Experimental Investigation and Multi-Gene Genetic Programming Simulation of Portland Clinker Burnability

In this study, the effect of chemical composition of the raw material on the clinker burnability was studied by determination of free CaO (wt %) content of clinker. The burnability of two types of Portland clinker was investigated for silica modules of 2.3, 2.5 and 2.7 and lime saturation factor of 0.88–0.98. In addition, using the Multi-gene genetic programming (MGGP) model, the burnability of clinker was predicted. The results of MGGP model indicated that the performance of the model for predicting the amount of free CaO (wt %) was acceptable. Moreover, using MGGP, a promising correlation was introduced for accurately calculating the amount of free CaO (wt %). The performance of this correlation was compared with FL-Smidth, and it was established that the average errors of MGGP correlation and FL-Smidth equation were 2.95 and 7.45 %, respectively.

Used Tires as Fuel in Clinker Production: Economic and Environmental Implications

This work analyzes how gases emitted during the manufacture of clinker vary in a cement plant using two types of fuel: petroleum coke and unusable tires (UTs). This study is based on a case study using real time data on more than 40 process variables. Gases are analyzed from two points of the production process: from the sintering kiln, where the main focus of emissions to the atmosphere is by chimney, and from the preheater. The variation of CO and NOx depending on the oxygen and fuel type is studied. The SO2 levels are also analyzed and a decrease was observed when using the UTs. The quality of the clinker is compared according to the fuel type. The results are analyzed, on the one hand, by the quality of the clinker, determined by the content of the majority (C3S, alite) and minority (free CaO) phases, and, on the other hand, by the kiln sintering temperature, the most influential parameter in the productive process. It is verified that the clinker quality is maintained regardless of the type of fuel used. Therefore, the use of UTs as fuel could generate important economic and environmental benefits for cement companies.

Used Tires as Fuel in Clinker Production: Economic and Environmental Implications

The objective of this work is to compare how the gases emitted during the manufacture of the clinker vary in a cement plant, using two types of fuel: petroleum coke and unusable tires (UTs). The study is based on a case study using real time data on more than 40 process variables. Gases are analysed from two points of the production process: Sintering Kiln, main focus of emission to the atmosphere by chimney, and Preheater. The variation of CO and NOx depending on the oxygen and fuel type is studied. The SO2 levels are also analyzed, observing a decrease when using the UTs. The quality of the Clinker has been compared depending on the fuel type. The results are compared, on the one hand, with the quality of the clinker, determined by the content of the majority (C3S, Alite) and minority (Free CaO) phases, and, on the other hand, with the Kiln sintering temperature, the most influential parameter in the productive process. It is verified that Clinker quality is maintained, regardless of the type of fuel used. Concluding that the use of UTs as fuel can generate an important economic and environmental benefit for cement companies and their environment.

Dephosphorization behavior of reduced iron and the properties of high-P-containing slag

Reduced iron (1.74% P) is produced from oolitic hematite ore by coal-based reduction and magnetic separation. To realize the comprehensive utilization of Fe and P, the dephosphorization behavior of the reduced iron is investigated in the presence of CaO–SiO2–FeO–Al2O3 slag. The P content of the final iron and the P2O5 content of the high-P-containing slag are determined, and the phase composition and P2O5 solubility of the slag are analyzed. The P content can be decreased to 0.2% when the initial slag has a basicity of 3.5 and contains 55% FeO and 6% Al2O3. The phases of the high-P-containing slag are mainly Ca2Al2SiO7, Ca2SiO4, Ca5(PO4)2SiO4, and FeO, and P exists in the form of Ca5(PO4)2SiO4. Excessively high basicity or low content of FeO and Al2O3 results in free CaO, which affects the dephosphorization results. The change rule of the intensity of the Ca5(PO4)2SiO4 diffraction peak agrees well with the dephosphorization indexes, which further verify the accuracy of the dephosphorization experiments. Moreover, the P2O5 content and P2O5 solubility of the high-P-containing slag reached as high as 14.41 and 94.54%, respectively, indicating that it can be used as a phosphate fertilizer.

A Review of the Influence of Steel Furnace Slag Type on the Properties of Cementitious Composites

The type of steel furnace slag (SFS), including electric arc furnace (EAF) slag, basic oxygen furnace (BOF) slag, ladle metallurgy furnace (LMF) slag, and argon oxygen decarburization (AOD) slag, can significantly affect the composite properties when used as an aggregate or as a supplementary cementitious material in bound applications, such as concretes, mortars, alkali-activated materials, and stabilized soils. This review seeks to collate the findings from the literature to express the variability in material properties and to attempt to explain the source(s) of the variability. It was found that SFS composition and properties can be highly variable, including different compositions on the exterior and interior of a given SFS particle, which can affect bonding conditions and be one source of variability on composite properties. A suite of tests is proposed to better assess a given SFS stock for potential use in bound applications; at a minimum, the SFS should be evaluated for free CaO content, expansion potential, mineralogical composition, cementitious composite mechanical properties, and chemical composition with secondary tests, including cementitious composite durability properties, microstructural characterization, and free MgO content.

Stabilization of a Clayey Soil with Ladle Metallurgy Furnace Slag Fines

The research study described in this paper investigated the potential to use steel furnace slag (SFS) as a stabilizing additive for clayey soils. Even though SFS has limited applications in civil engineering infrastructure due to the formation of deleterious expansion in the presence of water, the free CaO and free MgO contents allow for the SFS to be a potentially suitable candidate for clayey soil stabilization and improvement. In this investigation, a kaolinite clay was stabilized with 10% and 15% ladle metallurgy furnace (LMF) slag fines by weight. This experimental study also included testing of the SFS mixtures with the activator calcium chloride (CaCl2), which was hypothesized to accelerate the hydration of the dicalcium silicate phase in the SFS, but the results show that the addition of CaCl2 was not found to be effective. Relative to the unmodified clay, the unconfined compressive strength increased by 67% and 91% when 10% and 15% LMF slag were utilized, respectively. Likewise, the dynamic modulus increased by 212% and 221% by adding 10% and 15% LMF slag, respectively. Specifically, the LMF slag fines are posited to primarily contribute to a mechanical rather than chemical stabilization mechanism. Overall, these findings suggest the effective utilization of SFS as a soil stabilization admixture to overcome problems associated with dispersive soils, but further research is required.

Obtaining low-energy cement from industrial raw material

The results of obtaining Portland cement by lowenergy technology using technogenic raw materials are presented. Coal wastes and tephritobasalt in a ratio of 1: 1 were used as the clay component, instead of scarce pyrite cinder, granular lead slags were used. The regularities of the influence of the compositions of the blends, saturation coefficient, silicate and alumina modules, firing modes on the chemical and mineral composition and quality of clinker and cement are established. The composition of the raw mixes was calculated according to the ROCS program, the content of free CaO in the clinker was determined. The strength of experimental cement was tested after 7 and 28 days of hardening. Its physical and mechanical characteristics and structure were studied.

Study on Preparation and Characterization of La2O3 Derived from Thai Monazite Ore Processing Supported Coal Fly Ash Catalyst

This research aims to study the preparation and characterization of La2O3 supported coal fly ash catalyst. Studied La2O3 and coal fly ash (CFA) were obtained from Thai monazite ore processing and local supplier, respectively. The catalyst was prepared by wet impregnation method. The influences of La2O3 loading and impregnation temperature on the chemical composition, crystalline phase and surface morphology of the catalyst were examined by varying the amount of La2O3 (5, 10 and 20 wt%) and the impregnation temperature (room temperature, 100, 150 and 200 °C). Characterizations such as WDXRF, XRD and SEM were carried out. The XRD results demonstrated that the La2O3 was highly dispersed on the CFA support. A high La2O3 loading resulted in an increase free CaO dissolvation during the impregnation which inhibited the interaction between SiO2 and La2O3. The impregnation temperature had no significant effect on the chemical and physical properties of the catalyst. The coexist of Fe3O4 in the CFA support might impact to hinder the incorporation of La2O3 into SiO2 matrix.