CA1087375A - Process for producing of high-purity alumina and hydraulic cement - Google Patents
Process for producing of high-purity alumina and hydraulic cementInfo
- Publication number
- CA1087375A CA1087375A CA257,529A CA257529A CA1087375A CA 1087375 A CA1087375 A CA 1087375A CA 257529 A CA257529 A CA 257529A CA 1087375 A CA1087375 A CA 1087375A
- Authority
- CA
- Canada
- Prior art keywords
- mixture
- heat exchanger
- alumina
- hydraulic cement
- silicate
- 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
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
- C01F7/16—Preparation of alkaline-earth metal aluminates or magnesium aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/18—Aluminium oxide or hydroxide from alkaline earth metal aluminates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/51—Particles with a specific particle size distribution
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a process for producing of high-purity alumina and hydraulic cement from low-grade aluminium carriers by means of extraction of a disintegrating product obtained as a result of the phase conversion of dicalcium silicate, characterized by homogenizing the starting mixture expediently pulverized in common together with limestone, heating to a temperature of 700 to 900°C in direct and/or counter-flow heat exchange in a heat exchanger system, then keeping in a rotary kiln at sintering temperature for 5 to 10 minutes and finally, converting into alumina and hydraulic cement in a known manner.
The present invention provides a process for producing of high-purity alumina and hydraulic cement from low-grade aluminium carriers by means of extraction of a disintegrating product obtained as a result of the phase conversion of dicalcium silicate, characterized by homogenizing the starting mixture expediently pulverized in common together with limestone, heating to a temperature of 700 to 900°C in direct and/or counter-flow heat exchange in a heat exchanger system, then keeping in a rotary kiln at sintering temperature for 5 to 10 minutes and finally, converting into alumina and hydraulic cement in a known manner.
Description
.
The present invention relates to a process for produc-ing high-purity alumina and hydraulic cement from low-grade aluminium bearing siliceous carriers, using a technology based on the phase conversion of dicalcium silicate in equipment com-prising a heat exchanger coupled with a sintering furnace.
Several methods are known to recover the aiuminium values of low-grade aluminium carriers such as low-grade bauxite, coal slag, fly ash and clay of which, however, only a few are !
economical, and commercial feasibility has been established only ; .
for those utilizing a process based on the phase conversion of - disintegrating dicalcium silicate and producing alumina and hydraulic cement fror.l the end product obtained. Such processes involve a reaction taking place between the aluminium carrier and limestone at high temperatures. As a result, the mixture will have chemical and physical characteristics permitting the alumin-ium content to be recovered at normal ~ressure and relatively low temperature by using a solution of soda for extraction. In principle the reaction can be brought about in both liquid an~
solid phase. Accordingly, the technologies to be used are melt-ing or sintering. For a physical and chemical point of view, this technology utilizes the polymorphy of di-calcium silicates, a property which results a volume-increase of the system due to the about 10% difference between the molar volume of B and y modifications as a result of a conversion taking place between them in the course of cooling of dicalcium silicates after heat treatment. The stress brought about by the volume increase '~
causes the sintered cake to disintegrate into a powder of a grain size below 25 ~ in its major part. In this way, a powdered product ready for caustic extraction can be obtained without external power input. Another advantage of this technology of modification is that the major part of the silicate contained in the raw material is converted into y-dicalcium silicate wh~ch ,~
The present invention relates to a process for produc-ing high-purity alumina and hydraulic cement from low-grade aluminium bearing siliceous carriers, using a technology based on the phase conversion of dicalcium silicate in equipment com-prising a heat exchanger coupled with a sintering furnace.
Several methods are known to recover the aiuminium values of low-grade aluminium carriers such as low-grade bauxite, coal slag, fly ash and clay of which, however, only a few are !
economical, and commercial feasibility has been established only ; .
for those utilizing a process based on the phase conversion of - disintegrating dicalcium silicate and producing alumina and hydraulic cement fror.l the end product obtained. Such processes involve a reaction taking place between the aluminium carrier and limestone at high temperatures. As a result, the mixture will have chemical and physical characteristics permitting the alumin-ium content to be recovered at normal ~ressure and relatively low temperature by using a solution of soda for extraction. In principle the reaction can be brought about in both liquid an~
solid phase. Accordingly, the technologies to be used are melt-ing or sintering. For a physical and chemical point of view, this technology utilizes the polymorphy of di-calcium silicates, a property which results a volume-increase of the system due to the about 10% difference between the molar volume of B and y modifications as a result of a conversion taking place between them in the course of cooling of dicalcium silicates after heat treatment. The stress brought about by the volume increase '~
causes the sintered cake to disintegrate into a powder of a grain size below 25 ~ in its major part. In this way, a powdered product ready for caustic extraction can be obtained without external power input. Another advantage of this technology of modification is that the major part of the silicate contained in the raw material is converted into y-dicalcium silicate wh~ch ,~
- 2 - ~fl~r product has a very poor solubi~ity in dilute solution of soda.
The aluminate liquor has a very good solubility in water, and is formed in addition to y-diealeium-silieate. The advantage of this is, that the aluminate iiquor prepared from calcium aluminate is only to a low extent contaminated with silica. Several pro-cesses to realize the technology described have become known.
Among them, Hungarian Patent No. 94.665 reports on -the production of self disintegrating hydraulic cement containing ~ -. aluminium. Hungarian Patents No. 122.738 and 140.323 diselose the produetion of water-soluble calcium aluminates and alumina ",, . . . ~
resp. and the phenomenon of disintegration is also mentioned but only in respect of mixture the mixing and cooling of the substance- -~
,. ~.
mixture Hungarian Patent No. 148.401 treats the theoretieal prob-lems of phase conversion and suggests a practical way to utilize - ;~
the phenomenon of disintegration. The phenomenon of disintegra-tion is further mentioned but not discusse~ in detail also by German Patents Wo. 824,197~ gO6,218 and 935,431. Another German ~ -Patent No. 1020.612, diseloses the ~roduetion of alumina and of hydraulie eement from elinker eontaining disintegrating diealeium ;
silieate. The problem of grain distribution being also treated here, however, the eoarse fraetion is eonsidered to be advantageous in respeet of alumina produetion. Hungarian Patent ~o. 162.162 diseusses the resonable methods to inaetivate inhibitors of dis-integration, by adding desoxidizing metals to the substance system.
Eaeh of the methods referred to uses sin~ering teeh-nology in rotary kiln when earried out on large-seale applieations.
Diffieulties are eneountered in the eourse of these eonventional methods of sintering with respect to the proper control of clinker-izing reactions and due to the fact that a saturated state, which --would be optimal in respeet of the diealeium-silieate/dodecacalcium heptaaluminate phases to be formed in homogeneous solid-phase
The aluminate liquor has a very good solubility in water, and is formed in addition to y-diealeium-silieate. The advantage of this is, that the aluminate iiquor prepared from calcium aluminate is only to a low extent contaminated with silica. Several pro-cesses to realize the technology described have become known.
Among them, Hungarian Patent No. 94.665 reports on -the production of self disintegrating hydraulic cement containing ~ -. aluminium. Hungarian Patents No. 122.738 and 140.323 diselose the produetion of water-soluble calcium aluminates and alumina ",, . . . ~
resp. and the phenomenon of disintegration is also mentioned but only in respect of mixture the mixing and cooling of the substance- -~
,. ~.
mixture Hungarian Patent No. 148.401 treats the theoretieal prob-lems of phase conversion and suggests a practical way to utilize - ;~
the phenomenon of disintegration. The phenomenon of disintegra-tion is further mentioned but not discusse~ in detail also by German Patents Wo. 824,197~ gO6,218 and 935,431. Another German ~ -Patent No. 1020.612, diseloses the ~roduetion of alumina and of hydraulie eement from elinker eontaining disintegrating diealeium ;
silieate. The problem of grain distribution being also treated here, however, the eoarse fraetion is eonsidered to be advantageous in respeet of alumina produetion. Hungarian Patent ~o. 162.162 diseusses the resonable methods to inaetivate inhibitors of dis-integration, by adding desoxidizing metals to the substance system.
Eaeh of the methods referred to uses sin~ering teeh-nology in rotary kiln when earried out on large-seale applieations.
Diffieulties are eneountered in the eourse of these eonventional methods of sintering with respect to the proper control of clinker-izing reactions and due to the fact that a saturated state, which --would be optimal in respeet of the diealeium-silieate/dodecacalcium heptaaluminate phases to be formed in homogeneous solid-phase
- 3 -reactions, could not be attained to a full extent. Owing to the ~ ;
features of rotary-kiln processes, so far carried out the ideal composition could not have even approached as the total amount on the one hand of dicalcium silicate is inherently less and, even in this reduced amount, a full ~ - ~ conversion will not take place. On the other hand, gehlenit/dicalcium aluminium silicate/ I
acting as an inhibitor upon disintegration is always formed in these processes and its presence is disadvantageous also in res-pect of recovering aluminium values.
Hence, in developing of the known processes, the object is set to control after proper adjustment of the composition of the starting mixture, the kinetics of the mineralogical pro-cess taking place, so as to obtain a product composed of dicalcium-silicate/dodecacalcium heptaaluminate and to increase the degree j~ !
of conversion into y - modification and thereby improve the ¦;
aluminium recovery and reduce the silica contamination content of the aluminate liquor for~ed and, finally, to obtain a high-purity alumina as an end product. To achieve this, maximu~
degree of conversion of the silicon content of the sintered cake ; 20 into y - dicalcium silica modification and a small grain size of the end product is needed, the latter ~eing ensured through intensified disintegration.
The present invention provides a process wherein a fine-grain mixture composed of low-grade aluminium carriers such as coal slag, fly ash, low grade bauxite, red mud, and clay and limestone, pulverized expediently together is heated to 700-900C -~while applying a fluidization of the mixture preferably in a heat exchanger system, then the mixture is held at sintering tempera-ture for 5 to 10 minutes in a furnace, allowing the sintered product to come to form in a major part the y - modification from the dicalcium silicate content of the sintered product consisting of dodecacalcium-heptaaluminate and dicalcium silicate, extracting ', . ." ~ .
~ ;```` ~087375 the aluminium content of the disintegrating material to produce -high-purity alumina from the aluminate solution so obtained poor in silica, and hydraulic cement from the residue. -Limestone is added to the aluminium carriers used as the starting mixture of the process in a ratio permitting the total silicon and aluminium content of the sintered cake to con-vert into dicalcium silicate and dodecacalcium heptaaluminate, respectiveiy. Expediently, the starting materials are so pul-verized that, according to sieve analysis, the fraction above 88 ~ is below 10%. This substance-mixture is heated to 700 to 900C, expediently in countercurrent with the hot flue gases of the kiln, by heat exchange with the aid of fluidization mixing.
Tn this preheating stage, procedures are taking place that are favourable from the point of view of the subsequent sintering, such as homogenization of the grains of pulverized limestone and aluminium carrier, partial decarbonization of limestone and due to the uniform heating formation of a porous and spongy product which is homogeneous both physically and chemically. This stage is responsible that so~id-phase reactions should occur intensively and homogeneous in sintering step resulting in a residence time of the pre-heated mixture as short as 5 to 10 minutes in the rotary kiln. Thus, a very uniform heating up of the total amount of material to sintering temperature (1260 to 1360C in general) `-is possible. As a result, the procedure of sintering which is otherwise rather sensitive becomes not only simple but also sur-prisingly short. The conversion, is ended when the total amount ; of the material calculated is converted into dicaicium silicate and dodecacalcium heptaaluminate, preventing thus the formation ! , of gehlenit [Ca2A12SiO7~, a compound having harmful effects in every respect when using the conventional rotary-kiln technologies where a longer residence at sintering temperature highly contri-butes to its formation.
- ``` 1~87375 In the process, there is a very intensive contact between the porous material leaving the heat exchanger and enter-ing the rotary kiln and the slightly reducing, atmosphere of the kiln. As a result, thereof, the favourable effect of the Fe lII]-ion produced in the slightly reducing atmosphere upon the beta-to gamma transition of dicalcium silicate can be utilized. A dual advantage is offered by the fact that as the desirable reactions are taking place quantitatively, the phase conversion causing the dicalcium silicate to disintegrate is more complete than in the ~0 known technologies. First, the overall grain size of the powder produced by disintegration is significantly smaller as compared with the product of conventional sintering and thus the extraction time and the danger of dissolving the silica in the liquor is decreased. On the other hand, due to the decreased content of -- modification, a smaller amount of silica can dissolve in aluminate liquor due to the indifference to water of the pre- ~-dominating y - modification as against the hydraulic ~ - modifica-; tion. A common result of these advantages is the high-purity alumina with rninor silica content that can be produced.
~ : .
The following Example is presented to illustrate the process of the invention:
44 tons of fly ash and 124 tons of lime stone have ~een ground and subjected to dry homogenization. The mixture is fed to a heat exchanger from where the mixture left for the rotary kiln.
Chemical analysis of the starting substance is as follows:
2 3 SiO2 CaO Fe23 Na2O MgO Halogen Fly ash % 31.0 45.0 6.0 8.0 1.6 1.2 0.3 Lime stone % 0.5 0.7 53.4 0.2 0.2 0.8 0.01 The temperature at which the mixture composed of spongy lumps left the heat exchanger was 900C. This material passed then through thé 1260~C sintering part of the kiln within 10 minutes and, after ieaving the kiln, the sintered cake disintegrated - ~ , '.
~`` 1087375 into a fine powder in the temperature range of 270 to 180C
during cooling. ;
Grain size distribution of this powder was, as follows:
grain size in ~ %
0 to 5 14.0 ~:
5 to 10 26.0 : 10 to 15 29.0 lS to 20 15.0 20 to 25 4.0 . .~ -1025 to 30 . 2.5 .
30 to 40 2.0 .
40 to 50 1.0 50 to 60 0 5 > 60 6.0 Mineralogical composition of the disintegrating product was as follows:
- dicalcium silicate . 58% of this ~-modification below 2~ .
dodecacalcium heptaaluminate 24% : ;
A very short time, not more than 10 minutes was enough : ~
to extract practically the total disintegrating product in the ~ ~ , known way, using soda solution. Due to the short extraction time and to the fact that dicalcium silicate was predominantly present in y-modification, the amount of dissolved silica was not more than 60 mg/l. As a result, an extremely pure alumina has been '`
obtained from the aluminate liquor by use of conventional tech- .
nology. Percentual distribution of impurities in the alumina was :~
as follows:
SiO2 0.014 Fe23 0.012 TiO 0.005 P2O5 0.006 ..:
: . - 7 --` -" 1087375 V O5 0.005 Na20 0.110 -The amount of alumina produced in this way was 9.8 tons with the residue of extraction amounting to 121 tons from which, after sintering with a technology known in the production of hydraulic cement and, with the addition of 5% of gypsum 109 tons of portland 600 quality hydraulic cement was produced.
,~
. . ~
: - 8 -
features of rotary-kiln processes, so far carried out the ideal composition could not have even approached as the total amount on the one hand of dicalcium silicate is inherently less and, even in this reduced amount, a full ~ - ~ conversion will not take place. On the other hand, gehlenit/dicalcium aluminium silicate/ I
acting as an inhibitor upon disintegration is always formed in these processes and its presence is disadvantageous also in res-pect of recovering aluminium values.
Hence, in developing of the known processes, the object is set to control after proper adjustment of the composition of the starting mixture, the kinetics of the mineralogical pro-cess taking place, so as to obtain a product composed of dicalcium-silicate/dodecacalcium heptaaluminate and to increase the degree j~ !
of conversion into y - modification and thereby improve the ¦;
aluminium recovery and reduce the silica contamination content of the aluminate liquor for~ed and, finally, to obtain a high-purity alumina as an end product. To achieve this, maximu~
degree of conversion of the silicon content of the sintered cake ; 20 into y - dicalcium silica modification and a small grain size of the end product is needed, the latter ~eing ensured through intensified disintegration.
The present invention provides a process wherein a fine-grain mixture composed of low-grade aluminium carriers such as coal slag, fly ash, low grade bauxite, red mud, and clay and limestone, pulverized expediently together is heated to 700-900C -~while applying a fluidization of the mixture preferably in a heat exchanger system, then the mixture is held at sintering tempera-ture for 5 to 10 minutes in a furnace, allowing the sintered product to come to form in a major part the y - modification from the dicalcium silicate content of the sintered product consisting of dodecacalcium-heptaaluminate and dicalcium silicate, extracting ', . ." ~ .
~ ;```` ~087375 the aluminium content of the disintegrating material to produce -high-purity alumina from the aluminate solution so obtained poor in silica, and hydraulic cement from the residue. -Limestone is added to the aluminium carriers used as the starting mixture of the process in a ratio permitting the total silicon and aluminium content of the sintered cake to con-vert into dicalcium silicate and dodecacalcium heptaaluminate, respectiveiy. Expediently, the starting materials are so pul-verized that, according to sieve analysis, the fraction above 88 ~ is below 10%. This substance-mixture is heated to 700 to 900C, expediently in countercurrent with the hot flue gases of the kiln, by heat exchange with the aid of fluidization mixing.
Tn this preheating stage, procedures are taking place that are favourable from the point of view of the subsequent sintering, such as homogenization of the grains of pulverized limestone and aluminium carrier, partial decarbonization of limestone and due to the uniform heating formation of a porous and spongy product which is homogeneous both physically and chemically. This stage is responsible that so~id-phase reactions should occur intensively and homogeneous in sintering step resulting in a residence time of the pre-heated mixture as short as 5 to 10 minutes in the rotary kiln. Thus, a very uniform heating up of the total amount of material to sintering temperature (1260 to 1360C in general) `-is possible. As a result, the procedure of sintering which is otherwise rather sensitive becomes not only simple but also sur-prisingly short. The conversion, is ended when the total amount ; of the material calculated is converted into dicaicium silicate and dodecacalcium heptaaluminate, preventing thus the formation ! , of gehlenit [Ca2A12SiO7~, a compound having harmful effects in every respect when using the conventional rotary-kiln technologies where a longer residence at sintering temperature highly contri-butes to its formation.
- ``` 1~87375 In the process, there is a very intensive contact between the porous material leaving the heat exchanger and enter-ing the rotary kiln and the slightly reducing, atmosphere of the kiln. As a result, thereof, the favourable effect of the Fe lII]-ion produced in the slightly reducing atmosphere upon the beta-to gamma transition of dicalcium silicate can be utilized. A dual advantage is offered by the fact that as the desirable reactions are taking place quantitatively, the phase conversion causing the dicalcium silicate to disintegrate is more complete than in the ~0 known technologies. First, the overall grain size of the powder produced by disintegration is significantly smaller as compared with the product of conventional sintering and thus the extraction time and the danger of dissolving the silica in the liquor is decreased. On the other hand, due to the decreased content of -- modification, a smaller amount of silica can dissolve in aluminate liquor due to the indifference to water of the pre- ~-dominating y - modification as against the hydraulic ~ - modifica-; tion. A common result of these advantages is the high-purity alumina with rninor silica content that can be produced.
~ : .
The following Example is presented to illustrate the process of the invention:
44 tons of fly ash and 124 tons of lime stone have ~een ground and subjected to dry homogenization. The mixture is fed to a heat exchanger from where the mixture left for the rotary kiln.
Chemical analysis of the starting substance is as follows:
2 3 SiO2 CaO Fe23 Na2O MgO Halogen Fly ash % 31.0 45.0 6.0 8.0 1.6 1.2 0.3 Lime stone % 0.5 0.7 53.4 0.2 0.2 0.8 0.01 The temperature at which the mixture composed of spongy lumps left the heat exchanger was 900C. This material passed then through thé 1260~C sintering part of the kiln within 10 minutes and, after ieaving the kiln, the sintered cake disintegrated - ~ , '.
~`` 1087375 into a fine powder in the temperature range of 270 to 180C
during cooling. ;
Grain size distribution of this powder was, as follows:
grain size in ~ %
0 to 5 14.0 ~:
5 to 10 26.0 : 10 to 15 29.0 lS to 20 15.0 20 to 25 4.0 . .~ -1025 to 30 . 2.5 .
30 to 40 2.0 .
40 to 50 1.0 50 to 60 0 5 > 60 6.0 Mineralogical composition of the disintegrating product was as follows:
- dicalcium silicate . 58% of this ~-modification below 2~ .
dodecacalcium heptaaluminate 24% : ;
A very short time, not more than 10 minutes was enough : ~
to extract practically the total disintegrating product in the ~ ~ , known way, using soda solution. Due to the short extraction time and to the fact that dicalcium silicate was predominantly present in y-modification, the amount of dissolved silica was not more than 60 mg/l. As a result, an extremely pure alumina has been '`
obtained from the aluminate liquor by use of conventional tech- .
nology. Percentual distribution of impurities in the alumina was :~
as follows:
SiO2 0.014 Fe23 0.012 TiO 0.005 P2O5 0.006 ..:
: . - 7 --` -" 1087375 V O5 0.005 Na20 0.110 -The amount of alumina produced in this way was 9.8 tons with the residue of extraction amounting to 121 tons from which, after sintering with a technology known in the production of hydraulic cement and, with the addition of 5% of gypsum 109 tons of portland 600 quality hydraulic cement was produced.
,~
. . ~
: - 8 -
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing high-purity alumina and hydraulic cement from a low-grade aluminium bearing siliceous carrier which comprises homogenizing a finely divided mixture of the low grade aluminium bearing silicons carrier and limestone, heating the mixture in a fluidized state to a temperature of 700 to 900°C , in heat exchange in a heat exchanger system, maintaining the heated mixture in a rotary kiln at sintering temperature for 5 to 10 minutes to yield sintered material containing dodecacalcium hepta-aluminate and the .beta.-modification of di-calcium silicate which material is allowed to cool and undergo disintegration by reason of the phase change of the dicalcium silicate to the .gamma.-modification and recovering alumina from the dodeca-calcium hepta-aluminate by dissolving in a caustic alkali solution and recovering and roasting the residue to yield the hydrolic cement.
2. A process as claimed in claim 1, in which the low grade aluminum bearing silicate carrier and the limestone are pulverized together.
3. A process as claimed in claim 2, in which the sieve analysis of the mixture gives a fraction of above 88µ
below 10%.
below 10%.
4. A process as claimed in claim 1, in which the mixture is heated in a heat exchanger system in direct flow.
5. A process as claimed in claim 1 in which the mixture is heated in a heat exchanger system using hot flue gases of the rotary kiln in countercurrent flow.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HUTA-1367 | 1975-07-23 | ||
| HU75TA1367A HU175544B (en) | 1975-07-23 | 1975-07-23 | Process for producing self dusting klinker for producing aluminium oxide of high purity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1087375A true CA1087375A (en) | 1980-10-14 |
Family
ID=11001858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA257,529A Expired CA1087375A (en) | 1975-07-23 | 1976-07-22 | Process for producing of high-purity alumina and hydraulic cement |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5248599A (en) |
| AT (1) | AT366655B (en) |
| BR (1) | BR7604766A (en) |
| CA (1) | CA1087375A (en) |
| DE (1) | DE2615590C3 (en) |
| FR (1) | FR2318824A1 (en) |
| GB (1) | GB1520186A (en) |
| HU (1) | HU175544B (en) |
| ZA (1) | ZA764055B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2521577C2 (en) * | 2012-10-23 | 2014-06-27 | Александр Валерьевич Александров | Production of aluminium-bearing cake |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55109232A (en) * | 1979-02-09 | 1980-08-22 | Pfizer | Synthetic rhombohedral magnetite and production method thereof |
| MX157475A (en) * | 1981-07-06 | 1988-11-23 | Ind Penoles Sa De Cv | IMPROVEMENTS IN A PROCEDURE FOR THE RECOVERY OF ALUMINA FROM ALUMINOSILIC MATERIALS |
| DE19727979C2 (en) * | 1997-07-01 | 1999-09-02 | Rheinische Kalksteinwerke | Process for the production of alumina cement |
| CN109970434B (en) * | 2019-04-17 | 2021-09-24 | 郑州市新郑梅久实业有限公司 | Ceramsite sand and production process thereof |
| CN110845159A (en) * | 2019-12-16 | 2020-02-28 | 焦作千业水泥有限责任公司 | Preparation method for producing portland cement clinker by coal gangue |
| CN114620958B (en) * | 2022-04-01 | 2024-03-12 | 西安建筑科技大学 | Process and system for synergistically activating coal gangue by using hot air of cement kiln |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE343264C (en) * | ||||
| FR501835A (en) * | 1916-03-07 | 1920-04-27 | Electro Metallurg Francaise | Processes for preparing lime aluminate for the manufacture of pure alumina |
| BE429208A (en) * | 1937-08-02 | |||
| US2283849A (en) * | 1939-07-25 | 1942-05-19 | William Sokolec | Method of producing alumina |
| FR1248038A (en) * | 1959-10-28 | 1960-12-09 | Electrochimie Electrometallurg | Anhydrous aluminas manufacturing process |
| GB1249345A (en) * | 1967-10-25 | 1971-10-13 | United States Steel Corp | Cement clinkers and method of making same |
| DE2048207A1 (en) * | 1970-10-01 | 1972-04-06 | Kloeckner Humboldt Deutz Ag | Equipment for the production of alumina from alumina hydrate |
-
1975
- 1975-07-23 HU HU75TA1367A patent/HU175544B/en not_active IP Right Cessation
-
1976
- 1976-03-25 AT AT0218476A patent/AT366655B/en not_active IP Right Cessation
- 1976-04-09 DE DE2615590A patent/DE2615590C3/en not_active Expired
- 1976-07-07 ZA ZA764055A patent/ZA764055B/en unknown
- 1976-07-15 GB GB29574/76A patent/GB1520186A/en not_active Expired
- 1976-07-19 FR FR7621946A patent/FR2318824A1/en active Granted
- 1976-07-22 CA CA257,529A patent/CA1087375A/en not_active Expired
- 1976-07-22 JP JP51087686A patent/JPS5248599A/en active Granted
- 1976-07-22 BR BR7604766A patent/BR7604766A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2521577C2 (en) * | 2012-10-23 | 2014-06-27 | Александр Валерьевич Александров | Production of aluminium-bearing cake |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5722887B2 (en) | 1982-05-15 |
| DE2615590B2 (en) | 1980-07-03 |
| ZA764055B (en) | 1977-06-29 |
| FR2318824B1 (en) | 1981-06-12 |
| ATA218476A (en) | 1981-09-15 |
| FR2318824A1 (en) | 1977-02-18 |
| BR7604766A (en) | 1977-08-02 |
| DE2615590A1 (en) | 1977-02-17 |
| DE2615590C3 (en) | 1985-06-20 |
| AT366655B (en) | 1982-04-26 |
| JPS5248599A (en) | 1977-04-18 |
| HU175544B (en) | 1980-08-28 |
| GB1520186A (en) | 1978-08-02 |
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