RECEIVING METALS FROM SECONDARY RAW MATERIALS. POWDER OF SILVER

Abstract

Purpose of research. Powder of silver is one of the most widely used materials in industry. In the free or sintered (compressed) state, it is widely used in medicine as an element of antiseptics, in electronics as the basis of conductive pastes, conductive adhesives and contacts intended for closing and opening electrical circuits, in the production of multilayer ceramic capacitors, etc. Due to its high electrical conductivity, powder of silver is also used as a cathode material in solar cells. In today's conditions, the development of materials for alternative energy sources is quite relevant. Powder of silver can be used as a component of the active mass in chemical current sources. It is known that the characteristics of the active mass are influenced by the properties of the powder, namely, the size and shape of the particles. Materials and methodology. In this work, it was proposed to use boards of radio-electronic equipment as raw materials for the production of powders of silver. The reductant, recovery rate and modes of obtaining finely dispersed powders of silver after processing of secondary raw materials were identified. Results. The influence of the parameters of the reduction of powders of silver, namely, the type of reducing agent and the rate of reduction, was studied. It was established that in the process of forming powders of silver, a developed morphology and space between particles are formed, which increases the surface area, due to which the performance characteristics of various devices, in which powder of silver can be used as a component, will improve. Scientific novelty. Factors that affect the size and shape of powder of silver particles, namely, the type of reducing agent and the rate of reduction, have been established. Conclusions. It was established that the size of particles of silver depends on the speed of recovery. The stronger the reducing agent, the higher the rate of metal reduction, and the larger the particle size. Changing the speed of recovery (slowing down or speeding up) allows you to get particles of silver with the desired size. The indisputable advantage of the method of obtaining powder of silver by reduction is the formation of high-purity metal, which positively affects the properties.