Effect of cations (Mg2+, Zn2+, Cd2+) on formation of the mineral phase in Ca(NO3)2-Mg(NO3)2-Na2HPO4-H2O system

Synthesis of hydroxyapatite in the system Ca(NO3)2-Me(NO3)2-NaHPO4-H2O with pH in the range of 6-12.2 is performed, and hydroxyapatite of B-type is formed. The effect of magnesium, zinc and cadmium ions on the properties of hydroxyapatite is studied. It is shown that as the concentration of these ions increases, the crystallinity of hydroxyapatite and the Ca/P ratio decreases. It is found that in all the experiments Zn2+ cations affect the hydroxyapatite structure to a lesser extent which results in less structural defects, wherein the Ca/P ratio attains the highest values. It is shown that the solubility of the samples containing zinc ions is greater than that of the samples with other additives

Effect of cations (Mg2+, Zn2+, Cd2+) on formation of the mineral phase in Ca(NO3)2-Mg(NO3)2-Na2HPO4-H2O system

Synthesis of hydroxyapatite in the system Ca(NO3)2-Me(NO3)2-NaHPO4-H2O with pH in the range of 6-12.2 is performed, and hydroxyapatite of B-type is formed. The effect of magnesium, zinc and cadmium ions on the properties of hydroxyapatite is studied. It is shown that as the concentration of these ions increases, the crystallinity of hydroxyapatite and the Ca/P ratio decreases. It is found that in all the experiments Zn2+ cations affect the hydroxyapatite structure to a lesser extent which results in less structural defects, wherein the Ca/P ratio attains the highest values. It is shown that the solubility of the samples containing zinc ions is greater than that of the samples with other additives

ТЕРМОДИНАМИЧЕСКИЕ ФУНКЦИИ ОБРАЗОВАНИЯ ТВЕРДОЙ ФАЗЫ В СИСТЕМЕ Fe(II)/Ni(II) – ДИБУТИЛДИТИОФОСФАТ АММОНИЯ – ДИИЗООКТИЛДИТИОФОСФАТ АММОНИЯ

The formation of precipitates of dibutyldithiophosphate–diisooctyldithiophosphate of nickel(II) and iron(II) are investigated by the potentiometric method. Solubility products for Ni-containing and Fe-containing precipitates of ammonium dibutyldithiophosphate and diisooctyldithiophosphate are calculated. It is shown that an increase in temperature differently affects the deposition process, notably, solubility for complexes of Fe(II) ions decreases overall the ionic strength range (I = 0÷0,75), while it decreases for Ni(II) ions only at low values of this characteristic (I = 0÷0,25), and the precipitate dissolves at a high ionic strength. Thermodynamic characteristics of the precipitate formation of dibutyldithiophosphate–diisoocryldithiophosphate of iron(II) and nickel(II), notably, the variation in the Gibbs energy, enthalpy, and entropy are calculated based on the data on the solubility product. It is shown that the solvation of components exerts the determining effect on the mentioned process, and it is largest in range I = 0,50÷0,75 in the case of iron(II) ions and at I = 0÷÷0,25 in the case of nickel (II) ions.Потенциометрическим методом изучены процессы формирования осадков дибутилдитиофосфата–диизооктилдитио-фосфата никеля (II) и железа (II). Проведены расчеты произведений растворимости для Ni- и Fe-содержащих осадков дибутилдитиофосфата и диизооктилдитиофосфата аммония. Показано, что увеличение температуры по-разному влияет на процесс осаждения: для комплексов ионов Fe(II) во всем интервале ионных сил (I = 0÷0,75) растворимость уменьшается, тогда как для ионов Ni(II) она снижается только при низких значениях этого показателя (I = 0÷0,25), а при высоких – осадок растворяется. На основании данных по произведению растворимости рассчитаны термодинамические характеристики процесса образования осадков дибутилдитифофосфата–диизооктилдитиофосфата железа (II) и никеля (II) – изменение энергии Гиббса, энтальпия и энтропия. Показано, что на указанный процесс определяющее влияние оказывает сольватация компонентов, причем в случае ионов железа (II) оно наибольшее в интервале I = 0,50÷0,75, а для ионов никеля (II) – при I = 0÷0,25

ОЦЕНКА ФЛОТАЦИОННОЙ АКТИВНОСТИ СМЕСИ ФОСФОРСОДЕРЖАЩИХ СОБИРАТЕЛЕЙ

The complexing ability of phosphorus-containing collectors relative to copper (II) ions is investigated. The values of EMF for the concentration element for the ammonium dibutyl dithiophosphate–ammonium diisooctyl dithiophosphate (1 : 1) mixture are calculated. It is established that a mixture of phosphorus-containing collectors possesses the maximal affinity to copper (II) ions. Foaming properties of ammonium dibutyl dithiophosphate, ammonium diisooctyl dithiophosphate, and their mixture in the concentration range of 10–3–10–6 mol/L are determined. It is shown that the foam prepared in a solution of the mixture with the concentration of substances of 10–5 mol/L possesses the highest stability. The flotation activity of ammonium dibutyl dithiophosphate and its mixture with ammonium diisooctyl dithiophosphate is evaluated. The possibility of using the mixture for the collective flotation of the copper ore of the Nurkazgan deposit is established. Проведены исследования комплексообразующей способности фосфорсодержащих собирателей по отношению к ионам меди (II). Рассчитаны величины ЭДС концентрационного элемента для смеси дибутилдитиофосфат аммония – диизооктилдитиофосфат аммония (1 : 1). Установлено, что максимальным сродством к ионам меди (II) обладает смесь фосфорсодержащих собирателей. Определены пенообразующие свойства дибутилдитиофосфата аммония, диизооктилдитиофосфата аммония и смеси в интервале концентраций 10–3–10–6 моль/л. Показано, что наибольшей устойчивости достигает пена, полученная в растворе смеси при концентрации веществ 10–5 моль/л. Проведена оценка флотационной активности дибутилдитиофосфата аммония и его смеси с диизооктилдитиофосфатом аммония. Установлена возможность использования смеси для коллективной флотации медной руды месторождения «Нурказган».

Influence of alternating electric current on the process of heat accumulation in a mixture of Na2SO4·10H2O–Na2S2O3·5H2O

One of the most critical tasks of modern energy is accumulating thermal energy due to the inefficient use of thermal energy during the underloading of power systems in which heat-accumulating materials are used. Therefore the paper studies the effect of alternating electric current on the heat-accumulating properties in a mixture based on Na2SO4·10H2O. It is established that the AC effect leads to an increase in the melt crystallization temperature of Na2SO4·10H2O and Na2S2O3·5H2O and also contributes to the return of heat. The selection of the treatment mode of the Na2SO4·10H2O–Na2S2O3·5H2O (50: 1 wt.) mixture by the AC was carried out. It was shown that the latent heat of melting of 329 kJ/kg is achieved at 500000 Hz frequency