# US 11,440,801 B2 · Treatment of spent cannabis biomass with activating agent > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,801 B2 - Document ID: US11440801B2 - Status: Granted - Kind: B2 - Application number: 16/706,666 - Filed: 2019-12-06 - Published: 2021-06-10 - Granted: 2022-09-13 - Earliest claimed: 2019-12-06 - Assignees: Nextleaf Solutions Ltd. - Applicants: Nextleaf Solutions Ltd. - Inventors: Xuan Jia; David Michael Novitski - Web page: https://patentgrep.com/patent/US11440801B2 ## CPC - B01D 3/346: {the gas being used for removing vapours, e.g. transport gas} - C01B 32/318: characterised by the starting materials - B01D 8/00: Cold traps; Cold baffles (pumps for evacuating by condensing or freezing F04B37/08) - C01B 32/324: from waste materials, e.g. tyres or spent sulfite pulp liquor - C01B 32/348: Metallic compounds - C01B 32/378: Purification - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract A process to transform spent cannabis biomass into activated carbon via a treatment involving a chemical activation process. The spent cannabis biomass is mixed with an activating agent and then subjected to a heat treatment. The spent cannabis biomass is heated in stages, the first to remove water and volatile components, and the second to reclaim leftover cannabinoids. During a third, higher temperature stage, the biomass is converted to activated carbon. ## Claims ### Claim 1 A process for treating spent cannabis biomass comprising: mixing spent cannabis biomass with an activating agent to result in an impregnated spent cannabis biomass; raising the impregnated spent cannabis biomass to a first temperature that is sufficient to remove water and volatile components from the impregnated spent cannabis biomass; raising the impregnated spent cannabis biomass to a second temperature that is sufficient to recover cannabinoids from the impregnated spent cannabis biomass, wherein the second temperature is higher than the first temperature; collecting the recovered cannabinoids by directing them into chilled ethanol: raising to a third temperature the impregnated spent cannabis biomass, wherein the third temperature is higher than the second temperature; and maintaining the impregnated spent cannabis biomass at the third temperature until the impregnated spent cannabis biomass has been transformed into activated carbon. ### Claim 2 (depends on 1) The process of claim 1, wherein: the activating agent is KOH, H3PO4 or ZnCl2; and the spent cannabis biomass is mixed with the activating agent at a ratio of between 1:0.5 and 1:3 by weight. ### Claim 3 (depends on 1) The process of claim 1, wherein the activating agent is mixed with the spent cannabis biomass for 2 to 24 hours. ### Claim 4 (depends on 1) The process of claim 1, wherein: the impregnated spent cannabis biomass is maintained at the third temperature for 0.5 to 2 hours; and the third temperature is between 500 and 900° C. ### Claim 5 (depends on 1) The process of claim 1, wherein the first temperature is 100±20° C. and the second temperature is 170-500° C. ### Claim 6 (depends on 5) The process of claim 5, wherein the first temperature is 100° C. and the second temperature is 500° C. ### Claim 7 (depends on 1) The process of claim 1, wherein the impregnated spent cannabis biomass is heated in a fixed bed reactor that has an exhaust line with a bypassable cold trap, the process comprising purging the fixed bed reactor with nitrogen before heating the impregnated spent cannabis biomass. ### Claim 8 (depends on 7) The process of claim 7, comprising, while raising the impregnated spent cannabis biomass to the first temperature, directing vapor evaporated from the impregnated spent cannabis biomass to bypass the cold trap. ### Claim 9 (depends on 8) The process of claim 8, comprising, while raising the impregnated spent cannabis biomass from the first temperature to the second temperature, passing vapor evaporated from the impregnated spent cannabis biomass through the cold trap. ### Claim 10 (depends on 1) The process of claim 1, comprising maintaining the impregnated spent cannabis biomass at the first temperature until all the water is removed from the impregnated spent cannabis biomass. ### Claim 11 (depends on 1) The process of claim 1, comprising collecting water and volatile components from the impregnated spent cannabis biomass using a cold trap, while the impregnated spent cannabis biomass is below and at the first temperature. ### Claim 12 (depends on 1) The process of claim 1, comprising maintaining the impregnated spent cannabis biomass at the second temperature until all the cannabinoids have been recovered from the impregnated spent cannabis biomass. ### Claim 13 (depends on 1) The process of claim 1, comprising maintaining the impregnated spent cannabis biomass at the third temperature for 1 hour. ### Claim 14 (depends on 1) The process of claim 1, comprising passing nitrogen gas over the impregnated spent cannabis biomass throughout the process. ### Claim 15 (depends on 1) The process of claim 1, comprising milling the spent cannabis biomass to an average particle size below 2 mm prior to mixing the spent cannabis biomass with the activating agent. ### Claim 16 (depends on 1) The process of claim 1, comprising washing the activated carbon with hot deionized water when the activating agent is acidic. ### Claim 17 (depends on 1) The process of claim 1, comprising washing the activated carbon with a diluted HCl solution and then washing the activated carbon with deionized water, when the activating agent is alkaline. ### Claim 18 (depends on 1) The process of claim 1, wherein the chilled ethanol is at a temperature between 0° C. and −40° C.