SUMMARY

Iron ore quality in Cao Bằng Province and its usage value for producing sponge iron

Phạm Hoè, Nguyễn Đình Tiết, Lã Xuân Liên,

Kiều Cao Thăng, Dương Văn Sự, Trần Thanh Phúc

This article is based on the multi-yeare document collection, survey and evaluation of iron ore quality in Ngườm Cháng, Na Lũng and Nà Rụa mines, and Khuổi Tông, Bản Luộc, Bản Nùng I and Bản Nùng II mine points of Cao Bằng province. The results show that mines and mine points (all referred to as mines) are skarn origin, with small, scattered but good quality reserves. Among the above-mentioned mines, the Bản Luộc mine has the lowest iron contents: TFe in ore range from 57.44-62.40%, 52.92% in average; TFe in disseminated ore fluctuates from 39.6%-42.43%, 41.01% in average; Ngôm Cháng deposit its the richest: TFe in ore ranging from 62-63%, 62.5% in average, TFe in disseminated ore ranged from 40-59.9%, 51% in average, the remaining mines were medium. Bản Luộc mine was selected as a mine filed for producing technology research. The results of material composition and technological feasibility of iron ore show that iron distribution characteristics are mainly concentrated at the particle level of 0.2 - 30.0 mm. In the level of 10.0 to 30.0 mm clay minerals and soils are just needed to be cleaned then ran through the conveyor belt to meet the product requirements, while reducing the noxious elements such as Si, Mn, S and P are about the permissible limit of the technology in "Direct recovering for iron ore” to produce sponge iron. The Việt Nam Minerals and Metallurgy Company (MIREX) used the above-mentioned ore to produce sponge iron. Up to now, MIREX iron and alloy steel factory in Cao Bằng has been running relatively stable with good quality products. Sponge iron has a total iron content of 89.92-94.67%, ferrous iron of 77.63-87.59%, carbon content of 0.76-1.25, sulfur and phosphorus contents are below 0.80% and 0.04%, respectively. With the above quality of spongy iron, MIREX has successilly processed over 105 grades of alloy steels for economy and national defence.

Người biên tập: TS. Vũ Lê Tú