherein the process eliminates agglomeration thereby eliminating milling process for conversion into fine particles and hence reduces duration as well as cost of the manufacturing process.
• Yet another object of the invention is to provide Boehmite particulate material containing 80 to 84 wt. % Boehmite embedded in 3 to 10 wt. % silica treated with 3 to 10 wt. % silane.
• Still another object of the invention is to provide Boehmite particulate material having particle size in the range of 5 to 8 micron and may be used as flatting / matting agent.
• Figure 1 illustrates an XRD pattern of Boehmite particulate material prepared according to Example 1.
• Embodiments of the invention are not mutually exclusive, but may be implemented in various combinations.
• the described embodiments of the invention and the disclosed examples are given for the purpose of illustration rather than limiting of the scope of invention. Further the terms disclosed in the embodiments are merely exemplary methods of the invention, which may be embodied in various forms.
• the mother liquor is separated from the plant of manufacturing of CPC Green.
• This mother liquor of the CPC Green mainly contains Aluminium chloride, Copper etc. and is treated with sodium sulphide to get copper as Copper sulphide, which is separated out.
• the resultant clear mother liquor, which is free from copper and other impurities; is neutralized with soda ash solution to get Aluminium hydroxide slurry.
• This slurry is filtered in filer press, washed and dried to get Aluminium hydroxide. Aluminium hydroxide thus obtained is used in the present invention.
• Aluminium hydroxide is recovered from the waste containing Aluminium chloride, Aluminium sulfate, Aluminium carbide or any other Aluminium salt by hydrolyzing the waste with soda ash;
• step (b) preparing slurry containing 2 to 10 wt. % of silane and 2 to 10 wt. % of silica by making 2 to 10 wt. % of aqueous slurry of silane with stirring followed by adding 2 to 10 wt. % of micro fine precipitated silica powder having average particle size of 3 ⁇ and stirring the slurry over night at low speed; c. mixing slurry obtained in step (a) into step (b) followed by subjecting the reaction mixture to hydrothermal treatment at temperature in the range of 90°C to 250°C for at least 4 hours; and
• step (c) collecting Boehmite particulate material obtained in step (c) by either centrifuging or filter pressing the reaction mixture or any other conventional means followed by drying the product by either spray drying or spin flash drying or any other conventional means and optionally pulverizing to get fine flaky particles with particle size 5 to 8 micron.
• step (a) comprises recovering Aluminium hydroxide from the waste, a mother liquor containing Aluminium chloride by hydrolyzing the waste with soda ash followed by filtering the product by filter press followed by spray drying to obtain Aluminium hydroxide.
• step (a) comprises preparing 4 wt. % of aqueous slurry of Aluminium hydroxide powder by adding Aluminium hydroxide in water with stirring for 30 minutes.
• step (b) 3 to 10 wt. % of silane is added in water followed by stirring the slurry for at least 30 minutes followed by adding 3 to 10 % of micro fine precipitated silica powder having average particle size of 3 ⁇ and stirring the slurry for at least for 4 to 16 hours, preferably 12 hours at 30 rpm speed.
• silane used in the step (b) is selected from dimethyl silane, vinyl silane, polyvinyl silane, etc.
• step (b) More preferably, vinyl silane is used in step (b).
• step (c) of hydrothermal treatment is carried out at temperature of 130°C for at least 4 hours.
• waste used in the present invention is a mother liquor of CPC Green containing Aluminium chloride.
• the resultant Boehmite particulate material has fine flaky particles with preferred particles size of 5 to 8 micron measured by using laser diffraction method.
• Boehmite particulate material having 80 to 84 wt. % of Boehmite along with base material as micro fine precipitated silica powder (8 to 10 wt. %) treated with silane (8 to 10 wt. %); said particulate material have particle size in the range of 5 to 8 micron.
• the polymrophic crystals of Boehmite particulate material are studied by the x-ray diffraction.
• Boehmite particulate material The XRD pattern of Boehmite particulate material is illustrated in Figure 1, which demonstrates crystalline nature of Boehmite particulate material and having characteristic peaks at 14.475, 14.051 , 49.224, 28.209 and 5.863 Angle, 2-Theta° which confirms the formation of Psuedo-Boehmite
• Boehmite particulate matter of the invention having 80 to 84 wt. % of Boehmite along with base material as micro fine precipitated silica powder (8 to 10 wt. %) treated with silane (8 to 10 wt. %) with preferred particles size 5 to 8 micron having characteristic peaks of XRD at 14.475, 14.051 , 49.224, 28.209 and 5.863 Angle, 2-Theta°.
• the Boehmite particulate material prepared according to the invention was analyzed for their performance as flatting agent in the coating.
• Acrylic PU resin is selected for study and compared with standard Evonic silica OK 412 as a flatting agent.
• Boehmite particulate material prepared according to the invention is added in Acrylic PU resin with stirring at 1200 RPM.
• the samples were tested for gloss with Glossometer (BYK Gardner GmBH) vis-a-vis with standard flatting agent Evonic Silica OK 412.
• the comparative results showed excellent gloss reduction when we have batch containing Boehmite particulate material of the invention as compared to the standard thus very good matting effect is observed vis-a-vis standard.
• a coating composition comprising 3 to 5 % of Boehmite particulate material prepared according to the invention; having matting affect.
• the process for manufacturing of Boehmite particulate material is very cost-effective as starting material, aluminum hydroxide, used in the present invention is recovered from mother liquor of CPC Green or any other liquor containing Aluminium chloride, Aluminium sulfate, Aluminium carbide or any other Aluminium salt.
• silane eliminates agglomeration and hence, eliminating milling process used for conversion of agglomerates into fine particles and hence reduces duration as well as cost of the manufacturing process.
• Example 1 Boehmite comprising 80 wt. % of Boehmite, 10 t. % silane and 10 wt. % silica
• Boehmite particulate material confirms its crystalline nature i.e.Pseudo Boehmite Loss on drying ⁇ 1 %
• Example 2 Boehmite comprising 84 wt. % of Boehmite, 8 wt. % silane and 8 wt. % silica
• Boehmite particulate material confirms its crystalline nature i.e. Pseudo Boehmite. Loss on drying ⁇ 1 %.
• Example 3 Boehmite comprising 90 wt. % of Boehmite, 5 wt.% silane and 5 wt. % silica
• Boehmite particulate material confirms its crystalline nature i.e.Pseudo Boehmite. Loss on drying ⁇ 1 %.
• Example 4 Boehmite comprising 94 wt. % of Boehmite, 3 wt. % silane and 3 wt. % silica
• Boehmite particulate material confirms its crystalline nature i.e.Pseudo Boehmite. Loss on drying ⁇ 1 %.
• Example 5 Boehmite comprising 96 wt. % of Boehmite, 2 wt. % silane and 2 wt. % silica
• Boehmite particulate material confirms its crystalline nature i.e.Pseudo Boehmite. Loss on drying ⁇ 1 %.
• Boehmite particulate material prepared according to examples 1 to 5, were loaded in 10 gm of two component Acrylic PU resin and apply stirring in disperse mat at 1800 to 2000 rpm for 10 min. 2 gm curing agent was added and centrifuged at 3000 rpm for 1 min and the composition was applied on pre-treated wood surface with 150 micron film thickness and measure gloss on glossometer. The same experiment was repeated with standard Evonic silica OK 412 as a flatting agent. The gloss was measured by using Glossometer for the standard as well as Boehmite particulate material of the invention and comparative results are showed in Table 1. Table l : Comparative Results of Gloss
• Acrylic PU resin Acrylic PU resin
• Boehmite comprising 90 wt.
• Boehmite comprising 96 wt.
• the Boehmite particulate material prepared according to example 1 showed improved results at 3 % and 5% as compared to the Boehmite particulate material prepared according to examples 2 to 5.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Inorganic Chemistry (AREA)
• Processing Of Solid Wastes (AREA)
• Silicon Compounds (AREA)
• Glanulating (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 2014
  • 2014-04-22 IN IN1494MU2013 patent/IN2013MU01494A/en unknown
  • 2014-04-22 WO PCT/IN2014/000260 patent/WO2014181346A2/en not_active Ceased

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