A New, Carbon-Negative Precipitated Calcium Carbonate Admixture (PCC-A) for Low Carbon Portland Cements

Abstract

The production of Portland cement accounts for approximately 7% of global anthropogenic CO2 emissions. Carbon CAPture and CONversion (CAPCON) technology under development by the authors allows for new methods to be developed to offset these emissions. Carbon-negative Precipitated Calcium Carbonate (PCC), produced from CO2 emissions, can be used as a means of offsetting the carbon footprint of cement production while potentially providing benefits to cement hydration, workability, durability and strength. In this paper, we present preliminary test results obtained for the mechanical and chemical properties of a new class of PCC blended Portland cements. These initial findings have shown that these cements behave differently from commonly used Portland cement and Portland limestone cement, which have been well documented to improve workability and the rate of hydration. The strength of blended Portland cements incorporating carbon-negative PCC Admixture (PCC-A) has been found to exceed that of the reference baseline—Ordinary Portland Cement (OPC). The reduction of the cement clinker factor, when using carbon-negative PCC-A, and the observed increase in compressive strength and the associated reduction in member size can reduce the carbon footprint of blended Portland cements by more than 25%.

Recycling CO2 from flue gas for CaCO3 nanoparticles production as cement filler: A Life Cycle Assessment

“…In fact, Climate change of 1 kg of Portland cement is 0.96 kg CO 2 eq while for the nano-added cement it is 0.3 kg CO 2 eq , meaning a reduction of 69 % in the CC category. McDonald et al, (2019) [38] stated that the exploitation in the cement industry of the carbon dioxide contained in the flue gas to produce calcium carbonate can reduce the carbon footprint of blended Portland cements by more than 25 %. In spite of their promising results, they recommend a full LCA of calcium carbonate cements in order to ger more accurate results.…”

Mechanical and Durability Properties of Portland Limestone Cement (PLC) Incorporated with Nano Calcium Carbonate (CaCO3)

“…Further, previous studies have shown that nano CaCO 3 can provide comparable benefits to other higher-cost nanomaterials [ 23 , 24 ]. Additionally, nano CaCO 3 can be produced within the cement plant utilizing the waste CO 2 using an integrated approach for green and economical cement production [ 25 , 26 ], thus is an environment-friendly technology. This approach will help mitigate the adverse impacts of cement plants on the environment while also providing extra revenue for the cement plant owners.…”

Decarbonisation of calcium carbonate at atmospheric temperatures and pressures, with simultaneous CO2 capture, through production of sodium carbonate

“…10 Industrially, Na 2 CO 3 is mainly produced through the Solvay process which requires large amount of thermal energy and CaCO 3 calcination. 33 The produced Na 2 CO 3 can have several uses in the industry: (1) for flue gas CO 2 sequestration through the production of NaHCO 3 , 34,35 (2) as an alkali activator for cements, either directly or in the production of activators such as sodium silicates, 36,37 (3) in the production of precipitated calcium carbonate from brine for use as a cement admixture, 38 (4) to regenerate the necessary NaOH, 21,[39][40][41] and/or (5) sold for the manufacture of other commodities (e.g. glass).…”