Quantities Of CaCO3 Research Articles

Application of 2K full factorial on the production of charcoal briquettes made from coconut shell

The production of charcoal briquettes using 2k full factorial Design in Design Expert V12 software was utilized in this research work. The factors considered are: Quantity of CaCO3, Quantity of NaNO3 and Quantity of Starch binder. Analysis of variance (ANOVA) indicates that the linear effect of all the factors: A (Quantity of Catalyst), B (Quantity of CaCO3) and C (Quantity of Starch) are significant with P-values of 0.0050, 0.0062, and 0.0003 respectively. Other significant effects are the interactive effect of BC (Quantity of NaNO3 and Quantity of Starch) and that of the combine effect of all the three (3) factors (ABC) with P-values of 0.0125 and 0.0031 respectively. The Model F-value of 755.59 implies the significant of the model. The coefficient of determinant (R2) for the model of 0.9995 and Adjusted R2 of 0.9981 shows that the model equation has a very good fit to the experimental data. Briquettes produced from Run 7 and 4 have the least volatile matter of 1.54% and 1.67% respectively, the lowest ash content of 2.14% and 2.19 % respectively and the highest percentage fix carbon of 97.67% and 96.56% respectively.

Effects of Air Entrainment on Bacterial Viability in Cement Paste.

This study investigated the effect of air entrainment (AE) on bacterial viability in cementitious materials. Specimens were fabricated with Portland cement, urea, calcium lactate, and ureolytic bacteria, and with varying amounts of an AE agent. Specimens with different amounts of the AE agent were fabricated, and then a compressive strength test, quantitative polymerase chain reaction, X-ray diffraction, and thermogravimetry were used to investigate the mechanical properties, viability of bacteria, and hydrates of the specimens. The highest compressive strength was achieved by the specimen with 0.3% AE agent, while the compressive strength of the specimens decreased considerably when the incorporated AE agent was over 0.6%, due to increased porosity. The quantitative polymerase chain reaction result showed that the cell number of the viable bacteria was increased by incorporation of the AE agent, which also corresponded with an increase in CaCO3 due to microbial mineral formation. The obtained result confirmed the positive effect of AE agent incorporation in cementitious materials containing bacterial admixtures, as the viability of bacteria, which play a vital role in self-healing efficiency of concrete, was increased by the space provided by the AE agent in the cement matrix. In addition, the quantity of CaCO3 and the compressive strength were highest when 0.3% AE agent was incorporated.

High-Precision Simultaneous 18O/16O, 13C/12C, and 17O/16O Analyses for Microgram Quantities of CaCO3 by Tunable Infrared Laser Absorption Spectroscopy.

Stable isotope ratios (18O/16O, 13C/12C, and 17O/16O) in carbonates have contributed greatly to the understanding of Earth and planetary systems, climates, and history. The current method for measuring isotopologues of CO2 derived from CaCO3 is primarily gas-source isotope ratio mass spectroscopy (IRMS). However, IRMS has drawbacks, such as mass overlap by multiple CO2 isotopologues and contaminants, the requirement of careful sample purification, and the use of major instrumentation needing permanent installation and a high power electrical supply. Here, we report simultaneous 18O/16O, 13C/12C, and 17O/16O analyses for microgram quantities of CaCO3 using a tunable mid-infrared laser absorption spectroscopy (TILDAS) system, which has no mass overlap problem and yields high sensitivity/precision measurements on small samples, as small as 0.02 μmol of CO2 (equivalent to 2 μg of CaCO3) with standard errors of less than 0.08 ‰ for 18O/16O and 13C/12C (±0.136 ‰ and ±0.387 ‰ repeatability; n = 10). In larger samples of CO2, 0.68 μmol (or 68 μg of CaCO3), standard error is less than 0.04 ‰ for 18O/16O and 13C/12C (< ±0.1 ‰ repeatability; n = 10) and 0.03 ‰ for 17O/16O (±0.069 ‰ repeatability; n = 10). We also show, for the first time, the relationship between 17O/16O ratios measured using the TILDAS system and published δ17O values of international standard materials (NBS-18 and -19) measured by IRMS. The benchtop TILDAS system, with cryogen-free sample preparation vacuum lines for microgram quantities of carbonates, is therefore a significant advance in carbonate stable isotope ratio geochemistry and is a new alternative to conventional IRMS.

ChemInform Abstract: Structural Studies of CaAl12O19, SrAl12O19, La2/3+δAl12‐δO19, and CaAl10NiTiO19 with the Hibonite Structure; Indications of an Unusual Type of Ferroelectricity.

AbstractThe title hibonite‐type compounds are prepared by repeated firing of appropriate quantities of CaCO3, SrCO3, La2O3, NiO, Al2O3, and TiO2 in air (1300 °C for CaAl12O19, 1500 °C for all other compounds).

Elucidating the Role of the Aluminous Source on Limestone Reactivity in Cementitious Materials

When limestone (CaCO3) is present in ordinary portland cement (OPC), carbonate‐AFm phases (i.e., hemi‐ and/or mono‐carboaluminate) are stabilized at the expense of the sulfate‐AFm, which is more commonly found in cement systems. In OPC, the quantity of AFm hydrates formed is often limited by the availability of aluminum. Therefore, as a means of enhancing AFm phase formation, this study elucidates the role of aluminous sources including: calcium aluminate cements, metakaolin, and a hydratable alumina to determine if their addition would enhance limestone reactions and carbonate‐AFm formation in cement systems. The results of a detailed study including: X‐ray diffraction, strength measurements, thermogravimetric analysis, and thermodynamic calculations are used to quantify solid phase constitutions, and the extent of limestone reacted. The results suggest that, the amount of limestone reacted and the specific carbonate‐AFm formed is sensitive to both, the nature of the aluminous source and limestone content. Pozzolanic reactions which occur when metakaolin is used as an aluminous source are noted to be especially beneficial in offsetting the effects of OPC replacement. It is noted that although the different aluminous materials react with different quantities of CaCO3 during hydration, enhanced carbonate‐AFm formation alone is insufficient to ensure strength equivalence, when OPC is replaced by limestone.

&lt;b&gt;Alternative liming blends for fish culture&lt;/b&gt;

Calcium carbonate (limestone) is a safe but slow-acting product for aquaculture liming. Calcium oxide (lime) is a fast-acting but dangerous product. It would be interesting to have simultaneously a safe and fast-acting liming product. The present work aimed to evaluate two alternative liming blends for tilapia culture. The culture water was initially acidified with HCl. Next, the same quantity of CaCO3 (control), Na2CO3+CaSO4 or Na2CO3+CaCl2 was applied to the culture water. There were also non- limed tanks. One hundred and twenty Nile tilapia juveniles (1.6 ± 0.1 g) were stocked in twenty 250-L culture tanks for 10 weeks. All products used were similarly efficient in increasing the alkalinity of water. The probable better environment for algal growth in the limed tanks caused an increase in the DO2 concentrations and a decrease in CO2, total ammonia nitrogen, nitrite and phosphorus, in relation to the non-limed tanks. The highest final body weight of fish was observed in the Na2CO3+CaCl2 tanks. The lowest final body weight was verified in the CaCO3 tanks. It was concluded that the alternative blend of Na2CO3 plus CaCl2 is a better liming product than the standard CaCO3 for Nile tilapia culture.

THE INFLUENCE OF POLYMER LATEX AND SILICA FUME ADDITIVES ON THE PROPERTIES OF CEMENT MORTAR AND CONCRETE

The article maintains that while mixing acryliated latex, cement, fillings, and relaxing additives, flexible, resilient and well sticking to concrete mortars are obtained. Their properties—the lengthening of a mortar layer, tensile strength and strength of adhesion to concrete—may be regulated while changing the quantities of cement and plasticisers. 10–30 % silica fume and Stoniškiai carbonate opoca additives grant to usual Portland cement mortar or concrete the resistance to sulfate corrosion. When the quantity of cement in concrete exceeds 400 kg/m3, an increased quantity of hydraulic additive is necessary 20–30%. Opoca additive ensures a better Portland cement resistance to sulfate action than the same quantity of CaCO3 and Norwegian silica fume mixture. This fact is explained by a larger activity of opoca. However silica fume activity may be increased by reducing silica fume to smaller units, for example by mixing it with coarse aggregate. In hardening, concrete silica fume and other hydraulic additives react with Ca(OH)2 deriving from cement, that's why in hardened concrete free lime diminishes and less secondary expansion units are created. There are vivid peaks of CaSO4·2H2O and Ca(OH)2 in XRD patterns of decayed samples. This research shows that gypsum formation is the main reason of concrete decay in Na2SO4 solution.

THE INFLUENCE OF POLYMER LATEX AND SILICA FUME ADDITIVES ON THE PROPERTIES OF CEMENT MORTAR AND CONCRETE

Abstract The article maintains that while mixing acryliated latex, cement, fillings, and relaxing additives, flexible, resilient and well sticking to concrete mortars are obtained. Their properties—the lengthening of a mortar layer, tensile strength and strength of adhesion to concrete—may be regulated while changing the quantities of cement and plasticisers. 10–30 % silica fume and Stoniskiai carbonate opoca additives grant to usual Portland cement mortar or concrete the resistance to sulfate corrosion. When the quantity of cement in concrete exceeds 400 kg/m3, an increased quantity of hydraulic additive is necessary 20–30%. Opoca additive ensures a better Portland cement resistance to sulfate action than the same quantity of CaCO3 and Norwegian silica fume mixture. This fact is explained by a larger activity of opoca. However silica fume activity may be increased by reducing silica fume to smaller units, for example by mixing it with coarse aggregate. In hardening, concrete silica fume and other hydraul...