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Spent cerium-based glass-polishing slurry secondary resource

Used aqueous glass-polishing suspension containing ceria-based abrasive, fine glass particles and other process-derived components. The curated 2015 case is waste collected in several portions over six months from the Dioptra optical-glass-polishing factory in Turnov, Czech Republic, which used Cerox-type ceria polishing powders. Sedimentation partially dewatered the waste to approximately 50% water before treatment. Table 1 reports dry-solid XRF composition as oxide equivalents, including 8.85 wt% CeO2, 1.49 wt% La2O3 and 57.6 wt% SiO2. These are a reported waste-composition example, not universal proportions or quantitative mineral abundances. The mixed used slurry is distinct from pure cerium, reagent ceria, fresh polishing powder and the recovered ceria-rich product. Constituent criticality is not inherited by this resource.

Microbial & Biochemical Mechanisms (1)

Reductive acid digestion and carbonate-mediated recovery of ceria-rich oxide

recovery

Nitric-acid digestion with hydrogen peroxide transferred rare earths from the used polishing waste into solution while glass-rich solids remained undissolved. The authors interpret peroxide as a reductant that converts cerium to its trivalent soluble form. Carbonate precipitation, separation and calcination then produced a physically isolated ceria-rich solid that retained lanthanum and minor impurities. This is a demonstrated nonmicrobial laboratory recovery sequence, not a bioleaching observation, pure-element isolation or proven industrial recycling operation.

Experimental Context & Analytical Limits:
Partially dewatered factory waste was treated with concentrated nitric acid and hydrogen peroxide, each reported at 20% excess over stoichiometry relative to total rare-earth content, with peroxide added in portions. The mixture was stirred at 65-70 degrees C for three hours, cooled until the next day and filtered. The leachate was diluted to 0.2 mol/L total rare earths. Gaseous ammonia first neutralized excess acid to pH above 4, after which carbon dioxide and ammonia precipitated rare-earth carbonates around pH 7.2; the reported CO2:NH3 molar ratio was 5:1. After the pH rose to 9.5, ammonia was stopped, carbon dioxide continued for one hour, and the mixture was left until the next day. The separated precipitate was washed, dried at 110 degrees C, and annealed for two hours at selected temperatures from 200 to 900 degrees C. Solid composition used XRF, total dissolved rare earths complexometric titration, and product characterization XRD, SEM and thermal analysis. The paper does not give a recovery-stage batch mass, complete liquid volumes, replicate count, uncertainty or closed element mass balance. A pure cerous-nitrate-derived B-400 comparison belongs to subsequent product-performance tests; it is not a fresh-versus-spent-waste leaching control. No microbial treatment or living organism was used.
Curated Evidence Points:
Sections 2.1-2.4 and 3, Table 1 and Figures 1-3 support industrial waste provenance and the laboratory isolation of a ceria-rich product. The authors report approximately 70% cerium yield during acid digestion and describe subsequent precipitation, drying and calcination losses as negligible. These are reported approximate outcomes, not independently reconstructed yields with demonstrated uncertainty. Table 1 gives 92.8 wt% CeO2 equivalent and 3.75 wt% La2O3 equivalent in the recovered dry solid, compared with 8.85 and 1.49 wt% in the waste. Those assays indicate enrichment, not 92.8% recovery or elemental cerium purity. Product images and XRD confirm separated solids and a ceria-type crystalline phase.
Section 3 describes changing waste composition over the sampling period and a much richer historical waste from the same factory; that earlier feed and its different heating requirement are not treated as the present experiment. No matched acid-only or peroxide-omission recovery control resolves each reagent's incremental contribution. Quality-control blanks, duplicate performance measurements and fitted kinetic parameters in Sections 2.5 and 3.1 concern subsequent degradation assays, not replicate metal-recovery trials. The carbonate precursor lacked a unique resolved composition. Product XRD found a fluorite-type ceria structure despite measured lanthanum and other components, which does not establish chemically pure CeO2 or the calcium-fluoride mineral fluorite. Proposed ease of scaling is not demonstrated plant deployment.

Sources & References

  1. janos2015: Janos, Kuran, Ederer, Stastny, Vrtoch, Psenicka, Henych, Mazanec and Skoumal (2015). Recovery of Cerium Dioxide from Spent Glass-Polishing Slurry and Its Utilization as a Reactive Sorbent for Fast Degradation of Toxic Organophosphates. Advances in Materials Science and Engineering 2015, Article 241421, eight article pages. DOI 10.1155/2015/241421. Sections 2.1-2.4 and 3, Table 1 and Figures 1-3 establish the waste and chemical recovery.
    https://doi.org/10.1155/2015/241421 (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T04:38:08.667802+00:00 codex (GPT-6; codex) CREATE Created a spent mixed glass-polishing slurry resource with a nonmicrobial chemical recovery sequence, separating reported digestion yield, dry oxide-equivalent compositions and laboratory product isolation.

Record source: data/records/spent-cerium-glass-polishing-slurry.yaml