Kumsal Alüvyon Cevherlerinden Elde Edilen Yüksek Fosforlu İlmenitte Fosfor Azaltımına Yönelik Zenginleştirme Süreci

The present invention relates to a beneficiation process for phosphorus reduction in ilmenite, and in particular to a beneficiation process for phosphorus reduction in high‑phosphorus ilmenite from beach placer ores.

Beach placer ores are composed of valuable minerals such as ilmenite, zircon, rutile and monazite. Generally, the collected beach placer ilmenite is subjected to gravity concentration to enrich the valuable minerals including ilmenite, zircon, rutile and monazite into a concentrate. For example, many concentrators in Hainan Province adopt this method. The enriched wet concentrate is then dried (either by heating or sun‑drying), screened through an 80‑mesh sieve, with the +80 mesh oversize discarded and the undersize fed to a disc magnetic separator to obtain low‑phosphorus ilmenite, as shown in Figure 1. This portion of concentrate, due to its low phosphorus content, can be sent directly for smelting. The tailings from the disc magnetic separator are then subjected to a scavenging stage on another disc magnetic separator, yielding a scavenger concentrate which is high‑phosphorus ilmenite. Because the phosphorus content of this high‑phosphorus ilmenite exceeds the smelting requirement (i.e., phosphorus above 0.04%, in some cases reaching above 0.11%), this high‑phosphorus ilmenite becomes a waste material and is discarded. At present, a considerable quantity of such waste material has accumulated in Hainan Province. Depending on the mining area, the yield of this high‑phosphorus ilmenite varies; in some areas, the output of high‑phosphorus ilmenite is twice that of the low‑phosphorus ilmenite concentrate, resulting in a serious waste of national resources. The scavenger tailings, consisting of zircon, rutile and monazite, are sent to the zircon cleaning circuit. Regarding the discarded high‑phosphorus ilmenite, some attempts have been made to explore its utilisation, for example, the Jiangxi Institute of Metallurgy tried to treat it by a combined magnetic separation and flotation method, but without success, mainly because the phosphorus content could not be reduced to meet smelting requirements.

The object of the present invention is to provide a beneficiation process that is technically feasible and economically rational, capable of reducing the phosphorus content in high‑phosphorus ilmenite to a level that meets smelting requirements for low‑phosphorus ilmenite, thereby making full use of national resources and creating wealth for the country.

The technical solution of the present invention is based on the characteristic that the impurity phosphorus in high‑phosphorus ilmenite, and the minerals intergrown or associated with it, have poor electrical conductivity. Through high‑voltage electrostatic separation, the separation objective is achieved, thereby substantially reducing the impurity phosphorus content in high‑phosphorus ilmenite to obtain low‑phosphorus ilmenite.

The beneficiation process of the present invention for phosphorus reduction in high‑phosphorus ilmenite from beach placer ores includes feed drying (by heating or sun‑drying), screening and magnetic separation, şu özellikleriyle karakterize edilen the magnetic separation employs an induced‑roll magnetic separator to first separate non‑magnetic minerals, followed by electrostatic separation on a high‑voltage electrostatic separator to further separate non‑conductive minerals, finally obtaining a low‑phosphorus ilmenite concentrate that is both magnetic and conductive.

In the beneficiation process of the present invention, the induced‑roll magnetic separator operates at a working current of 8–14 A, and the high‑voltage electrostatic separator operates at a voltage of 18–25 kV.

The specific beneficiation process of the present invention is as follows: the high‑phosphorus ilmenite is dried (by heating or sun‑drying) and then screened through an 80‑mesh sieve; the +80 mesh oversize is discarded, and the –80 mesh undersize is used as feed. This feed is first separated on an induced‑roll magnetic separator, and the resulting magnetic product is then fed to a high‑voltage electrostatic roll separator for further separation. The product obtained is a low‑phosphorus ilmenite concentrate that meets smelting requirements, while the tailings are combined with the tailings from the induced‑roll magnetic separator. As shown in Figure 1, the separation results are as follows:

Phosphorus removal rate: 34–81%

According to the process flowsheet of the present invention, the products obtained fully meet smelting requirements, thereby enabling the reutilisation of mineral resources that were previously discarded.

The process of the present invention can also be applied to improve existing ilmenite beneficiation flowsheets for beach placer ores. For example, the existing ilmenite beneficiation flowsheet shown in Figure 3 can be improved to the flowsheet shown in Figure 2. The specific process is: starting from the gravity concentrate, after drying (by heating or sun‑drying), it is directly subjected to rougher magnetic separation on an induced‑roll magnetic separator; the resulting concentrate is then subjected to cleaner electrostatic separation on a high‑voltage electrostatic separator, yielding an ilmenite concentrate with phosphorus content below 0.04%. The rougher magnetic tailings, consisting of zircon, rutile and monazite, can be sent directly to the zircon cleaning circuit.

The induced‑roll magnetic separator offers advantages such as high magnetic field intensity, good separation efficiency, large processing capacity and high titanium recovery. By changing from the original disc magnetic separator flowsheet (one rougher and one scavenger) to the new flowsheet of one rougher on an induced‑roll magnetic separator followed by one cleaner on a high‑voltage electrostatic separator, an ilmenite concentrate meeting smelting requirements can be obtained.

When the feed contains TiO₂ 11–18%, after treatment by the beneficiation process of the present invention, an ilmenite concentrate with TiO₂ > 50% and phosphorus content below 0.04% can be obtained, while the ilmenite recovery is increased by more than 20%.

By adopting the above beneficiation process, the present invention, compared with the prior art, features a simple flowsheet, good separation efficiency, low production cost and significant economic benefits, making full use of national resources. It is a technically feasible and economically rational beneficiation process for treating ilmenite, with broad potential for推广应用.

Description of Figures:

• Figure 1: Beneficiation process flowsheet of the present invention

• Figure 2: Improved ilmenite beneficiation process flowsheet

• Figure 3: Existing ilmenite beneficiation process flowsheet

Örnek:

According to the flowsheet shown in Figure 1, high‑phosphorus ilmenite from beach placer ores was dried (by heating or sun‑drying) and screened through an 80‑mesh sieve; the +80 mesh oversize was discarded, and the –80 mesh undersize was used as feed. This feed was passed through an induced‑roll magnetic separator to separate magnetic minerals, with the working current controlled at 8–14 A. It was then subjected to electrostatic separation on a high‑voltage electrostatic separator, with the voltage controlled at 18–25 kV, to separate non‑conductive minerals, thereby obtaining a qualified low‑phosphorus ilmenite concentrate. The results are shown in the table below.