Integration of CO 2 Capture and Mineral Carbonation by Using Recyclable Ammonium Salts

The Results and Discussion section reports selective dissolution with NH4HSO4: 91% of magnesium but only 17% of silicon dissolved from serpentine in one experiment. The Introduction reports 70% serpentine dissolution using sulfuric acid, but gives no comparable measure of selective leaching. The paper therefore supports the ammonium-salt part of the claim, not the asserted superiority over sulfuric acid. (LLM, conf=0.82)

The Experimental Section describes raising the pH of an acidic serpentine solution to remove impurities before magnesium carbonation, and the Mass balance section reports silica in the dissolution residue and iron in the residue or pH-swing precipitate. But the paper does not establish that indirect processes generally separate all the named products at 90% purity: it reports 80% pure hydromagnesite in Precipitation studies, no calcium-carbonate product, and a byproduct with at most 27.5 wt% iron in the Conclusions. Its approximately 90% figure for that experiment is carbonation efficiency, not product purity; page numbers are unavailable in our copy. (LLM, conf=0.90)

The Experimental Section describes an indirect process that extracts magnesium from serpentine and precipitates hydromagnesite. But Results and Discussion > Precipitation studies reports 80% purity for the measured product in experiment 7, not >93 wt%. The Conclusions calls the product “pure” without establishing the claimed threshold; the reported 95.9% is carbonation efficiency, not purity. Page numbers are unavailable in our copy. (LLM, conf=0.88)

The Introduction mentions a batch autoclave used in another study but gives no liquid-to-solid ratio. The Results and Discussion section reports a 1:2 mass ratio of Mg to NH4HCO3, which is not a liquid-to-solid ratio. Searches for “autoclave,” “liquid-to-solid,” and related terms found no statement that the lowest autoclave L/S ratio is 2 kg kg−1; page numbers were unavailable in our copy. (LLM, conf=0.76)

The Introduction (page unavailable) mentions a batch autoclave only when describing another study. The Results and Discussion section on carbonation ratios (page unavailable) examines Mg/NH4HCO3/NH3 ratios, not liquid-to-solid ratios. Searches for L/S ratios below 2, inadequate stirring, and gas–liquid or solid–liquid mass transfer found no passage addressing the claim. (LLM, conf=0.76)

The Results and Discussion section on Mg/NH4HCO3/NH3 ratios links reagent ratios to carbonation efficiency, not liquid-to-solid (L/S) ratios. Searches for L/S ratio and liquid-to-solid ratio found no passage saying that most aqueous carbonation experiments use a higher L/S ratio to improve conversion. Page numbers were unavailable in our copy. (LLM, conf=0.76)