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THE CONCLUSION AND CONCLUSIONS

The kinetics of hydrolytic and oxidising dissolution of the synthesised nickelous sulphide (II) in solutions of sulfuric acid, peroxide compound of hydrogen, hydrogen nitrate (including in the presence of iron and copper cations) by a method of a rotating disk in the conditions of an equally accessible surface is investigated.

Dependences of specific speed of these processes on concentration of a reagent, rn a solution, temperature, intensity of agitating and duration of interaction are studied.

The mathematical models are received, allowing to calculate specific speed of dissolution of nickelous sulphide at simultaneous change of the listed parametres, interpretation is yielded them fiziko'himicheskaja.

Interaction modes are positioned, details of the mechanism of the studied processes are revealed. The proved schemas of interaction corresponding to observable kinetic dependences are offered.

The carried out research allows to draw following conclusions:

1. To interaction of nickelous sulphide (II) with acids precede fast hydration of a surface of sulphide and it protonizatsija.

2. Dissolution NiS in sulfuric acid solutions at its concentration from 0.005 to 5.0 mole-ekv/dm3 proceeds in a kinetic mode on the hydrolytic mechanism. The most probable limiting stage of process is adsorption H3O+на gidratirovannoj and protonirovannoj sulphide surfaces.

3. In solutions of peroxide compound of hydrogen nickelous sulphide (II) dissolves in a kinetic mode on the hydrolytic mechanism at small concentration of peroxide compound (till 0.01) and oxidising - at higher. The most probable limiting stage at the oxidising mechanism is adsorption gidroksilgidroksonija (Н3О2 +) on gidratirovannoj and protonirovannoj sulphide surfaces.

4. Interaction NiS with hydrogen nitrate solutions proceeds in a kinetic mode on the hydrolytic mechanism at strength of acid to 0.1 MOLE/dm3. In more concentrated solutions the oxidising mechanism of the dissolution is observed, thus one of products is element sulphur. However its occurrence does not result in to retardation of transferring of nickel in a solution. A probable limiting stage is oxidizer adsorption (for example, a product of transformation of acid - NO2) on gidratirovannoj and protonirovannoj sulphide surfaces.

5. Addition in a solution of hydrogen nitrate of ions Fe3+или Cu2+приводит to acceleration of transferring of nickel from a sulphide surface in a solution. These ions are catalysts of the studied process. The increase in ion density of copper and iron over 0.004 mole-ekv/dm3 does not result in to the further acceleration of process of dissolution NiS, possibly, owing to the adsorptive saturation of a surface of sulphide by catalyzing ions.

6. The constructed adequate mathematical models of processes of dissolution of nickelous sulphide (II) and received at them fiziko'himicheskoj interpretations kinetic characteristics can be used for working out of perspective technologies of hydrochemical evolution of nickel from sulphidic raw materials.

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A source: PITCHUGINA Anna Igorevna. KINETICS of HYDROLYTIC And OXIDIZING DISSOLUTION of NICKELOUS SULPHIDE (II). The dissertation AUTOABSTRACT on competition of a scientific degree of a Cand.Chem.Sci. Tver - 2016. 2016

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