According to the grade of nickel [(> 3%) ~ (>: 8%), Ni] and impurity magnesium oxide (MgO content is lower than 6% ~ 20%) are divided into 10 grades (see Table 43.6). Nickel concentrates generally need to determine items such as nickel, nickel oxide, copper, cobalt, iron, silicon dioxide, sulfur, lead, cadmium, chromium, arsenic, mercury and platinum. For the analysis methods of each element, see 43.4 Determination of Associated Elements in this chapter and 43.3. 1 or 43.3.2 Gravimetric or volumetric determination of nickel in this chapter.