Origin and characterization of fly ashes from cellulose industries containing high proportions of free lime and anhydrite

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Cement and Concrete Research

DOI:https://doi.org/10.1016/S0008-8846(99)00116-7· OSTI ID:20002045

Hauser, A; Eggenberger, U; Peters, T

Fly ashes from cellulose industries originate from different internal waste combustion processes. Because they contain considerable amounts of free lime and anhydrite, they are potential secondary raw materials for the production of building products. The source of the CaO is a Ca-bisulfite-sludge originating from the cellulose extraction process. The CaO/anhydrite ratio in this lime-sulfate fly ash depends on the extent of sulphur reduction by organic carbon during the combustion process. A second type of Al-bearing ash contains additionally lowly reactive calcium silicates and highly reactive calcium aluminate phases originating from combusted paper sludge containing kaolinite. Both ashes show a reduced reactivity compared to commercial lime as it is used for the production of autoclaved aerated concrete. The reduced activity is related to the coated surfaces of the CaO and elevated sulfate and alkali contents.

• Research Organization: Mineralogisch-Petrographisches Inst., Bern (CH)
• OSTI ID: 20002045
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 10 Vol. 29; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ALUMINATES
ANHYDRITE
BUILDING MATERIALS
CALCIUM OXIDES
CELLULOSE
CHEMICAL COMPOSITION
FLY ASH
PHASE STUDIES
WASTE PRODUCT UTILIZATION