Features of the pyrolysis process of waste batteries using carbon black as an additive in the construction industry

Abstract

The paper discusses the technology for recycling used lithium-ion batteries. At the same time, one of the important components in the technology for processing such waste is the recycling of anode material with the extraction of graphite or carbon black, which can be used in the production of fire bricks. It has been shown that materials and compounds contained in lithium-ion batteries are sources of hazardous waste of the second hazard class. At the same time spent accumulators are a source of valuable secondary material resources and contain in their composition up to 16 % wt. % of graphite.The paper proposes to consider the process of processing anode materials of lithium-ion batteries in order to obtain graphite and carbon black from them by pyrolysis. Experimental studies were carried out on the process of decomposition of cathode and anode materials of lithium-ion batteries separately, as well as their mixture by pyrolysis. When studying the kinetics and mechanism of pyrolysis of carbon-containing materials, thermogravimetric analysis of the following materials was carried out: 1) powdered graphite grade GAK-2 (GOST 10273-79); 2) graphite released from the anode during manual disassembly of the LKIT; 3) mechanically activated powders containing cathode material LiNiMnCoO2. The characteristics of the pyrolysis process were assessed using thermogravimetric and differential thermogravimetric analyses. Pyrolysis characteristics demonstrate that organic substances contained in batteries can decompose at a pyrolysis temperature of 500 °C for cathode materials and 450 °C for anode materials. This subsequently leads to higher efficiency in the extraction of valuable components with shorter grinding times. It has been shown that the decomposition of a mixture of lithium-ion battery materials removes a larger amount of organic components than the pyrolysis of anode and cathode materials separately. In this case, the rate of decomposition of the mixture of materials occurs more slowly. The activation energy values for lithium-ion battery materials after the pyrolysis stage were determined. The content of components in powder obtained after the pyrolysis stage was determined using the method of atomic emission spectrometry with inductively coupled plasma.