scholarly journals Features of isothermal crystallization of ammonium sulphate

2021 ◽  
pp. 33-43
Author(s):  
Illia Iatsiuk ◽  
Yaroslav Hotskyi ◽  
Yaroslav Korniienko ◽  
Andrii Stepaniuk
Keyword(s):  
Aqueous Solutions ◽  
Soil Fertility ◽  
Ammonium Sulfate ◽  
Morphological Structure ◽  
Mineral Fertilizers ◽  
Bone Meal ◽  
Humic Compounds ◽  
Ph Level ◽  
Mass Crystallization ◽  
Isothermal Mass

Soil fertility is rapidly decreasing due to irrational land use, erosion and soil pollution and adverse weather conditions. The use of composite granular organic-mineral fertilizers that contain mineral and organic components allows the soil fertility to be increased in the most effective and safe manner for the environment. In the production of granular composite fertilizers in a fluidized bed granulator, the process of isothermal mass crystallization is the main parameter that affects the quality. The effect of impurities on the morphological structure of ammonium sulfate microcrystals during mass crystallization on the surface was investigated by means of microscopic analysis. The influence of temperature and pH of the solution on the structure and shape of the microcrystal layer was studied. The process of mass crystallization depends on the presence of impurities, pH and temperature. Given the fact that there is no analytical or theoretical dependence describing the influence of impurities on the morphological structure, the influence is determined experimentally. The presence of even a small content of surfactants and other impurities in the ammonium sulfate solution has a significant effect on the morphological structure of ammonium sulfate microcrystals, which is revealed as reduction in the concentration of impurities in ammonium sulfate obtained by coke-chemical method. The pH level of the medium affects the structure and shape of microcrystals: smaller crystals with a layered structure are formed in the case of weakly alkaline medium with pH = 8 and smaller microcrystals with a granular structure are formed in the case of pH = 4. Therefore, it is important to maintain the required pH level of the medium during the mass crystallization of ammonium sulfate. In isothermal mass crystallization of saturated aqueous solutions of ammonium sulfate with humic compounds and bone meal proceeding on a surface with temperature 90 °C, small elongated crystals with microcrystal sizes from 10 to 100 μm are formed. Impurities of bone meal and humic compounds in the form of inclusions are placed between the crystals of ammonium sulfate: namely, the endosegregation of impurities in the microcrystalline framework is observed. As the concentration of organic matter in the solution increases, which crystallizes as droplets on the surface, rubble and dendrites are formed outside the initial droplet placement. This phenomenon is explained by the increase of diffusion resistance at the center of the drop; as a result, ammonium sulfate crystallizes in the zone with lower resistance. The process of isothermal mass crystallization of saturated aqueous solutions of ammonium sulfate with admixtures of humic compounds, bone meal and other target components in the specified ratios will create new highly effective fertilizers. The obtained results allow formulating theoretical bases for the formation of solid structures based on ammonium sulfate with admixtures of organic and mineral components.

scholarly journals CREATION OF GRANULAR COMPOSITE MATERIALS WITH MULTILAYER STRUCTURE

2020 ◽  
pp. 50-55
Author(s):  
Ya.G. Hotskiy ◽  
A.R. Stepaniuk
Keyword(s):  
Ammonium Sulfate ◽  
Multilayer Structure ◽  
Morphological Structure ◽  
Single Layer ◽  
Solid Particles ◽  
Oil Refining ◽  
Technological Basis ◽  
Other Substances ◽  
Composite Granules ◽  
Mass Crystallization

Granular products are widely used in many industries for the production of catalysts in oil refining and organic synthesis, drugs, food products, fertilizer production, etc. The main advantages of granular products are ease of operation and storage. Depending on the morphological structure, the granules obtained as a result of the technological process are divided into one-component, single-layer, composite-coated granule, multilayer granule, frame granule, and combinations thereof. In this paper, we consider, as an example, the technological basis of granulation of aqueous solutions of ammonium sulfate with impurities of humates, calcium carbonate and other substances with the formation of multilayer composite granules in a fluidized bed granulator. The processes of dehydration and mass crystallization during granulation, namely the influence of the drying rate and impurities on the kinetics of the evaporation process of the dispersed heterogeneous solution on solid particles have been studied. In the process of mass crystallization, when the saturation concentration is reached by removing the solvent, the processes of nucleation and crystal growth occur with the formation of a crystalline framework of ammonium sulfate crystals between, which impurities of organic matter and other components are evenly distributed in the volume of the formed micro layer. It was confirmed that the obtained granules of the composite granular fertilizer have a composite multilayer structure with a uniform distribution of suspended particles in the volume of the granule. Bibl. 14, Fig. 4.

scholarly journals INVESTIGATION OF THE EVAPORATION AND CRYSTALLIZATION OF A SESSILE DROP OF AMMONIUM SULFATE SOLUTION ON A SMOOTH HEATED SURFACE.

2021 ◽  
Vol 43 (4) ◽  
pp. 51-61
Author(s):  
Ya.H. Hotskyi ◽  
G.K. Ivanitsky ◽  
A. R. Stepaniuk
Keyword(s):  
Ammonium Sulfate ◽  
Sessile Drop ◽  
Heated Surface ◽  
Sulfate Solution ◽  
Morphological Properties ◽  
Evaporation Process ◽  
Bone Meal ◽  
Important Place ◽  
Equilibrium Evaporation ◽  
Mass Crystallization

Creation of new composite granular fertilizers with layered structure, which are formed due to the layered mechanism of granulation in the granulator of the fluidized bed is an urgent task. The process of forming these granules is achieved due to the layered granulation mechanism, the basis of which is the formation of a layer of solids on the surface of the granules by mass crystallization. In the production of granular fertilizers based on ammonium sulfate with the addition of organic and inorganic impurities an important place is occupied by the processes of evaporation and mass crystallization, which determine the morphological properties of the obtained granular material. During the experimental study of the evaporation process, it was found that the process consists of three main evaporation periods: the heating period from the initial temperature to equilibrium, the period of equilibrium evaporation and the decreasing drying rate period with crust formation, during which a solid crystal structure is formed. The beginning of each period according to the example of drying droplets in a gas stream during spray drying is described by the nature of the change in droplet temperature. This paper presents the obtained thermograms of the process of evaporation of droplets with a diameter of 3–7 mm 40%, 50% and 60% aqueous solutions of ammonium sulfate with the addition of a mixture of bone meal. The evaporation of 40%, 50% and 60% solutions of ammonium sulfate with the addition of a mixture of bone meal, with a given ratio of AS: BM on a dry residue of 60:40 and 80:20 on a surface temperature of 95°C in the second evaporation period crystalline nuclei appear, and the concentration of solute is close to saturated and almost unchanged, so that the evaporation rate and temperature of the drop, as can be seen from the thermogram, remain constant temperature for all solutions of ammonium sulfate. Increasing the content of bone meal from 8 to 24% to shift the wet thermometer in the kinetics of the evaporation process. The paper also presents the results of morphological analysis of the obtained solid crystallized drops of ammonium sulfate with impurities of bone meal. It was found that the solid crystallized drop of ammonium sulfate with bone meal consists of a framework of microcrystals of ammonium sulfate, with a reduced size of 10 to 80 μm, bone meal in the form of inclusions is placed in the frame, the particle size of bone meal varies up to 100 μm, indicating that the solution is a suspension.

scholarly journals The Influence of Tillage Systems, Fertilizers and Plant Protection on Biological Indicators of Fertility of Soddy Podzolic Gleyic Soil

2020 ◽  
Author(s):  
Е.В. Чебыкина
Keyword(s):  
Soil Fertility ◽  
Plant Protection ◽  
Close Correlation ◽  
Biological Indicators ◽  
Chicken Manure ◽  
Mineral Fertilizers ◽  
Tillage Systems ◽  
Tillage System ◽  
Fertilizer System ◽  
Spring Rape

Представлены результаты исследований агроэкологической оценки разных систем обработки и видов удобрений при выращивании ярового рапса в условиях агроландшафта с дерново-подзолистыми глееватыми почвами. При проведении полевых и лабораторных опытов в 2019 году изучалось последействие заделки органо-минерального субстрата (был внесён в почву в 2017 г.), состоящего из обеззараженного куриного помёта и отработанных вегетационных матов, на биологические показатели плодородия почвы. В ходе исследований было установлено, что заделка органо-минерального субстрата способствует поддержанию почвенного плодородия. Так, содержание органического вещества увеличилось на 10,8% при отвальной системе обработки и на 7,8% – при поверхностной, по сравнению с контролем без удобрений. Существенного влияния изучаемых систем обработки почвы и удобрений на активность почвенного фермента каталаза и целлюлозразлагающих микроорганизмов обнаружено не было. Активность каталазы в большей степени определялась системой удобрений, их последействие проявилось в тенденции к снижению ферментативной активности. Урожайность ярового рапса зависела от биологических показателей плодородия почвы, в ходе корреляционно-регрессионного анализа были выявлены средние по тесноте взаимосвязи, в частности с активностью целлюлозоразлагающих микроорганизмов (r = –0,5693) и фермента каталаза (r = 0,5457). Между изучаемыми биологическими показателями плодородия почвы не обнаружено тесных корреляционных связей. К существенному снижению урожайности ярового рапса (на 13,4%) приводило проведение поверхностной системы обработки почвы в сравнении с отвальной. Применение органо-минерального субстрата самостоятельно и особенно в сочетании с минеральными удобрениями обеспечивало достоверную прибавку урожая зелёной массы ярового рапса. The results of researches of the agroecological assessment of different tillage systems and types of fertilizers when growing spring rape in conditions of cultivated land with soddy podzolic gleyic soils are presented. When conducting field and laboratory experiments in 2019, the afteraction of covering of the organo-mineral substrate (it was introduced into the soil in 2017), consisting of disinfected chicken manure and worked vegetation mats on biological indicators of soil fertility was studied. As part of study it was found that covering of the organo-mineral substrate contributes to maintaining soil fertility. Thus, the content of organic matter increased by 10.8% with the moldboard tillage and by 7.8% with the surface one compared with the control without fertilizers. No significant effect of the tillage systems and fertilizers under study on the activity of the soil enzyme catalase and cellulose decomposing microorganisms was found. Catalase activity was largely determined by the fertilizer system, their aftereffect was manifested in a tendency to a decrease in enzymatic activity. The yield of spring rape depended on the biological indicators of soil fertility, during the correlation and regression analysis medium-sized relationships were found, in particular, with the activity of cellulose decomposing microorganisms (r = –0.5693) and the enzyme catalase (r = 0.5457). Close correlation was not found between the studied biological indicators of soil fertility. A significant decrease in the yield of spring rape (by 13.4%) was caused by a surface tillage system in comparison with the moldboard one. The use of organic-mineral substrate independently and especially in combination with mineral fertilizers provided a reliable increase in the yield of green mass of spring rape.

scholarly journals Scientific bases of the humus stabilization in ordinary chernozem in Russia

2019 ◽  
Vol 52 (1) ◽  
pp. 113
Author(s):  
Oleg Goryanin ◽  
Anatoly Chichkin ◽  
Baurzhan Dzhangabaev ◽  
Elena Shcherbinina
Keyword(s):  
Soil Fertility ◽  
Humus Content ◽  
Perennial Grasses ◽  
Crop Rotations ◽  
Organic Fertilizers ◽  
Annual Rainfall ◽  
Ordinary Chernozem ◽  
Mineral Fertilizers ◽  
Plant Residues ◽  
Middle Volga Region

<p>The influence of long-term use of mineral and organic fertilizers, crop rotations, plant residues, soil treatment systems on humus content of common chernozems and stabilization of productivity of field crops in the arid conditions of the Middle Volga region is considered on the example of researches in the Samara area. The zone climate of field experiments is characterized as extremely continental. The sum of the active temperatures (above 10°C) is 2,800-3,000°C. The average annual rainfall is 454.1 mm with fluctuations over the years from 187.5 mm to 704.6 mm. At some years, precipitation does not happen within a month or more. Hydrothermal index in May-August is 0,7, the duration of the frost-free period is 149 days. If the humus content in the region is 4.35-4.52%, then, it is necessary to introduce 6.7-8.0 t/ha of manure per year to maintain the balance of the deficit. The introduction of biological methods for the conservation and reproduction of soil fertility (green fertilizers, perennial grasses, straw as fertilizer) reduces the loss of humus by 0.15-0.24 t/ha. This makes it possible to increase the payback of mineral fertilizers, which must be taken into account when developing fertility reproduction systems for soils. In the variants with minimal and differentiated cultivation of the soil during crop rotation in 30 years of the study, the loss of humus in the 0-30 cm layer decreased by 0.04 - 0.73% (43-789 kg per year with maximum values in the combination of direct seeding of spring crops with deep loosening for a number of crop rotations is 4.14%, significantly exceeding the control (by 0.54%). The decrease in soil fertility in the variants with constant plowing and minimal tillage contributed to an increase in the conjugation of productivity of crops with humus. Based on the research, in order to preserve the fertility of the soil of ordinary chernozem, it is necessary to use green fertilizer, leguminous perennial grasses. In the regional rotations of crop production, new generation technologies are recommended, the basis of which is differentiated tillage with the use of crushed straw as fertilizer.</p>

scholarly journals Optimizing Soil Fertility Management Strategies to Enhance Banana Production in Volcanic Soils of the Northern Highlands, Tanzania

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 289 ◽  
Author(s):  
Akida I. Meya ◽  
Patrick A. Ndakidemi ◽  
Kelvin M. Mtei ◽  
Rony Swennen ◽  
Roel Merckx
Keyword(s):  
Soil Fertility ◽  
Management Strategies ◽  
Farming Systems ◽  
Animal Manure ◽  
Cattle Manure ◽  
Organic N ◽  
Mineral Fertilizers ◽  
Soil Fertility Management ◽  
Fertility Management ◽  
N Dose

Banana is an important crop in high altitude areas of Tanzania, grown widely both as a food staple and as the main source of income. However, its production is constrained by low soil fertility, a result of gradual nutrient mining by the crop. Currently, soil fertility management in banana-based farming systems in the country relies mainly on applications of animal manure. However, the amount of manure produced in most farms is not enough to replenish soil fertility due to the small number of animals kept by smallholder resource-poor farmers who are the major producers in the country. Field experiments were conducted at three sites with varying soil types and contrasting weather conditions along the altitudinal gradients on the slopes of the volcanic mountains of Kilimanjaro and Meru, northern Tanzania to (1) investigate the effect of mineral nitrogen (mineral N) fertilizer applications on the growth and yield of Mchare banana (Musa spp., AA, a traditional East African highland cooking banana sub-group), at the four levels of 0, 77, 153, and 230 kg N ha−1 year−1 as a starter strategy to improve the current soil fertility management strategies, and (2) evaluate the effect of the combined use of inorganic and organic N sources on growth and banana fruit production as an alternative strategy to manage soil fertility and minimize animal manure requirements. The treatment factors were trial sites (Tarakea, Lyamungo, and Tengeru) as the main factor and N fertilization strategies (as urea alone, sole cattle manure, and in combination with urea, sole common bean (Phaseolus vulgaris L.) haulms as well as in combination with urea) as a sub factor. Bean haulms and cattle manure were applied each year for two years. Fertilization at 153 kg N ha−1 year−1 derived solely from urea significantly (p < 0.001) resulted in high yield increment of up to 42% relative to the control. However, the increase was highest (52%) with the same N dose derived from cattle manure in combination with urea at 50% substitution. Sole bean haulms resulted in a smaller yield increment, the same as the lowest N dose from the sole urea fertilization treatment. The study concludes that soil fertility management in smallholder banana-based farming systems should not solely rely on animal manure and mineral fertilizers.

SEQUENCING INTEGRATED SOIL FERTILITY MANAGEMENT OPTIONS FOR SUSTAINABLE CROP INTENSIFICATION BY DIFFERENT CATEGORIES OF SMALLHOLDER FARMERS IN ZIMBABWE

2014 ◽  
Vol 51 (1) ◽  
pp. 17-41 ◽  
Author(s):  
H. NEZOMBA ◽  
F. MTAMBANENGWE ◽  
R. CHIKOWO ◽  
P. MAPFUMO
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Smallholder Farmers ◽  
Mineral Fertilizers ◽  
Soil Productivity ◽  
Soil Fertility Management ◽  
Management Options ◽  
Integrated Soil Fertility Management ◽  
Fertility Management ◽  
Maize Grain

SUMMARYResearch has proved that integrated soil fertility management (ISFM) can increase crop yields at the field and farm scales. However, its uptake by smallholder farmers in Africa is often constrained by lack of technical guidelines on effective starting points and how the different ISFM options can be combined to increase crop productivity on a sustainable basis. A 4-year study was conducted on sandy soils (<10% clay) on smallholder farms in eastern Zimbabwe to assess how sequencing of different ISFM options may lead to incremental gains in soil productivity, enhanced efficiency of resource use, and increase crop yields at field scale. The sequences were primarily based on low-quality organic resources, nitrogen-fixing green manure and grain legumes, and mineral fertilizers. To enable comparison of legume and maize grain yields among treatments, yields were converted to energy (kilocalories) and protein (kg) equivalents. In the first year, ‘Manure-start’, a cattle manure-based sequence, yielded 3.4 t ha−1of maize grain compared with 2.5 and 0.4 t ha−1under a woodland litter-based sequence (‘Litter-start’) and continuous unfertilized maize control, respectively. The ‘Manure-start’ produced 12 × 106kilocalories (kcal); significantly (p< 0.05) out-yielding ‘Litter start’ and a fertilizer-based sequence (‘Fertilizer-start’) by 50%. A soyabean-based sequence, ‘Soya-start’, gave the highest protein production of 720 kg against <450 kg for the other sequencing treatments. In the second year, the sequences yielded an average of 5.7 t ha−1of maize grain, producing over 19 × 106kcal and 400 kg of protein. Consequently, the sequences significantly out-performed farmers’ designated poor fields by ~ fivefold. In the third year, ‘Soya-start’ gave the highest maize grain yield of 3.7 t ha−1; translating to 1.5 and 3 times more calories than under farmers’ designated rich and poor fields, respectively. In the fourth year, ‘Fertilizer-start’ produced the highest calories and protein of 14 × 106kcal and 340 kg, respectively. Cumulatively over 4 years, ‘Manure-start’ and ‘Soya-start’ gave the highest calories and protein, out-performing farmers’ designated rich and poor fields. Sunnhemp (Crotalaria junceaL.)-based sequences, ‘Green-start’ and ‘Fertilizer-start’, recorded the highest gains in plant available soil P of ~ 4 mg kg−1over the 4-year period. Assessment of P agronomic efficiencies showed significantly more benefits under the ISFM-based sequences than under farmers’ designated rich and poor fields. Based on costs of seed, nutrients and labour, ‘Soya-start’ gave the best net present value over the 4 years, while ‘Fertilizer-start’ was financially the least attractive. Overall, the ISFM-based sequences were more profitable than fields designated as rich and poor by farmers. We concluded that ISFM-based sequences can provide options for farm-level intensification by different categories of smallholder farmers in Southern Africa.

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