Impacts of Nickel Nanoparticles on Mineral Carbonation

Marius Bodor,Tom Van Gerven,Rafael M Santos,Yi Wai Chiang,Maria Vlad

doi:10.1155/2014/921974

Marius Bodor, Tom Van Gerven + Show 3 more

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https://doi.org/10.1155/2014/921974

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Abstract

This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP) as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags), on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO2 bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.

Highlights

With a capacity exceeding the needs to sequester all the anthropogenic CO2 emissions [1], mineral carbonation represents one of the most promising methods for the mitigation of carbon dioxide originating from industrial sources
Due to the relatively high stability of natural minerals that could be used in mineral carbonation processes, CO2 sequestration through this method is for the moment economically challenging [2]
Seeing as only continuous casting (CC) slag benefited from nickel nanoparticles (NiNP) addition, it can be said that only those materials that carbonate rapidly can benefit from NiNP addition in the early phases of the reaction, since when carbonation is slow, the rate limiting step is from the very beginning the dissolution of alkaline earth metals from the mineral matrix, rather than CO2 availability in solution

Summary

Introduction

With a capacity exceeding the needs to sequester all the anthropogenic CO2 emissions [1], mineral carbonation represents one of the most promising methods for the mitigation of carbon dioxide originating from industrial sources (e.g., power plants, steel refineries, cement kilns, etc.). The advantages of using industrial wastes in mineral carbonation processes consist in the high reactivity of these materials compared to natural minerals and in their positioning near CO2 sources, reducing transport related costs to a minimum. These materials are not available in a sufficient quantity to sequester the entire excess of industrial CO2 emissions, they can offer the means to kick-start the meaningful implementation of accelerated CO2 mineralization. These methods are most generally split in two main categories: direct and indirect [3, 4], depending on whether CO2 reacts in the presence of the alkaline solids, or if the alkaline component are first extracted into solution by lixiviants prior to residual solids separation and CO2

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