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EP-4739808-A1 - A METHOD FOR PRODUCING TITANIUM DIOXIDE FROM WASTE LITHIUM TITANATE BATTERIES

EP4739808A1EP 4739808 A1EP4739808 A1EP 4739808A1EP-4739808-A1

Abstract

The present invention relates to the field of waste lithium-ion battery. More particularly, the present invention relates to a method for producing titanium dioxide from waste lithium titanate batteries in a commercially feasible manner. The method recovers the titanium with purity of titanium dioxide greater than 98% by following simple physical processes such as shredding, roasting, leaching and precipitation. The method is clean, green and environment friendly.

Inventors

  • BARIK, Smruti Prakash
  • PRABAHARAN, G
  • KUMAR, Bhuvnesh
  • GUPTA, NITIN

Assignees

  • Attero Recycling Pvt. Ltd.

Dates

Publication Date
20260513
Application Date
20240705

Claims (11)

  1. 1. A method for producing titanium dioxide from waste lithium titanate batteries, characterized in that, the method comprises the steps of: a) shredding cells obtained by dismantling discharged spent lithium titanate (LTO) batteries to obtain a shredded material; b) removing organic matrix by roasting the shredded material of step (a) at a predetermined temperature for 2-3 hours and obtaining a roasted material; c) washing the roasted material of step (b) with water followed by wet sieving to collect a slurry and a metal part separately; d) filtering the slurry of step (c) to obtain a precipitated cake and a filtrate and reusing the filtrate in next batch; e) blending the precipitated cake of step (d) with sulphuric acid taken in a predefined ratio followed by pugging at a pre-determined temperature for a predetermined time to obtain a pugged material; f) leaching the pugged material of step (e) with a pre-defined concentration of dilute sulphuric acid for a pre-determined time to obtain a leach slurry; g) filtering the leach slurry of step (f) to obtain a leach liquor and a residue; h) precipitating selectively titanium from the leach liquor of step (g) at a predetermined pH by adding a suitable precipitating agent under agitation for a pre-determined time to obtain a slurry and a cake; i) filtering the slurry of step (h) to obtain a titanium cake (under wet condition) and a filtrate and taking the filtrate for base metal recovery; and j) washing the titanium cake of step (i) with water to remove free sodium salt in the form of sodium sulphate and obtaining a washed cake of titanium carbonate followed by roasting of the washed cake at a temperature range of 600-850°C for 2-3 hours to obtain titanium dioxide.
  2. 2. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1 , wherein the spent lithium titanate (LTO) batteries of step (a) are discharged through the steps comprising of: i) connecting spent lithium titanate (LTO) batteries to a discharging apparatus; ii) initiating the discharging process by monitoring ampere through ammeter and voltage through voltmeter; iii) monitoring subsequently the discharging process until the current in ampere and voltage came down to zero; and iv) disconnecting the spent lithium titanate (LTO) batteries from the discharging apparatus to obtain discharged batteries.
  3. 3. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1 , wherein the discharged batteries of step (a) are dismantled manually to collect cells and other components including aluminium, printed circuit board, plastic, steel, and rubber separately.
  4. 4. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein a single shaft shredder or a twin shaft shredder having an output size less than 10 mm is used for shredding the cells of step (a).
  5. 5. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein the pre-determined temperature in step (b) is in a range of 400-600°C.
  6. 6. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein the pre-defmed ratio of the sulphuric acid in step (e) and the precipitated cake of step (d) is (0.9-1.1):1 and the pre-determined temperature and the pre-determined time in step (e) is in a range of 150-250°C and 2-4 hours, respectively.
  7. 7. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1 , wherein the pre-defmed concentration of dilute sulphuric acid of step (f) is 5-15%w/v and the pre-determined time of step (f) is 2-3 hours.
  8. 8. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1 , wherein the pre-determined pH in step (h) is in a range of 0.5- 1.5, and the pre-determined time of step (h) is 2-3 hours.
  9. 9. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein the suitable precipitating agent in step (h) is selected from soda ash solution (25% w/v), calcium carbonate, calcium hydroxide, sodium hydroxide, ammonium carbonate or ammonium hydroxide.
  10. 10. The method for producing titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein the method recovers titanium in a range of 95-97% in the form of titanium dioxide.
  11. 11. The method for producing of titanium dioxide from waste lithium titanate batteries as claimed in claim 1, wherein the purity of titanium dioxide is in a range of 98-99%.

Description

“A METHOD FOR PRODUCING TITANIUM DIOXIDE FROM WASTE LITHIUM TITANATE BATTERIES” FIELD OF THE INVENTION The present invention relates to the field of waste lithium-ion batteries. More particularly, the present invention relates to a method for producing titanium dioxide from waste lithium titanate batteries. BACKGROUND OF THE INVENTION A lithium-titanate or lithium-titanium-oxide (LTO) battery is a modified lithium-ion battery in which the anode material is lithium-titanate that enables the availability of more surface area as compared to other anode material like carbon or lithium iron phosphate. Moreover, the charging in case of lithium-titanate is faster and quicker as compared to other anode material. Since, the lithium titanate battery is free of carbon due to which it does not get overheated like those of the other batteries, which have low energy storage systems, hence the lithium titanate battery is safe and user-friendly to be used in any application. The lithium titanate batteries are used in different applications like UPS, electrical power trains, solar-powered street lights, fast-charge stations, and forklifts. Other applications for LTO batteries include aerospace and military uses, and more The continuous usage of lithium titanate battery may cause harm to the environment as it produces harmful gas on excessive usage, due to which the battery gets swelled up (especially at high temperatures). The gas produced by the lithium titanate battery causes environmental pollution to a large extent. Besides the advantages and disadvantages of lithium titanate battery, the recycling of waste/spent lithium titanate battery is still not explored commonly on a large scale. Conventionally, the most commonly used method for recycling the spent lithium titanate battery involves dismantling, shredding, melting or dissolving the shredded battery in acid. Rest of the materials are recovered for the purpose of manufacturing other batteries or to be used for some other purpose. However, most of the studies that include the recycling of the lithium titanate batteries, claim to recover only the cathode part of the battery to obtain high valuable metals, while the study on recovering the anode part of the battery still remains unexplored. CN108550946A discloses about a method of recycling lithium chloride and titanium dioxide from lithium titanate waste material, whereby the waste lithium titanate material is calcined for 1-5 hours at 200-500°C. Lithium is selectively leached in HC1+H2O2 solution from the calcined mass, which is further crystallized as LiCl or precipitated as Li2CO3. Then, the residual mass is calcined at 600-1000°C to yield TiO2. The limitation of the invention is that, the process includes higher temperature ranges. CN109546252A discloses about circulating and recycling method for valuable metal in negative pole piece of waste lithium titanate battery. The method comprises the steps of: calcining the negative pole piece of the waste lithium titanate battery to obtain a calcined product; leaching the calcined product in an alkaline solution, and then filtering the calcined product by centrifugation to remove residues, so as to obtain a first filtrate; slowly adding an acidic substance into the first filtrate to remove aluminium (Al), and then filtering the filtrate to obtain a second filtrate; performing primary extraction and purification on the second filtrate to obtain a first extracted organic phase containing impurities and a first raffmate containing valuable metal; performing secondary extraction on the first raffmate to obtain a second extracted organic phase and a second raffmate, performing acid pickling and reverse extraction on the second extracted organic phase to obtain a second strip liquor, performing concentration drying on the second strip liquor to obtain metatitanic acid, and calcining the metatitanic acid to obtain analytically pure titanium dioxide; and performing evaporation and concentration as well as cooling crystallization on the second raffmate to obtain battery -level lithium carbonate. However, the method involves the use of a large number of chemicals such as strong acids, alkaline solution, extractants like di (2 -ethylhexyl) phosphoric acid, saponifying agents and the calcination of the metatitanic acid to obtain the high-purity titanium dioxide is specifically achieved at a very high range of temperature of 500- 900°C for long duration of 10-35 hours. Hence, the method is lengthy, time consuming, complex and neither commercially feasible nor environment-friendly due to the use of harmful chemicals. CN109037722A discloses about a method of recycling lithium in waste and old lithium titanate series lithium ion battery negative electrode that involves the steps of: charging waste lithium titanate battery; disassembling the fully charged battery to obtain a negative electrode sheet, and a positive electrode sheet; placing the negative electrode plate at 150°C; heat t