IL40909A - Process for making magnesia - Google Patents

Process for making magnesia

Info

Publication number
IL40909A
IL40909A IL40909A IL4090972A IL40909A IL 40909 A IL40909 A IL 40909A IL 40909 A IL40909 A IL 40909A IL 4090972 A IL4090972 A IL 4090972A IL 40909 A IL40909 A IL 40909A
Authority
IL
Israel
Prior art keywords
cake
magnesium hydroxide
sludge
pressure
compacting
Prior art date
Application number
IL40909A
Other versions
IL40909A0 (en
Original Assignee
Steetley Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Steetley Ltd filed Critical Steetley Ltd
Publication of IL40909A0 publication Critical patent/IL40909A0/en
Publication of IL40909A publication Critical patent/IL40909A/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/42Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on chromites
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01FCOMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00Compounds of magnesium
    • C01F5/02Magnesia
    • C01F5/06Magnesia by thermal decomposition of magnesium compounds
    • C01F5/08Magnesia by thermal decomposition of magnesium compounds by calcining magnesium hydroxide
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/03Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/12Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on chromium oxide
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/44Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminates
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00Physical properties of inorganic compounds
    • C01P2006/10Solid density

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Treatment Of Sludge (AREA)

Claims (13)

1. CLAIMS, 1. A process for making magnesia wherein a sludge of magnesium hydroxide is simultaneously dewatered and compacted to give a cake of magnesium hydroxide containing at least 67.5% by weight of solids and having a green bulk density of at least 1.15 grams/cc and wherein the cake thereby obtained is converted by a suitable heat treatment into magnesium oxide.
2. A process as "claimed in claim 1 wherein the sludge of magnesium hydroxide contains from 150 grammes to JJOO grammes of magnesium hydroxide per litre.
3. A process as claimed in claim 1 or claim 2 wherein the. cake of magnesium hydroxide has a green bulk density greater than 1.20 grams/cc.
4. A process .as claimed in any one of the preceding claims wherein the magnesium hydroxide has been obtained by, (i) treating a solution containing magnesium ions, for example, brines, sea water and the like, with alkali and separating the precipitate of magnesium hydroxide, for example, by settling; (ii) treating minerals containing magnesium with acid, such as hydrochloric acid, and precipitating magnesium hydroxide from the solution which results from such treatment; or · (iii) thermal decomposition of■ magnesium chloride to magnesium oxide and subsequent conversion of the oxide to the hydroxide.
5. process as claimed in any one of the preceding claims wherein the operation- of simultaneously dewatering and compacting the magnesium hydroxide sludge involves the application of pressures greater than 00 pounds per square inch.
6. A process as' claimed in claim 5 wherein the pressure is in the range from 400 to 10,000 pounds per square inch. ' »
7. A process as claimed in claim 6 wherein the pressure is in the range from 750 to 7,500 pounds per. square inch.
8. A process as claimed in any one of the preceding claims wherein dewatering and compacting are effected by feeding the magnesium hydroxide sludge to a filter and applying pressure thereto.
9. · A process as claimed in claim 8 wherein the filter comprises a cylindrical filter cloth around a hollow cylindrical supporting perforated core, pressure being applied hydraulically to the material being filtered usually via a flexible sleeve which surrounds it.
10. . A process as claimed in claim 8 or claim 9 wherein the filtration is effected in two stages, a first stage at relatively low pressure and second stage at relatively high pressure.
11. . A process as- claimed in -claim 10 wherein the. first stage of the filtration is effected at a pressure of from ^tOO to 1000 psi and the second stage is effected at a pressure greater than 1000 psi, after' addition of a further quantity of sludge to the filter cake obtained in the first stage.
12. . A process as claimed in any one of claims 1 to 7 wherein dewatering and compacting are effected by feeding the sludge to a perforated mould lined with a filter cloth and applying pressure to the sludge via a piston adapted to slide within the mould.
13. . A process as claimed in any one of the preceding claims wherein dewatering and compacting are carried out at a temperature above ambient. Ik. A process as claimed in any one of claims 1 to 12 wherein dewatering and compacting are- carried out at a temperature in the range 25°C to 100°C. 15 · A process as claimed in any one of the preceding claims wherein the sludge incorporates a surface active agent. if 1β . A process as. claimed in any one of the preceding claims wherein the heat treatment comprises calcining the magnesium hydroxide cake to a maximum temperature of about 1200°C to yield ah active or caustic magnesia. 17. A process as claimed in claim 16 wherein the cake is calcined to a temperature of about 1000°C. 18. A process as claimed in any one of claims 1 to 15 wherein the heat treatment comprises dead burning the magnesium hydroxide cake by heating to a temperature above l600°C. 19. A process as claimed in claim 18 wherein the cake is dead burnt by heating to a temperature · up to 2000°C. 20. A process as claimed in claim 18 or claim 19 wherein dead burning is carried out in a rotary kiln. 21. A process as claimed in any one of claims 18 to 20 wherein the cake is pelletized prior to dead burning. 22. A process as claimed in claim 21 wherein the cake to be pelletized has been dewatered and compacted to a solids content of at least by weight . 23. A process as claimed in claim 22 wherein the cake has been dewatered and compacted to a solids content of from 80 to 95$ by weight. 24. A process as claimed in claim 22 or claim 23 wherein dewatering and compacting have been carried out at a pressure greater than 2,000 pounds per square inch . 25.. A process as claimed in claim 22 or claim 23 wherein dewatering and compacting have been carried out at a pressure between 400 and 2000 pounds per square inch and the cake has subsequently been partially dried. 26. A process as claimed in claim 25 wherein partial drying is effected to a water content of from 5 to 20$ by weight. 27.. A process as claimed in any one of claims 21 to 26 wherein the cake is broken down into granules before pelletization . 28. A process as claimed in any one of the preceding claims wherein there is mixed with the sludge of magnesium hydroxide a finely divided refractory compound or a precursor therefor. 29. A process as claimed in claim 28 wherein the refractory compound is selected from lime-bearing materials, chrome-bearing materials, zircon, zirconia and zirconium salts, silica, iron oxide (Fe^ O^) and alumina . 30. A process as. claimed in claim 28 wherein finely divided chrome ore, known as chrome flour, is mixed with the sludge of magnesium hydroxide and chrome ore of comparatively large particle size is mixed with the filter cake. 31. A process for making magnesia as claimed in claim 1 and substantially as hereinbefore described in any one of Examples 1 to 7· 32. Caustic magnesia whenever produced by the process as claimed in claim 16 or claim 17. 33. Dead burned magnesia whenever produced by the process as claimed in any one of claims 1 to 15 and 18 to 31. 3k . Refractory aggregates and refractory shapes, fo example, bricks and blocks, when made from dead burned magnesia as claimed in claim 33. 35· A furnace wall or lining whenever constructed wholly or partly from refractory shapes as claimed in claim >k .
IL40909A 1971-12-01 1972-11-23 Process for making magnesia IL40909A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB5582071 1971-12-01
GB1548272*[A GB1407199A (en) 1971-12-01 1972-04-04 Process for making magnesia

Publications (2)

Publication Number Publication Date
IL40909A0 IL40909A0 (en) 1973-01-30
IL40909A true IL40909A (en) 1976-01-30

Family

ID=26251324

Family Applications (1)

Application Number Title Priority Date Filing Date
IL40909A IL40909A (en) 1971-12-01 1972-11-23 Process for making magnesia

Country Status (15)

Country Link
JP (1) JPS5318000B2 (en)
AT (1) AT342486B (en)
BG (1) BG25661A3 (en)
CA (1) CA973685A (en)
ES (1) ES409157A1 (en)
FI (1) FI57392C (en)
FR (1) FR2162117B1 (en)
GB (1) GB1407199A (en)
IE (1) IE37428B1 (en)
IL (1) IL40909A (en)
IT (1) IT975906B (en)
NL (1) NL7216384A (en)
NO (1) NO133491C (en)
RO (1) RO62603A (en)
YU (2) YU298172A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5919275U (en) * 1982-07-27 1984-02-06 ヨコタ工業株式会社 C type ring clincher

Also Published As

Publication number Publication date
GB1407199A (en) 1975-09-24
IT975906B (en) 1974-08-10
JPS5318000B2 (en) 1978-06-12
CA973685A (en) 1975-09-02
YU39016B (en) 1984-02-29
FI57392C (en) 1980-08-11
NO133491C (en) 1976-05-12
BG25661A3 (en) 1978-11-10
AT342486B (en) 1978-04-10
FR2162117B1 (en) 1976-06-04
JPS4865197A (en) 1973-09-08
NL7216384A (en) 1973-06-05
NO133491B (en) 1976-02-02
IE37428B1 (en) 1977-07-20
FI57392B (en) 1980-04-30
ATA1021372A (en) 1977-07-15
IL40909A0 (en) 1973-01-30
ES409157A1 (en) 1975-11-16
YU298172A (en) 1982-02-28
RO62603A (en) 1978-05-15
IE37428L (en) 1973-06-01
FR2162117A1 (en) 1973-07-13

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