Grade Calcium Carbonate Research Articles

Dietary contribution of iron from limestone and dicalcium phosphate for broiler chickens

Iron is routinely supplemented in broiler feeds aiming to prevent dietary deficiencies. Limestone and phosphates are very rich in Fe; however, its contribution from these sources have not been thoroughly investigated with chickens. The present research was conducted to evaluate live performance and blood parameters of broilers when using limestone and dicalcium phosphate as sources of Fe. A total of 576 one-day-old male Cobb x Cobb 500 were allocated into a total of 72 battery cages, 6 treatments with 12 replication cages of 8 chicks at placement. Chicks were fed diets formulated with corn, soybean meal (SBM) with laboratory grade calcium carbonate and phosphoric acid (having traces of Fe). All chicks were fed a common prestarter without Fe supplementation (analyzed total 58.2 ± 2.4 mg/kg Fe) from placement to 7 d. Allocation of birds to dietary treatments was completely randomized on day 8. Treatments had increasing Fe derived from commercial limestone and dicalcium phosphate (analyzed Fe 7,218 and 4,783 mg/kg, respectively) progressively replacing calcium carbonate and phosphoric acid to provide graded increases in total Fe (analyzed Fe in the feeds were 57.6 ± 2.1, 92.0 ± 2.3, 124.1 ± 2.7, 159.3 ± 3.1, 187.2 ± 3.2, 223.7 ± 3.6 mg/kg, respectively). There were no effects of dietary Fe on live performance, hematocrit, and hemoglobin the end of the study on day 28 (P > 0.05). Increasing dietary Fe from commercial limestone and dicalcium phosphate led to a linear reduction in the percent ileal digestible Fe. However, linear increments in Fe retention, serum ferritin and liver Fe occurred when compared to feeds without Fe derived from limestone and phosphate dicalcium. It is concluded that Fe from limestone and dicalcium phosphate can be partially utilized by broiler chickens. It was estimated that the Fe retained from limestone and dicalcium phosphate is of 1.9%. Broilers fed corn-soy feeds (58.2 mg/kg Fe) do not require supplemental Fe.

Iron requirements of broiler chickens as affected by supplemental phytase.

Iron is routinely supplemented in broiler feeds intending to prevent dietary deficiencies. The present research was conducted with the objective of assessing Fe requirements of broilers when fed supplemental phytase. A total of 1,280 1-d-old male Cobb × Cobb 500 were distributed in a 2 × 5 factorial arrangement (phytase-supplemented feeds × 5 graded increases of supplemental Fe) in 80 battery cages, eight replications of eight chicks each. The trial was replicated once. Chicks were fed a Fe-deficient diet without phytase (Fe analyzed at 31.30 ± 3.79 mg/kg) from placement to 7 d and then randomly distributed into battery cages with corresponding dieting treatments with or without phytase and graded increases of supplemental Fe. Feeds were formulated with corn and soybean meal (SBM), laboratory-grade calcium carbonate, and phosphoric acid; therefore, the vast majority of dietary Fe originated from corn and SBM (analyzed diet had 53.3 ± 1.41 mg/kg Fe). Phytase was added in excess to the producer recommendation of 1,000 FYT (4,452 ± 487 FYT/kg analyzed) such that phytate degradation was expected to be maximized. Supplemental Fe was from laboratory-grade ferrous sulfate heptahydrate (FeSO47H2O) which was increasingly added to the feeds (analyzed Fe in the supplemented feeds were: 53.3 ± 1.41, 65.5 ± 0.59, 77.2 ± 1.97, 87.6 ± 1.72, 97.7 ± 1.33 mg/kg). There were no interactions between phytase and dietary Fe for any response throughout the study (P > 0.05). Supplementing phytase had no effects on Fe intake or Fe excretion, as well as on hematocrit (Ht), hemoglobin (Hb), ferritin, Fe contents in the liver or thigh muscle color (P > 0.05). However, phytase-supplemented feeds produced better live performance as well as higher ileal digestible energy and Fe digestibility (P < 0.05). No effects were found for dietary Fe in live performance at day 28 (P > 0.05). On the other hand, increasing dietary Fe led to linear increases in Fe retention and excretion, Fe contents in livers, as well as Ht and Hb at 14 d (P < 0.05). Quadratic responses (P < 0.05) were observed for Hb at 21 d, serum ferritin on days 14, 21, and 28 (maximum responses were 83.3, 104.0, 91.9, and 88.3 mg/kg Fe, respectively). In conclusion, supplementing Fe adding to a total of 97.7 mg/kg dietary Fe did not affect live performance traits. However, the average of Fe-related blood parameters was maximized at 91.9 mg/kg dietary Fe. Supplementing phytase provided a significant increase in Fe digestibility.

Dissolution rates of hydrated lime, Ca(OH) 2 in fresh, oligohaline, mesohaline and euhaline waters and its significance for liming of shrimp culture ponds

This study aimed at assessing the dissolution rates of hydrated lime, Ca(OH)2 in fresh, oligohaline, mesohaline and euhaline waters and discussing its significance for liming of shrimp culture ponds. Appropriate volumes of seawater and distilled water were mixed to prepare oligohaline (1–4 g/L) and mesohaline waters (4–15 g/L). One gram of analytical grade calcium carbonate, CaCO3, or one gram of analytical grade calcium hydroxide, Ca(OH)2, were applied in 10-L gallons filled with seawater (39.9 g/L), 10.7 g/L, 4.2 g/L and distilled water (0.0 g/L). The final TA of water was significantly higher for Ca(OH)2 than for CaCO3 only at salinities 4.2 and 10.7 g/L. It was concluded that hydrated lime, Ca(OH)2 is a better liming option than agricultural limestone, CaCO3 for moderately saline, hard and/or buffered waters (−4.5 ≤ Langelier saturation index, LSI ≤ −0.7). In poorly saline, hard and/or buffered waters (LSI < −4.5), limestone and lime would increase water TA similarly. Neither limestone nor lime should be applied on highly saline, hard and/or buffered waters (LSI > −0.7) because a TA decrease is expected.

Cytotoxicity, Uptake Behaviors, and Oral Absorption of Food Grade Calcium Carbonate Nanomaterials.

Calcium is the most abundant mineral in human body and essential for the formation and maintenance of bones and teeth as well as diverse cellular functions. Calcium carbonate (CaCO3) is widely used as a dietary supplement; however, oral absorption efficiency of CaCO3 is extremely low, which may be overcome by applying nano-sized materials. In this study, we evaluated the efficacy of food grade nano CaCO3 in comparison with that of bulk- or reagent grade nano CaCO3 in terms of cytotoxicity, cellular uptake, intestinal transport, and oral absorption. Cytotoxicity results demonstrated that nano-sized CaCO3 particles were slightly more toxic than bulk materials in terms of oxidative stress and membrane damage. Cellular uptake behaviors of CaCO3 nanoparticles were different from bulk CaCO3 or Ca2+ ions in human intestinal epithelial cells, showing efficient cellular internalization and elevated intracellular Ca2+ levels. Meanwhile, CaCO3 nanoparticles were efficiently transported by microfold (M) cells in vitro model of human intestinal follicle-associated epithelium, in a similar manner as Ca2+ ions did. Biokinetic study revealed that the biological fate of CaCO3 particles was different from Ca2+ ions; however, in vivo, its oral absorption was not significantly affected by particle size. These findings provide crucial information to understand and predict potential toxicity and oral absorption efficiency of food grade nanoparticles.

Magnetic field effect on fractionation of carbon isotopes in the reaction of Ca(OH)2 with air carbon dioxide

213 The nuclear spin (magnetic) isotope effect was dis covered by A. L. Buchachenko and coworkers in 1976 [1]. In the first experiments, the isotope effect for sta ble carbon isotopes was studied in the photolysis of dibenzyl ketone, and further studies of the magnetic field effect on carbon isotope fractionation were car ried out using only organic substances [2]. In the present work, we revealed for the first time the magnetic field effect on the carbon isotope com position in the course of formation of an inorganic compound, calcite CaCO3. The experiments on studying the magnetic field effect on the carbon isotope fractionation during for mation of calcite were carried out by the following scheme. A natural calcium carbonate (limestone) and a reagent grade calcium carbonate were decom posed at 1000°C in an electric furnace to completely remove СО2 CaCO3 = CaO + CO2. The weight loss after the calcination was 42–43 wt %; the theoretical weight loss is 44 wt %. Calcium oxide obtained was mixed with water to form calcium hydroxide: CaO + H2O = Ca(OH)2. A thin layer of a water suspension of Са(ОН)2 was applied to a glass plate and kept in air for several weeks at room temperature, which resulted in the formation of calcium carbonate: Ca(OH)2 + CO2 = CaCO3. In all experiments, two plates with calcium hydroxide were used simultaneously. One of them was placed in the magnetic field, another, control one, was out of the field. The plates were disposed perpendicular to Earth’s magnetic field. The starting compounds had the following isotopic compositions (δ13C‰, PDB standard): –1.090 for the limestone, –42.805 for the reagent grade calcium car bonate, and from –7 to –10 for air carbon dioxide [3]. In the first run, the plate with Ca(OH)2 was placed in the field of a permanent magnet, which was located on the edge of the plate (Fig. 1). The isotopic compo sitions at different distances from the magnet were determined in 500 h. The δ13С values at distances equal to 0.5, 1, and 2 cm from the magnet were –22, ⎯26, and –27‰, respectively. The isotopic composi tion of Ca(OH)2 on the control plate was δ 13С = ⎯26.645‰, PDB. A similar result was obtained when Ca(OH)2 was applied to a steel plate not exposed to the magnetic field. In the second run, a glass plate with dimensions of 90 × 15 mm uniformly covered with Ca(OH)2 obtained PHYSICAL CHEMISTRY

Laboratory Scale Production of Commercial Grade Calcium Carbonate from Lime-Soda Process

Quality precipitated calcium carbonate has much demand in various chemical and allied industries as filler, surface coating, whitening, adhesive etc. A study was carried out by modifying classical lime-soda process to obtain high quality precipitated calcium carbonate. The experiments were carried out in two stages using commercial and analytical grades of sodium carbonate and lime as reactants. After causticization, the filtrates from the washing of calcium carbonate were used to prepare all solutions for reactions in next stage. The precipitated calcium carbonate obtained from the process was analyzed and comparisons were made with the commercially available precipitated calcium carbonate produced from carbonation method. The calcium carbonate produced from causticization was superior to those produced by carbonation method in the country. The crystal structure of carbonate was calcite.Keywords: Causticization; Settle Volume; Bulk Density; Yield.DOI = 10.3329/cerb.v12i0.1490 Chemical Engineering Research Bulletin 12 (2008) 1-6

Nanometer grade calcium carbonate PVC marketed in China

Nanometer grade calcium carbonate PVC marketed in China

Kinetics and mechanism of formation of monocalcium aluminate, CaAl2O4

The kinetics of the reaction for the formation of monocalcium aluminate (CaAl 2 O 4 ) using 1:1 molar mixtures of A.R. grade calcium carbonate and A.R. α-Al 2 O 3 or gibbsite have been investigated in the range 1150–1400 °C using quantitative X-ray diffraction analysis. The phases Ca 3 Al 2 O 6 and Ca 12 Al 14 O 33 were found to be intermediates in the formation of CaAl 2 O 4 , whereas CaAl 4 O 7 was formed via an initial side reaction. The formation of CaAl 2 O 4 from the oxides was found to fit well with the diffusion controlled model of Ginstling and Brounshtein. The activation energy for the formation of CaAl 2 O 4 from the amount of CaAl 2 O 4 formed from the reaction of calcite with α-Al 2 O 3 was determined to be 205±10 kJ mol -1 .

A thermogravimetric study of the reaction of hydrogen chloride gas with calcined limestone: Determination of kinetic parameters

The reaction of hydrogen chloride gas with calcined limestone was carried out experimentally using a thermorecording balance. Reaction temperatures in 0.5–5.0 mol.% were used. Determination of the kinetic parameters was carried out using calcined AR grade calcium carbonate powder to avoid competing reaction rates. Gas phase mass transfer effects were minimized and in the absence of internal diffusion, the reaction was found to be first order with system was found to be around 22000 J mol −1. Through study of comparative reaction rates, the reaction was found to be more rapid than those of o

Effect of Particle Size of the Calcium Source on Performance of Broiler Chicks Fed Diets with Different Calcium and Phosphorus Levels

Broiler chicks were fed diets differing in calcium (Ca) level, source, and particle size. The basal diet fed in most experiments contained .62% total phosphorus and .49% Ca from sources other than the Ca sources being compared. Performance was not affected by Ca source in diets with .9% Ca. In diets with 1.5% Ca, gain and bone ash were significantly lower with a powdered, USP grade calcium carbonate than with limestone particles passing through a l,000-μ screen and retained by a 417-μ screen. Crushing these particles to allow them to pass through a 74-μ screen caused them to behave like the powdered calcium carbonate. Particles of this limestone had to at least pass through a 147-μ screen to cause a greater reduction in gain; the finest particles tested (passed a 74-μ screen) reduced performance most. When graded levels of fine and medium particles were fed, the higher levels reduced gain, and less of the fine particles was required to produce a given reduction. In a high Ca-low P diet, fine particles of the Ca source were more deleterious than medium. Apparently, chicks can shunt excess Ca in the form of medium particles (150 to 1,000 μ) through the digestive system better than they can the more reactive, fine particles.

Influence of dietary lead and calcium on tissue lead accumulation and depletion, lead metabolism and tissue mineral composition in sheep.

Two experiments were conducted to study the metabolism and tissue accumulation and depletion of dietary Pb in sheep. In Exp. 1, a feeding trial, 33 wethers, 56 kg initially, were assigned randomly to two dietary treatments: .25% Ca plus 1,000 ppm Pb or .50% Ca plus 1,000 ppm Pb. Supplemental Ca and Pb were supplied as reagent grade calcium carbonate or reagent grade lead acetate. The experiment was divided into two phases of 75 and 180 d; during the first phase, diets contained 1,000 ppm supplemental Pb and during the second phase, diets contained 3 ppm Pb. Calcium level remained constant within treatments throughout both phases. Sheep were slaughtered at various intervals during both phases and tissue samples taken. Lead increased in all tissues during the accumulation period and decreased during the depletion period; however, kidney was the only tissue in which Pb concentration declined to control values by 180 d. Dietary Ca reduced (P less than .05) the concentration of Pb deposited in liver, but not in other tissues. Interactions of dietary Ca and Pb on tissue concentration of various minerals occurred. In Exp. 2, a balance trial, 27 wethers, 53 kg initially, were allotted randomly to four treatments in a 2 X 2 factorial arrangement. Diets contained either 0 or 1,000 ppm supplemental Pb as reagent grade lead acetate and .25 or .50% total Ca with supplemental Ca from calcium carbonate. Increasing dietary Pb increased (P less than .05) percentage of Pb retained and increased (P less than .01) whole blood Pb concentration (1.0 vs 1.42 micrograms/ml).

Heat Resistance of Neoprene Vulcanizates

Abstract The resistance of neoprene vulcanizates to degradation when exposed to heat is increased markedly by compounding with selected calcium salts in place of magnesium oxide. The preferred material is a product containing 36% calcium oxide prepared by calcining reagent grade calcium carbonate in a laboratory muffle furnace at 1600° F for 30 minutes. Calcium salts of fatty acids containing 18 carbon atoms in the fatty acid portion of the molecule also are effective. The calcium salt of a more highly unsaturated fatty acid is an effective antiozonant. The stress-strain properties and resistance to compression set and swelling in oil are similar for compounds employing calcium salts compared with magnesium oxide. Calcium salts reduce the processing safety of the compounds, and the resistance of the vulcanizates to swelling in water.