EP0165945A4 - Procede pour ameliorer la purete d'hydroxydes de metal alcalin. - Google Patents

Procede pour ameliorer la purete d'hydroxydes de metal alcalin.

Info

Publication number
EP0165945A4
EP0165945A4 EP19850900029 EP85900029A EP0165945A4 EP 0165945 A4 EP0165945 A4 EP 0165945A4 EP 19850900029 EP19850900029 EP 19850900029 EP 85900029 A EP85900029 A EP 85900029A EP 0165945 A4 EP0165945 A4 EP 0165945A4
Authority
EP
European Patent Office
Prior art keywords
alkali
metal
alkaline
compounds
contaminants
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP19850900029
Other languages
German (de)
English (en)
Other versions
EP0165945A1 (fr
Inventor
Heiko Wunder
John David Gillett
Jack Scukovic
Allan John Bennett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
North Broken Hill Ltd
Original Assignee
North Broken Hill 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 North Broken Hill Ltd filed Critical North Broken Hill Ltd
Publication of EP0165945A1 publication Critical patent/EP0165945A1/fr
Publication of EP0165945A4 publication Critical patent/EP0165945A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/12—Combustion of pulp liquors
    • D21C11/122—Treatment, e.g. dissolution, of the smelt
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
    • C01D1/04—Hydroxides
    • C01D1/28—Purification; Separation
    • C01D1/32—Purification; Separation by absorption or precipitation
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0064—Aspects concerning the production and the treatment of green and white liquors, e.g. causticizing green liquor
    • D21C11/0078—Treatment of green or white liquors with other means or other compounds than gases, e.g. in order to separate solid compounds such as sodium chloride and carbonate from these liquors; Further treatment of these compounds

Definitions

  • This invention relates to a method of increasing the purity of alkali-metal hydroxides.
  • Sodium hydroxide and other alkali-metal hydroxides produced by known means may contain, as well as some carbonate, inorganic contaminants derived from a variety of sources associated with the manufacture, storage, use or regeneration of those hydroxides. These sources of contaminants include raw materials, chemical reagents, water supplies and materials of construction of industrial plant.
  • sources of contaminants include raw materials, chemical reagents, water supplies and materials of construction of industrial plant.
  • the alkali-metal hydroxide is manufactured or regenerated by a process in which material comprising or containing alkali-metal carbonate, alkali-metal bicarbonate or alkali-metal organic salt or salts is heated together with an amphoteric oxide of a transition metal to obtain a salt or mixed oxide of general formula (M-0) .
  • M an alkali-metal (e.g. Na, K) and R is a transition metal (e.g. Ti, Fe)
  • said salt or mixed oxide then being hydrolysed to yield the alkali-metal hydroxide.
  • the method of the invention is applicable particularly to Prior Art Category A although not exclusively thereto.
  • This present invention is applicable y ⁇ t more particularly although again not exclusively when an embodiment of Prior Art Category A is employed for the regeneration of sodium hydroxide from the spent liquors (e.g. black liquor) resulting from sulphur-free alkaline pulping of wood or of other lignocellulosic material and where the transition-metal amphoteric oxide used in said regeneration is ferric oxide.
  • spent liquors e.g. black liquor
  • transition-metal amphoteric oxide used in said regeneration is ferric oxide.
  • the sodium hydroxide solution usually contains a minor proportion " of unreacted sodium carbonate.
  • the combustion during the firing stage is assumed to convert organic salts of sodium into sodium carbonate which , together with the sodium carbonate initially present in the spent pulping liquor then reacts with the ferric oxide to form predominantly ⁇ -sodium ferrite and carbon dioxide gas. This latter reaction is represented by the equation:-
  • the transition-metal amphoteric oxide may make a particularly substantial contribution of inorganic contaminants, possibly rendering the product undesirable or unsuitable for use in certain applications.
  • the chemical elements present as contaminants in the alkali-metal hydroxide may be at least in part in soluble or colloidally-dispersed forms not readily amenable to purely mechanical me «ns of removal such as filtration and may include the transition-metal whose amphoteric oxide is used and also elements originally present as impurities in that - + -
  • transition-metal • amphoteric oxide Impurities in the transition-metal • amphoteric oxide may be particularly abundant when this is in the form of a naturally-occurring ore (e.g. hematite, ilmenite) , even if that ore has undergone a degree of beneficiation.
  • a naturally-occurring ore e.g. hematite, ilmenite
  • An ability to use naturally-occurring ores is desirable because these are cheaper than synthetic or highly purified forms of the transition-metal amphoteric oxides.
  • Aluminium, silicon, iron and manganese are among elements "that may be present in sufficiently large amounts as contaminants in alkali-metal hydroxide obtained via Prior Art Category A to be undesirable when the alkali-metal hydroxide is used in applications such as the manufacture of papermaking pulp from lignocellulosic materials, the manufacture of rayon or the manufacture of soap.
  • aluminium and silicon can form sludges and scale deposits containing minerals such as cancrinite and analcite in heat-transfer equipment in contact with the spent pulping liquor.
  • Iron and manganese may also incorporate in such mineral deposits but in addition may cause discolouration of the pulp, may catalyse oxidative degradation of the pulp fibres on aging or when oxygen is used as a reagent in the pulping or pulp-bleaching operations and may catalyse decomposition of hydrogen peroxide when this is used as a pulp-bleaching agent.
  • the present invention concerns a method devised primarily to lessen the aluminium content of contaminated alkali-metal hydroxides, but we have found that application of the method may also effect a lessening of other contaminants including iron.
  • This present invention is characterised by the minimisation of contaminants, which may be effected either by preventing contaminants from entering the - 9- - "
  • solution of alkali-metal hydroxide as this is produced, or by removing contaminants from a contaminated solution- of alkali-metal hydroxide.
  • the invention utilises alkaline earth compounds to render contaminants insoluble, thereby lessening the entry of contaminants into the solution of alkali-metal hydroxide, or promoting removal of contaminants from a contaminated solution of alkali-metal hydroxide.
  • at least part of the contaminant content previously in dissolved or other difficultly separable forms in the solution is incorporated into a solid phase removable by filtration, sedimentation, centrifuging or like means of solid-liquid separation.
  • Suitable alkaline earth compounds are the carbonates, basic carbonates, oxides, hydroxides or water-soluble organic or inorganic salts .of alkaline earths (e.g. of Mg, Ca, Sr, Ba) . A mixture of two or more of these compounds, or a compound within these categories, but containing more than one alkaline earth, may also be used.
  • Magnesium is the alkaline earth in a preferred embodiment of this invention.
  • the contaminants removable by the process of the invention include aluminium and iron.
  • the form in which aluminium is rendered insoluble by application of this present invention when the alkaline-earth compound used- is one of magnesium is indicated by X-ray diffraction analysis to be predominantly hydrotalcite, whose .formula may be written as MggAl 2 (OH),gCO.-..4H 2 0.
  • the compound of an "alkaline-earth and preferably of magnesium to be used according to this present invention may be introduced into or brought into contact with the alkali-metal hydroxide solution after this has been separated from the reformed amphoteric oxide, but in a particularly preferred embodiment of the invention may be introduced at an earlier stage so that it is present during and/or immediately after the hydrolysis operation, and its solid reaction product then accompanies the reformed amphoteric oxide when this is separated from the alkali-metal hydroxide solution.
  • hydrotalcite contains carbonate, it is necessary that for aluminium to be removed in the form of this or analogous compounds of other alkaline earths a source of carbonate must be present during the application of the method of the invention. In the case of Prior Art Category A, the residual alkali-metal carbonate normally present is usually sufficient.
  • magnesium oxide is the alkaline-earth compound used in a preferred embodiment of this present invention.
  • Economical means of obtaining magnesium oxide suitable for use in that embodiment include the calcining of naturally-occurring carbonate minerals such as magnesite and dolomite.
  • aluminium is rendered insoluble mainly by reaction of the magnesium oxide component rather than of the calcium oxide component.
  • An alkali-metal hydroxide solution may be treated with the alkaline-earth compound at any temperature in the range from the freezing point up to and including the boiling point of said solution.
  • a sodium hydroxide solution clarified by centrifuging and containing total sodium at 5.56 mole/kg and of 89.1 per cent causticity was produced from evaporated spent sulphur-free alkaline pulping liquor and hematite ore according to an embodiment of Prior Art Category A. Natural dolomite was calcined for two hours at 1100 C to give a granular product containing 25.2 per cent magnesium by mass and allowed to cool. - S -
  • Portions of the sodium hydroxide solution each of approximately 80 g were heated to 80°C, mixed with different amounts of the calcined dolomite, immediately vigorously agitated for 30 minutes while maintaining the temperature at 80°C then filtered without prior cooling.
  • a further similar-sized portion of the sodium hydroxide solution was treated in identical manner except that no calcined dolomite or other additive was used.
  • a filtered sodium hydroxide solution containing total sodium " at 5.42 mole/kg and of 83.8 per cent causticity was produced from hematite ore and laboratory-grade sodium carbonate according to an embodiment of Prior Art Category A.
  • a 33.85 g portion of this solution was heated to 80°C, mixed with 50.04 g of laboratory-grade magnesium sulphate heptahydrate, immediately vigorously agitated for 30 minutes while maintaining said temperature then filtered without prior cooling.
  • a second similar-sized portion of the sodium hydroxide solution was treated identically except that no magnesium sulphate or other additive was used.
  • a granular solid containing ⁇ -sodium ferrite and with an Fe:Na mole ratio of 1.42 was obtained according to an embodiment of Prior Art Category A by firing in air a mixture of evaporated spent sulphur-free alkaline pulping liquor and hematite ore and allowing the product to cool. Natural dolomite was calcined at 1100°C for two hours and allowed to cool, giving a granular solid containing 25.2 per cent magnesium by mass.
  • One hundred grammes of the solid containing J-sodium ferrite were mixed with 4.40 g of the calcined dolomite and then with 60 ml of distilled water and continuously agitated for one hour at 80°C to hydrolyse the ferrite and leach out the resultant sodium hydroxide into solution. The sodium hydroxide solution was then filtered without prior cooling. A second and similar-sized portion of the solid containing sodium ferrite was treated identically except . that no calcined dolomite was used.
  • Granular calcined dolomite of Example 1 was ground to powder.
  • a 200.8-g portion of an impure sodium hydroxide solution of total sodium content 6.12 mol/kg and of causticity 83.6 per cent was heated to 100°C, mixed -with 2.53 g of the powdered calcined dolomite and immediately placed under continuous vigorous agitation while maintaining said temperature.
  • samples of that solution were withdrawn from the reaction mixture through filters without prior cooling.
  • a second portion of the impure sodium hydroxide solution was heated to 100°C and filtered with no addition of calcined dolomite or other additive.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

Dans un procédé pour améliorer la pureté d'hydroxydes de métal alcalin, on utilise des composés de métal alcalino-terreux pour rendre les impuretés insolubles, diminuant ainsi la pénétration d'impuretés dans une solution d'hydroxyde de métal alcalin ou favorisant le retrait d'impuretés d'une solution contaminée d'hydroxydes de métal alcalin. La présente invention peut être appliquée en particulier pour augmenter la pureté d'hydroxydes de métal alcalin régénéré à partir de liqueur épuisée résultant de la pulpation alcaline exempte de soufre du bois ou la pureté d'un autre matériau naturel contenant des fibres cellulosiques.
EP19850900029 1983-12-23 1984-12-24 Procede pour ameliorer la purete d'hydroxydes de metal alcalin. Withdrawn EP0165945A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU3009/83 1983-12-23
AUPG300983 1983-12-23

Publications (2)

Publication Number Publication Date
EP0165945A1 EP0165945A1 (fr) 1986-01-02
EP0165945A4 true EP0165945A4 (fr) 1986-07-17

Family

ID=3770460

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850900029 Withdrawn EP0165945A4 (fr) 1983-12-23 1984-12-24 Procede pour ameliorer la purete d'hydroxydes de metal alcalin.

Country Status (8)

Country Link
EP (1) EP0165945A4 (fr)
JP (1) JPS61500783A (fr)
AU (1) AU3785285A (fr)
BR (1) BR8407243A (fr)
FI (1) FI853215L (fr)
IT (1) IT1177487B (fr)
WO (1) WO1985002834A1 (fr)
ZA (1) ZA849901B (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0784716B2 (ja) * 1985-10-29 1995-09-13 三菱重工業株式会社 アルカリパルプ廃液から苛性ソ−ダを回収する方法
AU2021274310A1 (en) * 2020-05-22 2022-12-22 Suzano S.A. Methods of treating a kraft process recovery cicle to reduce metal levels at the kraft process

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB381697A (en) * 1931-09-19 1932-10-13 Erik Ludvig Rinman Method of relieving alkaline waste liquors from the soda or sulphate pulp manufacture, of silica
US2628155A (en) * 1948-12-20 1953-02-10 Gruen Bengt Herman Emanuel Method for the recovery of spent liquors from the cooking of cellulose from raw material containing silica
DE1076485B (de) * 1958-01-29 1960-02-25 Inst Zellstoff Verfahren zur Entfernung der Kieselsaeure aus silikatreichen, alkalischen Zellstoffablaugen, insbesondere im kontinuierlichen Betrieb

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB335371A (en) * 1929-07-15 1930-09-25 Erik Ludvig Rinman Method of alkalizing the waste liquors from the soda or sulphate pulp manufacture for the purpose of dry distilling the same
AU450309B2 (en) * 1972-11-13 1974-07-04 Oji Paper Co. Ltd. Method for directly converting sodium carbonate into caustic soda and application of said method to pulp and paper industry
CA1115490A (fr) * 1978-04-20 1982-01-05 Geoffrey H. Covey Methode de regeneration des alcalis
CA1188485A (fr) * 1982-03-25 1985-06-11 Kien L. Nguyen Regeneration des alcalis

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB381697A (en) * 1931-09-19 1932-10-13 Erik Ludvig Rinman Method of relieving alkaline waste liquors from the soda or sulphate pulp manufacture, of silica
US2628155A (en) * 1948-12-20 1953-02-10 Gruen Bengt Herman Emanuel Method for the recovery of spent liquors from the cooking of cellulose from raw material containing silica
DE1076485B (de) * 1958-01-29 1960-02-25 Inst Zellstoff Verfahren zur Entfernung der Kieselsaeure aus silikatreichen, alkalischen Zellstoffablaugen, insbesondere im kontinuierlichen Betrieb

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
See also references of WO8502834A1 *
TAPPI, vol. 68, no. 4, April 1985, pages 33,35, Easton, Penn., US; "The removal of aluminum from the recovery system of a closed kraft pulp mill" *

Also Published As

Publication number Publication date
EP0165945A1 (fr) 1986-01-02
BR8407243A (pt) 1985-11-26
IT8424161A0 (it) 1984-12-21
FI853215A0 (fi) 1985-08-21
WO1985002834A1 (fr) 1985-07-04
IT1177487B (it) 1987-08-26
JPS61500783A (ja) 1986-04-24
FI853215L (fi) 1985-08-21
ZA849901B (en) 1985-08-28
AU3785285A (en) 1985-07-12

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): DE FR SE

17P Request for examination filed

Effective date: 19851230

A4 Supplementary search report drawn up and despatched

Effective date: 19860717

17Q First examination report despatched

Effective date: 19870909

STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19880120

RIN1 Information on inventor provided before grant (corrected)

Inventor name: GILLETT, JOHN, DAVID

Inventor name: WUNDER, HEIKO

Inventor name: SCUKOVIC, JACK

Inventor name: BENNETT, ALLAN, JOHN