CA1174008A - Additive for road surface - Google Patents
Additive for road surfaceInfo
- Publication number
- CA1174008A CA1174008A CA000389127A CA389127A CA1174008A CA 1174008 A CA1174008 A CA 1174008A CA 000389127 A CA000389127 A CA 000389127A CA 389127 A CA389127 A CA 389127A CA 1174008 A CA1174008 A CA 1174008A
- Authority
- CA
- Canada
- Prior art keywords
- additive
- red mud
- aluminum
- sodium
- gel
- 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.)
- Expired
Links
Landscapes
- Road Paving Structures (AREA)
Abstract
ADDITIVE FOR ROAD SURFACE
ABSTRACT OF THE DISCLOSURE
The additive to a bituminous road cover is to be com-prised of red mud and aluminum hydroxide gel having resulted from partial or complete neutralization of alkali included in sodium aluminum silicate and sodium aluminate; silicon-dioxide gel is also preferably included. Sodium chloride may be included as an antifreeze. The neutralization is carried out by means of hydrochloric and/or sulfuric acid, possibly blended with an acidic aluminum salt of these acids.
Following blending of the components, they are dried and ground to below l-mm grain size. Adding of higher hydro-carbons reduces dust formation.
ABSTRACT OF THE DISCLOSURE
The additive to a bituminous road cover is to be com-prised of red mud and aluminum hydroxide gel having resulted from partial or complete neutralization of alkali included in sodium aluminum silicate and sodium aluminate; silicon-dioxide gel is also preferably included. Sodium chloride may be included as an antifreeze. The neutralization is carried out by means of hydrochloric and/or sulfuric acid, possibly blended with an acidic aluminum salt of these acids.
Following blending of the components, they are dried and ground to below l-mm grain size. Adding of higher hydro-carbons reduces dust formation.
Description
11'74008 1 BACRGROUND OF THE INV~NTION
3 The present invention relates to road or pavement 4 surface material on the basis of red mud and to a method of making same.
7 German Patent 18 05 829, for instance, discloses a 8 red mud material to be used as a filler in a bituminous 9 pavement for roads. In accordance with this patent, red mud is particularly suited for the purpose mentioned above if 11 prior to separation from the residual aluminate liquor or lye 12 3~ to 10% (by weight) of caustic or slaked lime is added, 13 the amount being calculated with the CaO content referenced 14 to dry, red mud. The filtered, strained off red mud is subsequently conventionally dried and ground. Supplementing 16 the state of the art, reference is made, in addition, to 17 ~German Patent 23 06 145, being a patent ~f addition to the 18 ~ classifying Patent 18 05 829. This patent of addition dis-19 closes an improving of metering this known fillers, also /advan-called "red filler," by means of spray-drying, thus bei~g an- 7 21 tageous method of drying. Any suggestion of a gel formation 22 during dressing the red mud cannot be derived from this 23 reference.
11740(~8 DESCRIPTION OF THE INVENTION
It is an object of the present invention to provide a new and improved red mud filler for road surface pavement.
Surprisingly, it was found that such a pavement material can be made better and more economically if the alkalies contained in the red mud are neutralized, partially or completely, under formation of an aluminum hydroxide gel; and the resulting reaction product is dried and, subsequently, ground.
Accordingly, the present invention provides an additive for a road surface pavement comprising red mud and aluminum hydroxide gel, having a granular consistency and a grain size of below 1 mm and resulting from at least partial neutralization of alkali in the red mud.
The invention also provides a method of making an additive for a road surface cover material, comprising the steps of providing a quantity of red mud;
blending thereto and stirring into the red mud a neutralizing agent for at least partial neutralization of alkali included in the red mud, whereby a gel results; and drying and grinding the gel.
If the red mud includes sodium aluminum silicate, this alkaline is neutralized under concurring formation of a gel that includes aluminum hydroxide and silicon dioxide. It was unforeseeable that the filler containing aluminum hydroxide gel is very well suited for road surface pavements. The final product is free from dust. The method of making it is simple and economical.
The red mud resulting as a residue in the so-called Bayer treatment (bauxite residue) contains up to 1.5% ~by weight) alkali ~calculated as to NaOH) and depending upon the scrubbing process. This alkali is present as a water-soluble sodium aluminate. Also included is 13% by weight sodium aluminum silicate (Na2O . AQ2O3 , 2SiO2) which is not a solution. Upon neutralizing, the sodium aluminum silicate decomposes into SiO2 gel, AR(OH)3, and the corresponding quantity of sodium salt.
~.,, :11'74(~ 8 1 Preferably, acidic aluminum salts are used as a
3 The present invention relates to road or pavement 4 surface material on the basis of red mud and to a method of making same.
7 German Patent 18 05 829, for instance, discloses a 8 red mud material to be used as a filler in a bituminous 9 pavement for roads. In accordance with this patent, red mud is particularly suited for the purpose mentioned above if 11 prior to separation from the residual aluminate liquor or lye 12 3~ to 10% (by weight) of caustic or slaked lime is added, 13 the amount being calculated with the CaO content referenced 14 to dry, red mud. The filtered, strained off red mud is subsequently conventionally dried and ground. Supplementing 16 the state of the art, reference is made, in addition, to 17 ~German Patent 23 06 145, being a patent ~f addition to the 18 ~ classifying Patent 18 05 829. This patent of addition dis-19 closes an improving of metering this known fillers, also /advan-called "red filler," by means of spray-drying, thus bei~g an- 7 21 tageous method of drying. Any suggestion of a gel formation 22 during dressing the red mud cannot be derived from this 23 reference.
11740(~8 DESCRIPTION OF THE INVENTION
It is an object of the present invention to provide a new and improved red mud filler for road surface pavement.
Surprisingly, it was found that such a pavement material can be made better and more economically if the alkalies contained in the red mud are neutralized, partially or completely, under formation of an aluminum hydroxide gel; and the resulting reaction product is dried and, subsequently, ground.
Accordingly, the present invention provides an additive for a road surface pavement comprising red mud and aluminum hydroxide gel, having a granular consistency and a grain size of below 1 mm and resulting from at least partial neutralization of alkali in the red mud.
The invention also provides a method of making an additive for a road surface cover material, comprising the steps of providing a quantity of red mud;
blending thereto and stirring into the red mud a neutralizing agent for at least partial neutralization of alkali included in the red mud, whereby a gel results; and drying and grinding the gel.
If the red mud includes sodium aluminum silicate, this alkaline is neutralized under concurring formation of a gel that includes aluminum hydroxide and silicon dioxide. It was unforeseeable that the filler containing aluminum hydroxide gel is very well suited for road surface pavements. The final product is free from dust. The method of making it is simple and economical.
The red mud resulting as a residue in the so-called Bayer treatment (bauxite residue) contains up to 1.5% ~by weight) alkali ~calculated as to NaOH) and depending upon the scrubbing process. This alkali is present as a water-soluble sodium aluminate. Also included is 13% by weight sodium aluminum silicate (Na2O . AQ2O3 , 2SiO2) which is not a solution. Upon neutralizing, the sodium aluminum silicate decomposes into SiO2 gel, AR(OH)3, and the corresponding quantity of sodium salt.
~.,, :11'74(~ 8 1 Preferably, acidic aluminum salts are used as a
2 neutralizer, such as aluminum chloride. The utilization
3 of this particular salt is of particular advantage owing
4 to the additional formation of A~(OH)3 gel. In lieu of aluminum chloride, other aluminum salts can be used, such 6 as aluminum sulfate and aluminum nitrate.
8 A further advantage of the method as per the invention 9 is to be seen in the feature that acids can be used for neutralization, even cheap waste acids such as hydrochloric 11 acid, sulfuric acid, or blends of these acids.
}3 The red mud is advantageously used filter wet in this 14 method at, i.e., a residual water content of about 35% to 50~
(weight). The red mud has a pasty consistency in such a state.
16 The aluminum salt is preferably worked into the red mud in 17 a solution. Upon cessation of applying shearing forces pur-18 suant to blending the red mud suspension solidifies into a 19 gel. After drying the gel in, e.g., a rotating drum drier at temperatures in excess of 100C, a grainy substance results 21 which is ground down to a grain size smaller than lmm. The 22 ground product is not hygroscopic, but quite fluid and exhibits 23 a very good ability to bond with a bitumenous substance or 24 asphalt. Upon adding higher hydrocarbons, such as heating or diesel oil, to the dry substance prior to grinding, the 26 bonding capacity of the filler is further enhanced. The amount ,~
~.~.740(~8 li MEI-7126 1 of neutralizing agent is limited (upper limit) by the 21 alkali content of the red mud. This amount should be 31 chosen in accordance with the desired consistency of gelling.
4 l
8 A further advantage of the method as per the invention 9 is to be seen in the feature that acids can be used for neutralization, even cheap waste acids such as hydrochloric 11 acid, sulfuric acid, or blends of these acids.
}3 The red mud is advantageously used filter wet in this 14 method at, i.e., a residual water content of about 35% to 50~
(weight). The red mud has a pasty consistency in such a state.
16 The aluminum salt is preferably worked into the red mud in 17 a solution. Upon cessation of applying shearing forces pur-18 suant to blending the red mud suspension solidifies into a 19 gel. After drying the gel in, e.g., a rotating drum drier at temperatures in excess of 100C, a grainy substance results 21 which is ground down to a grain size smaller than lmm. The 22 ground product is not hygroscopic, but quite fluid and exhibits 23 a very good ability to bond with a bitumenous substance or 24 asphalt. Upon adding higher hydrocarbons, such as heating or diesel oil, to the dry substance prior to grinding, the 26 bonding capacity of the filler is further enhanced. The amount ,~
~.~.740(~8 li MEI-7126 1 of neutralizing agent is limited (upper limit) by the 21 alkali content of the red mud. This amount should be 31 chosen in accordance with the desired consistency of gelling.
4 l
5 ~ In conjunction with the foregoing, it must further
6 ¦ be considered surprising that the red-mud-based filler as
7 ¦ described turns into an excellent antifreeze additive for road
8 ¦ building if antifreeze substances, such as sodium chloride,
9 ¦ is added. It is essential here that the alkali substances
10 ¦ contained in the red mud are neutralized only after the
11 ¦ antifreeze compound has been added. The aluminum hydroxide
12 gel on the antifreeze compound delays, in an unforeseeable
13 manner, the access of water to that compound and, thus,
14 delays its prematurely going into solution. Thus, adding of expensive hydrophobic agents is no longer necessary.
16 Accordingly, the chances for a practical use of antifreeze 17 compounds in road building have been increased considèrably.
19 The use of aluminum chloride as a neutralizing agent is of particular advantage owing to the concuring formation 21 of A~(OH)3 gel and sodium chloride because the chloride is 22 already present in the red mud as an antifreeze. Additionally, 23 one enhances the geeling component in this manner. The red 24 mud is liquified upon adding solid sodium chloride so that the acidic aluminum salt, solved or unsolved, can easily be 26 worked into the red mud suspension which will solidify upon 27 cessation of shearing.
I' MEI-7126 ljThe amount of crystalline sodium chloride added 21~ is approximately the twofold to thre~fold quantity of red 3 mud, referenced to the dry weight of the red mud. The 4 amount of a neutralizing agent is upwardly limited by the alkali content of the red mud; this amount is preferably 6 chosen under consideration of the desired gelling consistency.
8 The invention is further explained with reference to 9 the following examples:
11 Example 1 12 Filter-wet red mud is used as a raw material having a water 13 content of 46.3% and a total Na2O content of 6.1% (referenced 14 to dry weight). 1.1% Na2O is present as soluble sodium aluminate and 4.9% Na2O is present in insoluble sodium 16 aluminum silicate.
18 2000 kg of such red mud are intensively stirred in order to 19 obtain a liquid mash. 45 kg AQC~3, in a 20% solution, was added to that mash. After 5 minutes of exposure, a paste 21 formed which was dried in a drum drier at a temperature 22 of 145C without caking upon the drier. 5% diesel oil was 23 blended into that dry substance which was ground thereafter 24 to a grain size smaller than 1 mm. The oil additive did not interfer with grinding. A nondusting product was obtained 26 having very good properties as a filler.
1174V~3 Example 2 Ij 3 1000 kg red mud as per Example 1 was exposed to high shear 4 forces in a forced blender so that a liquid mash was pro-duced. The mash was blended with 45 kg H2SO4 in a 40% solu-6 tion. Heat was developed and, after 4 minutes, the material 7 solidified into a paste. The paste was dried at 14SC in 8 a drum drier without caking upon the drier. Following the 9 adding of 5~ diesel oil, the still basically dry product was easily ground to a grain size under 1 mm and without 11 the development of any dust. The product had a pH-value 12 of 6.0 and exhibited excellent properties as a filler for }3 road building.
56 Example 3 17 The red mud used as raw material has a water content of 42~
18 and an Na2O content of 6.1% (by weight, referenced to a dry 19 substance). 1.1% Na20 is present as sodium aluminate and 5% Na2O is present as sodium aluminum silicate.
22 100 kg of this red mud are intimately blended with 100 kg 23 table salt, the result is a liquid mash. 20 kg aluminum 24 chloride solution (corresponding to 4.7 kg A~CQ3) are blended into this mash. A paste is formed under the development of 26 heat which can be dried at 130C without caking upon a drum 2a 1 I -7-l drier. The dry product is not hygroscopic and can easily 2 be ground to below l-mm grain size. .Upon adding 5% diesel 3 oil prior to grinding, formation of dust is reduced but 41 grinding is not made more difficult.
61 Example 4 ql 8 ¦ lO0 kg red mud as per Example 3 are blended with lO0 kg table 9¦ salt so that a liquid blend results. lO kg of a 36% HCQ solu-lO ¦ tion are blended into the mash. As heat developes, the ll ¦ material solidifies to a puncture-proof composition. The 12 ¦ reaction product is dried in a drum drier at l40C and, }3 ¦ after adding of 6% light-weigt heating oil, the product is 14 ¦ ground to below l-mm grain size. The product when blended in that fashion with light-weight heating oil can be ground 16 quite well with only little dust being formed.
18 Finally, it should be mentioned that an additive made 19 as per any of the examples should be used as a 4% to 5% addi-20 ¦ tive for and in a bituminous road cover. The desired freezing 21 ¦ point reduction of surface water can be expected to occur.
22 l 23 The invention is not limited to the embodiments described 24 above; but all changes and modifications thereof, not constitu-ting departures from the spirit and scope of the invention, 26 are intended to be included.
,~ _
16 Accordingly, the chances for a practical use of antifreeze 17 compounds in road building have been increased considèrably.
19 The use of aluminum chloride as a neutralizing agent is of particular advantage owing to the concuring formation 21 of A~(OH)3 gel and sodium chloride because the chloride is 22 already present in the red mud as an antifreeze. Additionally, 23 one enhances the geeling component in this manner. The red 24 mud is liquified upon adding solid sodium chloride so that the acidic aluminum salt, solved or unsolved, can easily be 26 worked into the red mud suspension which will solidify upon 27 cessation of shearing.
I' MEI-7126 ljThe amount of crystalline sodium chloride added 21~ is approximately the twofold to thre~fold quantity of red 3 mud, referenced to the dry weight of the red mud. The 4 amount of a neutralizing agent is upwardly limited by the alkali content of the red mud; this amount is preferably 6 chosen under consideration of the desired gelling consistency.
8 The invention is further explained with reference to 9 the following examples:
11 Example 1 12 Filter-wet red mud is used as a raw material having a water 13 content of 46.3% and a total Na2O content of 6.1% (referenced 14 to dry weight). 1.1% Na2O is present as soluble sodium aluminate and 4.9% Na2O is present in insoluble sodium 16 aluminum silicate.
18 2000 kg of such red mud are intensively stirred in order to 19 obtain a liquid mash. 45 kg AQC~3, in a 20% solution, was added to that mash. After 5 minutes of exposure, a paste 21 formed which was dried in a drum drier at a temperature 22 of 145C without caking upon the drier. 5% diesel oil was 23 blended into that dry substance which was ground thereafter 24 to a grain size smaller than 1 mm. The oil additive did not interfer with grinding. A nondusting product was obtained 26 having very good properties as a filler.
1174V~3 Example 2 Ij 3 1000 kg red mud as per Example 1 was exposed to high shear 4 forces in a forced blender so that a liquid mash was pro-duced. The mash was blended with 45 kg H2SO4 in a 40% solu-6 tion. Heat was developed and, after 4 minutes, the material 7 solidified into a paste. The paste was dried at 14SC in 8 a drum drier without caking upon the drier. Following the 9 adding of 5~ diesel oil, the still basically dry product was easily ground to a grain size under 1 mm and without 11 the development of any dust. The product had a pH-value 12 of 6.0 and exhibited excellent properties as a filler for }3 road building.
56 Example 3 17 The red mud used as raw material has a water content of 42~
18 and an Na2O content of 6.1% (by weight, referenced to a dry 19 substance). 1.1% Na20 is present as sodium aluminate and 5% Na2O is present as sodium aluminum silicate.
22 100 kg of this red mud are intimately blended with 100 kg 23 table salt, the result is a liquid mash. 20 kg aluminum 24 chloride solution (corresponding to 4.7 kg A~CQ3) are blended into this mash. A paste is formed under the development of 26 heat which can be dried at 130C without caking upon a drum 2a 1 I -7-l drier. The dry product is not hygroscopic and can easily 2 be ground to below l-mm grain size. .Upon adding 5% diesel 3 oil prior to grinding, formation of dust is reduced but 41 grinding is not made more difficult.
61 Example 4 ql 8 ¦ lO0 kg red mud as per Example 3 are blended with lO0 kg table 9¦ salt so that a liquid blend results. lO kg of a 36% HCQ solu-lO ¦ tion are blended into the mash. As heat developes, the ll ¦ material solidifies to a puncture-proof composition. The 12 ¦ reaction product is dried in a drum drier at l40C and, }3 ¦ after adding of 6% light-weigt heating oil, the product is 14 ¦ ground to below l-mm grain size. The product when blended in that fashion with light-weight heating oil can be ground 16 quite well with only little dust being formed.
18 Finally, it should be mentioned that an additive made 19 as per any of the examples should be used as a 4% to 5% addi-20 ¦ tive for and in a bituminous road cover. The desired freezing 21 ¦ point reduction of surface water can be expected to occur.
22 l 23 The invention is not limited to the embodiments described 24 above; but all changes and modifications thereof, not constitu-ting departures from the spirit and scope of the invention, 26 are intended to be included.
,~ _
Claims (23)
PROPERTY FOR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An additive for a road surface pavement comprising red mud and aluminum hydroxide gel, having a granular consistency and a grain size of below 1 mm and resulting from at least partial neutralization of alkali in the red mud.
2. An additive as in claim 1 and including additionally silicon dioxide gel.
3. An additive as in claim 1, said aluminum hydroxide having been produced upon neutralizing alkali in the red mud included therein as sodium aluminate.
4. An additive as in claim 1, including additionally an antifreeze.
5. An additive as in claim 4, the antifreeze being sodium chloride.
6. An additive as in claim 1, the grains carrying higher hydrocarbons.
7. A method of making an additive for a road surface cover material, comprising the steps of providing a quantity of red mud; blending thereto and stirring into the red mud a neutralizing agent for at least partial neutraliza-tion of alkali included in the red mud, whereby a gel results; and drying and grinding the gel.
8. A method as in claim 7, including further adding an antifreeze prior to said blending step.
9. A method as in claim 7, the neutralizing agent being an acidic aluminum salt.
10. A method as in claim 9, the salt being aluminum chloride.
11. A method as in claim 7 or 10, the agent being or including aluminum sulfate.
12. A method as in claim 7, the neutralizing agent being an inorganic acid.
13. A method as in claim 12, the acid being or including hydrochloric acid.
14. A method as in claim 12 or 13, the acid being or including sulfuric acid.
15. A method as in claim 7, the neutralizing agent being a blend of an acidic aluminum salt and of an inorganic acid.
16. A method as in claim 7, the red mud as provided having a residual moisture content of approximately 35% to 50% by weight.
17. A method as in claim 7 and including the step of adding a higher hydrocarbon after the drying but prior to the grinding.
18. A method as in claim 17, the hydrocarbon being diesel oil.
19. A method as in claim 17, the hydrocarbon being a light-weight heating oil.
20. A bituminous road cover material including an additive as claimed in claim 1 or 2.
21. An additive as in claim 2, a portion of the hydroxide having resulted from neutralizing sodium aluminum silicate.
22. A method as in claim 7, the alkalies being neutralized are at least in parts included in sodium aluminate.
23. A method as in claim 7 or 22, the alkalies being neutraliæed are at least included in parts in sodium aluminum silicate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000389127A CA1174008A (en) | 1981-10-30 | 1981-10-30 | Additive for road surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000389127A CA1174008A (en) | 1981-10-30 | 1981-10-30 | Additive for road surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174008A true CA1174008A (en) | 1984-09-11 |
Family
ID=4121308
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000389127A Expired CA1174008A (en) | 1981-10-30 | 1981-10-30 | Additive for road surface |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1174008A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101925536B (en) * | 2007-12-26 | 2013-05-15 | 昭和电工株式会社 | Process for neutralizing bauxite dissolution residual substance and process for producing aluminum hydroxide |
| WO2022233039A1 (en) * | 2021-05-07 | 2022-11-10 | 德州学院 | Method for preparing composite pigment filler for coating by using red mud |
-
1981
- 1981-10-30 CA CA000389127A patent/CA1174008A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101925536B (en) * | 2007-12-26 | 2013-05-15 | 昭和电工株式会社 | Process for neutralizing bauxite dissolution residual substance and process for producing aluminum hydroxide |
| US8679427B2 (en) | 2007-12-26 | 2014-03-25 | Showa Denko K.K. | Process for neutralizing bauxite dissolution residual substance and process for producing aluminum hydroxide |
| US20140186240A1 (en) * | 2007-12-26 | 2014-07-03 | Showa Denko K.K. | Process for neutralizing bauxite dissolution residual substance and process for producing aluminum hydroxide |
| US9175367B2 (en) | 2007-12-26 | 2015-11-03 | Showa Denko K.K. | Process for neutralizing bauxite dissolution residual substance and process for producing aluminum hydroxide |
| WO2022233039A1 (en) * | 2021-05-07 | 2022-11-10 | 德州学院 | Method for preparing composite pigment filler for coating by using red mud |
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