Abstract: A method for improving the reactivity of carbonated recycled concrete paste including sulfur in an oxidation state lower than 6+ as supplementary cementitious material includes the steps: providing a starting material including recycled concrete paste; carbonation of the starting material with carbon dioxide contained in an exhaust gas containing from 2 to 15 Vol.-% oxygen and/or from 35 to 400 vppm sulfur dioxide to provide carbonated recycled concrete paste; and oxidation of the carbonated recycled concrete paste simultaneously or subsequently to the carbonation with an added oxidizing agent to provide the supplementary cementitious material, and method for making composite cements.

Abstract: Carbon capture method for an industrial plant off-gas involves removing mercury and/or other heavy metals from the off-gas by contacting the off-gas with an at least partially hydrated cement paste as sorbent in a scrubber before a concentration step of the off-gas to concentrate CO2. The at least partially hydrated cement paste is simultaneously carbonated and loaded with the mercury and/or other heavy metals during contacting with the off-gas and is used as supplementary cementitious material in composite cement. The at least partially hydrated cement paste is used as sorbent in a scrubber before a concentration step of the off-gas to concentrate CO2.

Abstract: The present disclosure relates to an apparatus and method for processing old concrete. The old concrete comprises cement rock and an aggregate, including sand and/or gravel. The method includes: grinding the old concrete in a grinding device; classifying the ground old concrete in a classifying device into at least two products of different grain fractions. The grinding is effected at a grinding pressure of less than 50 MPa. The apparatus includes a grinding device for grinding the old concrete, and a classifying device for classifying the ground old concrete into at least two products of different grain fractions. The grinding device is designed, and configured, in such a way that the grinding of the old concrete is effected at a grinding pressure of less than 50 MPa.

Abstract: A method for separating hydrated concrete paste from aggregate includes the steps of providing a feedstock comprising waste concrete with a D10?0.1 mm and a D90?100 mm, passing the feedstock, a water containing liquid and carbon dioxide into a fragmentation vessel, where the wet feedstock is subjected to electric-pulse fragmentation, withdrawing fragmented solid material from the fragmentation vessel, separating the fragmented solid material from admixed liquid phase, separating the fragmented solid material into a fine fraction with a maximum particle size of 250 ?m to provide the carbonated recycled concrete paste and a coarse fraction, recycling the coarse fraction into the fragmentation vessel and/or discharging the coarse fraction as clean aggregate, use of the recycled concrete paste obtained thereby as supplementary cementitious material or filler.

Abstract: A method for converting a starting material containing at least 40 wt.-% of calcium silicon (hydr)oxide phases and calcium aluminum (hydr)oxide phases into an SiO2 rich SCM and a calcium carbonate additive includes the steps: providing the starting material with a D90 of ?1 mm, mixing the starting material with water or adjusting the water content to provide a starting material slurry having a solid:liquid weight ratio from 2:1 to 1:100, passing the starting material slurry together with carbon dioxide into a gravity separation reactor, subjecting the starting material slurry and carbon dioxide to centrifugal motion inside the reactor, and removing a heavy slurry from a first outlet of the reactor, removing a light slurry of lower density particles from a second outlet of the reactor, and removing liquid at a third outlet of the reactor.

Abstract: A method for manufacturing a composite cement comprising a cement and calcined clay has the steps of providing the cement, providing calcined clay by grinding a material comprising clay compounds and at least one of quartz and/or feldspar, separating the clay compounds from quartz and/or feldspar by classification and calcination of the clay compounds to provide the calcined clay, and mixing the cement with the calcined clay to provide the composite cement.