Low-Temperature Calcination of Belite-Calcium Sulphoaluminate Cement Clinker and the Hydration Process

2021 ◽  
Vol 33 (12) ◽  
pp. 04021350
Author(s):  
Wei Guo ◽  
Jialin Qiu ◽  
Qin Chen ◽  
Xiao Wang ◽  
Tao Yang
Keyword(s):  
Low Temperature ◽  
Hydration Process ◽  
Cement Clinker ◽  
Sulphoaluminate Cement ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement

Effect of Gypsum on Hydration Degree and Structure of Hardened Paste of Alite-Strontium Calcium Sulphoaluminate Cement

2011 ◽  
Vol 306-307 ◽  
pp. 1024-1028
Author(s):  
Qiu Ying Li ◽  
Ling Chao Lu ◽  
Shou De Wang
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Cement Clinker ◽  
Hardened Cement ◽  
Hydration Degree ◽  
Synthesis Conditions ◽  
Sulphoaluminate Cement ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement ◽  
Curing Age

Synthesis conditions and performance of alite-strontium calcium sulphoaluminate cement have been studied by introducing strontium calcium sulphoaluminate into Portland cement clinker. The effects of gypsum on compressive strength, hydration degree and structure of hardened alite-strontium calcium sulphoaluminate cement paste were studied in this paper. Composition and structure of the hardened cement paste were analyzed by XRD and SEM. Results show that appropriate content of gypsum could contribute to the hydration of alite-strontium calcium sulphoaluminate cement. When gypsum content is 9%, the compressive strengths for 1d, 3d and 28d curing age are 30.7MPa, 59.5MPa and 105.5MPa, and the corresponding hydration degree are 40.4%, 57.5% and 85.8%, respectively. The hydration products of alite-strontium calcium sulphoaluminate cement are mainly ettringite (AFt), Ca(OH)2, C-S-H gel. Large amount of AFt formed at early curing age provides a sound basis for early compressive strength, and a lot of C-S-H gel generated at later curing age increases the density of the hardened paste.

Determination of Tricalcium Silicates Crystal Forms in Belite-Barium Calcium Sulphoaluminate Cement

2014 ◽  
Vol 541-542 ◽  
pp. 204-208
Author(s):  
Yan Ting Zhao ◽  
Xi Chen ◽  
Ling Chao Lu ◽  
Yong Bo Huang ◽  
Jie Zhang
Keyword(s):  
Cement Clinker ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
Sulphoaluminate Cement ◽  
Cement System ◽  
Calcium Sulphoaluminate ◽  
Diffraction Peaks ◽  
Method Of Extraction ◽  
Calcium Sulphoaluminate Cement

Chemical method of extraction was adopted in the study, and aqueous solution of potassium hydroxide and sucrose (KOSH) was used to obtain the clinker rich in silicate phases (alite and belite) in order to get the crystal forms of tricalcium silicates (C3S) in the belite-barium calcium sulphoaluminate cement clinker. The crystal forms of C3S were finally determined by XRD (X-ray diffraction) spectrums through its characteristic windows of the diffraction spectrums. Results shows that, C3S exists in the innovative cement system mainly in the form of M1; C2.75B1.25A3can completely dissolve in KOSH solution while its dissolution is inhibited in the cement system; after KOSH treatment, diffraction peaks of C4AF disappear totally and peaks of C3A has weakened to great extent; for the cement clinker, the clinker ground for 90min has the best extraction rate.

Influences of Microelement on Microstructure and Mechanical Performance of Alite-Strontium Calcium Sulphoaluminate Cement

2010 ◽  
Vol 168-170 ◽  
pp. 466-471 ◽  
Author(s):  
Qiu Ying Li ◽  
Ling Chao Lu ◽  
Shou De Wang
Keyword(s):  
Mechanical Performance ◽  
Sintering Temperature ◽  
Cementitious Material ◽  
Cement Clinker ◽  
Testing Conditions ◽  
Sulphoaluminate Cement ◽  
Portland Cement Clinker ◽  
New Type ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement

Alite-strontium calcium sulphoaluminate cement, a new type of cementitious material, is synthesized by combining strontium calcium sulphoaluminate with minerals of Portland cement clinker. The influences of excessive SO3 and SrO on the microstructure and performances of this cement are studied by XRD, SEM-EDS and lithofacies. The results show that the optimal excessive mass fraction of SO3 and SrO are 50% and 80%. The compressive strength of the cement prepared under the testing conditions reaches to 32.8MPa, 66.8MPa and 126.4MPa at 1d, 3d and 28d curing ages, respectively. The additions of SO3 and SrO are benefit to improve the content of strontium calcium sulphoaluminate, and promote the formation of alite at low sintering temperature.

scholarly journals Calcination of Calcium Sulphoaluminate Cement Using Pyrite-Rich Cyanide Tailings

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 971
Author(s):  
Kaiwei Dong ◽  
Feng Xie ◽  
Wei Wang ◽  
Yongfeng Chang ◽  
Chunlin Chen ◽  
...  
Keyword(s):  
Gold Mining ◽  
Mining Industry ◽  
Cement Clinker ◽  
Optimal Conditions ◽  
Strength Criteria ◽  
Calcination Process ◽  
Sulphoaluminate Cement ◽  
Tailings Dams ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement

Pyrite-rich cyanide tailings (CTs) are industrial hazardous solid wastes arising from the gold mining industry. Every year, hundreds of millions of tons of cyanide tailings are produced and discharged to tailings dams. It is of great significance to dispose of cyanide tailings harmlessly and resourcefully. The feasibility of calcination of calcium sulphoaluminate (CSA) cement clinker using pyrite-rich cyanide tailings as Fe2O3 and SO3 sources was investigated for this paper. The behavior of pyrite during the calcination of cyanide tailings under various calcination conditions and the properties of calcium sulphoaluminate cement clinker were examined. The results show that it is feasible to produce calcium sulphoaluminate cement clinker using pyrite-rich cyanide tailings. The optimal conditions for the calcination of calcium sulphoaluminate cement using pyrite-rich cyanide tailings are confirmed. During the calcination process, the cyanides decompose into carbonate, CO2, and N2. The pyrite decomposes into Fe2O3 and SO2, and they react with CaO and Al2O3 to form the intermediates of CaSO4, 2CaO·Fe2O3, and CaO·2Al2O3, which further react to form 3CaO·3Al2O3·CaSO4, 4CaO·Al2O3·Fe2O3, and 12CaO·7Al2O3. The calcium sulphoaluminate cement prepared by pyrite-rich cyanide tailings exhibits excellent mechanical properties and meets the compressive strength criteria of 42.5 grade calcium sulphoaluminate cement.

Performance of Belite-Barium Calcium Sulphoaluminate Cement Prepared by Substituting Fly Ash for Clay

2011 ◽  
Vol 306-307 ◽  
pp. 1066-1070
Author(s):  
Pi Qi Zhao ◽  
Wen Zong ◽  
Shou De Wang ◽  
Gui Yun Wang ◽  
Ling Chao Lu
Keyword(s):  
Sintering Temperature ◽  
Cement Clinker ◽  
Petrographic Analysis ◽  
X Ray Diffraction ◽  
Sulphoaluminate Cement ◽  
Speed Up ◽  
Calcium Sulphoaluminate ◽  
And Performance ◽  
Sintering Condition ◽  
Calcium Sulphoaluminate Cement

The mineral structure and performance of belite-barium calcium sulphoaluminate cement clinkers were investigated by petrographic analysis, X-ray diffraction and scanning electron microscopy. The experimental results showed that the minerals of calcium barium sulphoaluminate (C2.75B1.25A3) and C2S could coexist in the belite-barium calcium sulphoaluminate cement clinker, and the optimal sintering temperature was 1380°C, at which, more C2.75B1.25A3was formed, well developed and also evenly distributed in the optimal sintering condition. If the sintering temperature exceeded 1380°C, the decomposition of C2.75B1.25A3 would speed up and the C3S became inactivate for its excessive development. In the optimal sintering condition, the compressive strength of the prepared cement at 3, 7, 28 d were 32.6, 47.9, 88.5 MPa respectively, which exhibited excellent mechanical properties.

Effect of Slag on Expansion of Alite-Calcium Barium Sulphoaluminate Cement

2011 ◽  
Vol 306-307 ◽  
pp. 1003-1006
Author(s):  
Shou De Wang ◽  
Ling Chao Lu ◽  
Xin Cheng
Keyword(s):  
Experimental Results ◽  
Expansion Rate ◽  
Cement Clinker ◽  
Crystal Formation ◽  
Sulphoaluminate Cement ◽  
Calcium Sulphoaluminate ◽  
Safety Range ◽  
Calcium Sulphoaluminate Cement ◽  
Slag Content

The influences of slag on the expansion of alite-calcium barium sulphoaluminate cement were studied. The experimental results indicated that the formation of ettringite and Ba-bearing ettringite are the main expansion sources of alite-calcium barium sulphoaluminate cement clinker with only gypsum. In addition to the ettringite and Ba-bearing ettringite, the Mg(OH)2 crystal formation was another probably the expansion source. The expansion rate of alite-calcium barium sulphoaluminate cement increased with slag content rising. Even if the content of slag in cement arrived at 20%, the soundness of alite-calcium sulphoaluminate cement its expansion was still in the safety range.

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