Nepheline Formation Potential in Sludge Batch 4 (SB4)

Nepheline Formation Study for Sludge Batch 4: Phase 3 Experimental Results

“…Peeler et al 1,25 provided insight into the potential impact of nepheline formation on SB4 glasses based on the Lilliston 23 SB4 compositional projections. In that study (referred to as Phase 1), twelve SB4-based glasses were fabricated (only two of which were prone to nepheline formation using the 0.62 value 22 as a guide) and the durability of each was measured.…”

“…24 The combination of high Al 2 O 3 and Na 2 O concentrations, coupled with lower SiO 2 concentrations as waste loadings are increased (given the primary source of SiO 2 is from the frit), shifts the composition toward the nepheline phase field, raising the potential for nepheline crystallization. Therefore, strategic frit development efforts 4 have been made to suppress the development of nepheline formation by lowering the Na 2 O content while increasing B 2 O 3 , Fe 2 O 3 , and/or Li 2 O concentration in the frit.…”

Sludge Batch 4: Model Based Assessments of the February 2007 Sludge Projection

“…They are being carried forward in this assessment to provide insight into their potential use with the latest SB4 compositional projection shown in Table 3-1. The "P-series", T1-1, "418-m" series, and the "200-m" series of frits have been developed to minimize the potential for nepheline formation given its impact on durability (Peeler et al (2005 and and Fox et al (2006a and). In general, these frits have lower Na 2 O concentrations than the "sliding scale series" with the differences being accounted for by increases in Perhaps of most interest to SB4 is the Frit 503-m series (also shaded in Table 3-2).…”

“…In addition, the potential for the formation of a nepheline primary crystalline phase was also included in the assessment using a nepheline discriminator function as described by Li et al (2003). 5 Based on recent experimental results (Peeler et al (2005 and and Fox et al (2006a and), a strategy for controlling or limiting access to WLs at which nepheline formation can lead to detrimental effects on durability was recommended. In response to this need, Edwards et al (2006) provided the technical basis for implementing the nepheline discriminator into PCCS for SB4 processing.…”

Refinement of the Nepheline Discriminator: Results of a Phase Ii Study

“…2 This constraint uses the inequality that was first proposed by Li 1 and later verified as applicable to DWPF-type glasses. [3][4][5][6][7] The nepheline discriminator is given as The current equation uses only the concentrations of the SiO 2 , Na 2 O and Al 2 O 3 components in the glass in predicting whether or not nepheline is likely to crystallize. However, several other components have been shown to impact the propensity for nepheline crystallization, including B 2 O 3 and CaO (potential DWPF frit components), among others.…”