Effects of accelerated carbonation on carbon dioxide uptake and compressive strength of biomass ash artificial aggregates

Ash disposal is a major cost to most power plants. Utilising ashes in construction products could enable the transition to a circular economy for power plants, bring higher value to the ashes and lower the need for virgin raw materials in the construction industry, while potentially help climate change mitigation via accelerated carbonation. In this study, three accelerated carbonation methods for artificial aggregate manufacturing from two biomass combustion fly ashes were studied: post-granulation CO2 curing in an autoclave, simultaneous tumbling drum granulation and CO2 curing, and carbonated water granulation. The control samples were granulated with water only. The effect on compressive strength was measured from repeated tests with single granules and the effect on carbon dioxide uptake was measured with both quantitative analysis on TG-DSC-QMS graphs and high-temperature oxygen combustion gas analysis of ground samples. It was found that all carbonation methods increased the compressive strength of the granules. Both post-granulation CO2 curing in an autoclave and simultaneous tumbling drum granulation and CO2 curing significantly increased the carbon content of the granules. Based on the results, 1 ton of fresh ash from the power plant could bind up to 166 kg more CO2 when manufactured into carbonated artificial aggregates rather than water granulated aggregates. We note, that the baseline comparison for ash granulation concepts with regards to the climate impact is not zero as the ashes carbonate also naturally in contact with ambient air. More studies on quantitative analysis of natural carbonation of ashes are encouraged

Carbon dioxide use and removal : Prospects and policies

This report presents an overview of the current status of carbon capture, utilisation and storage (CCUS) and carbon dioxide removal (CDR), in terms of and main technologies, markets and policies, especially from the perspective of Finland. CDR refers to technologies and practices, which can remove carbon dioxide (CO2) from the atmosphere and store it in a manner intended to be permanent. CCUS refers to permanent storage of captured CO2 or to the utilisation of captured CO2 as a feedstock for different products which also form short- or long-term storage over their life cycle. The products can range from fuels (short lifetime) to performance polymers (long lifetime) and to mineral products (often permanent storage). The market assessment included also quantitative and qualitative estimates for future development in size and growing CCUS and CDR solutions. Finland’s export potential in the technologies and products was also investigated. The policy environment of the technologies was assessed in terms of greenhouse gas accounting and reporting rules under the UNFCC and EU legal frameworks. Moreover, an international benchmarking of national policies was carried out to survey good practices in peer jurisdictions. Taking note of the assessed main technology options, the policy overview was used to identify policy development needs and to provide recommendations accordingly.This publication is part of the implementation of the Government Plan for Analysis, Assessment and Research. (tietokayttoon.fi) The content is the responsibility of the producers of the information and does not necessarily represent the view of the Government

Extraction of magnesium from mine tailings for carbon dioxide mineralization: A preliminary study of the effect of ammonium sulfate to tailings ratio on products and yield

Carbon capture and storage is needed to achieve deep cuts in industrial carbon dioxide (CO2) emissions. One option for storing carbon dioxide is its mineralization, which is especially useful in regions with available mine tailings but no nearby geological formations suitable for carbon dioxide storage. A multi-step mineralization route has been developed at Åbo Akademi University. In this study the first step, thermal extraction of magnesium, was further improved for two magnesium-rich Finnish mine tailings as raw materials. In the experiments, the maximum yield of extracted magnesium was similar (57–65%) to that of previous studies for both tailings with a ratio of 1:3 of mine tailings to ammonium sulfate ((NH4)2SO4), but only slightly better than with a ratio of 1:2 (55–58%). It was also found that increasing the average temperature from 410 to 460 °C slightly decreased the yield. Moreover, increasing the amount of the extracting agent, ammonium sulfate, can increase the possibility of obtaining efremovite ((NH4)2Mg2(SO4)3) instead of magnesium sulfate (MgSO4). This new knowledge of the effect of the reagent ratios on the formation of extraction products like efremovite could be exploited in further studies to minimize water consumption and thus energy use in ammonium sulfate recycling.<br/

Anatomia do lenho de Mimosa flocculosa Burkart

O lenho de Mimosa flocculosa Burkart é anatomicamente descrito, com base em material procedente de Colombo, Paraná. Foram observados os seguintes caracteres: placas de perfuração simples; elementos vasculares curtos; pontoações intervasculares alternas, ornamentadas; parênquima paratraqueal; raios heterogêneos; fibras libriformes; e ausência de estratificação