scholarly journals The impact of functional groups of the surface of carbon materials on the efficiency of purification of extraction phosphoric acid from fluorine compounds

2019 ◽  
Vol 2 ◽  
pp. 11-18
Author(s):  
Smirnov N.N. ◽  
Konoval A.V. ◽  
Smirnova D.N. ◽  
Kochetkov S.P.

The environmental problems of the production of extraction phosphoric acid and the effect of fluorine on the human body are discussed in the article. The creation of the industry of phosphoric fertilizers on the basis of processing of fluorine-containing phosphate raw materials and fluorine-containing compounds, the development of their application require the study of environmental consequences arising from this, because fluorine is characterized by high mobility in the biological cycle of metabolism. For the purification of phosphoric acid from fluorine was used carbon adsorbents such as active charcoal brand BAU, natural graphite deposits Kyshtymsky, P514 soot, charcoal. Experiments on the purification was carried out on non-evaporated half-hydrated extraction phosphoric acid which was produced by joint stock company «Apatit» in Cherepovets city in Russia. The following analyses were carried out: IR-Fourier spectrometry, research of acid–base properties of carbon materials by potentiometric titration, potentiometric method of fluorine determination in extraction phosphoric acid. It is mentioned that the carbon black P514 is the most efficient adsorbent for purification of extraction phosphoric acid. The total number of functional groups on its surface is 0.62 mmol/g, the degree of purification from fluorine compounds is 94.8%.

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1499
Author(s):  
Ján Jobbágy ◽  
Peter Dančanin ◽  
Koloman Krištof ◽  
Juraj Maga ◽  
Vlastimil Slaný

Recently, the development of agricultural technology has been focused on achieving higher reliability and quality of work. The aim of the presented paper was to examine the possibilities of evaluating the quality of work of wide-area irrigation machinery by monitoring the coefficients of uniformity and non-uniformity of irrigation. The object of the research was pivot irrigation machinery equipped with sprinklers with a total length from 230 to 540 m. The commonly applied quality of work parameter for wide-range irrigators is the irrigation uniformity coefficient according to Heermann and Hein CUH. Work quality evaluations were also carried out through other parameters applicable in practice, such as irrigation uniformity coefficients calculated according to Christiansen CU, Wilcox and Swailes Cws, and our introduced parameters, the coefficient ar (derived from the degree of unevenness according to Oehler) and the degree of uniformity γr (derived from the degree of non-uniformity according to Voight). Other applied parameters for determining the quality of work of wide-range irrigation machinery were the coefficients of irrigation uniformity according to Hart and Reynolds CUhr, further according to Criddle CUcr and subsequently according to Beale and Howell CUbr. Next, the parameters of the non-uniformity coefficient according to Oehler a, the coefficient of variation according to Stefanelli Cv, the degree of non-uniformity according to Voigt γ and the degree of non-uniformity according to Hofmeister Ef were evaluated. Field tests were performed during the growing season of cultivated crops (potatoes, corn and sugar beet) in the village of Trakovice (agricultural enterprise SLOV-MART, southwest of the Slovakia) and in the district of Piešťany (Agrobiop, joint stock company). During the research, the inlet operating parameters (speed stage, inlet pressure, irrigation dose), technical parameters (number of sprayers, total length, number of chassis) and weather conditions (wind speed and temperature) were recorded. The obtained results were examined by one-way ANOVA analysis depending on the observed coefficient or input conditions and subsequently verified by Tukey and Duncan tests as needed. Irrigation uniformity values ranged from 67.58% (Cws) to 95.88% (CUbh) depending on the input conditions. Irrigation non-uniformity values ranged from 8.58 (a, Ef) to 32.42% (Cv). The results indicate a statistically significant effect of the site of interest and thus the impact of particular field conditions (p < 0.05). When evaluating the application of different coefficients of irrigation uniformity, the results showed a statistically significant effect only in the first test (p = 0.03, p < 0.05). During further repeated measurements, the quality of work increased due to the performed inspection of all sprayers and the reduction in the influence of the wind.


Author(s):  
Firuza Alisherovna Umarova ◽  
◽  
Kamal Saidakbarovich Rizaev ◽  
Nemat Kayumovich Olimov ◽  
Zaynab Enverovna Sidametova ◽  
...  

Analysis of the assortment of sedatives registered in the Republic of Uzbekistan showed that sedatives are represented on the pharmaceutical market of the country by such dosage forms as drops, solutions, tinctures, syrups, medicinal herbal raw materials, capsules and tablets. Considering that sedatives registered in the form of a substance, with the exception of the dry extract of Leoglycyrfl produced by “Uzkimyofarm”, there are practically no names of S.K. Islambekov in the Joint Stock Company. In this regard, we consider it expedient to create a new sedative medicinal product of herbal origin in the form of a substance and obtain dosage forms based on it.


2017 ◽  
Vol 4 (2) ◽  
pp. 112
Author(s):  
Ngoc Hung Dang ◽  
Thi Viet Ha Hoang ◽  
Manh Dung Tran

This study is conducted for investigating the impact of cost control on business efficiency of small and medium-sized enterprises (SMEs) in the area of Thai Binh, Vietnam for the period from 2012 to 2014. Impacting factors were built and verified on business efficiency of SMEs including (i) Cost of goods sold ratio, (ii) Financial expense ratio, (iii) Administration expense ratio, (iv) Firm size, (v) Financial leverage, (vi) Assets structure, and on Pre-tax return on sales ratio and Pre-tax return on assets ratio. The study employed regression models of OLS, FEM, REM and GLS with multi-year dataset of SMEs in Thai Binh province. The results show that the ratios of cost of goods sold, financial leverage, and administration expenses have negative relation with business efficiency, but affecting Return on sales (ROS) and Return on assets (ROA). In addition, financial leverage, assets structure and firm size have small impacts on ROS and ROA. Also, basing on the findings, SMEs operating in the form of joint stock company have higher business efficiency than those operating in the form of limited liability company.


2015 ◽  
Vol 19 (1) ◽  
pp. 96-109 ◽  
Author(s):  
Magdalena KAPELKO ◽  
Alfons OUDE LANSINK

This paper estimates technical efficiency in the Spanish construction sector before and after the start of the current financial crisis, and examines the impact of socio-economic factors on technical efficiency. Bias-corrected efficiency measures are obtained using Data Envelopment Analysis with bootstrap for a sample of medium-sized and large construction firms over the period 2000–2010. Next, bias-corrected efficiency scores are regressed on the variables explaining efficiency using bootstrap truncated regression. The results show that technical efficiency is very low and is significantly lower after the beginning of the financial crisis than before. Firms with the highest technical efficiency scores have the lowest input-ratio for material and employee costs to output and the highest for fixed assets. The examination of the determinants of technical efficiency indicates that efficiency is higher for firms that export, are highly leveraged, are integrated in the form of joint stock company, and are located in Spanish regions with higher GDP per capita, while firms with high stock relatively to turnover have lower technical efficiency. Technical efficiency increases with size for relatively small sized construction firms, but decreases beyond a critical firm size, while technical efficiency decreases with age for young firms, but eventually increases for older firms.


Afrika Focus ◽  
1989 ◽  
Vol 5 (3-4) ◽  
Author(s):  
Jan Van Criekinge

The present day railway system in West Africa is the result of the transportpolicy developed by the colonial powers (France, Great Britain and Germany) at the end of the 19th century. lt is remarkable that no network of railways, like in Southern Africa, was brought about. The colonial railways in West Africa were built by the State or by a joint-stock company within the borders of one colony to export the raw materials from the production centres to the harbours. Nevertheless railways were built for more than economical grounds only, in West Africa they had to accomplish a strategic and military role by "opening Africa for the European civilization". Hargreaves calls railways the "heralds of new imperialism" and Baumgart speaks of the own dynamics of the railways, to push the European colonial powers further into Africa... The construction of a railway needed a very high capital investment and the European capitalists wouldn't like to take risks in areas that were not yet "pacified". It is remarkable how many projects to build a Transcontinental railway right across the Sahara desert largely remained on paper. Precisely because such plans did not materialize, however, the motive force they provided to such imperialist actions as political-territorial annexations can be traced all the more clearly.The French built the first railway in West Africa, the Dakar - St-Louis line (Senegal), between 1879 and 1885. This line stimulated the production of ground-nuts, although the French colonial-military lobby has had other motives. The real motivation became very clear at the construction of the Kayes - Bamako railway. Great difficulties needed the military occupation of the region and the violent recruitment of thousands of black labourers, all over the region. The same problems transformed the building of the Kayes-Dakar line into a real hell. Afterwards the Sine Saloum region has been through a "agricultural revolution", when the local ground-nuts-producers have been able toproduce forforeign markets. The first British railways were built in Sierra Leone and the Gold Coast-colony (Ghana). In Nigeria railway construction stimulated the growth of Lagos as an harbour and administrative centre. Lugard had plans for the unification of Nigeria by railways. The old Hausa town of Kano flourished after the opening of the Northern Railway, for other towns a period of decline had begun. Harbour cities and interior railwayheads caused an influx of population from periphery regions, the phenomenon is called "port concentration". Also the imperial Germany built a few railwaylines in theirformer colony Togo, to avoid the traffic flow off to the British railways. If s quite remarkable that the harbours at the Gulf of Guinea-coast developed much later than the harbours of Senegal and Sierra Leone.After the First World War only a few new railways were constructed, the revenues remained very low, so the (colonial) state had to take over many lines. The competition between railways and roadtransport demonstrated the first time in Nigeria, it was the beginning of the decline of railways as the most important transportsystems in West Africa. Only multinational companies built specific railways for the export of minerals (iron, ore and bauxite) after the Second World War, and the French completed the Abidjan - Ouaga-dougou railway (1956).The consequences of railway construction in West Africa on economic, demographic and social sphere were not so far-reaching as in Southern Africa, but the labour migration and the first labour unions of railwaymen organized strikes in Senegal and the Ivory Coast mentioned the changing social situation.The bibliography of the West African railways contains very useful studies about the financial policy of the railway companies and the governments, but only afew railways were already studied by economic historians. KEY WORDS : bibliographical survey, colonial history, economic and demographic consequences, railway development, West Africa 


2020 ◽  
Vol 11 (514) ◽  
pp. 282-287
Author(s):  
I. V. Nagorna ◽  
◽  
Y. Y. Halkina ◽  

The article is aimed at finding ways to optimize costs at the production subdivision «Operational wagon depot Kupyansk» of the Regional division «Southern Railway» of the Private Joint Stock Company «Ukrainian Railways» on the basis of the performed analysis of the composition and structure of costs, profitability, the impact of the amount of costs on performance indicators, the level of costs per 1 UAH of the consummated services, and operational analysis. The views of scholars on the term «costs» are explored. It is defined that cost management is quite a complex and important process in the course of carrying out economic activity along with determining the quality of further results of enterprise. The main methodological bases of cost management, economic condition of the enterprise are researched. Optimization measures for further development of the enterprise are proposed, which will allow to use its resources more efficiently, to achieve an increase sales and maximize profits. The authors provide recommendations on managing the enterprise costs in order to stimulate the growth of competitiveness. The focus is placed on the mechanism of minimizing the costs of the enterprise in the total amount of net income, because efficient use of costs can not be carried out without structural changes in the sphere of their management. It is identified that cost management is an interconnected complex of works, which forms and influences the behavior of costs during economic activity, as well as is aimed at achieving the optimal level of costs. The proposed measures as to optimizing costs can be used by directors and managers of the enterprise to make informed decisions on the prospective development of the enterprise.


Author(s):  
Nicolay N. Smirnov ◽  
Daria N. Smirnova ◽  
Aleksandr P. Ilyin ◽  
Sergey P. Kochetkov

The qualification of phosphoric acid is carried out depending on the use of phosphates of various deposits and the necessary quality of the final products. An acquisition of phosphoric acid of the required quality should be carried out taking into account three aspects: resource-energy, ecology and complex processing. Solving the problems of one aspect entails solving the problems of the other aspects. The rational use of natural resources and the reduction of environmental pollution is the determining factor in the choice of technological regimes for complex processing of raw materials with a reduction in the volume of waste of all kinds or transferring them into forms easily recyclable or specially stored. The absence of economically sound technologies for processing phosphogypsum determines its preferential warehousing. The second component that requires recycling is fluorine. In this regard, the purification of phosphoric acid from fluorine should use technologies that realize the trapping of fluorine compounds released into the gas phase. This is relevant from the point of view of the complexity of processing raw materials with the extraction of rare-earth elements. The use of mechanochemical activation makes it possible to achieve a nanoscale level. To a lesser extent, this aspect relates to the stage of sulfuric acid decomposition, proceeding with the participation of three phases: solid, liquid and gas. In turn, the surface structure of the gas-liquid layer plays the role of an energy barrier for evaporation. To establish the basic energy patterns of concentration and defluorination n the disc apparatus and to optimize the process, a thermophysical model was developed in which the range of effective parameters was determined by the joint solution of a number of equations for the desired ingredients in the phosphoric acid concentration range of 52-65%. The solution of the problem of complex purification of wet-process phosphoric acid can be carried out by adsorption methods that allow to remove to some extent almost all impurities.For citation:Smirnov N.N., Smirnova D.N., Ilyin A.P., Kochetkov S.P. Problems and prospects of production and qualification of phosphoric acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 48-56.


2021 ◽  
Vol 70 (2) ◽  
pp. 122-124
Author(s):  
О.В. Клепиков ◽  
С.А. Куролап

Using the example of Open Joint Stock Company «Pavlovskgranit», located in the Voronezh region, the level of impact of technogenic factors (air pollution and noise) during the extraction and production of crushed granite was estimated. It was established that 61 pollutants enter the atmospheric air from 134 sources of pollution. The main contribution to the total volume of emissions (1881.0 tons/year) is made by inorganic dust with a SiO2 content of 70-20% - 73.4%, sulfur dioxide - 9.8%, carbon monoxide - 114.3 tons/year. Blasting operations in open pits during the extraction of crushed granite are the leading production process that makes a significant contribution to the volume of emissions. At the same time, the remoteness of industrial sites from the territory of residential development, the presence of a sanitary protection zone, allows us to speak about the admissibility of the impact of concentrations of pollutants in the air and the noise factor at the border of the territory of the nearest residential development.


2013 ◽  
Vol 801 ◽  
pp. 7-12 ◽  
Author(s):  
Ján Kosiba ◽  
Ľubomír Hujo ◽  
Juraj Tulík ◽  
Milan Rašo

This paper deals with the lifetime test of a tractor hydraulic pump. The basic indicator of hydraulic pump lifetime is flow characteristics. This paper presents the results of the performance test of ecological hydraulic fluid. These results were subjected to statistical analysis. Based on these data, it is possible to express a minimum impact of ecological hydraulic fluid on hydraulic pump lifetime. The test was carried out in cooperation between the Department of Transport and Handling (Slovak University of Agriculture in Nitra) and Slovnaft, a.s. (joint-stock company), and supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic – VEGA, ref. No 1/0857/12.


2014 ◽  
Vol 20 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Violeta Leskevicienė ◽  
Dalia Nizevicienė

Phosphoanhydrite was obtained by processing dihydrate phosphogypsum generated during phosphoric acid production at Joint Stock Company (JSC) Lifosa (Lithuania). The influence on the properties of phosphoanhydrite of the treament process? parameters was determined, including the conditions of phosphogypsum neutralisation in the lime suspension; temperature and duration of calcination of neutralized phosphogypsum to phosphoanhydrite; fineness of ground anhydrite; selection of additives activating the hydration of anhydrite and their amounts. Upon adding activators of anhydrite hydration, K2SO4 or Na2SO4, the data of XRD and IR spectral analysis show that the specimens after 1 day of phosphoanhydrite hydration with additives contain complex salts - syngenite upon using K2SO4 additive and glauberite in the case of Na2SO4 additive. These additives act as crystallization centers and accelerate hydration. It has been determined that the specimens of phosphoanhydrite calcined at a temperature of 900 ? C with 2 % K2SO4 additive have the best physical and mechanical properties. Already after 1 day of hardening the specimens acquired a compressive strength of 21.18 MPa, and after 28 days of hardening they had a compressive strength of 58.5 MPa (dry specimens).


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