GB2598213B : Method of recycling nickel from waste battery material
Publication Date: 08-Feb-2023
Current Owner: JOHNSON MATTHEY PLC
1st Inventor: BARBARA BREEZE (GB)
This granted Great British patent is assigned to Johnson Matthey and the 1st Inventor is Dr Barbara Breeze – currently Circularity Strategist at Johnson Matthey Technology Centre (JMTC), Sonning Common, UK.
The patent refers to work on recovering nickel from waste battery cathode material via a gas-phase process. Typical materials include lithium nickel oxide (LMO), lithium nickel manganese oxide (LNMO) and common NCM battery materials. In some embodiments the material is an NCMA formulation. According to the patent example, the method involves heating the material to 700 °C in a reaction vessel then passing a mixture of hydrogen and carbon monoxide (syngas) at elevated pressures (150-200 kPa or 6-8 MPa) and temperatures (140-200°C) over the material for around 1 h followed by nitrogen as the temperature is cooled to around 50 °C. Subsequently the syngas mixture is resumed. The exit gases are reacted with concentrated sulfuric acid in a series of gas
scrubbers in counter-current mode. (See Figure 1). The gas mix reacting with the sulphuric acid contains CO and Ni(C0)4. The resulting product is nickel sulfate which can be processed back to battery grade material in a closed loop system according to the following equation:
Ni(CO)4 + H2SO4 -> NiSO4 + H2 + 4CO
Any unreacted syngas and CO recovered from the nickel carbonyl can be returned to the black mass treatment stage. There is an option to also treat the battery material with formic acid to leach out lithium and to make nickel formate prior to the reduction with syngas. Ni formate can be separated from the Co formate due to the difference in decomposition temperatures (250°C c.f. 310°C) by heating the material to 270°C. Furthermore, the method relies on the difference in boiling points between different metal carbonyls. For instance, Ni(CO)4 has a boiling point of 43°C c.f. Fe(CO)5 (which may also be present) which has a b.p. of 104°C.
