he strength of iron ore pellet structure is one of the top indicator in its overall market value and remains a pre-condition for further successful shipping of pellets from a producer to an end consumer. A formation of silicate calcium sintered mass (of pyroxene-olivinic origin) in the mineral part is one of the most frequent analyzed aspects in pellet structure formation. This has to do with polymorphic transition in the course of cooling which leads to changes in crystal geometry and an internal stress is increasing. An objective of the present paper is qualitative assessment of the factor which affects the strength of pellets produced from concentrates with high beneficiation grade. A math model and experimental data are employed in the present study. The obtained results prove that a role of silicate bond in pellet strength formation is diminished while performing a transition to the high grade iron-bearing concentrates. And in return, a combination of “ore mineral - ore mineral” appears to be more feasible. A likelihood for calcium silicate to form is dropped down from 6% (absolute) to 3% (absolute) when reducing a silica oxide content in the pellets. Accordingly, a negative impact of flux additives on the strength will be diminished (due to softening of structure). Thus, the less calcium silicate content in the structure, the lower is internal stress in a sintered mass during crystallization process. The pellet strength is determined largely by sintering of iron oxides, rather than by strength of silicate bond, while a beneficiation degree of concentrate is being improved. Eventually, the above factors create a demand for technical solutions on intensification of solid-phase stage of the sintering, an optimal utilization of free energy on the concentrate surface, along with formation of green pellets with a uniform structure without defects (cracks, cavities etc.). When a likelihood of calcium silicate formation is growing by each 10% (relative), it results in pellet strength reduction by value within 0.8 to 2.03 daN or by 3…8% (relative).