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Mostafa Mahinroosta - One of the best experts on this subject based on the ideXlab platform.
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Resistance of red clay brick waste/Phosphorus Slag-based geopolymer mortar to acid solutions of mild concentration
Journal of Building Engineering, 2021Co-Authors: Mostafa Vafaei, Ali Allahverdi, Peng Dong, Nabil Bassim, Mostafa MahinroostaAbstract:Abstract This work is devoted to the investigation of the resistance of geopolymer cement (GC) mortar based on mixture of red clay brick waste (RCBW) and Phosphorus Slag (PHS) in exposure to HCl and H2SO4 solutions of mild concentration. For this purpose, the GC mortar specimens were exposed to pH = 3 of each acid solution for 24 months. To prepare GC mortar, blend of RCBW and PHS was activated by water glass and NaOH and then hydrothermally cured. For comparison purpose, reference specimens were also prepared using high alumina and Portland cements. The durability of mortar specimens was evaluated by measuring the changes in compressive strength and mass as key parameters at predetermined time intervals. The structural and compositional changes of the reaction products were studied using appropriate characterization techniques. The obtained results disclosed that GC mortar exhibited an excellent acid resistance compared to reference mortars exhibiting significantly lower durability properties. The exposure to H2SO4 caused more deterioration in all specimens than the exposure to HCl owning to the adverse effect of gypsum formation, which results in the expansion and cracking of the paste matrix.
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A Temperature–Age Model For Prediction of Compressive Strength of Chemically Activated High Phosphorus Slag Content Cement
International Journal of Civil Engineering, 2017Co-Authors: Ali Allahverdi, Mostafa Mahinroosta, Shima PilehvarAbstract:Prediction of compressive strength by a proper model is a fast and cost-effective way for evaluating cement quality under various curing conditions. In this paper, a logarithmic model based on the results of an experimental work conducted to investigate the effects of curing time and temperature on the compressive strength development of chemically activated high Phosphorus Slag content cement has been presented. This model is in terms of curing time and temperature as independent variables and compressive strength as dependent variable. For this purpose, mortar specimens were prepared from 80 wt.% Phosphorus Slag, 14 wt.% Portland cement, and 6 wt.% compound chemical activator at Blaine fineness of 303 m^2/kg. The specimens were cured in lime-saturated water under temperatures of 25, 45, 65, 85, and 100 °C in oven. The model has two adjustable parameters for various curing times and temperatures. Modeling has been done by applying dimensionless insight. The proposed model can efficiently predict the compressive strength of this type of high Phosphorus Slag cement with an average relative error of less than 4%.
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Superior Sodium Sulfate Resistance of a Chemically Activated Phosphorus Slag–Based Composite Cement
Journal of Materials in Civil Engineering, 2017Co-Authors: Ali Allahverdi, Milad Akhondi, Mostafa MahinroostaAbstract:AbstractThis study is devoted to durability performance of a chemically-activated Phosphorus Slag-based composite cement (CAPSCC) against sodium sulfate attack. For this purpose, enough mortar specimens were prepared from Phosphorus Slag (80% by weight), Type II portland cement (14% by weight), and a compound chemical activator (6% by weight) at water-to-cement ratio of 0.37 and exposed to 5% sodium sulfate solution after being cured. Mortar specimens of both Types II and V portland cements (PC2 and PC5) were also prepared and used as control for comparison purposes. Based on experimental test results, after 12 months of exposure to 5% sodium sulfate solution, PC2, PC5, and CAPSCC exhibited 12.7, 7.5, and 2.1% loss in compressive strength, respectively. Measurements of expansion and weight changes were also done. Advanced studies by X-ray diffractometry and scanning electron microscopy were performed to characterize the products of the degradation process. All obtained results together confirmed the super...
Zha Zuo-tong - One of the best experts on this subject based on the ideXlab platform.
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Study on Fe Leaching Kinetic in the Acid Solution Process of Yellow Phosphorus Slag
Bulletin of the Chinese ceramic society, 2012Co-Authors: Zha Zuo-tongAbstract:When yellow Phosphorus Slag is leached by acid to prepare the white carbon black,the appearance quality of product is directly affected by leaching efficiency of iron,this paper studies iron dynamic properties in the course of acid leaching;the study results indicate that acid leaching process is a liquid-solid reaction controlled by chemical reaction and may be described by the unreacted shrink core model,and its apparent activation energy Ea is 21.70 kJ/mol,with reaction order 0.5005.
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Experimental study on producing calcium sulfate with yellow Phosphorus Slag
2011Co-Authors: Zha Zuo-tongAbstract:With yellow Phosphorus Slag as the raw material and nitric acid as leaching agent,SiO2 was separated from the yellow Phosphorus Slag in the form of amorphous hydrated silicon dioxide.The calcium was entered into leaching liquor in the form of calcium nitrate,which was precipitated with sulphuric acid,and the high quality calcium sulfate product was obtained after washing and drying.The influence of the factors like mass concentration of sulphuric acid,the volume ratio of H2SO4 to Ca(NO3)2,the stirring speed and the reaction temperature on the product quality of calcium sulfate was discussed.The characterization of the surface structure of calcium sulfate was performed by FTIR,TG-DTA and XRD.The result shows that the mass fraction of CaSO4 in the product can reach 99.66%,and the mass fraction of H2O is 19.43%,which was analyzed to be the product of CaSO4·2H2O by FTIR,TG-DTA and XRD.The optimum technical conditions are as follows: H2SO4 mass fraction 20%,the volume ratio of H2SO4 to Ca(NO3)2 0.6 ∶ 1,stirring speed 200 r/min,reaction time 30 min.
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Experimental Study on Refining White Carbon by Yellow Phosphorus Slag
Bulletin of the Chinese ceramic society, 2010Co-Authors: Zha Zuo-tongAbstract:With the yellow Phosphorus Slag as raw materials and nitric acid as leaching agent,the alcium was separated from the yellow Phosphorus Slag in the form of calcium nitrate.After washing,drying and calcining,the high quality white carbon black product was obtained,which mass fraction of silica(SiO2) could reach 98.80%,the mass fraction of Fe was 11 mg/kg,specific surface area was 201 cm2 /g.The study shows that the optimum technical conditions of refine were that the stirring speed was 360 r/min,the reaction time was 4 h,the reaction temperature was 80 ℃,the fluid-solid ratio was 10:1,the concentration of nitric acid was 20%,the washing terminal pH of the leaching residue was 6.0.
Igor Yurievich Silachyov - One of the best experts on this subject based on the ideXlab platform.
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Recovery of rare earth metals as critical raw materials from Phosphorus Slag of long-term storage
Hydrometallurgy, 2017Co-Authors: Z S Abisheva, Elmira Abdikhalikovna Sargelova, Marina Nikolayevna Kvyatkovskaya, Z B Karshigina, Ata Akcil, Ye G Bochevskaya, Igor Yurievich SilachyovAbstract:The present research is directed towards processing of Slag originating during the yellow Phosphorus production. The Slag was investigated using physical and chemical treatment methods. The following group of rare earth elements were identified in Phosphorus Slag such as: Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Tm, Yb, Lu. Thermodynamic calculation for reactions probability of phosphorous Slag components with nitric acid was made. Nitric-acid leaching of Slag generated during Phosphorus production was investigated for extraction of rare earth metals (REMs). Silicon containing cake obtained after leaching was suitable for precipitated silicon dioxide production. Behaviour of associated components such as calcium, aluminium and iron was studied during the leaching process. The following optimum parameters were selected for leaching studies: nitric acid concentration was 7.5 mol/dm3; solid-to-liquid ratio was 1:2.6–3; temperature was 50–80 °С; process duration was 1 h; pulp stirring rate was 500 rpm and the recovery of rare-earth metals, calcium, aluminum and iron into the solution were seen to be 85%, 98%, 80.7%, and 11.8%, respectively. Cake produced as a result of leaching contained ∼ 80–85% of amorphous SiO2. The solution obtained after Phosphorus Slag leaching was processed through solvent extraction methods to concentrate and separate it from basic macroimpurities. After precipitation of REMs oxalates from strip liquor and calcination of the precipitate a concentrate was obtained, which contained ∼ 17% of ∑ REMs oxides.
Ali Allahverdi - One of the best experts on this subject based on the ideXlab platform.
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Resistance of red clay brick waste/Phosphorus Slag-based geopolymer mortar to acid solutions of mild concentration
Journal of Building Engineering, 2021Co-Authors: Mostafa Vafaei, Ali Allahverdi, Peng Dong, Nabil Bassim, Mostafa MahinroostaAbstract:Abstract This work is devoted to the investigation of the resistance of geopolymer cement (GC) mortar based on mixture of red clay brick waste (RCBW) and Phosphorus Slag (PHS) in exposure to HCl and H2SO4 solutions of mild concentration. For this purpose, the GC mortar specimens were exposed to pH = 3 of each acid solution for 24 months. To prepare GC mortar, blend of RCBW and PHS was activated by water glass and NaOH and then hydrothermally cured. For comparison purpose, reference specimens were also prepared using high alumina and Portland cements. The durability of mortar specimens was evaluated by measuring the changes in compressive strength and mass as key parameters at predetermined time intervals. The structural and compositional changes of the reaction products were studied using appropriate characterization techniques. The obtained results disclosed that GC mortar exhibited an excellent acid resistance compared to reference mortars exhibiting significantly lower durability properties. The exposure to H2SO4 caused more deterioration in all specimens than the exposure to HCl owning to the adverse effect of gypsum formation, which results in the expansion and cracking of the paste matrix.
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A Temperature–Age Model For Prediction of Compressive Strength of Chemically Activated High Phosphorus Slag Content Cement
International Journal of Civil Engineering, 2017Co-Authors: Ali Allahverdi, Mostafa Mahinroosta, Shima PilehvarAbstract:Prediction of compressive strength by a proper model is a fast and cost-effective way for evaluating cement quality under various curing conditions. In this paper, a logarithmic model based on the results of an experimental work conducted to investigate the effects of curing time and temperature on the compressive strength development of chemically activated high Phosphorus Slag content cement has been presented. This model is in terms of curing time and temperature as independent variables and compressive strength as dependent variable. For this purpose, mortar specimens were prepared from 80 wt.% Phosphorus Slag, 14 wt.% Portland cement, and 6 wt.% compound chemical activator at Blaine fineness of 303 m^2/kg. The specimens were cured in lime-saturated water under temperatures of 25, 45, 65, 85, and 100 °C in oven. The model has two adjustable parameters for various curing times and temperatures. Modeling has been done by applying dimensionless insight. The proposed model can efficiently predict the compressive strength of this type of high Phosphorus Slag cement with an average relative error of less than 4%.
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Superior Sodium Sulfate Resistance of a Chemically Activated Phosphorus Slag–Based Composite Cement
Journal of Materials in Civil Engineering, 2017Co-Authors: Ali Allahverdi, Milad Akhondi, Mostafa MahinroostaAbstract:AbstractThis study is devoted to durability performance of a chemically-activated Phosphorus Slag-based composite cement (CAPSCC) against sodium sulfate attack. For this purpose, enough mortar specimens were prepared from Phosphorus Slag (80% by weight), Type II portland cement (14% by weight), and a compound chemical activator (6% by weight) at water-to-cement ratio of 0.37 and exposed to 5% sodium sulfate solution after being cured. Mortar specimens of both Types II and V portland cements (PC2 and PC5) were also prepared and used as control for comparison purposes. Based on experimental test results, after 12 months of exposure to 5% sodium sulfate solution, PC2, PC5, and CAPSCC exhibited 12.7, 7.5, and 2.1% loss in compressive strength, respectively. Measurements of expansion and weight changes were also done. Advanced studies by X-ray diffractometry and scanning electron microscopy were performed to characterize the products of the degradation process. All obtained results together confirmed the super...
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Efflorescence Formation and Control in Alkali-Activated Phosphorus Slag Cement
International Journal of Civil Engineering, 2016Co-Authors: Hojjatollah Maghsoodloorad, Ali AllahverdiAbstract:Efflorescence formation is an important soundness issue to be considered with alkali-activated cements. In this study, the impact of activator type on the efflorescence formation severity and methods of efflorescence reduction in alkali-activated Phosphorus Slag cement are investigated. Different alkaline activators including NaOH, KOH and liquid sodium silicate of different silica modules (Ms = SiO_2/Na_2O) were used for alkali-activation of Phosphorus Slag. Additions of high alumina cements (Secar 71 and 80) and application of hydrothermal curing condition at 85 °C for 7 h with different pre-curing times (1, 3 and 7 days) in humid environment (relative humidity of 95 %) and 25 °C were used for efflorescence control in alkali-activated Phosphorus Slag cement. Sodium containing activators resulted in more severe efflorescence formation compared with those of potassium containing activators. Also presence of liquid sodium silicate intensified efflorescence formation. Based on the results obtained, application of an optimum pre-curing stage in humid environment before hydrothermal curing regime stabilizes the cement matrix and improves the effectiveness of hydrothermal conditions.
Li Bei-xin - One of the best experts on this subject based on the ideXlab platform.
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Properties and Preparation of Iron Tailings-Phosphorus Slag Based Composite Mineral Addition with Cascade-Grinding
Bulletin of the Chinese ceramic society, 2015Co-Authors: Li Bei-xinAbstract:Through different test means such as laser granularity analyzer, RRB( Rosin-RammlerBennett) equation fitting and determination of strength,the influences of grinding order and grinding time on the preparation and properties of tailings-Phosphorus Slag based composite mineral addition( called TPCMA) with cascade-grinding were studied,meanwhile,mortar strength ratio,XRD and SEM were used to study the index of activity and micro-reaction. The results show grinding Phosphorus Slag which is hard but high activity first step should improve the fineness of TPCMA and its overall activity index.Reasonable combination of grinding time is better for improving the uniformity of TPCMA particle and the mortar liquidity. Iron tailings powder itself has a weak pozzolanic activity,while the TPCMA pozzolanic activity was improved significantly compared with iron tailings powder,and the pozzolanic activity was mainly reflected at the later stage of hydration.