Selection and Validation of Alternate Slag Sources for Saltstone Production - 16145
- Savannah River Remediation LLC (United States)
- Vitreous State Laboratory, The Catholic University of America (United States)
To stabilize low activity salt solution produced at the Savannah River Site (SRS) the salt waste is mixed with a combination of fly ash (FA), ground granulated blast furnace slag (GGBFS), and ordinary Portland cement (OPC) to form a grout termed saltstone. Upon curing, the low activity waste is encapsulated within the hardened cementitious matrix. While the sources of the dry feed components have remained unchanged for several years, SRS was recently notified that its domestic source of GGBFS would no longer be available due to the shutdown of the steel making plant that produced the ferrous slag as a by-product. This shut-down follows a trend in the reduction of domestic ferrous slag sources. Alternate GGBFS vendors were sought and a program developed to validate the alternate sources for use in saltstone. GGBFS is primarily utilized in the construction industry as a replacement for OPC and the requirements of a GGBFS source, based on an American Society for Testing and Materials (ASTM) standard, are predominantly limited to demonstrating that the GGBFS replacement will provide equivalent strength in comparison to the baseline OPC-based concrete. This affords the construction industry significant flexibility with respect to the GGBFS source that can be used. In contrast, GGBFS has a role of significantly more importance when utilized in saltstone. In particular, the reducing blast furnace environment under which GGBFS is produced yields reducing species, such as sulfide (S{sup 2-}) and ferrous iron (Fe{sup 2+}), which are believed to facilitate the long-term immobilization of redox sensitive contaminants (e.g. technetium-99 ({sup 99}Tc)). In addition, a change in GGBFS source has the potential to impact the rheological properties and the reactive heat generation of the grout, which may adversely affect the ability to pump the grout to a Saltstone Disposal Unit (SDU) and the temperatures attained within an SDU, respectively. As such, alternate GGBFS sources for the processing of saltstone require significantly more scrutiny than is prescribed by the ASTM standard. Four alternate GGBFS sources were evaluated. All four sources met the ASTM requirements, only one source was considered viable for use in saltstone based on preliminary evaluation. The other three sources will require a more intensive assessment to determine their potential applicability. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 22838029
- Report Number(s):
- INIS-US-19-WM-16145; TRN: US19V1222083384
- Resource Relation:
- Conference: WM2016: 42. Annual Waste Management Symposium, Phoenix, AZ (United States), 6-10 Mar 2016; Other Information: Country of input: France; 6 refs.; available online at: http://archive.wmsym.org/2016/index.html
- Country of Publication:
- United States
- Language:
- English
Similar Records
Degradation Of Cementitious Materials Associated With Saltstone Disposal Units
Degradation of Saltstone Disposal Unit Cementitious Materials