scholarly journals Study of Semi-Dry High Target Solidification/Stabilization of Harmful Impurities in Phosphogypsum by Modification

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 462
Author(s):  
Fenghui Wu ◽  
Can Yang ◽  
Guangfei Qu ◽  
Liangliang Liu ◽  
Bangjin Chen ◽  
...  

Phosphogypsum (PG) treatment is one of the research hotspots in the field of environmental protection. Many researchers both at home and abroad have devoted themselves to studies on harmless resource treatment of PG, but the treatment technology is unable to meet the demand of PG consumption due to the huge production and storage demands. In order to solve the problem of PG pollution, this study explored the different solidified effects of various modification formulations on the hazardous components in PG, using industrial solid waste calcium carbide slag (CCS) as an alkaline regulator; Portland cement (PC), polyaluminum chloride (PAC) and CaCl2 as the main raw materials of the solidification and stabilization formula and the water content in PG as the reaction medium. The results showed that CCS (0.5%), PC (0.4%) and PAC (0.3%) had a more significant solidified effect on phosphorus (P) and fluoride (F). PAC was added in two steps and reacted under normal temperature and pressure, and its leaching toxicity meets the requirements of relevant standards, which laid an excellent foundation for PG-based ecological restoration materials and filling materials, with low economic cost, simple process and strong feasibility. This will provide great convenience for the later mining and metallurgy.

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 877 ◽  
Author(s):  
Neslihan Doğan-Sağlamtimur ◽  
Ahmet Bilgil ◽  
Magdalena Szechyńska-Hebda ◽  
Sławomir Parzych ◽  
Marek Hebda

Bottom ash (BA) is an industrial solid waste formed by the burning of coal. The environmental problems and storage costs caused by this waste increase with every passing day. In this study, the use of BA as an additive (clay substitute) in fired brick production was investigated. The study consisted of two stages. In the first stage, cylinder blocks were produced from clay used in brick production. The second stage was the examination of the experimental substitution of clay with 10, 20, 30 and 40% BA. Samples were fired at 900, 1000, 1100 and 1150 °C to produce fired brick samples. The unit weight, compressive strength (before and after freeze–thawing) and water absorption were analyzed for the samples. The unit weight values decreased in the samples containing BA. The mechanical properties met the conditions prescribed in the relevant standards; i.e., all of the samples fired at 1100 and 1150 °C had a sufficient compressive strength over 20 MPa. The high potential of fired bricks for the construction industry was proved. BA can be used as a clay substitute, while the developed protocol can be used to effectively produce fired bricks.


2000 ◽  
Vol 15 (1) ◽  
pp. 2-8 ◽  
Author(s):  
N.C. Wagner ◽  
S. Ramaswamy ◽  
U. Tschirner

AbstractA pre-economic feasibility study was undertaken to determine the potential of cereal straw for industrial utilization in Minnesota. Specifically, utilizing straw for pulp and paper manufacture was of interest. The availability of cereal straw fiber supplies at various locations across the state of Minnesota, along with pre-processing issues such as transportation, harvesting, handling, and storage, are discussed and priced. The greatest economic advantage of straw for industrial use appears to be the low cost of the raw material compared to traditional raw materials. This also provides an excellent opportunity for additional income for farmers. The methodology and information provided here should be helpful in evaluating the feasibility of utilizing straw for other industrial purposes in other parts of the world. However, in some Third World countries, long-standing on-farm, traditional uses of cereal straws for fuel, fiber, and animal feed may limit their availability for industrial utilization.


Author(s):  
Janmejay Pant ◽  
. Ripudhaman

Standardization in Ayurvedic formulations ensures the establishment of standards for the quality and purity of raw materials, quality control during the drug manufacturing process, production of a good quality finished product, storage and distribution to maintain the quality of the final product. It is an essential tool for establishing quality control methods for Ayurvedic drugs. In Ayurveda, standardization has been well defined and documented in the classical and contemporary texts. Still, these have been written with an individualistic intent and not for industrial or commercial purposes.  Careful contemplation of the classical literature of Ayurveda was done, the current guidelines of WHO on standardization of herbal drugs, latest researches on the same via the internet were explored and examined in the purview of the newest standardization procedures.  In this article, an attempt has been made to bring to light the classical references related to standardization, the milestones in this on-going pursuit have been exhibited, with the use of the latest scientific methods being incorporated for a standardized Ayurvedic drug. It can be concluded from the review that standardization in Ayurveda is an on-going process where one needs to be strictly vigilant about the new scientific methods to study the fine chemical procedures and the intermediate compounds formed, but at the same time be aware of the classical. Ayurvedic methods concepts of the procedure. Asava-arista's medicinal characteristics of Ayurvedic classical dosage forms, liquid dosage forms based on self-generated alcohol with faster absorption, long shelf life, and increased market conformity have led to a continuous rise in demand. New fermentation methods and packaging innovations tend to have been embraced by many Ayurvedic processing units. The importance of standardization of such goods is underlined by these advances in manufacturing, distribution and storage. Therefore, it is of concern to examine the latest manufacturing situation and the standardization of the dosage type regarding the procedure and the consistency and effectiveness of the finished product. In addition to the effort to include criteria of consistency and standardization, the study consists of an overview and deliberates on the importance of improvements made to the conventional preparation processes, ingredients and material used in the process and the potential impact on its efficacy.


2021 ◽  
Vol 4 (3(60)) ◽  
pp. 6-8
Author(s):  
Iryna Koval

The object of research is the process of water disinfection at the influence of gas from bacteria of a particular genus with different amounts per unit volume of water. Due to the annual increase in the amount of pollutants in natural waters, new opportunities to improve microbiological indicators of water quality are being explored. There are many different ways to disinfect it, both physical and chemical. However, no single method has been found to purify aqueous media from microorganisms that would ensure their effective destruction. It is proposed to study the activity of specific microorganisms during the bubbling of inert gas through the aqueous medium. The microorganisms studied were rod-shaped sporogenic cells of Bacillus cereus bacteria type. The test gas was inert helium. The study used continuous gas bubbling throughout the process, which allowed to mix microbial water efficiently and prevent the formation of stagnant zones in the reaction medium. In particular, active gas mixing facilitates its access to each cell. The gas supply rate corresponded to 0.2 cm3/s, and its flow rate was 0.7 dm3 for one hour of bubbling through microbial water. The duration of the entire research process was 7200 s. The constant temperature of the microbial water (T=288±1 K) was maintained during the experiment by cooling the glass reactor with running water. An in-depth method of culturing bacterial cells was used. A decrease in the number of microorganisms was observed throughout the helium supply process, despite the different initial amounts in the water. The highest destruction degree of bacillus (77.06 %) was obtained at the lowest studied concentration in water (NM01=3.4·104 CFU/cm3). This is due to the fact that less microbial load provides better conditions for access of helium to the cell and their effective destruction. The proposed method of water purification allowed to achieve a sufficiently high degree of water disinfection from sporogenic rod-shaped bacteria after the action of helium alone. In particular, it has been experimentally proven that the efficiency of the water disinfection process depends on the concentration of microorganisms per unit volume of water. Due to the treatment of contaminated water with gas, it is possible to obtain high rates of its purification and the application of this method for practical purposes in water treatment technology.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6355
Author(s):  
Haylemar de Nazaret Cardenas-Rodriguez ◽  
Rosa Martins ◽  
Levy Ely Lacerda Oliveira ◽  
Erik Leandro Bonaldi ◽  
Frederico de Oliveira Assuncao ◽  
...  

The city of Aripuana is one of the largest wood producer in the state of Mato Grosso, Brazil. Wood residues are used in the electricity generation at three thermoelectric plants in this region. However, the plants have high costs in transporting the wood residues (due to poor road conditions). Hence, this paper compares the energy performance of wood residues in natura and compacted as briquettes by calculating the heating value and determining the influence of moisture content on the energy characteristics of wood residues. The goal is to demonstrate the viability of using briquettes in order to improve thermoelectric generation. The wood residues from this region are affected by the high humidity of the biome. An alternative to improve the use of energy contained in the wood residues is to produce briquettes with lower humidity. This allows one to maintain high levels of heat energy in a lower volume, facilitating handling and storage. The results show that the use of briquettes improved the performance of thermoelectric plants, generating 1 MW of electricity power with less than 1 ton of briquettes. This contributes to the preservation of the environment, reducing operating costs, transportation and storage of the raw materials.


2020 ◽  
pp. 36-40
Author(s):  
O.V. Sycheva ◽  
V.G. Kayshev

The main dysnutrition of the Russian population is the excess of caloric intake over an indicator of the energy consumption level. One of the ways to solve this problem is the production of functional food products or enriched functional products. The essence of this is that only those micronutrients that are really in short supply should be used in the fortification of products. These should be products of mass consumption, and especially those that undergo refining, which results in the loss of micronutrients. The use of raw materials and ingredients only of natural (animal, vegetable, mineral) origin allows creating active complexes that qualitatively alter the physiological properties of the product and can affect many product characteristics and processes such as physico-chemical, structural, mechanical and organoleptic characteristics of the product, the processes of color formation, fermentation, oxidation, and storage capacity. However, sometimes a strong passion for enriching the product with useful macro- and micronutrients affects the taste characteristics. Therefore, when developing recipes and technologies for new-generation products, it is crucial that the enrichment of the product with important and necessary elements should not deteriorate the organoleptic characteristics. At the same time, it is essential to ensure the safety of products without compromising consumer properties. The diet should contain all the nutrients necessary for a person in sufficient quantities and balanced with each other in the most favorable proportions


Author(s):  
Anna Alfocea-Roig ◽  
Sergio Huete-Hernandez ◽  
Alex Maldonado-Alameda ◽  
Jessica Giro-Paloma ◽  
Josep Maria Chimenos-Ribera ◽  
...  

Climate change has become one of the world’s leading threats. Currently, the construction industry has a high environmental footprint. For this reason, the scientific and technological sector is looking for new materials to reduce the environmental consequences of this division. It is well known that the valorisation of different by-products can contribute to the reduction of the energy global consumption and CO2 emissions. Magnesium Phosphate Cement (MPC) can be obtained by using Low Grade Magnesium Oxide (LG-MgO) as a by-product from the industrial process of magnesite calcination. In this research, a Sustainable MPC (Sust-MPC) for different construction purposes is developed by using LG-MgO along with monopotassium phosphate KH2PO4 (MKP) as raw materials. The increasing use of synthetic fibres in clothing, as well as China’s competitive prices on Animal Fibres (AF) market, have led to a commercial interest fibre decrease for wool-like AF in Spain. This study aims to formulate a Sust-MPC cement with Animal Fibre (AF) to reduce the cost of the new material (Sust-MPC-AF) and to increase the thermal insulation, allowing the use of Sust-MPC-AF in several potential applications. Besides, it should be emphasized that the final pH of Sust-MPC is neutral, which allows containing natural fibres. To develop Sust-MPC-AF, some properties such as thermal conductivity, density, Modulus of Elasticity (MoE), flexural strength, and economic cost were evaluated using the Design of Experiments (DoE). The DoE studies allowed obtaining a model for further optimization considering minimum thermal conductivity and cost dosages. The formulation 30L-25EW presents the minimum conductivity (λ=0.140 W·m-1·K-1). Therefore, two optimal dosages (36L-25EW and 24L-22EW) are obtained by considering mixing variables such as AF/Cement ratio (AF/C) and AF/Extra Water ratio (AF/EW).


Author(s):  
Rodica Sturza

The presented results reflect the researches carried out over the last decade, having as their object the soil, water, vegetal raw materials, and wines from the Republic of Moldova. The analysis of the possible anthropogenic contamination (NAA method) demonstrated the absence of systematic soil pollution. A total of 30 elements were determined in soil samples and the soil-leaves-fruit transfer factors were calculated. Approximately 3000 samples of local wines have been analysed to determine the residual quantities of pesticides. POPs were not found in any of the wine samples. In most of the examined cases (> 60% of samples), the lack of organic pesticide residues was observed. The migration of phthalates into different solutions from polymeric materials (PVC, rubber) and the influence of the temperature on the extraction rate were investigated. It has been shown that the contamination with phthalate residues occurs predominantly at the stage of grape processing, technological treatment, and storage.


2022 ◽  
pp. 123-150
Author(s):  
Suzita Ramli ◽  
Jun Xian Wong

Transmission of hazardous materials could be aggravated by inappropriate handling and storage practices. This results in cross-contamination to foodstuff or cooking utensils. The introduced hazards in the food supply chain might lead to client and reputation loss. The implementation of food safety is necessary to secure safety concerns. All employees should take initiative to be aware and have good attitudes regarding proper hygiene and sanitary practices to assure their product integrity and safety for human consumption. Therefore, this chapter delivered the appropriate and standard food safety protocols to all individuals involved in food storage, preparation, and serving. The scope was structured into (1) identification of hazardous ingredients, (2) purchasing and receiving raw materials, (3) transporting and storage, (4) cooking and reheating, (5) food serving and displaying, (6) leftover storage, and (7) cleaning and sanitation.


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