The rare earth resources in Liangshan area are mainly distributed in the Wei Niuping rare earth mining area of ​​Suining County, followed by the Dechang rare earth mining area. The annual processing of raw ore is 150,000 to 200,000 tons, and the annual output of rare earth concentrate is 10,000 tons.

I. Mine and ore properties

Maoniuping rare earth mine in Sichuan Province Bureau of Geology and Mineral Resources 109 geological team to carry out lead, zinc mine when the check points, found in the census work in 1985 and 1986. The deposit is a basic pegmatite- calcite carbonate rare earth deposit. The rare earth mineral is mainly fluorocarbon antimony ore, a small amount of silicon- titanium ore and fluorocarbon calcium antimony ore. The associated minerals are mainly barite , fluorite and iron. , manganese and other minerals, a small amount of galena. In 1994, the geological report of the mining area survey (including detailed investigation) pointed out that the C+D+E grade reserves were 21.46% tons (REO) and the industrial reserves were 1 million tons. The average grade of 3.70 percent rare earth, is a large rare earth deposits that REE europium, yttrium and the like, higher than the same type of heavy rare-mine grade. The distribution of rare earth elements in rare earth minerals of this deposit is shown in Table 1.

The ore is divided into lump ore and powder ore from the particle size. The mineral inlay size of the lump ore is coarse, generally >1.0 mm, of which the fluorocarbon antimony ore is generally 1 to 5 mm, the particle size is extremely coarse, easy to grind, and the monomer dissociation degree. it is good. Powdered ore is the product of weathering of the original rock. The weathering is relatively thorough. The local weathering depth is 300m, forming a black weathered slime that accounts for about 20% of the ore. They are iron-manganese amorphous oxide aggregates. The black weathered slime has a particle size of 80% below -320 mesh, containing REO2% to 7%, and contains strontium and barium. The main chemical composition of the raw ore in Maoniuping is shown in Table 1.

Table 1 Table of main chemical components of Yu Niuping ore (%)

Second, ore beneficiation process and technical indicators

The ore produced in Maoniuping is a mixed ore with lump ore and powdery nature. The black slime affects the flotation of rare earth minerals. Therefore, it is very important to remove mud before flotation.

As the ore grindability easy to choose, rare earth mine in Maoniuping found early (late 1980s), rare earth concentrate optimistic about the market, we have built more than 100 small-scale mining and beneficiation plant.

The mine was dug and dug, and the small ore dressing planted everywhere. In 1995, it was reduced to 39 years of concentrating plants (up to 20 in early 2000), and there are three representative mineral processing processes.

(1) Single re-election process. The ore grinding to -200 mesh 62% is divided into four grades by hydraulic classification tank, which are separately sorted on the grooved silt shaker to obtain three fluorocarbon antimony concentrates containing REO 30%, 50% and 60%. The total job recovery rate was 75%.

(2) Magnetic separation-re-election combined process. The ore containing REO 3.2% was subjected to magnetic separation (weak magnetic separation, strong magnetic separation) to obtain a magnetic product containing REO 5.64%. The magnetic separation operation recovery rate was 74.2% (yield 42%), and the magnetic separation was coarse. The concentrate is divided into four grades by hydraulic classification tank, which are re-elected by shaker respectively. The re-election of total concentrate contains REO52.3%, the yield is 3.56%, and the rare earth recovery rate is about 55%.

(3) Re-election-flotation process. The first section of the original ore is ground to -200 mesh, accounting for 50%. It is divided into four grades by hydraulic classification tank, which are re-elected by shaker (removing the slime and some light specific gravity gangue) and re-electing with REO3 0%. Crude concentrate, rare earth recovery rate of 74.50%.

The coarse concentrate is re-ground to -200 mesh and 70%, and is floated with a combination of sodium carbonate, water glass and C5-9 hydroxydecanoic acid, and floated by a coarse, one sweep, and a closed circuit process to obtain a REO 50%. ~60% of rare earth concentrate, rare earth recovery rate of 50% to 60%, the process flow is shown in Figure 1.

Fig.1 Flow chart of re-election-flotation process of yakouping rare earth mine

The three beneficiation processes are more widely used in the re-election-flotation process (such as Changlan Rare Earth Co., Ltd.), but the recovery rate of rare earths is relatively low. The crude was re-election flotation reagent to concentrate waterglass, H ₂ O ₅ and combinations of agents mixed phosphorus acid 1:1 flotation pulp pH8 ~ 9 under conditions to obtain a concentrate grade of 69.09% rare earth, The recovery rate of flotation operation was 89.82%, and the recovery rate of rare earth in the re-election-flotation process was 66.92%. The mineral processing technical index has been significantly improved.

The working principle of continuous coconut shell Carbonization Furnace,which is adopting advanced smoke-free and environment-friendly carbonization process.

 The whole set of equipment consists of four parts: