Cement production is one of the largest industrial sources of CO 2 emissions due to the thermal decomposition of limestone (CaCO 3 ). We integrate the chemical engineering strategy into the cement production and propose a novel process of “Carbonate Dry Reforming of Methane (CaDRM)” that converts the limestone (CaCO 3 ) directly into the cement clinker precursor (CaO) and syngas (CO + H 2 ) through reacting with methane (CH 4 ). Thermodynamic analysis indicates the reaction temperature of CaDRM is lowered by at least 200 °C compared with CaCO 3 thermal decomposition. Lab-scale experimental studies show a 95 % CaO yield at a 91 % syngas selectivity and 90 % CH 4 conversion in CaDRM using cement raw meal at 700 °C. Process simulation scale-up and economic analysis indicate CaDRM pathway can reduce 37.2 % CO 2 emission in comparison with the conventional CaCO 3 thermal decomposition pathway. More significantly, the net profit of $271.0/t (clinker) can be achieved by the value-added syngas products and the energy saving. The economic and environmental benefits of the proposed CaDRM strategy can help its future commercial deployment.
Ming Zhao,Yeping Ge,Yurong Li,Xiaoyan Song,Xinping Zhang
The advancement of Eu 2+ -activated luminescent materials tailored to exhibit a range of properties is crucial for addressing the specific demands of various application fields. However, the lack of suitable lattice sites in numerous compounds for stable Eu 2+ incorporation restricts their potential for diverse optical properties. Herein, a facile strategy of carbon and hydrogen coreduction utilizing graphite crucibles is proposed to effectively achieve the impressive luminescence of Eu 2+ at trivalent Y sites in Rb 3 Y(PO 4 ) 2 :Eu phosphors. Rb 3 Y(PO 4 ) 2 :Eu exhibits blue-violet emission when Eu 2+ predominantly occupies the Rb1 and Rb2 sites. Inspiringly, by facilitating the reduction of more Eu 3+ to Eu 2+ , a yellow emission band at 550 nm arising from Eu 2+ at Y sites emerges, enabling the realization of single-component white-emitting and yellow-emitting Rb 3 Y(PO 4 ) 2 :Eu phosphors. The diverse luminescent properties of Rb 3 Y(PO 4 ) 2 :Eu expand its potential applications in different white light source devices and optical thermometry. This work presents an innovative synthetic strategy to develop remarkable Eu 2+ luminescence at trivalent cation sites, thereby broadening the optical properties of the material and enabling multifunctional applications.
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