Development of ferritization processing of galvanic waste involving the energy­saving electromagnetic pulse activation of the process

摘要

This paper considers the prospect of improving the level of environmental safety of industrial enterprises resulting from the implementation of a resource-saving technology for processing the wastes of galvanic production by a ferritization method using the electromagnetic pulse activation of the process. The influence of different activation techniques of the ferritization process has been experimentally determined: thermal and electromagnetic pulse at stable technological parameters (СΣ=10.41 g/dm3; Z=4/1; рН=10.5; τ=25 min; ʋ=0.15 m3/h) on the degree of extraction of heavy metal ions from galvanic wastes. It has been shown that the best processing indicators were achieved at the following mode characteristics for generating electromagnetic pulse discharges: the amplitude of magnetic induction 0.298 Tl, the frequency of pulses from 0.5 to 10 Hz. Such an activation technique ensures the proper degree of heavy metal ions extraction – 99.97 % enabling the use of purified solutions at an enterprise water circulation system. A structural study has been performed into the phase composition and physical properties of ferritization sediments. The environmentally safe ferritization sediments that were obtained under the thermal and electromagnetic pulse activation techniques are characterized by a high degree of compaction, exceeding 90 %, and the crystalline structure with the maximum content of ferrite phases with magnetic properties. In addition, as shown by experiments on heavy metal leaching, these sediments are characterized by a high degree of their immobilization, which reaches 99.96 %, in contrast to galvanic sludge from the neutralization of wastewater, <97.83 %. The method of electromagnetic pulse activation also has the undeniable energy advantages compared to the high-temperature one: energy costs are reduced by more than 42 %. The proposed process for galvanic waste processing by the improved method of ferritization prevents pollution of the environment, ensures efficient and rational use of water, raw materials, and energy in the system of galvanic production