Research of calcium oxide hydration in calcium nitrate solutions

Abstract

Mineral fertilizers are one of the important factors of agriculture intensification and increasing of food products quantity. The volume of fertilizers production and its domestic consumption in Ukraine indicate that nitrogen fertilizer using only comes nearer to the required number of science-based. One of the most widespread artificial fertilizers is the calcium nitrate. Aim: The aim is to study and theoretically substantiate the processes occurring in the preparation of suspensions of calcium hydroxide Са(ОН)₂ in solution of calcium nitrate Ca(NО₃)₂.  Materials and methods: The technical calcium oxide (quicklime) DSTU BV.2.7-90-99, solutions of calcium nitrate of 15, 20, 25, 30, 35 and 40% Ca(NО₃)₂ concentrations were used in the work. The content of lime in the preparation of a suspension in the solution changed (in terms of calcium oxide CaO) from 150 g/dm³ to the maximum possible. Each of these solutions saturated at 40 °С in lime to maximum concentration. Suitable for use in these experiments and in the technology of calcium nitrate obtaining are considered the solutions (suspensions) that within 12 hours did not lose their mobility (transportability). Results: Results: The experimental results show that increasing of the concentration of calcium nitrate in solution within the range 15...40%, the amount of lime that you can put into the solution without loss of transportability decreases. Further increasing of lime quantity in solutions concentrations causes to its solidifying, loss of mobility (transportability). Calculations showed that in the presence of calcium nitrate the solubility of Са(ОН)₂ is reduced nearly by order that can lead to the formation of calcium oxide CaO the solid phase Са(ОН)₂ on the surface, which also can form hydrogen bonds with the components of the solution. As the probability of formation of hydrogen bonds in solutions is high, there is a possibility of formation of clusters.