Light Calcium Carbonate Research Articles

Preparation and Compression Resistance of Lightweight Concrete Filled with Lightweight Calcium Carbonate Reinforced Expanded Polystyrene Foam.

Lightweight concrete is widely used in the construction industry due to its low density and high strength. In this paper, lightweight concrete was prepared by a simple two-step method. Firstly, the light calcium carbonate reinforced epoxy macrospheres (LCR-EMS) material was obtained by adhering calcium lighter carbonate powder to the expanded polystyrene foam spheres (EPS) material using the "balling method". In the second step, the LCR-EMS was mixed with water, cement, and the hollow glass microspheres (HGMS) material using the "molding method" to obtain lightweight concrete. The combination of macroscopic photographs and microscopic morphology shows that the LCR-EMS material itself is uniformly encapsulated and well bonded to the matrix. Test results show that the density of the lightweight concrete decreases with an increase in the volume fraction of stacked LCR-EMS, the diameter, and the proportion of HGMS in the matrix, but it decreases with a decrease in the number of layers of LCR-EMS. The compressive strength of lightweight concrete exhibits a completely opposite trend. When three layers of LCR-EMS were used as filler material, the density and compressive strength of the concrete were 1.246 g/cm3 and 8.19 MPa, respectively. The density and maximum compressive strength of lightweight concrete were 1.146 g/cm3 and 6.37 Mpa, respectively, when filled with 8-9 mm-2L-90 svol% of LCR-EMS and 40 wt% of HGMS in the matrix. Compared with lightweight concrete filled with 90% EPS, the density increased by 20% while the compressive strength increased by 300%.

Light calcium carbonate improves pullulan biosynthesis by Aureobasidium pullulans under high concentration of sugar.

The effects of light calcium carbonate (CaCO3) on pullulan biosynthesis by Aureobasidium pullulans NCPS2016 were investigated. Light CaCO3 enhanced pullulan production by 12.4% when added to the low concentration of fructose broth compared with K2HPO4. Pullulan production was further improved when increasing both the concentrations of light CaCO3 and fructose. Compared to K2HPO4, light CaCO3 improved the activities of UDP-glucose pyrophosphorylase, α-phosphoglucose mutase, UDP-glucosyltransferase, and glucosyltransferase relevant to pullulan biosynthesis, and the gene transcriptional levels of UDP-glucose pyrophosphorylase, α-phosphoglucose mutase, UDP-glucosyltransferase, and glucose kinase were enhanced. During 30-liter fermentation, 144.3g/L of purified pullulan was produced from 200g/L of fructose and 15g/L of light CaCO3 within 168h, with the yield and productivity of 0.72g/g and 0.86g/L/h respectively. This is the first report that light CaCO3 improves pullulan production significantly.

Present Situation and Prospect of Comprehensive Utilization of Phosphogypsum

Phosphogypsum is a by-product of the wet process of phosphoric acid production. Although the main component of phosphogypsum is calcium sulfate, it also contains a variety of impurities harmful to the environment. How to economically and comprehensively utilize phosphogypsum to turn waste into treasure has become a global problem. Since the industrialization of wet process phosphoric acid, people have been studying the comprehensive utilization of phosphogypsum, including the direct utilization of phosphogypsum for impurity removal and the reuse of phosphogypsum after dissolution and transformation. At present, the treatment of phosphogypsum is not short of technology, but the profit of phosphogypsum treatment. Recent research has found that phosphogypsum can be completely dissolved by a chemical and metallurgical cycling process and transformed into calcium and sulfur products with market competitiveness and economic benefits. These include high-quality calcium sulfate dihydrate, light calcium carbonate, and gypsum whiskers with high added value. This is another step forward for the final solution to the problem of phosphogypsum stacking endangers environmental safety.

Synthesis of CaCO3-Based Hyperdispersants and Their Application in Aqueous Coatings

As an essential pigment particle in white water-based coatings, light calcium carbonate (CaCO3) is difficult to disperse in water-based systems. The hard-to-disperse particles agglomerate, causing the viscosity of the coating to rise, which in turn affects the quality of the coating. Therefore, in order to obtain efficient dispersion, the hyperdispersant SSS–MPEGA–DMAEA (SMD) has been prepared in this study using sodium styrene sulfonate (SSS), polyethylene glycol monomethyl ether acrylate (MPEGA), and dimethylaminoethyl acrylate (DMAEA) as monomers through aqueous solution polymerization. Firstly, we utilized the central composite design method to conduct mathematical modeling of the monomer ratios so as to optimize the dispersion performance of the hyperdispersants. Secondly, the structural characteristics and molecular weight distribution of SMD were characterized by 1H NMR spectroscopy and GPC. Then, the effect of SMD on the dispersion of the CaCO3 slurry was investigated through particle size distribution and TEM measurements. Finally, we applied the SMD in aqueous white coatings and tested the surface properties of the paint film by SEM as well as the stability of the paint film. The results showed that SMD can significantly reduce the viscosity and particle size of the CaCO3 slurry. The waterborne coatings prepared by SMD had good storage stability and corrosion resistance, so the materials owned broad application prospects.

CO2 mineralization of carbide slag for the production of light calcium carbonates

The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption, leading to massive flue gas and carbide slag emissions. Currently, the carbide slag with high CaO content is usually stacked in residue field, easily draining away with the rain and corroding the soil. In this work, we coupled the treatment of flue gas and carbide slag to propose a facile CO2 mineralization route to prepare light calcium carbonate. And the route feasibility was comprehensively evaluated via experiments and simulation. Through experimental investigation, the Ca2+ leaching and mineralization reaction parameters were determined. Based on the experiment, a process was built and optimized through Aspen Plus, and the energy was integrated to obtain the overall process energy and material consumption. Finally, the net CO2 emission reduction rate of the entire process through the life-cycle assessment method was analyzed. Moreover, the relationship between the parameters and the CO2 emission life-cycle assessment was established. The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO2)−1 of energy (including heat energy of 979.32 kW·h·(t CO2)−1 and electrical energy of 175.37 kW·h·(t CO2)−1), and the net CO2 emission reduction rate was 35.8%. The light CaCO3 product can be sold as a high value-added product. According to preliminary economic analysis, the profit of mineralizing can reach more than 2,100 CNY·(t CO2)−1.

Research on the Damping Performance of Mining Highly Efficient Water-Retaining Colloidal Material Against the Spontaneous Combustion of Coal

In order to solve the shortcomings of the traditional mining anti-extinguishing gel material such as low strength and poor water retention, a high hydrocolloid anti-extinguishing material was developed with sodium alginate and light calcium carbonate as the base material and gluconolactone as the retarder, which was mixed and reacted. The base material ratio of highly efficient water-retaining colloidal material for coal void filling was determined as 2% SA + 0.5% PCC + 1% GDL with a moulding time of 4.5 min, while the base material ratio of highly efficient water-retaining colloidal material for extinguishing high temperature fires was 2.5% SA + 1% PCC + 1% GDL with a moulding time of 2.5 min. The highly efficient water-retaining colloidal material was found to reduce the concentration of signature gas and delay the characteristic temperature point and increase the activation energy of coal oxidation, which indicates that the highly efficient water-retaining colloidal material can effectively inhibit the spontaneous combustion process of coal at low temperature stage. Infrared spectroscopy experiments were conducted to investigate the microscopic resistance mechanism of the highly efficient water-retaining colloidal material, and the results showed that the highly efficient water-retaining colloidal material mainly reduce the activity of Ar-C-O-, -COO-, -CH3, -CH2 and -OH in coal to inhibit the spontaneous combustion of coal.

Elemental Impurities in Pediatric Calcium Carbonate Preparations-High Throughput Quantification and Risk Assessment.

Calcium carbonate which is extracted from the Earth in combination with other mineral impurities, is largely used in preparations for pediatric supplements. Elemental impurities in drug products pose toxicological concerns without therapeutic benefits. Thus, it is very urgent to assess the safety of chronic exposure to elements that may be present in trace amounts. In the present study, we developed high throughput ICP-MS method for the quantitative determination of 62 elemental impurities in high matric calcium carbonate samples and validated according to USP 233. Calcium carbonate preparations which state clearly used for child (including neonates, infants, toddlers and children) from 9 manufactures and two types of raw materials (light calcium carbonate and ground calcium carbonate) were investigated in terms of the content and variability of 62 elemental impurities. According to the results, ground calcium carbonate was more suitable to be used in pediatric preparations concerning elemental impurities. Parts of elemental impurities in CaCO3 preparations which are derived from the raw materials and the preparation process, may cause potential risks for children. These results indicate that it is necessary to establish a modern instrumental analysis method to evaluate and control elemental impurities in CaCO3 raw materials and preparations.

Fabrication and characterization of a novel environment-friendly inorganic fireproof adhesiveused for fire resistant doorsets

A novel environment-friendly inorganic fireproof adhesive was prepared with sodium silicate, fumed silica, light calcium carbonate, aluminum hydroxide and magnesium hydroxide by high-speed mixing and ball milling. The bond strength, formaldehyde and VOC emissions, thermal properties and fire performance of such adhesive were investigated. The bond strength of the adhesive was increased with the adding of the fumed silica, which reached 1.8 MPa when the amount of fumed silica was 1.5 wt.%. Formaldehyde and VOC emissions of this adhesive were far lower than those of the requirements in Chinese standards. The combustion grade of this adhesive could achieve A1 and its smoke toxicity grade could achieve AQ1, which was the safest grade of flammability for building materials.

Leaching calcium from phosphogypsum desulfurization slag by using ammonium chloride solution: Thermodynamics and kinetics study

Abstract Phosphogypsum (PG) desulfurization slag is a calcium-rich residue from reductive decomposition of PG using sulfur as the reductant. We proposed a technology of preparation light calcium carbonate with PG desulfurization slag, which mainly contains two steps: leaching and carbonizing. In this work, we concentrated on the former, in which ammonium chloride aqueous solution was utilized as leaching agent to extract calcium from the slag, and conducted thermodynamics and kinetics study on it. FactSage software was employed to do thermodynamic and phase equilibrium diagram calculations. The influence of leaching conditions including agitation speed, initial concentration of leaching solution, reaction temperature, and liquid/solid ratio on the calcium leaching rate were discussed in detail by means of experiment optimal design. A kinetic model developed from the shrinking core model was given to describe the leaching process. The apparent kinetic activation energy (Ea) of the leaching reaction was calculated to be 10.58 kJ·mol−1.

Assessing the effects of different agro-residue as substrates on growth cycle and yield of Grifola frondosa and statistical optimization of substrate components using simplex-lattice design

Grifola frondosa is an economically important edible and medicinal mushroom usually produced on substrate consisting of sawdust supplemented with wheat bran. Cultivation of G. frondosa on crop straw (corn cob, corn straw, rice straw, and soybean straw) as a substrate was optimized by using the D-optimum method of the simplex-lattice design, and the alternative of crop straw as a substitute for sawdust in the substrate composition was determined by the optimized model. The results showed that there was a significant positive correlation existing between the yield and corn cob. The growth cycle was negatively correlated with sawdust, corn cob and soybean straw, with sawdust significantly shortening the growth cycle of G. frondosa. The optimized high-yielding formula included 73.125% corn cob, 1.875% rice straw, 23% wheat bran and 2% light calcium carbonate (CaCO3) (C/N = 48.40). The average yield of the first flush was 134.72 ± 4.24 g/bag, which was increased by 39.97% compared with the control formula. The biological efficiency (BE) was 44.91 ± 1.41%, which was increased by 38.53% compared with the control. Based on the results of this study, corn cob can replace sawdust as one of the main cultivation substrates of G. frondosa.

Toughening polypropylene by tiny amounts of fillers

PurposeThe purpose of this paper is to prepare new modified polypropylene (PP) with phenolic microspheres (PFMs). Furthermore, the crystallinity and mechanical properties of PP modified by fillers (silicon dioxide [SiO2] and light calcium carbonate [CaCO3], respectively) have also been investigated and compared.Design/methodology/approachFor effective toughening, three different fillers were added into the PP matrix. PP composites were prepared through melt blending with double-screw extruder and injection moulding machine.FindingsIt was found that with the addition of 3 Wt.% PFM, the impact strength was maximum in all PP composites and increased by 1.4 times compared to pure PP. Scanning electron microscopy (SEM) and polarised optical microscopy (POM) analysis confirmed that 3 Wt.% PFM, 3 Wt.% SiO2 and 2 Wt.% CaCO3 were optimal to add in PP and PFM to give the best compatibility with PP.Research limitations/implicationsPFM particles not only are tougher and less brittle and can offer other advantages such as enhanced machinability, but also are important organic materials and have a good compatibility with polymer for reinforcing polymer properties.Practical implicationsThe method developed provided a simple and practical solution to improving the toughness of PP.Social implicationsThere will be thermoplastic plastics with higher toughness in domestic, packaging and automotive applications, particularly at lower temperatures.Originality/valueThe PP modified by tiny amounts of fillers in this work had high toughness, which can be applied as an efficient material widely used in domestic, packaging and automotive applications.

Removal of methyl orange from aqueous solution by mineral-based porous granulated material

Sodium bentonite, graphite, light calcium carbonate and diatomite were used as parent minerals for the mineral-based porous granulated material (MPGM) which was tested for the removal of methyl orange (MO), a cationic dye, from aqueous solution. The adsorption capacity was evaluated under the conditions of varied initial pH, adsorbent dosage, dye concentration, temperature, reaction time, and static regeneration. Experimental results showed that the maximum capacity of MPGM adsorbing MO was more than 80 mg·g−1. The adsorption equilibrium and kinetics of MPGM followed typical pseudo-first-order and Langmuir adsorption models respectively. The thermodynamic parameters of ΔG○, ΔH○ and ΔS○ showed that the adsorption was an endothermic and spontaneous process without remarkable change. The spent MPGM was regenerated 5 times and probable pathway for the efficient and re-utilizing adsorbent has been proposed. The results indicate that MPGM has a structure of silicon-aluminium-calcium-carbon, and could be employed as porous, low density, and large specific surface area alternatives for the removal of cations dyes from industrial wastewater.

Calcium carbonate capsules production with an automatic encapsulator in the galenic laboratory of the hospital pharmacy of ASL CN2

BackgroundCalcium carbonate capsules is a drug used in the hospitals with nephrology-department but it doesn't exist like industrial drug in Italy. Normally is acquired by external companies like food-integrator or...

Emulsifying Effect of Solid Particles on Epoxy Resin E-44

Emulsify epoxy resin E-44 with heavy calcium carbonate, light calcium carbonate, aerosil, surface-modified aerosil and bentonite BP-187. The experimental results show that neither heavy calcium carbonate nor light calcium carbonate has emulsifying effect. O/W type emulsion can not be obtained with aerosil and bentonite BP-187. Surfactant-modified aerosilCTAB-SiO2and DTAB-SiO2do have emulsifying effect, and they can transform into more stable O/W type emulsion. The synergy between BP-17, EP-1 and CTAB-SiO2is obvious. Hydrophilic emulsifier EP-1 could be replaced by CTAB-SiO2or BP-187 completely or partly to prepare stable O/W emulsion. The TEM result show that the disperse phase of the emulsion produced by CTAB-SiO2and the compound emulsifier of CTAB-SiO2and BP-187 is irregular floc, and the disperse phase of the aqueous emulsion produced by the compound emulsifier of CTAB-SiO2and EP-1 is regular globular or ellipsoidal multiple emulsion.

Wet Surface Modification of Light Calcium Carbonate Powder by Aluminate Coupling Agent

The modification of light calcium carbonate powder was studied by wet surface modification in n-Butanol and water solution. The modification process was analyzed by modifying temperature, rotation speed, aluminate coupling agent dosage and n-Butanol percentage. The characters of modified calcium carbonate were investigated by the contact angles with water/glycerol/liquid paraffin/DOP and infrared spectroscopy (IR). The contact angles/water of modified CaCO3 powder obtained in optimum conditions was 134.5°. The results indicated that the surface property of CaCO3 powder changed from the hydrophilicity to the lipophilicity.

The effect of pyrolytic carbon black prepared from junked tires on the properties of ethylene-propylene-diene copolymers (EPDM)

Pyrolytic carbon black (PCB) made from used tires was used in ethylene-propylene-diene copolymers (EPDM). The microstructure of PCB was characterized by scanning electron microscopy (SEM). PCB was compounded with EPDM to prepare EPDM vulcanizates. The effects of PCB on the processing properties of EPDM compounds and the mechanical properties of vulcanizates were investigated and compared with other traditional fillers such as semi-reinforcing furnace black (N774), light calcium carbonate (CaCO3) and thermal black (N990). At the same time, the rheological behavior of EPDM compounds filled with different fillers was characterized by capillary rheometrics. The SEM photos showed that the particle shape was quiet different from that of CaCO3 and N990, it was similar to that of N774. The primary particle size was smaller than that of N774, but the aggregate size of PCB was larger than that of N774. The effect of PCB on the pro- cessing properties of EPDM compounds was similar to that of other fillers. Among the four fillers, PCB imparted EPDM compounds with higher Mooney viscosity. With the increase of filler content, the scorch time and optimum curing time of EPDM compounds changed little. The reinforcing effect of PCB was similar to that of N990, but inferior to that of N774. With the increase of PCB content, tensile strength, tear strength, and modulus at 100% elongation of EPDM vulcanizates increased significantly. When EPDM was filled with 50 phr PCB, the tear strength of EPDM vulcanizates increased by 3 times, compared with that of EPDM gum vulcanizates. The appearance of EPDM extrudate filled with PCB was coarser than that of other fillers.

Manufacture Process of Light Calcium Carbonate from Limestone

This process and parameters of fabricating light calcium carbonate from limestone were discussed in the paper. Raw limestone in experiment comes from Luquan city, Hebei province. The results of chemistry and XRD analysis indicate that ingredient of this limestone is mainly calcium carbonate, dolomite, silicon dioxide, which takes 83.81%, 11.03% and 1.67% separately, and a few of other impurities. The process includes calcinations, assimilation, carbonation, drying and others. It was ascertainable that the time of calcinations exceeded 5 hours at 850~ 950 and loss of calcinations was 42%. The time of assimilation was around 25 minutes at 70~90The time of carbonation was about 30 minutes at 50~90, and the airflow was about 160L/min and PH of latex after carbonation was 7.2~7.4. The light calcium carbonate product was obtained in experiment, whose fine sphere size was about 10 nanometer, with the agglomeration particle size 2~3μm. The degree of white improved from 42 to 76. As a result, the comprehensive properties of the produce were improved consumedly.

Study of Carbonizing Processes for Sintered Dolomite

It is the easy and widely used way to make light calcium carbonate and magnesium carbonate from dolomite by carbonizing process. During this process, the dolomite is calcined at different temperature, from 700°C to 950°C to get the mixture including either calcium carbonate and magnesia or calcia and magnesia. Then the mixture is blended with water in different temperature from room temperature to 80°C. As a result, it is supposed to get calcium hydroxide and magnesium hydroxide, but XRD analysis reveals that it is not accord with the theory. Magnesium hydroxide can not be obtained during this reaction. After the carbonization process, the calcium carbonate and a kind of mixture which is composed with different crystal phase of Mg5(CO3)4(OH)2[H2O]4 have been produced, instead of magnesium carbonate. The magnesia is gotten when the mixture is calcined at 450~750°C.

ホタテ貝殻および石灰石を原料としたａｒａｇｏｎｉｔｅの合成 逐次反応による形態制御

Aragonite-type of light calcium carbonate was synthesized by the successive reaction using calcined-hydrous scallop shells and calcined lime stones in the aqueous system with Mg2+ ions under the CO2 bubbling. In order to obtain the high aspect ratios of aragonite, the reaction temperature and concentrations of Ca2+ ions in the 2nd step were important. The aspect ratio of aragonite increased when the reaction temperature was higher in the 2nd step than in the 1st step of the successive reaction. When the smaller amounts of calcium source were added in the 2nd step than in the 1st step, and the reaction temperature was lower in the 2nd step than in the 1st step, large particles of aragonite were produced with no smooth surfaces. The successive reaction was useful to extend the variety of morphologies in aragonite.

廃ホタテ貝殻焼成物を原料とするａｒａｇｏｎｉｔｅ型軽質炭酸カルシウムの合成 第３報 常温水溶液系における高純度ａｒａｇｏｎｉｔｅの生成

Aragonite-type light calcium carbonate was synthesized from calcined scallop shell at ambient temperature in the aqueous system with Mg2+ ions under the CO2 bubbling for 4 hours. The important factors to obtain high purity of aragonite were the mole ratio of Ca2+/ Mg2+, flow rate of CO2 , reaction time, pH and temperature. Under the optimum condition, the purity of aragonite in products was determined to be more than 99.4 (w/w) %, by XRD and FTIR analyses. The specific surface area was obtained to be 5-8 m2 g-1 by the BET method, and the morphology was characterized in wisker with several micrometers in length by SEM.