US5288857A
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Lignin preparation and method for its manufacture
Assignee: Ligno Tech Sweden AB
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Filing: 1993-02-16
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Granted: 1994-02-22
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Expires: 2013-02-16
Abstract
Abstract The invention relates to a lignin preparation prepared from black liquor derived from an alkali delignification process, such as the sulphate process, soda process or polysulphide process. The lignin preparation comprises mainly lignin and at least the major part of the sodium content of the lignin separated from the black liquor deriving from such processes has been replaced with calcium, therewith to provide a lignin preparation having improved properties which render the preparation more suitable for use as fuel.
Inventors
- 👤 Wilhelm Aarsrud
- 👤 Hans Bergstrom
- 👤 Ingemar Falkehag
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:59
CPC Classifications
C; C08; C08H; C08H6/00; C10; C10L; C10L5/00; C10L5/40; C10L5/44; D; D21; D21C; D21C11/00; D21C11/0007; Y; Y02; Y02E; Y02E50/00; Y02E50/10; Y02E50/30
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
144 words
A lignin fuel preparation which upon combustion will form an ash having an elevated melting point, said preparation containing predominantly lignin obtained by precipitation from black liquor derived directly from an alkali delignification process selected from the group consisting of the sulphate process, the soda process and the polysulphide process, and wherein the original sodium content of the lignin has been reduced by treating the lignin precipitate so as to be less than 2% by weight calculated on the dry weight of the lignin, and that sodium removed from the lignin has been replaced by calcium such that the calcium content of the lignin exceeds 2% by weight calculated on the dry weight of the lignin, said preparation further including an acid component selected from the group consisting of kaolin, silicon dioxide, aluminum oxide and slag, ash of an acid nature, and mixtures thereof.
Claim 2
Dependent Claim
144 words
A lignin fuel preparation which upon combustion will form an ash having an elevated melting point, said preparation containing predominantly lignin obtained by precipitation from black liquor derived directly from an alkali delignification process selected from the group consisting of the sulphate process, the soda process and the polysulphide process, and wherein the original sodium content of the lignin has been reduced by treating the lignin precipitate so as to be less than 2% by weight calculated on the dry weight of the lignin, and that sodium removed from the lignin has been replaced by calcium such that the calcium content of the lignin exceeds 2% by weight calculated on the dry weight of the lignin, said preparation further including an acid component selected from the group consisting of kaolin, silicon dioxide, aluminum oxide and slag, ash of an acid nature, and mixtures thereof.
Claim 3
Dependent Claim
35 words
A lignin preparation according to claim 1, wherein the original sodium content of the lignin has been reduced so as to be less than 1% by weight calculated on the dry weight of the lignin.
Claim 4
Dependent Claim
16 words
A lignin preparation according to claim 1, characterized in that its sintering temperature exceeds 1000° C.
Claim 5
Dependent Claim
14 words
A lignin preparation according to claim 3, wherein the sintering temperature exceeds 1100° C.
Claim 6
Dependent Claim
35 words
A lignin preparation according to claim 1, wherein the sodium content remaining is between 1.2-0.2% by weight, and the calcium content is at least 3% by weight, calculated on the dry weight of the lignin.
Claim 7
Dependent Claim
29 words
A lignin preparation according to claim 1, wherein the acid component is kaolin in a quantity of 5-50% by weight calculated on the ash obtained when burning the preparation.
Claim 8
Dependent Claim
27 words
A lignin preparation according to claim 6, wherein kaolin is present in a quantity of 5-30% by weight calculated on the ash obtained when burning the preparation.
Claim 9
Independent Claim
109 words
A method for producing a lignin fuel preparation, which upon combustion will form an ash having an elevated melting point, said preparation containing lignin derived from an alkali delignification process selected from the group consisting of the sulphate process, the soda process and the polysulphide process, which comprises extracting said lignin by precipitation from black liquor directly derived from one of said processes, separating the lignin precipitate from a black liquor residue by filtration, and removing at least a major part of the sodium content of the lignin by washing with an acid capable of forming a soluble calcium salt, down to a pH value of 9 or less.
Claim 10
Independent Claim
109 words
A method for producing a lignin fuel preparation, which upon combustion will form an ash having an elevated melting point, said preparation containing lignin derived from an alkali delignification process selected from the group consisting of the sulphate process, the soda process and the polysulphide process, which comprises extracting said lignin by precipitation from black liquor directly derived from one of said processes, separating the lignin precipitate from a black liquor residue by filtration, and removing at least a major part of the sodium content of the lignin by washing with an acid capable of forming a soluble calcium salt, down to a pH value of 9 or less.
Claim 11
Dependent Claim
27 words
A method according to claim 8, wherein the acid used during washing is sulphur-dioxide water, and the pH is lowered to a value between 7 and 9.
Claim 12
Dependent Claim
28 words
A method according to claim 8, characterized by introducing a calcium compound prior to said precipitation, so as to replace the sodium removed from the lignin with calcium.
Claim 13
Dependent Claim
15 words
A method according to claim 10, characterized in that the calcium compound is calcium carbonate.
Claim 14
Dependent Claim
29 words
A method according to claim 10, characterized by adding an acid compound containing silica, aluminum oxide, slag or ash of an acid nature, in addition to said calcium compound.
Claim 15
Dependent Claim
16 words
A method according to claim 8, characterized by adding a calcium compound to the lignin precipitate.
Claim 16
Dependent Claim
40 words
A method according to claim 13, characterized by filtering off the lignin precipitate so as to obtain a filtrate and a filter cake, and by adding the calcium compound while washing the filter cake, subsequent to removal of the filtrate.
Claim 17
Dependent Claim
45 words
A method according to claim 13, characterized by adding water to the lignin filter cake while washing so as to produce a slurried filter cake, washing the lignin down to a pH value below 4, and subsequently admixing calcium carbonate with the slurried filter cake.
Claim 18
Dependent Claim
43 words
A method according to claim 8, wherein the acid used for washing the lignin is selected from the group consisting of sulphuric acid and residual acid from ClO 2 preparation, down to a pH value below 8, and then adding a calcium compound.
Claim 19
Dependent Claim
28 words
A method according to claim 8, characterized by introducing a calcium compound during said precipitation process, so as to replace the sodium removed from the lignin with calcium.
References Cited (Backward Citations)
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