Method for producing battery-grade nickel sulfate by using laterite nickel ore

A method for producing battery-grade nickel sulfate by using laterite nickel ore, comprising the following steps:

• (1) sorting the laterite nickel ore to obtain lump ore and sediment ore;
• wherein the lump ore and the sediment ore are sorted according to a particle size, where a particle size of the lump ore is greater than 10 mm, and a particle size of the sediment ore is less than 10 mm
• (2) crushing the lump ore, and then performing heap leaching, to obtain a crude nickel sulfate solution A;
• (3) 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;
• wherein the high chromium ore comprises 30-40% by mass of chromium and 0.1-0.2% by mass of nickel;
• the low iron, high magnesium ore is mainly garnierite and comprises 1.5-2.1% by mass of nickel, 15-25% by mass of magnesium, 8-25% by mass of iron, and 35-50% by mass of silicon;
• and the high iron, low magnesium ore is mainly limonite and comprises 0.8-1.3% by mass of nickel, 30-50% by mass of iron, 0.1-10% by mass of magnesium, and 10-30% by mass of silicon;
• (4) blowing and performing water extraction on the low nickel matte, and then performing oxygen pressure leaching, to obtain a crude nickel sulfate solution B;
• (5) performing pressure leaching on the high iron, low magnesium ore to obtain a crude nickel sulfate solution C;
• and
• (6) performing extraction on the crude nickel sulfate solution A, the crude nickel sulfate solution B, and the crude nickel sulfate solution C, and then evaporating and crystallizing, to obtain battery-grade nickel sulfate;
• wherein, in the battery-grade nickel sulfate, a content of Mg<0.002 mass %, a content of Si<0.001 mass %, a content of magnetic substance<0.08 mass %, and a content of Co<0.002 mass %.