Provided is a method for separating copper from nickel and cobalt, which is capable of efficiently and selectively separating copper, and nickel and cobalt from an alloy containing copper, nickel and cobalt such as a highly anticorrosive alloy that is obtained by subjecting a waste lithium ion battery to a dry treatment and contains copper, nickel and cobalt. According to the present invention, an alloy containing copper, nickel and cobalt is brought into contact with an acid in the coexistence of a sulfurization agent, thereby obtaining a solid that contains copper and a leachate that contains nickel and cobalt.

Proposed is a method of selectively leaching lithium (Li) and aluminum (Al) from a mixed carbonate precipitate (MCP) and, more specifically, a method of selectively leaching Li and Al from an MCP, by which a high-purity MCP can be prepared through selective leaching of Li and Al contained in an MCP used as a raw material for recovering valuable metals including nickel (Ni), cobalt (Co), and manganese (Mn).

Disclosed is a method for producing battery-grade nickel sulfate by using laterite nickel ore comprising the following steps: sorting the laterite nickel ore to obtain lump ore and sediment ore; crushing the lump ore, and then performing heap leaching, to obtain a crude nickel sulfate solution A; separating the sediment ore to obtain high chromium ore, low iron, high magnesium ore, and high iron, low magnesium ore, and drying, roasting, reducing, and sulfurating the low iron, high magnesium ore to obtain low nickel matte; blowing and performing water extraction on the low nickel matte, and then performing oxygen pressure leaching, to obtain a crude nickel sulfate solution B; performing pressure leaching on the high iron, low magnesium ore to obtain a crude nickel sulfate solution C; and performing extraction on the crude nickel sulfate solutions A, B, and C, and then evaporating and crystallizing, to obtain battery-grade nickel sulfate.

The present invention provides a method for removing iron from an iron-containing solution containing an iron ion, comprising adding a lithium ion battery cathode material containing manganese to an acidic sulfuric acid solution to obtain a cathode material-containing solution, and then precipitating a manganese ion as manganese dioxide in a mixed solution obtained by mixing the iron-containing solution with the cathode material-containing solution while precipitating the iron ion contained in the iron-containing solution as a solid.

The present invention provides a method for removing iron from an iron-containing solution containing an iron ion, comprising adding a lithium ion battery cathode material containing manganese to an acidic sulfuric acid solution to obtain a cathode material-containing solution, and then precipitating a manganese ion as manganese dioxide in a mixed solution obtained by mixing the iron-containing solution with the cathode material-containing solution while precipitating the iron ion contained in the iron-containing solution as a solid.

The present invention provides a method for removing copper from lithium ion battery scrap containing copper, comprising a leaching step of adding the lithium ion battery scrap to an acidic solution and leaching the lithium ion battery scrap under a condition that an aluminum solid is present in the acidic solution; and a copper separating step of separating copper contained in the acidic solution as a solid from the acidic solution, after the leaching step.

The present invention provides a method for removing copper from lithium ion battery scrap containing copper, comprising a leaching step of adding the lithium ion battery scrap to an acidic solution and leaching the lithium ion battery scrap under a condition that an aluminum solid is present in the acidic solution; and a copper separating step of separating copper contained in the acidic solution as a solid from the acidic solution, after the leaching step.

A smelting method capable of obtaining an iron-nickel alloy having a high nickel grade of 4% or higher by effectively facilitating a reduction reaction of pellets formed using a nickel oxide ore as a raw material. The present invention is a method for smelting a nickel oxide ore, by which an iron-nickel alloy is obtained by forming pellets from a nickel oxide ore and reducing and heating the pellets. In the pellet production step S1, a mixture is obtained by mixing raw materials that contain at least a nickel oxide ore and a carbonaceous reducing agent. In the reduction step S2, a furnace floor carbonaceous reducing agent is laid on the floor of the smelting furnace in advance when placing the obtained pellets in the smelting furnace and the pellets are placed on the furnace floor carbonaceous reducing agent and then reduced and heated.

A nickel recovery process capable of decreasing nickel remaining in a byproduct by recovering nickel from the byproduct of electrolytic nickel manufacturing process by chlorine-leaching, and also, capable of simplifying a cementation step simultaneously, is provided. In a nickel recovery step S60, a nickel recovery step S70 and a nickel recovery step S80, nickel is recovered in each step from S.sup.0 slurry, residue flaker and chlorine-leached residue, which are byproducts of electrolytic nickel manufacturing process by chlorine-leaching, by using an aqueous solution containing 80 g/L to 390 g/L of chlorine and 30 g/L to 70 g/L of copper.

Provided is a method for producing a pellet capable of suppressing heat shock-induced crack occurrence, when nickel oxide ores are made into pellets and placed in a reducing furnace in a smelting process. In the method for producing a pellet from a nickel oxide ore, a nickel oxide ore, a binder and a carbonaceous reducing agent are mixed, the mixture is made into a lump, and then the resulting lump is subjected to a preheat treatment at a temperature of 350 C. to 600 C. In this preheat treatment, the lump more preferably undergoes the preheat treatment at a temperature of 400 C. to 550 C.