Solidification of CaCO3 containing SrCO3 by hydrothermal hot-pressing

1993 ◽  
Vol 8 (8) ◽  
pp. 1972-1976 ◽  
Author(s):  
Nakamichi Yamasaki ◽  
Tang Weiping ◽  
Kazumichi Yanagisawa
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Hot Pressing ◽  
Strontium Carbonate ◽  
Reaction Process ◽  
Carbonate Content ◽  
Mechanical Compression ◽  
Hydrothermal Conditions ◽  
Bonding Material

Powders of calcium carbonate with strontium carbonate were solidified by mechanical compression under hydrothermal conditions. The effects of hydrothermal conditions such as temperature, pressure, and ratio of Ca/Sr on the reaction process and microstructure of the solidified bodies were examined. Solidification of every powder easily proceeded with shrinkage above 200 °C to 300 °C. The compacts of strontium carbonate were more easily solidified, and compressive strength was 190 MPa and its density was 93.5%. The solidification with shrinkage of compacts consisting of mixed powders of calcium and strontium carbonates was accelerated with an increase in strontium carbonate content. It was revealed that the small amount of strontium carbonate powder acts as a bonding material among large calcium carbonate particles.

scholarly journals Mechanism of Sand Cementation with an Efficient Method of Microbial-Induced Calcite Precipitation

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5631
Author(s):  
Lu Wang ◽  
Shuhua Liu
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Efficient Method ◽  
Sand Particle ◽  
Carbonate Content ◽  
Calcite Precipitation ◽  
Sand Column ◽  
Cemented Sand ◽  
Initial Ph ◽  
Sand Particles

This paper presents an efficient method of microbial-induced calcite precipitation (MICP) for cementation of sand particles. First, the influence of initial pH value of the culture medium on the growth of bacteria was discussed. Then, the compressive strength and calcium carbonate content of cemented sand columns with different sand particle sizes were measured to indicate the cementation effectiveness. The microstructure of cemented sand columns as well as the mineral composition and distribution of calcium carbonate were characterised by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The results showed that the urease-producing bacteria S. pasteurii can be cultured at the initial pH values of 7–10, while a higher pH (e.g., 11) would hinder its growth and decrease its urease activity. The injection method of MICP with high standing time can cement sand columns effectively. Small average sand particle size of sand columns and high injection cycles can facilitate the gain of compressive strength, while calcium carbonate content of sand column higher than 8% can promote the increase of compressive strength. XRD results indicate that the fine grains generated on the surface of sand particles are calcite. The distribution of calcite on sand particles’ surface is broad and uniform. First, calcite was precipitated on the surface of sand particles, and then a precipitation layer was formed, which would connect sand particles through its high enough thickness and contribute to the development of compressive strength of the whole sand column.

Preparation and Characterization of Porous Hydroxyapatite Block Using a HHP Method

2006 ◽  
Vol 309-311 ◽  
pp. 1067-1070
Author(s):  
Hee Song ◽  
Soo Ryong Kim ◽  
Hae Jung Kim ◽  
Jong Hee Hwang ◽  
Woo Teck Kwon ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Cancellous Bone ◽  
Hot Pressing ◽  
Starting Material ◽  
Pressing Method ◽  
Porous Hydroxyapatite ◽  
Human Cancellous Bone ◽  
Natural Coral

Porous hydroxyapatite has been prepared using a hydrothermal hot pressing method from calcium carbonate as a starting material. SEM result shows porous hydroxyapatite block is formed of three dimensionally inter-connected pores of 100-400µm in size, similar to human cancellous bone. At the ~ 70% porosity, the compressive strength was about 4MPa, which is similar to that of the commercially available porous hydroxyapatite derived from natural coral.

Effects of Shell and Calcium Carbonate on Properties of Portland Cement

2012 ◽  
Vol 450-451 ◽  
pp. 495-498 ◽  
Author(s):  
Gui Yun Wang ◽  
Ling Chao Lu ◽  
Shou De Wang
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Calcium Carbonate ◽  
Portland Cement ◽  
Resistance Coefficient ◽  
Carbonate Content ◽  
Hardened Cement ◽  
Hydration Reaction ◽  
Calcium Carbonate Content ◽  
Acceleration Period

Different amounts of shell and calcium carbonate were added into the Portland cement, their influences on the compressive strength, sulfate corrosion resistance, hydration heat and porosity of the hardened cement paste were studied. Results show that with the increasing of shell content, the compressive strength decreases, however, modest reduction; as the increase of calcium carbonate content, the strength first increases and then decreases, the compressive strength reaches the highest value when the content is 15%. After addition of shell and calcium carbonate, the initial hydration reaction rate accelerates, meanwhile the induction period and acceleration period are brought forward. With the raising of shell and calcium carbonate content, the corrosion resistance coefficient increases gradually, and the sulfate corrosion resistance increases as well. The proportion of the harmless hole which diameter is smaller than 50nm increases after adding the shell and calcium carbonate, it’s beneficial to improve the performance of concrete.

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

scholarly journals Opto‐electrochemical Dissolution Reveals Coccolith Calcium Carbonate Content

2021 ◽  
Author(s):  
Minjun Yang ◽  
Christopher Batchelor-McAuley ◽  
Samuel Barton ◽  
Rosalind E.M. Rickaby ◽  
Heather A. Bouman ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Carbonate Content ◽  
Electrochemical Dissolution ◽  
Calcium Carbonate Content

scholarly journals A Novel Resorbable Composite Material Containing Poly(ester-co-urethane) and Precipitated Calcium Carbonate Spherulites for Bone Augmentation—Development and Preclinical Pilot Trials

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 102
Author(s):  
Claudia Rode ◽  
Ralf Wyrwa ◽  
Juergen Weisser ◽  
Matthias Schnabelrauch ◽  
Marijan Vučak ◽  
...  
Keyword(s):  
Composite Material ◽  
Calcium Carbonate ◽  
Bone Substitute ◽  
Pilot Trial ◽  
Carbonate Content ◽  
Precipitated Calcium Carbonate ◽  
Degradation Behaviour ◽  
Biodegradable Composite ◽  
Loss Of Mass

Polyurethanes have the potential to impart cell-relevant properties like excellent biocompatibility, high and interconnecting porosity and controlled degradability into biomaterials in a relatively simple way. In this context, a biodegradable composite material made of an isocyanate-terminated co-oligoester prepolymer and precipitated calcium carbonated spherulites (up to 60% w/w) was synthesized and investigated with regard to an application as bone substitute in dental and orthodontic application. After foaming the composite material, a predominantly interconnecting porous structure is obtained, which can be easily machined. The compressive strength of the foamed composites increases with raising calcium carbonate content and decreasing calcium carbonate particle size. When stored in an aqueous medium, there is a decrease in pressure stability of the composite, but this decrease is smaller the higher the proportion of the calcium carbonate component is. In vitro cytocompatibility studies of the foamed composites on MC3T3-E1 pre-osteoblasts revealed an excellent cytocompatibility. The in vitro degradation behaviour of foamed composite is characterised by a continuous loss of mass, which is slower with higher calcium carbonate contents. In a first pre-clinical pilot trial the foamed composite bone substitute material (fcm) was successfully evaluated in a model of vertical augmentation in an established animal model on the calvaria and on the lateral mandible of pigs.

FRAGMENT OR BROKEN? IMPROVING THE PLANKTONIC FORAMINIFERA FRAGMENTATION ASSESSMENT

Palaios ◽  
2021 ◽  
Vol 36 (5) ◽  
pp. 165-172
Author(s):  
JAIME YESID SUÁREZ-IBARRA ◽  
CRISTIANE FRAGA FROZZA ◽  
SANDRO MONTICELLI PETRÓ ◽  
MARIA ALEJANDRA GÓMEZ PIVEL
Keyword(s):  
Weight Loss ◽  
Calcium Carbonate ◽  
Planktonic Foraminifera ◽  
Carbonate Content ◽  
Sand Content ◽  
Future Studies ◽  
Software Analysis ◽  
Fragmentation Index ◽  
Area And Perimeter ◽  
Partial Damage

ABSTRACT Planktonic foraminifera tests can suffer dissolution, which usually involves partial damage, weight loss, and fragmentation. Since planktonic foraminifera assemblages, consisting of different resistant/susceptible species, can be strongly modified by dissolution, it is imperative to quantify its effect. The fragmentation index proposed 50 years ago has been used widely to measure preservation of planktonic foraminifera tests, but calibrations to this method are necessary. Some revisions are based on assumptions, like a certain number of fragments produced by a unique test, which is then used to compare whole tests with the dissolution remains. Likewise, researchers do not agree on what they count and how they identify what they count. Here we present a standardized and less subjective method, called fragmentation intensity (FI), to better assess the fragmentation of planktonic foraminifera through image software analysis, which includes both fragmentation remains (fragments and broken tests) and their measured area and perimeter. When compared to calcium carbonate content, grain sand content, and planktonic foraminifera tests per gram of dry sediment, the FI method derived better correlation values than the broken and fragments indexes. Future studies, in varying oceanographic contexts, can test this method to improve confidence, and eventually possibly adapt the index into a proxy for calcium carbonate undersaturation.

Measurement of high-alumina cement-calcium carbonate reactions using DTA

Clay Minerals ◽  
1984 ◽  
Vol 19 (5) ◽  
pp. 857-864 ◽  
Author(s):  
H. G. Midgley
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
High Alumina ◽  
Curing Time ◽  
Lower Strength ◽  
Alumina Cement ◽  
High Alumina Cement ◽  
Strength Tests ◽  
The Stability

AbstractHydrating high-alumina cement will react with calcium carbonate to form the complex mineral calcium carboaluminate hydrate, 3CaO.Al2O3.CaCO3.12H2O. This mineral is reported to be capable of providing strength in concrete and so may provide an alternative to the minerals normally found in the hydration of high-alumina cement, which may under certain conditions convert to other minerals with a loss in strength. Some doubt has been cast on the stability of calcium carboaluminate hydrate and it has been found that in hydrated high-alumina cement, calcium carboaluminate hydrate decomposes at temperatures in excess of 60°C. Cube compressive strength tests on high-alumina cement and high-alumina cement-calcium carbonate pastes have shown that the latter have a lower strength than pastes made with high-alumina cement alone. When cured at 50°C the high-alumina cement-calcium carbonate pastes show a loss in strength with curing time. Cements made with the high-alumina cement-calcium carbonate mixture always have a lower strength than those made with high-alumina cement alone and so no advantage is gained from their use.

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