Behaviour of single-crystal nickel alloy in the conditions of high-temperature hydrogen corrosion

This study presents the results of the investigation of the behaviour of ZhS32-VI single-crystal nickel alloy in hydrogen environment or argon atmosphere at 850°C. The microstructure and chemical composition of corrosion deposits were studied by scanning electron microscopy and X-ray energy-dispersive analysis. It has been established that in argon containing an admixture of oxygen a dense scale rich in cobalt and nickel oxides is formed. At atmosphere containing 65% hydrogen and 35% argon an increased content of aluminum in the surface composition was noted. The influence of 100% hydrogen leads to segregation of tungsten and rhenium with the formation of convex growths. The data of simultaneous thermal analysis revealed that the amount of desorbed hydrogen can be from 0.08 to 0.14%

Effect of sonochemical pretreatment of slurry depressors on sylvin flotation performance

The main source of potassium fertilizers is sylvinite ores consisting primarily of halite (NaCl), silicate and clay-carbonate slurries (clay-salt slurries). Processing of natural potash ores is mainly carried out by the flotation method, which separates KCl, NaCl, and clay-salt slurry. The research is aimed at revealing the effect of sonochemical pretreatment of the depressor reagents, CMC and starch, on dynamic viscosity, aggregate size, electrokinetic potential of these reagent solutions and sylvin flotation performance. It has been established that sonochemical treatment of depressor solutions decreases the size of aggregates of starch molecules by more than 133 times and that of aggregates of CMC molecules from 6 to 4 nm. It has been revealed that sonochemical treatment of anionic CMC solution shifts the electrokinetic potential towards the area of negative values with an increase in acoustic power, while sonochemical treatment of any acoustic power has no effect on the zeta potential of nonionic starch. It has been found that the sonochemical treatment lowers the dynamic viscosity of CMC and starch solutions: the viscosity of CMC solution at a maximum acoustic power of 420 W decreases by 44 % and the viscosity of starch solution at the same acoustic (ultrasonic) power decreases by 70 %. Furthermore, sonochemical pretreatment of sylvin flotation depressors contributes to an increase in KCl recovery and a decrease in the slurry content in the flotation concentrate. The possibility of reducing the consumption of ultrasonic treated depressor is also demonstrated. It is expedient to test the obtained findings in pilot-plant conditions

Investigation of the Immunological Effect of Fermented Epilobium Angustifolium Extracts at the Cell Level

ABSTRACT Epilobium angustifolium has been traditionally used to treat a number of diseases. The mode of action of Epilobium angustifolium extracts is still unknown. The aim of this study is to identify the influence of various commercially available extracts of fermented Epilobium angustifolium at the cellular level. Water and ethanol extracts of Epilobium angustifolium, as well as polar and nonpolar fractions were tested on cell level in the range of concentrations between 3 and 1000mkg / ml. It was shown that various fermented Epilobium angustifolium extracts could affect on cell proliferation and apoptosis of primary human lymphocytes

Investigation of the immunological effect of fermented epilobium angustifolium extracts at the cell level

Epilobium angustifolium has been traditionally used to treat a number of diseases. The mode of action of Epilobium angustifolium extracts is still unknown. The aim of this study is to identify the influence of various commercially available extracts of fermented Epilobium angustifolium at the cellular level. Water and ethanol extracts of Epilobium angustifolium, as well as polar and nonpolar fractions were tested on cell level in the range of concentrations between 3 and 1000mkg / ml. It was shown that various fermented Epilobium angustifolium extracts could affect on cell proliferation and apoptosis of primary human lymphocytes

Interaction of a potassium silicate binder with impurity components during formation of KC1 granules by the pelletizing method

The relevance of the work is caused by the significant impact of impurities in the cyclonic dust of potassium chloride on the quality of the granulated KC1 obtained by the method of treating the pellets, as well as by the necessity to assess the products of interaction of silicate binder (potassium silicic) with impurity components. The main aim of the research is to study the interaction of a silicate binder (potassium silicate) used for granulating potassium chloride with impurity components of cyclone dust KC1 and to evaluate the effect of interaction products on pellet characteristics obtained by pelletizing. The methods used in the study: the method of scanning electron microscopy, which is the main source of information about the state of the surface of the object; method of thermodynamic analysis, which allows determining the probability of reactions and the possibility of formation of new phases on KC1 granules; the method of qualitative analysis on the Bruker TENSOR 27 IR Fourier spectrometer with application of the «ATR Miracle» attachment used to prove the progress of transfer of octadecylamine hydrochloride to the base form, when it is treated with a solution of silicate binder (potassium silicate). The results. The authors have determined the products of interaction of potassium silicate with impurity components: calcium, magnesium, iron chloride, amine hydrochloric acid, present in the cyclonic dust of flotation potassium chloride at formation of KC1 granules by the pelletizing method. The effect of the interaction products on the granules obtained by the pelletizing method was estimated. With the help of electron-scanning microscopy, it is established that when ammonium chloride solution is applied to the surface of a hydrochloric amine solution, the amines are transformed into the basic form, while the continuous amine film is destroyed, globules are formed, and during crystallization the microcrystals of the binder (potassium silicic acid) crystallize. It was proved that the treatment of octadecylamine hydrochloride with a solution of potassium silicic acid leads to the transfer of octadecylamine hydrochloride to the base form, but the reaction is not complete and a part of the octadecylamine hydrochloride remains in the hydrophobic form, adversely affecting the granulation

Study of leonite crystallization from sulphate potassium-magnesium liquor

The relevance of the research consists in possibility of using leonite, obtained at crystallization from sulphate liquor, as a complex sulphate potassium-magnesium fertilizer. Production of such fertilizer is a promising direction in development of potassium industry. The main advantage of sulphate fertilizers is the possibility of using them for plants, which cannot endure the chlorine excess. In addition they can be used for different soils and large number of culture of plants. The main aim of the research is to investigate the crystallization stage in leonite production from polyhalite ore, to select the required mode of crystallization. The methods used in the study: modeling of technological process in laboratory conditions, determination of size, quantity and form of crystals, formed at different time intervals, by system of continuous video registration of suspension particles «PVM Lasentec V819», X-ray analysis of product, obtained at different conditions. The results. The authors have carried out the investigations of isothermal and polythermal crystallization of leonite and syngenite from sulphate potassium-magnesium liquors. It is shown that the mixture of leonite and syngenite is crystallized in isothermal mode, and pure leonite is formed in polythermal mode. The leonite crystal form transforms from globular in tabulated, and then in acicular, at polythermal crystallization. The mechanical abrasion of crystal occurs at achievement of size of 50 microns, the crystal size decreases, it is also related with recrystallization of globular crystals into tabulated ones. The leonite crystal acquires acicular form at process duration of 90 minutes or longer, the intensive growth of crystal size occurs. The findings. It was determined that it is advisable to carry out polythermal crystallization in complicated system K2SO4-MgSO4-CaSO4, it allows obtaining pure product - leonite, which is suitable for further use. There is a possibility to obtain crystal of the given size and form when controlling the parameters of polythermal crystallization. The process duration should not exceed 45 minutes (liquor temperature is 68 °С) if it is necessary to obtain globular crystal. The tabulated crystal can be prepared by liquor cooling to 45 °С. If process duration is more than 90 minutes (at liquor temperature below 45 °С), the acicular crystals are formed

Study of leonite crystallization from sulphate potassium-magnesium liquor

The relevance of the research consists in possibility of using leonite, obtained at crystallization from sulphate liquor, as a complex sulphate potassium-magnesium fertilizer. Production of such fertilizer is a promising direction in development of potassium industry. The main advantage of sulphate fertilizers is the possibility of using them for plants, which cannot endure the chlorine excess. In addition they can be used for different soils and large number of culture of plants. The main aim of the research is to investigate the crystallization stage in leonite production from polyhalite ore, to select the required mode of crystallization. The methods used in the study: modeling of technological process in laboratory conditions, determination of size, quantity and form of crystals, formed at different time intervals, by system of continuous video registration of suspension particles «PVM Lasentec V819», X-ray analysis of product, obtained at different conditions. The results. The authors have carried out the investigations of isothermal and polythermal crystallization of leonite and syngenite from sulphate potassium-magnesium liquors. It is shown that the mixture of leonite and syngenite is crystallized in isothermal mode, and pure leonite is formed in polythermal mode. The leonite crystal form transforms from globular in tabulated, and then in acicular, at polythermal crystallization. The mechanical abrasion of crystal occurs at achievement of size of 50 microns, the crystal size decreases, it is also related with recrystallization of globular crystals into tabulated ones. The leonite crystal acquires acicular form at process duration of 90 minutes or longer, the intensive growth of crystal size occurs. The findings. It was determined that it is advisable to carry out polythermal crystallization in complicated system K2SO4-MgSO4-CaSO4, it allows obtaining pure product - leonite, which is suitable for further use. There is a possibility to obtain crystal of the given size and form when controlling the parameters of polythermal crystallization. The process duration should not exceed 45 minutes (liquor temperature is 68 °С) if it is necessary to obtain globular crystal. The tabulated crystal can be prepared by liquor cooling to 45 °С. If process duration is more than 90 minutes (at liquor temperature below 45 °С), the acicular crystals are formed

Study of potassium hydrogensulfate neutralization

The relevance of the research is caused by the necessity to obtain the complex potassium sulfate fertilizers, which not contain chloride ion. The accumulation of chloride ion in soil leads to lower yields and increases the soil salinity level. The main aim of the work is to investigate potassium hydrogensulfate neutralization by ammonia in reactor with fluidized and fixed bed at different particle size; to establish the kinetic dependences of neutralization. The methods used in the study: theoretical analysis of processes, modeling of technological process in laboratory conditions, study of changes in the content of sulfuric acid in product in time by titration of product with sodium hydroxide, X-ray analysis of product, obtained by neutralization, finding of conversion degree of equation depending on time using the program «Table Curve 2D». The results. The authors have carried out the theoretical analysis of possible neutralizing ways and studied the hydrogen sulfate neutralization by ammonia gas in apparatus with fluidized and fixed bed. The equations of change in degree and rate of potassium hydrogensulfate neutralization by ammonia over time for particle sizes of potassium hydrogensulfate 0,3, 0,6 and 1,2 mm were obtained. The conclusions. It was ascertained that the most acceptable neutralizing agent is ammonia. The potassium hydrogensulfate should be neutralized by ammonia gas in apparatus with fluidized bed at linear gas velocity of 0,042 m/s. The end product of neutralization KHSO4 by ammonia gas in fluidized bed is the mixture of potassium and ammonium hydrogensulfate (КNH4H)2(SO4)3 and potassium hydrogen sulfate K5H3(SO4)4. It is not reasonable to use this substance as fertilizer, therefore, it requires additional neutralization by washing. The process is inhibited at neutralization in a fixed bed and residual sulfuric acid content in the product is higher than 8 %. The analysis of dependence of potassium hydrogensulfate neutralization degree on time in fluidized and fixed bed showed, that the neutralization degree increases, reaching a maximum at duration of 20 minutes, then it decreases gradually during the process in a fluidized bed, and it falls sharply during the neutralization in a fixed bed. The rate of chemical reactions in fluidized bed is determined by the size of reaction phase interface and it is limited by the formation and growth of reaction product nuclei, and limiting step in fixed bed is diffusion of ammonia molecules to the reaction zone

Study of potassium hydrogensulfate neutralization

The relevance of the research is caused by the necessity to obtain the complex potassium sulfate fertilizers, which not contain chloride ion. The accumulation of chloride ion in soil leads to lower yields and increases the soil salinity level. The main aim of the work is to investigate potassium hydrogensulfate neutralization by ammonia in reactor with fluidized and fixed bed at different particle size; to establish the kinetic dependences of neutralization. The methods used in the study: theoretical analysis of processes, modeling of technological process in laboratory conditions, study of changes in the content of sulfuric acid in product in time by titration of product with sodium hydroxide, X-ray analysis of product, obtained by neutralization, finding of conversion degree of equation depending on time using the program «Table Curve 2D». The results. The authors have carried out the theoretical analysis of possible neutralizing ways and studied the hydrogen sulfate neutralization by ammonia gas in apparatus with fluidized and fixed bed. The equations of change in degree and rate of potassium hydrogensulfate neutralization by ammonia over time for particle sizes of potassium hydrogensulfate 0,3, 0,6 and 1,2 mm were obtained. The conclusions. It was ascertained that the most acceptable neutralizing agent is ammonia. The potassium hydrogensulfate should be neutralized by ammonia gas in apparatus with fluidized bed at linear gas velocity of 0,042 m/s. The end product of neutralization KHSO4 by ammonia gas in fluidized bed is the mixture of potassium and ammonium hydrogensulfate (КNH4H)2(SO4)3 and potassium hydrogen sulfate K5H3(SO4)4. It is not reasonable to use this substance as fertilizer, therefore, it requires additional neutralization by washing. The process is inhibited at neutralization in a fixed bed and residual sulfuric acid content in the product is higher than 8 %. The analysis of dependence of potassium hydrogensulfate neutralization degree on time in fluidized and fixed bed showed, that the neutralization degree increases, reaching a maximum at duration of 20 minutes, then it decreases gradually during the process in a fluidized bed, and it falls sharply during the neutralization in a fixed bed. The rate of chemical reactions in fluidized bed is determined by the size of reaction phase interface and it is limited by the formation and growth of reaction product nuclei, and limiting step in fixed bed is diffusion of ammonia molecules to the reaction zone

Behaviour of single-crystal nickel alloy in the conditions of high-temperature hydrogen corrosion

This study presents the results of the investigation of the behaviour of ZhS32-VI single-crystal nickel alloy in hydrogen environment or argon atmosphere at 850°C. The microstructure and chemical composition of corrosion deposits were studied by scanning electron microscopy and X-ray energy-dispersive analysis. It has been established that in argon containing an admixture of oxygen a dense scale rich in cobalt and nickel oxides is formed. At atmosphere containing 65% hydrogen and 35% argon an increased content of aluminum in the surface composition was noted. The influence of 100% hydrogen leads to segregation of tungsten and rhenium with the formation of convex growths. The data of simultaneous thermal analysis revealed that the amount of desorbed hydrogen can be from 0.08 to 0.14%