Method for producing ternesite-belite calcium sulfoaluminate clinker
The present invention relates to the production of a ternesite-belite-calcium sulfoaluminate (ferrite) clinker. The invention also relates to the use of alternative raw materials for clinker production, for example raw materials based on industrial byproducts, including those of low quality, such as lump slag and ash having a low glass content and/or a high free lime content and/or a high content of crystalline high-temperature phases, as well as naturally occurring rocks and rock glasses of comparative chemical composition.
1. A method for producing a hydraulically reactive clinker by sintering a raw meal mixture, which contains sources for CaO, Al 2 O 3 (Fe 2 O 3 ), SiO 2 and SO 3 , wherein
the raw meal mixture is sintered in a temperature range of >1200° C. to 1350° C. over a period of time sufficient to convert the raw meal mixture into a clinker intermediate product,
the clinker intermediate product is tempered in a temperature range of 1200° C. to a lower limit of 750° C. over a period of time sufficient to obtain 5 to 75 wt % of C 5 S 2 $ and to convert an amount of aluminate and ferrate phases and residues of crystalline high-temperature phases of the raw meal mixture with remaining C$ into additional C 4 (A x F 1-x ) 3 $ and C 5 S 2 $, and
the clinker comprising main components C 4 (A x F 1-x ) 3 $, (α; β) C 2 S, and C 5 S 2 $ in the following proportions
C 5 S 2 $
5 to 75 wt %
C 2 S
1 to 80 wt %
C 4 (A x F 1−x ) 3 $
5 to 70 wt %
one or more
0 to 30 wt %,
secondary phases
wherein x is a number from 0.1 to 1, is cooled.
2. The method according to claim 1 , wherein natural raw materials selected from the group consisting of limestone, bauxite, clay/claystone, basalt, kimberlite, dunite, periodite, ingnimbrite, carbonatite, anhydrite, gypsum, and mixtures thereof,
and/or industrial byproducts selected from the group consisting of waste dump materials, red mud, brown mud, landfill materials, ash, slag, ceramic residues, sulfate plant muds, phosphogypsum, and mixtures thereof are selected as sources for CaO, Al 2 O 3 (Fe 2 O 3 ), SiO 2 and SO 3 for the raw meal mixture.
3. The method according to claim 2 , wherein bauxite, clay and/or industrial byproducts and residual materials having an Al 2 O 3 (Fe 2 O 3 ) content of at least 5 wt is/are selected as an Al 2 O 3 (Fe 2 O 3 ) source.
4. The method according to claim 1 , wherein a type and amount of one or more secondary phases are controlled by ratios by weight of CaO/Al 2 O 3 (Fe 2 O 3 ), CaO/SiO 2 and by a proportion of a sulfate carrier in the raw meal mixture.
5. The method according to claim 1 , wherein the hydraulically reactive clinker contains one or more secondary elements and/or compounds thereof selected from the group consisting of alkaline and alkaline earth metals, transition metals, metals, semi-metals, and non-metals in a proportion up to 20 wt %.
6. The method according to claim 1 , wherein industrial byproducts and process dusts are used as correcting agents for adjustment of an amount of CaO, Al 2 O 3 (Fe 7 O 3 ), SiO 2 and SO 3 and ratios by weight of CaO/Al 2 O 3 (Fe 7 O 3 ) and CaO/SiO 2 in the raw meal mixture.
7. The method according to claim 1 , wherein the raw meal mixture is ground to finenesses (according to Blaine) of 1500 to 10000 cm 2 /g.
8. The method according to claim 1 , wherein the raw meal composition, a content of correcting agents, the burning conditions, and regulation of the tempering process are selected in such a way that C 5 S 2 S and, instead of β-C 2 S, reactive modifications of C 2 S are produced to an increased extent.
9. The method according to claim 1 , wherein the clinker is ground to finenesses (according to Blaine) of 2000 to 10000 cm 2 /g, either with or without sulfate carriers in the form of alkaline and/or alkaline earth sulfates.
10. The method according to claim 1 , wherein the one or more secondary phases are calcium silicates, sulfates, calcium aluminates, spinels, representatives of the melilite group, periclase, free lime, or a glass phase, and the one or more secondary phases are present in an amount of 0.1 to 30 wt %.
11. The method according to claim 4 , wherein the one or more secondary phases are present in an amount of 5 to 15 wt %.
12. The method according to claim 10 , wherein the one or more secondary phases are present in an amount of 5 to 15 wt %.
13. The method according to claim 7 , wherein the fineness ranges from 2000 to 4000 cm 2 /g.
14. The method according to claim 9 , wherein the fineness ranges from 3000 to 6000 cm 2 /g.
15. The method according to claim 14 , wherein the fineness ranges from 4000 to 5000 cm 2 /g.
16. The method according to claim 1 , wherein the raw meal mixture is sintered over a period of 10 to 240 minutes.
17. The method according to claim 1 , wherein the raw meal mixture is tempered over a period of 15 to 30 minutes.
18. The method according to claim 16 , wherein the raw meal mixture is tempered over a period of 15 to 30 minutes.
19. The method according to claim 4 , wherein the one or more secondary phases are calcium silicates, sulfates, calcium aluminates, spinels, representatives of melilite group, periclase, free lime, quartz or a glass phase, and the one or more secondary phases are present in an amount of 0.1 to 30 wt %.
20. The method according to claim 3 , wherein the Al 2 O 3 (Fe 2 O 3 ) content is at least 10 wt. %.
21. The method according to claim 5 , wherein the Al 2 O 3 (Fe 2 O 3 ) content is at least 15 wt. %.
22. The method according to claim 5 , wherein the one or more secondary elements and/or compounds thereof are contained in a proportion of ≦15 wt. %.
23. The method according to claim 5 , wherein the one or more secondary elements and/or compounds thereof are contained in a proportion of ≦10 wt. %.
24. The method according to claim 1 , wherein during the cooling the clinker passes through the temperature range between 1200° C. and 1050° C. for a period of 25 min to 120 min.
25. The method according to claim 24 , wherein during the cooling the clinker passes through a range of 1050° C. to 750° C. for a period of 5 min. to 120 min. before being cooled rapidly.
26. The method according to claim 1 , wherein the clinker intermediate product is tempered in a temperature range of 1200° C. to a lower limit of 750° C. over a period of time sufficient to obtain at least 10 wt % of C 5 S 2 $.
27. The method according to claim 1 , wherein the clinker intermediate product is tempered in a temperature range of 1200° C. to a lower limit of 750° C. over a period of time sufficient to obtain at least 20 wt % of C 5 S 2 $.
28. The method according to claim 24 , wherein the clinker intermediate product is tempered in a temperature range of 1200° C. to a lower limit of 750° C. over a period of time sufficient to obtain at least 20 wt % of C 5 S 2 $.
29. The method according to claim 25 , wherein the clinker intermediate product is tempered in a temperature range of 1200° C. to a lower limit of 750° C. over a period of time sufficient to obtain at least 20 wt % of C 5 S 2 $.