CN103757368A

CN103757368A - Leaching method of lithium iron phosphate waste battery positive electrode material

Info

Publication number: CN103757368A
Application number: CN201310736566.6A
Authority: CN
Inventors: 龙炳清; 林春; 李贵
Original assignee: Sichuan Normal University
Current assignee: Sichuan Normal University
Priority date: 2013-12-29
Filing date: 2013-12-29
Publication date: 2014-04-30

Abstract

The invention provides a leaching method of a lithium iron phosphate waste battery positive electrode material, which comprises the following steps: putting a positive electrode material subjected to roasting pretreatment separated from lithium iron phosphate waste batteries into a pressure-resistant sulfuric-acid-corrosion-resistant container, pumping sulfuric acid into the container, sealing the container, pumping a (NH4)2SO3 solution into the container by using a filling pump, closing the (NH4)2SO3 solution inlet valve, and leaching.

Description

The leaching method of iron lithium phosphate refuse battery positive electrode material

Technical field

The present invention relates to a kind of leaching method of iron lithium phosphate refuse battery positive electrode material.

Background technology

Ferric phosphate lithium cell (the major metal element that positive electrode material contains is the battery of lithium, aluminium and iron) is a class novel battery, and this battery will produce a large amount of refuse batteries after using and scrapping.If this class battery contains, abandon into environment, will environment be produced to very large direct and potential hazard.Lithium iron phosphate battery positive material is mainly containing lithium, aluminium and iron, and wherein the total content of lithium is up to more than 4%, has very much a recovery value.The technique that reclaims at present lithium from iron lithium phosphate refuse battery positive electrode material is mainly wet processing.Leaching is a requisite process in wet processing.The leaching method of iron lithium phosphate refuse battery positive electrode material mainly contains hydrochloric acid leaching process, sulfuric acid leaching, nitric acid lixiviation process and nitration mixture (sulfuric acid adds nitric acid) lixiviation process at present.Hydrochloric acid leaching process, equipment corrosion is large, the large and contaminate environment of acid mist generation.The reductive agent (as hydrogen peroxide etc.) that sulfuric acid leaching consumption is more expensive.The nitric acid consumption of nitric acid lixiviation process is large, and can produce a large amount of oxynitride, contaminate environment.All there is the problem that improves how economically leaching velocity, raising metal leaching rate, reduces acid consumption and other supplementary product onsumption in all wet processings.Although nitric acid processing industry pure oxygen lixiviation process and nitration mixture processing industry pure oxygen lixiviation process have solved the problems referred to above preferably, but leaching plant is more complicated, and the required industrial pure oxygen amount of refuse battery leaching is little, refuse battery is processed enterprise, and manufacture pure oxygen is personal uneconomical on the spot, and storage, transportation and the use of industrial pure oxygen are cumbersome.Development equipment corrosion is little, leaching velocity is fast, leaching yield is high, acid consumes and other supplementary product onsumption is low, easy to use, the leaching method of the iron lithium phosphate refuse battery positive electrode material of basic non-environmental-pollution has larger practical value.

Summary of the invention

The problem leaching for current iron lithium phosphate refuse battery positive electrode material, the object of the invention is to find a kind of metal leaching rate high, leaching velocity is fast, leaching yield is high, acid consumption and other supplementary product onsumption are low, easy to use, need not expensive reductive agent, the leaching method of the iron lithium phosphate refuse battery positive electrode material of basic non-environmental-pollution, it is characterized in that will be isolated from iron lithium phosphate refuse battery, and the positive electrode material obtaining through roasting pretreatment puts into withstand voltage and container sulfuric acid corrosion resistant, and sulfuric acid is pumped into this container, then sealed vessel, and with injection pump by (NH ₄) ₂sO ₃solution pumps into container, after this closes (NH ₄) ₂sO ₃solution pumps into valve and leaches, and after leaching finishes, carries out liquid-solid separation, obtains required infusion solution.Temperature of reaction is 40 ℃～80 ℃, and the sulfuric acid starting point concentration of leaching is 1mol/L～4mol/L, and extraction time is 1h～3h, and leaching process stirs, and stirring velocity is 30r/min～120r/min.Sulphuric acid is to add the sulfuric acid theoretical consumption that in the positive electrode material of reaction vessel, all metal leaches (not deduct and generate AlPO ₄precipitation reduce sulfuric acid theoretical consumption) 110%～150%.(NH ₄) ₂sO ₃add-on be by positive electrode material all high-valency metals be reduced to the (NH of metal at a low price ₄) ₂sO ₃105%～120% of theoretical consumption.

The object of the present invention is achieved like this: at airtight and (NH ₄) ₂sO ₃under the condition existing, during the iron lithium phosphate refuse battery positive electrode material (metallic element in material be oxide form) of sulfuric acid leaching after roasting pretreatment, there is following main chemical reactions in leaching process:

Al ₂O ₃ + 3H ₂SO ₄ = Al ₂(SO ₄) ₃ + 3H ₂O

2LiFePO ₄ + 3H ₂SO ₄ = Li ₂SO ₄+ 2H ₃PO ₄ + 2FeSO ₄

2FePO ₄ + 2H ₂SO ₄+ (NH ₄) ₂SO ₃ + H ₂O = 2FeSO ₄ + (NH ₄) ₂SO ₄ + 2H ₃PO ₄

Al ₂(SO ₄) ₃ + H ₃PO ₄ = AlPO ₄

Due to (NH ₄) ₂sO ₃reducing power more much better than than the reducing power of hydrogen peroxide of generally using in existing leaching method, and need under strong acidic environment, could reduce, can reduce like this acidity of leaching process, the consumption of minimizing sulfuric acid and reductive agent, raising speed of response.(NH ₄) ₂sO ₃can thoroughly destroy FePO in positive electrode material ₄laminate structure, improve the leaching yield of lithium.(NH ₄) ₂sO ₃with H ₂sO ₄reaction generates H ₂sO ₃and SO ₂, the FePO in these resultants and positive electrode material ₄reaction is consumed, due to SO ₂in the aqueous solution, there is certain solubleness, be released in the SO in reactor upper space ₂less, and along with the carrying out reacting, SO ₂to constantly be consumed, so carry out under pressure-fired in whole reaction.

With respect to existing method, outstanding advantages of the present invention is to adopt (NH ₄) ₂sO ₃make reductive agent and leach iron lithium phosphate refuse battery positive electrode material, speed of response is fast, and such as reaction acidity is lower, and the consumption of sulfuric acid and reductive agent is little; FePO in positive electrode material ₄laminate structure destroy thoroughly, can improve the leaching yield of lithium; In leach liquor subsequent disposal, do not need to neutralize a large amount of acid, cost is lower; The waste amount producing in leach liquor subsequent disposal is few, has reduced pollution abatement costs, has obvious economic benefit and environmental benefit.

specific implementation method

embodiment 1: it is in the stainless steel cauldron of 2L that 100g iron lithium phosphate refuse battery positive electrode material (containing lithium 4.3%, aluminium 5.2%, iron 34.8%) is added to volume, adds the sulfuric acid 920ml of 1.5mol/L, adds (NH ₄) ₂sO ₃39g (200ml solution) stirs (stirring velocity 80r/min) and leaches 2.5h at 40 ℃～50 ℃, after leaching finishes, carries out liquid-solid separation, obtains 1180ml infusion solution (containing leached mud washing water).The leaching yield of lithium, aluminium and iron be respectively 99.3%, 0.01% and 99.2%(by entering lithium in infusion solution and leached mud washings, aluminium and iron, calculate).

Embodiment 2: it is in the stainless steel cauldron of 5L that 300g iron lithium phosphate refuse battery positive electrode material (containing lithium 4.3%, aluminium 5.2%, iron 34.8%) is added to volume, adds the sulfuric acid 1700ml of 3.0mol/L, adds (NH ₄) ₂sO ₃129g (700ml solution) stirs (stirring velocity 70r/min) and leaches 1h at 70 ℃～80 ℃, after leaching finishes, carries out liquid-solid separation, obtains 2200ml infusion solution (not comprising leached mud washing water).The leaching yield of lithium, aluminium and iron be respectively 99.6%, 0.01% and 99.4%(by entering lithium in infusion solution and leached mud washings, aluminium and iron, calculate).

Claims

1. the leaching method of an iron lithium phosphate refuse battery positive electrode material, being characterised in that will be isolated from iron lithium phosphate refuse battery, and the positive electrode material obtaining through roasting pretreatment is put into withstand voltage and container sulfuric acid corrosion resistant, and sulfuric acid is pumped into this container, then sealed vessel, and with injection pump by (NH ₄) ₂sO ₃solution pumps into container, after this closes (NH ₄) ₂sO ₃solution pumps into valve and leaches, after finishing, leaching carries out liquid-solid separation, obtain required infusion solution, temperature of reaction is 40 ℃～80 ℃, and the sulfuric acid starting point concentration of leaching is 1mol/L～4mol/L, and extraction time is 1h～3h, leaching process stirs, stirring velocity is 30r/min～120r/min, and sulphuric acid is to add 110%～150% of sulfuric acid theoretical consumption that in the positive electrode material of reaction vessel, all metals leach, (NH ₄) ₂sO ₃add-on be by positive electrode material all high-valency metals be reduced to the (NH of metal at a low price ₄) ₂sO ₃105%～120% of theoretical consumption.