Details

Autor(en) / Beteiligte

• Abudoureheman, Maierhaba
• He, Lanzhen
• Ma, Fangru
• Wei, Bo
• Wang, Jianjiang
• Zhu, Quan
• Yao, Hong

Titel

Depolymerization mechanism of MgO on a silicate microstructure under different CaO contents: a theoretical and experimental study

Ist Teil von

• New journal of chemistry, 2024-04, Vol.48 (16), p.748-7488

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The content of alkaline earth metals in Zhundong (ZD) coal ash has a great effect on its melting characteristics. Herein, the influence of MgO content on a silicate microstructure was studied using molecular dynamics simulation under the conditions of 40 mol% high calcium and 20 mol% low calcium. Moreover, the theoretical results were verified by the Fourier transform infrared (FTIR) spectroscopy analysis of synthetic coal ash. In the MgO-CaO-Al 2 O 3 -SiO 2 system, the results showed that the average bond lengths of Si-O and Al-O in the system are 1.61 and 1.75 Å, respectively, under the high calcium condition. With an increase in MgO content, Q 4 with a high degree of polymerization was depolymerized and changed into Q 1 , Q 2 and Q 3 with a low degree of polymerization; O t decreased, O b increased first and then decreased, and O nb increased. Under the low calcium condition, the average bond lengths of Si-O and Al-O were 1.61 and 1.76 Å, respectively. When the content of MgO increased, Q 4 was depolymerized into Q 2 and Q 3 , O t decreased, O nb increased, and O b only increased by 1%. Compared with Si 4+ , Mg 2+ easily attacks Al 3+ , and the degree of damage to the [AlO 4 ] 5− tetrahedron is greater. By comparing the distribution of oxygen and the degree of polymerization in the high calcium and low calcium systems, it was concluded that MgO more easily destroys the silicate networks of ash under the condition of high calcium CaO content of 40 mol%, which changes the viscosity and combustion characteristics of the system. The mechanism of the effect of MgO on the microstructure depolymerization of Zhundong coal ash under the condition of different CaO contents was studied using molecular dynamics simulation and experimental methods.