<p>The production of granulated nickel powders in size fractions of 20–45, 45–71, and 71–125 μm with specified chemical composition by hydrogen reduction of NiO for the fabrication of highly porous items was studied. Nickel carbonate powder was used as the starting material for preparing nickel oxide powder through thermal decomposition in air. Nickel oxide was reduced in hydrogen by two methods: in moving beds in a rotary furnace chamber and in stationary continuous tubular furnaces. The required chemical composition of the nickel powders was ensured by using high-purity nickel carbonate. The effect of temperature–time parameters of the reduction process was examined at 400, 475, 500, and 600°C for 1 and 2 h at a heating rate of 10°C/min. The nickel powders were separated into fractions by sifting through a set of calibrated sieves. The formation patterns and properties of the granulated nickel powders were established by comprehensive analysis involving X-ray diffraction, electron microscopy, and measurements of specific surface area and bulk density. The reduced granulated nickel powders were found to exhibit morphological features characterized by a hierarchical structure. The granule size in the reduced nickel powder depended on the NiO granule size, reduction temperature, and additional experimental conditions of reduction (fixed NiO powder bed in stationary mode, moving NiO powder bed in rotating mode, preliminary NiO powder granulation, and NiO powder granulation temperature). The nickel powders in the 45–71 μm and &gt;71 μm fractions consisted of sintered granules formed from finer granules with an average size of ~11–12 μm. The &lt;45 μm fraction consisted solely of granules with an average size of ~12 μm within the 10–20 μm range.</p>