Patent Description:
Nickel is an important national strategic element, and is widely applied to the fields of critical materials and high and new technologies, for example, batteries, stainless steel, and catalysis. Currently, nickel resources that can be developed and utilized by humans are mainly divided into two types: nickel sulfide ore and laterite-nickel ore. Since nickel sulfide ore has been exploited for a long period of time, recently, reserves decrease dramatically, and a resource crisis has occurred. However, the laterite-nickel ore resources are abundant, and can generate a plurality of intermediate products, for example, nickel oxide, nickel sulfide, and ferronickel.

Lithium ion batteries are a new type of secondary batteries developed in recent years, and a key to development of the lithium ion batteries is development of cathode and anode materials of the batteries. The cathode material is one of critical materials for producing the lithium ion batteries, and selection and quality of the cathode material directly decide characteristics and prices of the lithium ion batteries. Since reported for the first time in the year of <NUM>, a cathode material of a lithium nickel cobalt manganese oxide ternary layered structure has been a powerful competitor of the cathode material of the lithium ion batteries. However, a cycle life of the lithium ion battery is always limited, and thus recovery of waste lithium ion batteries has significant environmental and economic benefits.

<CIT> discloses a process for the recovery of transition metal from cathode active materials containing nickel and lithium, wherein said process comprises the steps of (a) treating a lithium containing transition metal oxide material with a leaching agent (preferably an acid selected from sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, oxalic acid and citric acid), (b) adjusting the pH value to <NUM> to <NUM>, and (C) treating the solution obtained in step (b) with metallic nickel, cobalt or manganese or a combination of at least two of the foregoing.

Chinese Patent <CIT> (Method for recovering waste lithium batteries) adopts steps, for example, pre-treating-reducing and acid leaching-removing impurities by using an iron powder, a nickel powder, a cobalt powder, a manganese powder, and sodium sulfide-hydrolyzing and precipitating by using sodium hydroxide, potassium hydroxide, lithium hydroxide, and aqueous ammonia-acidizing and dissolving by using sulfuric acid-concentrating and crystallizing, to realize the recovery of waste lithium batteries. Chinese Patent <CIT> (Method for recovering valuable metal from waste lithium nickel cobalt manganese oxide batteries) mainly includes steps, for example, discharging the waste lithium nickel cobalt manganese oxide batteries, pulverizing, roasting at a high temperature, leaching by using nitric acid, precipitating copper, iron, and aluminum ions by adding sodium chlorate, precipitating nickel, cobalt, and manganese by adding sodium hydroxide and aqueous ammonia, and precipitating lithium by adding sodium carbonate.

In the foregoing methods, impurities are removed and copper is precipitated by using a nickel powder, a cobalt powder, and a manganese powder, and the nickel powder, the cobalt powder, and the manganese powder react with acid, cannot replace copper ions, and cannot be fully dissolved. The nickel powder and the cobalt powder belong to valuable metals, and consequently the foregoing methods cause waste of resources. Copper is removed by using iron powder and sodium sulfide, and thus impurity elements in a solution system increase, which increases a production cost of subsequent impurity-removal and wastewater treatment. Meanwhile, a large amount of ferrous iron enters a reaction system, which increases a production cost for a subsequent step of removing iron, and also increases contamination of the environment caused by solid waste and a cost of treating the solid waste. Iron and aluminum ions are hydrolyzed by using a strong alkali, and thus valuable metals, nickel, cobalt, and manganese in the solution system are precipitated, causing waste in resources and an increase in a production cost. Copper, iron, and aluminum are precipitated by using sodium hypochlorite, and thus chloride ions are dissolved in the solution system. Chloride ions and strong oxidizing sodium hypochlorite corrode a device, a cost of removing impurities increases when entering a wastewater system, and the environment is contaminated when flowing into a river.

The features of the method according to the present invention are set out in the appended set of claims.

An objective of the present invention is to provide a method for purifying and removing impurities from a nickel cobalt manganese leaching solution. The method comprehensively utilizes manganese dioxide in manganese ore to oxidize ferrous iron, and consume residual acid, and then utilizes an elemental manganese powder to neutralize and adjust pH, to achieve the objective of purifying and removing impurities.

In order to achieve the objective mentioned above, the following technical solutions are used in the present invention:
A method for purifying a nickel cobalt manganese leaching solution includes the following steps:.

Preferably, in step (<NUM>), the nickel cobalt manganese leaching solution is one of a nickel cobalt manganese ternary battery waste leaching solution or a laterite-nickel ore leaching solution.

Preferably, in step (<NUM>), a temperature of the heating is <NUM>-<NUM>; and a time of the stirring is <NUM>-<NUM>.

In step (<NUM>), the manganese powder is a manganese oxide ore powder and a manganese carbonate ore powder; in step (<NUM>), and step (<NUM>), the manganese powder is an elemental manganese powder.

In step (<NUM>), the adjusting pH to acidity is adjusting pH to <NUM>-<NUM>. Preferably, from step (<NUM>) to step (<NUM>), a time of the reaction is <NUM>-<NUM>.

Preferably, in step (<NUM>), a temperature of the heating is <NUM>-<NUM>, and a time of the stirring is <NUM>-<NUM>.

In step (<NUM>), the adjusting pH to acidity is adjusting pH to <NUM>-<NUM>.

Preferably, in step (<NUM>), the copper slag is delivered to an electrolysis workshop for smelting and electrolyzing copper.

In step (<NUM>), the adjusting pH to alkalinity is adjusting pH to <NUM>-<NUM>.

Preferably, in step (<NUM>), the alkaline solution is one of sodium hydroxide or sodium carbonate.

Preferably, after step (<NUM>), the method further includes: taking the nickel and cobalt-precipitated solution for heating, stirring, adding sodium sulfide, and filtering, to obtain manganese sulfide and a lithium-contained manganese-precipitated solution.

More preferably, the lithium-contained manganese-precipitated solution enters a lithium-precipitation process, to obtain lithium carbonate.

Preferably, a molar ratio of the sodium sulfide to manganese in the nickel and cobalt-precipitated solution is (<NUM>-<NUM>) : <NUM>.

Preferably, in step (<NUM>), the acid solution is one of sulfuric acid or hydrochloric acid.

In step (<NUM>), the iron-aluminum slag is returned to step (<NUM>) to react with the nickel cobalt manganese leaching solution.

Preferably, in step (<NUM>), the adding water and slurrying the nickel cobalt manganese hydroxide is adding water and slurrying the nickel cobalt manganese hydroxide to a solid content of <NUM>-<NUM>%.

Experimental principles of the present invention:.

<FIG> is a flowchart of a process according to Example <NUM> of the present invention.

Element contents of a nickel cobalt manganese leaching solution of Embodiments <NUM>-<NUM> are shown in Table <NUM>.

Content of Mn in manganese oxide ore: <NUM>%, content of Mn in manganese carbonate ore: <NUM>%, and content of Mn in an elemental manganese powder: > <NUM>%.

A method for purifying a nickel cobalt manganese leaching solution includes the following steps:.

A method for recovering valuable metal from a waste lithium nickel cobalt manganese oxide battery material includes steps as follows:.

Element components of the nickel and cobalt-precipitated solution in Embodiments <NUM>-<NUM> are detected, and results are shown in Table <NUM>:.

It can be seen from the nickel and cobalt-precipitated solution in Table <NUM> that the element manganese and the element lithium are mainly further contained, lithium is further precipitated, to obtain lithium carbonate, and a lithium-precipitated liquid is extracted to prepare and obtain a battery-grade manganese sulfate solution, increasing the production revenue.

Element component contents of the iron-aluminum slag in Embodiments <NUM>-<NUM> are detected, and results are shown in Table <NUM>:.

It can be seen from the iron-aluminum slag in Table <NUM> that, components are mainly iron and aluminum, and the iron and the aluminum are returned to step (<NUM>) to mix with a manganese powder and then react with the nickel cobalt manganese leaching solution, which is more conducive to removing the iron and the aluminum.

Element component contents of the copper slag in Embodiments <NUM>-<NUM> are detected, and results are shown in Table <NUM>:.

Components of the accepted nickel cobalt manganese sulfate liquid in Embodiments <NUM>-<NUM> are detected, and results are shown in Table <NUM>:.

It can be learned from Table <NUM> that, in the accepted nickel cobalt manganese sulfate liquid of Embodiments <NUM>-<NUM>, a content of impurities is less than <NUM>%, which meets a solution purification standard. (Amass ratio of Fe, Al, and Cu to Ni, Co, and Mn is (<NUM>-<NUM>)*<NUM>-<NUM>, which reaches the solution purification standard).

Loss ratios of nickel, cobalt, and manganese in Embodiments <NUM>-<NUM> and Comparative Embodiment <NUM> are detected, and results are shown in Table <NUM>:.

It can be learned from Table <NUM> that the loss ratios of nickel, cobalt, and manganese of Embodiments <NUM>-<NUM> of the present invention are all less than <NUM>%, while the loss ratios of nickel, cobalt, and manganese of Comparative Embodiment <NUM> are <NUM>-<NUM> times more than those of Embodiments <NUM>-<NUM>. In addition, in Comparative Example <NUM>, copper, iron, and aluminum are precipitated by using sodium chlorate, and thus chloride ions are dissolved in the solution system. Chloride ions and strong oxidizing sodium chlorate corrode a device, a cost of removing impurities increases when entering a wastewater system, and the environment is contaminated when flowing into a river.

It can be learned from Tables <NUM>-<NUM> that the present invention oxidizes ferrous iron in the solution system by using manganese oxide ore, neutralizes and adjusts the pH value by using manganese carbonate ore, removes iron and aluminum, consumes the residual acid in the solution system and simultaneously leaches manganese carbonate ore to produce manganese sulfate, and removes copper by using an elemental manganese powder, preventing other impurities from entering the solution system, and decreasing loss of nickel, cobalt, and manganese.

Claim 1:
A method for purifying a nickel cobalt manganese leaching solution, comprising the following steps:
(<NUM>) heating a nickel cobalt manganese leaching solution, stirring, adding a manganese powder, adjusting pH to acidity, performing a reaction, and filtering, to obtain an iron-aluminum slag and an iron and aluminum-removed liquid;
(<NUM>) heating the iron and aluminum-removed liquid, stirring, adding a manganese powder, adjusting pH to acidity, performing a reaction, and filtering, to obtain a copper slag and a copper-removed solution;
(<NUM>) heating the copper-removed solution, stirring, adding an alkaline solution, adjusting pH to alkalinity, performing a reaction, and filtering, to obtain a nickel and cobalt-precipitated solution and nickel cobalt manganese hydroxide; and
(<NUM>) adding water and slurrying the nickel cobalt manganese hydroxide, heating, adding an acid solution to dissolve, adjusting pH to acidity, performing a reaction, heating, then adding a manganese powder, adjusting pH to acidity, and filtering, to obtain an iron-aluminum slag and an accepted nickel cobalt manganese sulfate liquid;
wherein, in step (<NUM>), the manganese powder is a manganese oxide ore powder and a manganese carbonate ore powder; in step (<NUM>), and step (<NUM>), the manganese powder is an elemental manganese powder;
in step (<NUM>), the adjusting pH to acidity is adjusting pH to <NUM>-<NUM>; in step (<NUM>), the adjusting pH to acidity is adjusting pH to <NUM>-<NUM>; in step (<NUM>), the adjusting pH to alkalinity is adjusting pH to <NUM>-<NUM>; and in step (<NUM>), the adjusting pH to acidity is adjusting pH to <NUM>-<NUM>; and
in step (<NUM>), the iron-aluminum slag is returned to step (<NUM>) to react with the nickel cobalt manganese leaching solution;
wherein, a main component of manganese oxide ore is MnO<NUM>, and a main component of manganese carbonate ore is MnCO<NUM>.