Question 2: What does the grade of iron ore mean? Chemical composition and iron content. If it is hematite, the general inspection report will only mention Fe, that is, the content of iron. If it is magnetite, the report will also contain ferrous iron, which is FeO. In addition, the index of iron ore also depends on silicon, aluminum, sulfur, phosphorus, crystal water and free water. Iron ore in some producing areas such as the Philippines depends on titanium, while iron ore in Malaysia depends on arsenic and chromium. Bulk ore depends on particle size and powder rate, coarse powder ore generally doesn't care much about powder rate, and pellet depends on strength.
Question 3: What is the average grade of ore bodies? Ore grade, also known as ore grade, refers to the enrichment degree and unit content of useful components in metal deposits and some nonmetal deposits (such as apatite, potassium salt and fluorite). It is the main symbol to measure the quality of mineral resources. Usually expressed in percentage, gram/ton, gram/cubic meter, gram/liter, etc. The grade of ore determines the value of mineral resources development and utilization, the direction of processing and utilization and the technological process of production. According to the content of useful minerals, mineral products are divided into three categories: ① cut-off grade. Dividing the lowest grade between ore and non-ore, that is, delineating the lowest grade of ore body, and failing to reach this index is called rock or mineralized rock; ② Average grade. The ore body, ore section or the whole mining area reaches the total average grade of industrial reserve ore to measure the richness of minerals; ③ Industrial grade, or critical grade. The lowest average grade of an industrially available ore section or ore body is the lowest grade that is technically possible and economically reasonable to develop and utilize under the current technical and economic conditions. Generally, high-grade ore is called rich ore, and vice versa. The higher the ore grade, the greater the utilization value and the better the production technical index; The lower the grade, the smaller the utilization value and the worse the production technical index. Different mineral resources have different requirements for their grade. For example, China stipulates that the industrial grade of iron ore is 20 ~ 60%, and generally requires manganese content in manganese ore to be above 20 ~ 25% and aluminum content in bauxite to be above 40%. With the development of productivity and the continuous progress of mineral processing and smelting technology, the critical grade of ore is also changing. For example, copper ore with copper content of 10% was mined at the beginning of 19 century, but now porphyry copper ore with copper content of 0.5% has been mined on a large scale.
Question 4: What is the percentage of used components (elements or compounds) in ore or products with geological grade of raw ore? The grade of raw ore indicates the rich and poor degree of raw ore, while the grade of concentrate reflects the rich and poor degree of some recovered components selected into concentrate. The minimum industrial grade and cut-off grade of ore are important indexes of ore industry, which change with the national economic policy, scientific and technological progress, geological conditions of ore deposits and ore demand. The lowest industrial grade refers to the lowest index of the average content of beneficial components in the independent mining section. The cut-off grade is the lowest index of the content of beneficial components in a single sample, so the boundary penalty points between ore and waste rock are divided. Cut-off grade and minimum industrial grade are the main indicators for delineating and calculating the industrial ore quantity in the table (the ore section equal to or greater than the minimum industrial grade is the industrial ore quantity in the table).