Research Progress for Gypsum Retarder

2014 ◽  
Vol 1015 ◽  
pp. 272-275
Author(s):  
Xiao Qiong Ren ◽  
Ya Nan Wu ◽  
Ying Li ◽  
Mo Han Lin ◽  
Feng Qing Zhao
Keyword(s):  
Organic Acids ◽  
Mechanical Strength ◽  
Building Materials ◽  
Setting Time ◽  
Strength Loss ◽  
Raw Material ◽  
Research Progress ◽  
High Quality ◽  
Protein Rich ◽  
Waste Mycelium

Gypsum retarder is an important additive of building materials. Commercial gypsum retarders are mainly composed of four types: organic acids, phosphates, protein and composite retarder. Although the effects of organic acids and phosphates have better retarding performances, there is still obvious a shortcoming that the mechanical strength reduces largely with time going by. Protein based retarders prolong the setting time of hemihydrates with less strength loss and higher costs. The gypsum retarder from waste mycelium, a protein-rich raw material, solved the problem of the disposal of waste mycelium from anti-biotic plants, while producing high-quality retarder for gypsum, shows potential for future.

Identification and enhancement of the thermal and mechanical properties of two types of plasters successively derived from gypsum: from the Safi basin and the High Atlas of Marrakech, Morocco

2020 ◽  
Author(s):  
imane baba ◽  
Mounsif Ibnoussina ◽  
Omar Witam
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Mechanical Strength ◽  
Setting Time ◽  
Density Measurement ◽  
Raw Material ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
X Ray Diffraction ◽  
High Atlas

<p>Over the past few decades, the construction industry has focused on sustainable, environmentally friendly and easily recyclable materials. The objective of this work is to characterize and enhance the thermal conductivity, mechanical strength and setting time of a composite material based on plaster and lime. This material is designed for use in plasters.</p><p>Two types of gypsum are studied, the first one belongs to the Safi basin, the second one characterizes the High Atlas of Marrakech and precisely Douar Tafza. Geologically speaking, the two sites have many similarities. They are characterized by a Meso-Cenozoic age coverage covering a deformed Paleozoic age basement.</p><p>The characterization of the plaster's raw material, gypsum, was necessary to determine its physical and geotechnical properties, mineralogy, thermal behaviour and microscopic structure. Several analyses have been developed such as: pycnometer density measurement, X-ray diffraction, infrared spectroscopy and scanning electron microscopy.</p><p>We made samples, of standardized dimensions, of two mixtures based on the two types of plaster reinforced by the addition of two types of lime from different localities. The latter are from Marrakech and the Agadir region. The water/plaster mass ratio was set at 0.75 and the addition of lime was achieved by increasing its percentage in slices by 12.5% and up to 50%.</p><p>The reinforcement of plaster with lime has enhanced its thermal and mechanical properties and setting time. The measurements show that the addition of lime has reduced the thermal conductivity and increased the mechanical strength of both types of plaster. In addition, following the addition of lime, the setting time has decreased and the basicity of the material has increased. Noting that the intrinsic properties of the raw material influence the mechanical and thermal properties of the material.</p><p><strong>Keywords:</strong>   plaster, enhancement, properties, mechanical, thermal, Morocco</p>

Study on Gypsum Retarder from Waste Penicillin Mycelium

2014 ◽  
Vol 878 ◽  
pp. 539-544
Author(s):  
Xiao Qiong Ren ◽  
Hong Jie Liu ◽  
Xue Song Liang
Keyword(s):  
Mechanical Strength ◽  
Sodium Citrate ◽  
Crystal Morphology ◽  
Treatment Time ◽  
Ph Value ◽  
Setting Time ◽  
Strength Loss ◽  
Sodium Polyphosphate ◽  
Pharmaceutical Factory ◽  
Treatment Conditions

A new kind of gypsum retarder was prepared from waste penicillin mycelium (WPM), a harmful solid waste from pharmaceutical factory. The results indicated that the optimum treatment conditions were pH value 11, temperature 80 °C and treatment time 1.5 h. Compared with sodium citrate and sodium polyphosphate, WPM retarder can effectively prolong the setting time of gypsum with less influence on mechanical strength. The crystal morphology microstructure of gypsum containing retarder was studied with SEM and the reason why the mechanical strength loss of gypsum were also explained in this paper.

scholarly journals Use of the Waste Foundry Sand in the Composition of Hot Sandy Dense Asphalt Concrete

2020 ◽  
Author(s):  
Kirill Yuryevich Tyuryukhanov ◽  
Konstantin Georgievich Pugin
Keyword(s):  
Elemental Composition ◽  
Asphalt Concrete ◽  
Building Materials ◽  
Raw Materials ◽  
Road Construction ◽  
Developed Countries ◽  
Raw Material ◽  
High Quality ◽  
Foundry Sand ◽  
Waste Foundry Sand

There is an increase in motorization worldwide, which in turn requires the construction of high-quality roads and highways. In both new construction and reconstruction of the pavement, large volumes of natural mineral materials are used, placing a large technogenic load on environmental objects during their extraction. In a number of regions of the Russian Federation, there are not sufficient volumes of conditioned raw materials for the production of high-quality composite building materials, such as asphalt concrete and cement concrete mixtures. The use of industrial waste in the composition of building materials addresses this issue while both solving environmental issues and reducing the cost of road construction. This article shows that developed countries successfully use the resource potential of waste in the production of building materials. This article proposes the use of waste foundry sand as the mineral raw material in the production of asphalt concrete. The article presents research on the following: geometric shape, elemental composition of the surface of the particles of the waste foundry sand; bitumen capacity; and the adhesion of bitumen. Based on the obtained data, a technology was developed for producing hot sandy asphalt concrete in which the waste foundry sand is used as a fine mineral aggregate. Physico-mechanical properties of the obtained samples of asphalt concrete satisfy the requirements established in GOST for asphalt concrete. Keywords: waste foundry sand, asphalt concrete, industrial material, elemental composition, bitumen

Optimization of an improved aqueous method for the production of high quality white sesame oil and de-oiled meal

2020 ◽  
Vol 71 (2) ◽  
pp. 349
Author(s):  
M. Lv ◽  
W. Wu
Keyword(s):  
Acid Value ◽  
Protein Isolate ◽  
Aqueous Salt Solution ◽  
Sesame Oil ◽  
Raw Material ◽  
National Standard ◽  
Hexane Extraction ◽  
High Quality ◽  
Aqueous Method ◽  
Protein Rich

Research into the production of white sesame oil by aqueous extraction has been promoted because of concerns about the environment, health, and cost. The advanced aqueous method using a 1.95:10 liquid-to-raw material ratio, which was finally developed in this study, recovered 96.06% white sesame oil and produced de-oiled meal with high quality (3.98% residual oil content). The acid value and peroxide value of the oil produced were quite low at 0.19 mg KOH/kg and < 3.25 mmol/kg, respectively, which were better than the values required by the Chinese national standard for first class edible sesame oils and oils produced by hexane extraction. No wastewater was discharged during the extraction of white sesame oils by an aqueous salt solution. The protein rich de-oiled meal may be a good material for making protein isolate with high purity (e.g. > 90%). It can also be a nutritious ingredient or raw material for producing many food products.

scholarly journals Conditioning techniques technogenic raw materials used for binders

2017 ◽  
Vol 2 ◽  
pp. 16-24
Author(s):  
Kochetkov S.P. ◽  
Bryl S.V. ◽  
Smirnov N.N. ◽  
Rukhlina N.I. ◽  
Rukhlin G.V.
Keyword(s):  
Air Conditioning ◽  
Building Materials ◽  
Raw Materials ◽  
Raw Material ◽  
High Quality ◽  
Calcium Carbonates ◽  
Materials Used ◽  
Technogenic Raw Materials

For production of binding building materials in Russia and worldwide, used a variety of calcium-containing natural raw material: calcium carbonates, aragonite (CaCO3); sulfates-gypsum (CaSO4∙2H2O,CaSO4); oxides and hydroxides (bauxite glinozemservice); perforate-apatites and phosphates (Ca5∙(PO4)3∙F). The article discusses the need for air-conditioning of phosphogypsum to ensure that he was suitable without restrictions for processing into high-quality gypsum binders.

scholarly journals Influence of the Calcination Temperature of Synthetic Gypsum on the Particle Size Distribution and Setting Time of Modified Building Materials

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5759
Author(s):  
Artur Koper ◽  
Karol Prałat ◽  
Justyna Ciemnicka ◽  
Katarzyna Buczkowska
Keyword(s):  
Calcination Temperature ◽  
Building Materials ◽  
Setting Time ◽  
Reference Sample ◽  
Particle Diameter ◽  
Raw Material ◽  
Diameter Distribution ◽  
Laser Method ◽  
Before And After ◽  
Different Temperatures

The paper assesses the influence of the calcination temperature of synthetic gypsum binder on the binding properties of innovative gypsum pastes, as well as on masonry and plastering mortars. The calcination process of gypsum binder was carried out at four different temperatures ranging from 170 to 190 °C. The specimens for testing were prepared on the basis of the obtained raw material with a constant water to gypsum ratio of w/g = 0.75. It was noted that the calcination temperature influenced the setting time of the gypsum. Based on synthetic gypsum, mixtures of masonry and plastering mortars modified with tartaric acid and Plast Retard were designed. During the experiment, the particle diameter distribution of aqueous suspensions of building and synthetic gypsum particles (before and after calcination) was determined using the Fraunhofer laser method. The dimensions of the obtained artificial gypsum grains did not differ from the diameters of the gypsum grains in the reference sample. On the basis of the conducted research, it was found that the waste synthetic gypsum obtained in the flue gas desulphurization process met the standard conditions related to its setting time. Therefore, it may be a very good construction substitute for natural gypsum, and consequently, it may contribute to environmental protection and the saving and respecting of energy.

scholarly journals Geopolymer coating as a protection of concrete against chemical attack and corrosion

2018 ◽  
Vol 49 ◽  
pp. 00101 ◽  
Author(s):  
Szymon Sikora ◽  
Ewa Gapys ◽  
Bartosz Michalowski ◽  
Tomasz Horbanowicz ◽  
Mariusz Hynowski
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
Organic Acids ◽  
Setting Time ◽  
Strength Loss ◽  
Corrosive Environment ◽  
Initial Value ◽  
Great Resistance ◽  
Chemical Attack ◽  
Inorganic Acids

In order to mitigate and prevent chemical attack and concrete corrosion one has to choose the right concrete to make it less permeable or isolate it from the corrosive environment by using a suitable coating. Here, we present the use of geopolymer mortar made of local waste materials and sodium silicate as a chemo-resistive coating for concrete. In this paper, the development of geopolymer mortar working parameters (e.g. setting time and adhesion to concrete) is described. Here, we investigated the resistance of concrete samples coated with geopolymer to 10% inorganic/organic acids and saturated solution of sodium chloride. During the soaking in corrosive environment, weight loss and compressive strength were measured. Geopolymer coating described in this work showed great resistance to organic and inorganic acids. Coating of concrete samples reduced their weight loss after exposure to organic acids from 15% to 2% with concomitant compressive strength loss from 49% to 9% of the initial value. The difference in chemical resistance for inorganic acids was even more visible. Coating of concrete samples reduced their weight loss after exposure to inorganic acids from 73% to 0.8% with adequate compressive strength loss from 96% to only 3.5% of the initial value.

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION

1970 ◽  
pp. 47-50
Author(s):  
I. A. Ilina ◽  
I. A. Machneva ◽  
E. S. Bakun
Keyword(s):  
Raw Materials ◽  
Thermal Characteristics ◽  
Environmental Safety ◽  
Raw Material ◽  
High Quality ◽  
Temperature Conductivity ◽  
Drying Temperature ◽  
Plant Raw Materials ◽  
Gel Forming Ability

  The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

The basis of quality of sheep pelts and fur products is morphological features of the skin of sheep

2020 ◽  
pp. 50-57
Author(s):  
I. Dmitrik ◽  
G. Zavgorodnyaya
Keyword(s):  
Mechanical Strength ◽  
Breaking Load ◽  
Hair Follicles ◽  
Morphological Features ◽  
High Density ◽  
Fat Cells ◽  
High Quality ◽  
Histological Features ◽  
Weakened Zone

The morphological and histological features of the skin and wool cover of sheep as the basis for the quality of fur sheep pelts have been studied. The most important properties of sheep pelts (uniformity, thinness and density of wool) are provide the possibility of producing high-quality fur semi-finished products from them. However, the features of the histostructure of fine-wool sheep determine the low mechanical strength of the “facial” layer of skin. As a result, the “front” layer during processing often cracks to the upper border of the reticular layer or even peels off from the latter, making the sheep pelt unsuitable for use on fur products. These defects in fur practice are called “cracking” and “peeling” of the facial layer. They are mainly peculiar to sheep pelts of fine-wooled sheep. In these animals due to the high density and tone of the coat, the roots and hair follicles, root vaginas, secretory departments, excretory ducts of the glands and other structures occupy a significant share of the volume in the thickness of the Pilar layer (up to 25–30 %). The share of fibrous structures remains less volume, and these structures themselves are relatively weakly developed, located loosely and loosely intertwined with each other. The accumulations of fat cells that occur here also cannot be attributed to skin-strengthening elements. In fine-fleece sheep the pilar layer is on average 60 % of the thickness of the dermis. Therefore, more than half of its thickness is a weakened zone. The strength of the “front” layer is not the same in different fine-wool breeds of sheep and in different animals within the breed. For example, the average breaking load for cod of the “front” layer in Soviet Merino pelts is 1,25 kg, and in Precoce is 2,49 kg.

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