フィリピンの大型ラテライト処理工場浸出滓中の鉄源の形態と選鉱性

ラテライト質ニッヶル浸出滓中の鉄源の回収と利用 (第1報)

抄録

Properties of the raw material and the leach residue of Nonoc laterite treating plant together with morphology, some physical and chemical properties, and mineral dressing behavior of the iron resources contained in the leach residue were investigated. The results obtained are summarized as follows:
(1) Properties of the leach residue.
a) Iron content in the leach residue varies from about 42 to 56% with changes of the operating time. On the other hand, the iron content greatly varies dependent on particle size of the residue. That is, the minus 20μm portion shows the maximum iron content, while 74 to 105μm of that shows the minimum one.
b) The leach residue contains a large quantity of fine particles. Weight percent of the minus 37μm reaches approximately 70%.
(2) Morphology, some physical and chemical properties of the iron resources.
a) The iron resources are mainly composed of magnetite-like iron oxides, which are accompanied by a small quantity of wustite.
b) Most of the magnetite-like iron oxides are not pure and they contain Mg²⁺, Cr³⁺, and Al³⁺ with a wide variation. The lattice constant values observed on two samples are 8.342 and 8.316Å, and their saturation magnetic moments are 44.4 and 35.1emu/g, respectively. These values are smaller than the respective values of normal magnetite.
(3) Mineral dressing behavior of the iron resources. Effective upgrading of the iron resources may be realized by magnetic separation on oversize of 20 to 37μm of the residue. Since undersize of 20 to 37μm is relatively high grade and refractory to magnetic separation, it can be used as a part of iron concentrate without separation. The above-mentioned idea seems to be favorable from the view points of cost saving and environmental quality control.