Yaroslavl State Technical University (Yaroslavl, Russia):

Ivanova V. A., Cand. Eng., Associate Prof., Head of the Chair “Technology of materials, standardization and metrology”, e-mail: ivanova-waleriya@mail.ru

Shamina E. O., Senior Lecturer, e-mail: shaminaeo@gmail.com

The researches to determine the effect of the density and porosity parameters, as well as the humidity of the environment, on the quantitative change in the moisture content of the foundry coke of commodity size were carried out. For the tests, casting coke samples of three size fractions of 40–60 mm, 60–80 mm, 80 mm and more than five different consignments were selected. The ash content (A^d, %) in various batches of foundry coke varied from 11.3 to 12.0; moisture (w_t^r, %) — from 4.5 to 4.9; the sulfur content (S_t^d) — from 0.4 to 0.6; strength (M₄₀, %) — from 73.2 to 76.8. During the experiment the mass of the samples and the humidity of the air were measured. Two-way analysis of variance of the results of the experiment showed the dependence of the mass fraction of the total moisture of samples of foundry coke of commodity size on air humidity, size fraction and consignment with significance level a = 0.05. It has been established that with an increase in the volume of open pores by a factor of two the amount of moisture in the samples of foundry coke increases by an average of 1.25 times. The mass fraction of the total moisture of the samples stored in a dry room increases with increasing size and with a decrease in the apparent relative density. However, the greatest value of the mass fraction of moisture over the entire period of research is observed for specimens of size fraction of 60–80 mm. With an increase in ambient humidity by 34%, the moisture content in the foundry coke increases on average by a factor of 10, with the largest increase in humidity typical for coke of size fraction of 60–80 mm. On average, a strong correlation between the apparent porosity and the average mass fraction of total moisture is observed in consignments (r = 0.75), and a significant correlation between the volume of open pores and the mass fraction of total moisture in samples not exposed to weather conditions (r = 0.60).

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