E. A. Frolova

Low-temperature anti-icing reagents in aqueous salt systems containing acetates and formiates

Ice-melting polytherms in binary and ternary aqueous salt systems containing metal and ammonium acetates and formiates were studied in the temperature range of 0 to −70°C. A number of salt mixtures that form low-temperature eutectics with ice were revealed to be promising as a basis for the development of anti-icing reagents. The properties of these salt mixtures, such as ice-melting ability, the character of their action on cement concrete, and corrosion activity with respect to metals and alloys, were estimated. An efficient corrosion inhibitor was selected.

Deicing properties of sodium, potassium, magnesium, and calcium chlorides, sodium formate and salt compositions on their basis

The deicing properties (ice eutectic point and ice-melting ability) have been determined for sodium, potassium, magnesium, and calcium chlorides, sodium formate, and compositions on their basis. It has been determined that, with the addition of large amounts (33–66%) of potassium chloride to sodium, magnesium, and calcium chlorides, the deicing properties of obtained compositions worsen compared to the properties of individual salts (the ice eutectic point increases and the ice melting ability decreases). Small additives of sodium formate (3–7%) or potassium chloride (10%) and sodium formate (3–7%) altogether to the compositions based on sodium and calcium chlorides do not improve their deicing properties, but substantially increase the cost of reagents. The use of the additives of the indicated substances within deicing compositions, as well as the use of potassium chloride and sodium formate as individual salts, as DRs for road network, rural roads, and main roads has been considered unreasonable.

Synthesis of basic yttrium nitrate

The reaction between yttrium nitrate and potassium hydroxide solutions was conducted at 25 and 50°C and at the boiling point of the reaction mixture, and the reaction products were studied. The Schreinemakers method, X-ray diffraction and crystal-optical analyses, IR spectroscopy, and electron microscopy demonstrated that X-ray amorphous yttrium hydroxide Y(OH)3 and basic yttrium nitrate Y(OH)2.5(NO3)0.5 · H2O are formed at 25 and 50°C as a poorly crystallized precipitate depending on the ratio between the initial reagents. Keeping the reaction products at the boiling temperature gives rise to a well-crystallized sample of basic yttrium nitrate.

Anti-icing agents based on magnesium and sodium acetates and chlorides

Phase equilibria in sections of the Mg(CH3COO)2-NaCl-H2O system at 0 to −30°C have been investigated, and, based on the data obtained, new anti-icing agents (solid and liquid ones) are suggested. The ice melting capacity of these agents under equilibrium conditions has been determined. The liquid agent causes no damage to Portland cement concrete pavements. The corrosivity of this agent toward carbon steel St3 has been determined. The agent can be made considerably less corrosive by introducing a corrosion inhibitor. The agents can be prepared using mineral raw materials, namely, bischofite (MgCl2 · 6H2O) and halite (NaCl).

Low-temperature anti-icing reagents in the Ca(NO3)2-Mg(NO3)2-CO(NH2)2-H2O system and their properties

The polytherms of ice melting in sections of the Ca(NO3)2-Mg(NO3)2-CO(NH2)2-H2O system with different component ratios were studied in the temperature interval from 0 to −40°C. A series of nitrate and nitrate-carbonate reagents that are promising for the creation of anti-acing reagents were found, which form eutectics with ice at temperatures from −25 to −39°C. Their properties, viz., melting properties with respect to ice and corrosiveness on metals and alloys, were determined. An effective corrosion inhibitor was selected.

Interactions in the system Mn(NO3)2-HCONH2-H2O

Solubilities and solid phases in the system Mn(NO3)2-HCONH2-H2O were studied by an isothermal method at 25°C. The congruently saturating compound Mn(NO3)2 · 2HCONH2 · 2H2O was isolated; the concentration conditions for its crystallization in the system were determined. The solid phases of the system were characterized by physicochemical methods (X-ray powder diffraction, differential thermal analysis, IR spectroscopy, and crystal-optical analysis).

Phase equilibria in water–salt systems from sodium, magnesium, and calcium nitrates and deicing properties of nitrate compositions

Phase equilibria have been studied in the sections of Mg(NO3)2–NaNO3–H2O and Ca(NO3)2–NaNO3–H2O systems at the ratio of salt components from 3: 1 to 1: 3 at temperatures of 0 to–35°C. A series of nitrate compositions has been determined, which are promising as deicing agents. Their theoretical (under equilibrium conditions) fusion ability with respect to ice at–5 to–10°C has been calculated. The corrosion activity of the composition of calcium and magnesium nitrates (1: 1) with respect to cement concrete (in collaboration with the test laboratory of OOO RSTs Opytnoe) has been measured. It has been found that the reagent meets criteria according to the action on cement concrete and can be used in aerodromes. This composition has been chosen as original for the development of a solid granular deicing agent on its basis for aerodromes.

Phase equilibria in the sodium formate–potassium formate–water system below 0°c and the anti-icing properties of salt compositions

Phase equilibria in the sodium formate—potassium formate—water system below 0°C along the NaHCOO : KHCOO = 5 : 1, 4 : 1, 3 : 1, 2 : 1, and 1 : 1 w/w sections have been investigated, the onset temperatures of ice crystallization from the aqueous solutions have been determined, and ice melting polytherms have been constructed for each section. The ice-melting capacity of the formate mixtures at —5 to —10°C has been calculated.

Crystal structure of magnesium(II) diaquatetracarbamidenitrate

Magnesium(II) diaquatetracarbamidenitrate nitrate was structurally studied. Crystals of composition [Mg(H2O)2(ur)4](NO3)2 (I) are monoclinic, Z = 2, P21/n, a = 6.449(1) Å, b = 17.670(2) Å, c = 7.578(1) Å; β = 91.637(2)°. In the structure of complex I, the central magnesium atom has octahedral geometry: the four carbamide molecules are in equatorial positions, and water molecules occupy axial positions.

Solubility isotherm of the Zn(NO3)2-HCONH2-H2O system at 25°C

The interaction of zinc nitrate and formamide in aqueous solutions at 25°C is studied. The compound Zn(NO3)2 · 2HCONH2 · 2H2O is found to crystallize over a wide range of component concentrations of the system. Its composition is determined, and physicochemical properties are studied by crystal-optical analysis, thermogravimetry, X-ray powder diffraction, and IR spectroscopy.