The initial form of the grains of gold found in the nature in most cases is a flat plate (a scaly form). However, during pneumoseparation, the toroidal shape of pieces of gold is often found and considered to be the most effective. Thus the task of estimating time of formation of a toroidal piece of gold is important. In the paper, we consider the evolution of the surface of a flat disk of malleable metal deformed by isotropic bombing with fine particles and develop a mathematical model of this evolution. We obtain a differential equation describing the change of the deformed surface of a round disk which is solved then by a Runge–Kutta method. Studying the solution of the equation, we found that the body rather quickly reaches the most stable toroidal form when the deformed surface gets its maximal value and then a slower transformation of the surface into the sphere follows. We estimate the time of formation of a toroid from a disk with certain parameters of the considered system. The received results could be used for developing more exact models of evolution of flat bodies bombed with fine particles. Keywords: mathematical model, differential equation, deformed surface, toroid, enrich.
При математическом моделировании процессов, происходящих в устройствах обогащения полезных ископаемых, появляются задачи определения вероятности местонахождения частицы на рабочих поверхностях устройств. В настоящей работе для решения подобной задачи предлагается статистический подход, т. е. при определении вероятности используется идея метода Гиббса. Рассмотрены проблемы моделирования процессов, происходящих в воздушном винтовом сепараторе. Разработаны математическая модель винтовой поверхности пневмосепаратора, модели движения частицы, потока невзаимодействующих частиц по рабочей поверхности сепаратора и алгоритм определения концентрации потока частиц. Рассчитанное распределение концентрации невзаимодействующих частиц на рабочей поверхности устройства отождествляется с распределением вероятности местонахождения одной частицы. Разработанный алгоритм определения вероятности положения частицы на рабочей поверхности пневмосепаратора может быть использован как элемент более сложной математической модели, например модели, где учитываются взаимодействия между частицами.
In mathematical modeling of mineral processing, there arise problems of determining the probability of the particle presence on the working surfaces of devices. In the paper, we propose a statistical approach to solving such problem, i. e., the idea of the Gibbs method is used. We consider problems of modeling processes in an air spiral separator. A mathematical model of the spiral surface of a pneumoseparator, a model of particle motion, a flux of noninteracting particles along the separator working surface, and an algorithm for determining the particle flux concentration are developed. The calculated distribution of the noninteracting particles concentration on the working surface of the device is identified with the probability distribution of the location of one particle. The developed algorithm for determining the probability of position of a particle on the working surface of the pneumoseparator can be used as an element of a more complex mathematical model, for example, a model where interactions between particles are taken into account.