Berylline beneficiation method

First, the hand selection method

The hand selection is a sorting method for manually selecting the beryl concentrate based on the difference in appearance characteristics (color, gloss, crystal form) between the beryl and the associated gangue minerals. Hand selection is often carried out on slow moving belts. The selected ore particle size is usually greater than 10 to 25 mm, and the determination of the lower particle size depends mainly on the economic effect. In order to improve the efficiency of hand selection, ore is often pre-selected for screening before hand selection, and if necessary, it needs to be washed, and the work area should have good lighting.

The hand selection method has always occupied a very important position in the production of beryl concentrates at home and abroad, and is the main method for producing beryl concentrates. At the beginning of the liberation, China's Xinjiang, Hunan, Jiangxi, and Guangdong provinces began to produce beryl concentrates from pegmatite or quartz veins by hand selection. In 1959, only the sapphire produced by Xinjiang and Hunan provinces was hand-selected. The concentrate is 2,800 tons. In 1962, the total production of the world beryl concentrate was 7,400 tons, and the hand-selected concentrate accounted for 91%. It should be noted that the manual labor intensity is high, the production efficiency is low, the selection index is poor, and the resources are wasted. It is gradually being replaced by other mechanical beneficiation methods. However, the beryl crystals in the pegmatite are coarse and easy to select, and the hand selection is still one of the important methods for producing beryl concentrate.

Figure 1 shows the principle flow of the beryl hand selection.

Figure 1 Principle process of beryl hand selection

Second, the flotation method

Flotation is an important method for selecting low-grade, fine-embedded beryl ore. Domestic and foreign mineral processing workers have conducted extensive and in-depth research on this, and proposed Lamb and Rabid City. ), Runke, Calgon, Eigeles, and many other methods of flotation beryl. Practice shows that beryl can be floated regardless of the use of cationic collector or anionic collector, but the effective separation of beryl and associated gangue cannot be achieved without the selective adjustment agent. Therefore, the beryl must be pre-treated with a conditioning agent before flotation. According to the pH of the medium in the pretreatment, the flotation process of beryl is divided into two categories: one is the acid process and the other is the alkali process.

Acid flotation process

The acid process is to pretreat the slurry with hydrofluoric acid (or sodium fluoride and sulfuric acid), activate the beryl, and then add a collector and a foaming agent to float the beryl. According to the order selected by the beryl in the process, the acid process can be further subdivided into an acid mixed flotation process and an acid preferential flotation process. The former, such as the process recommended by Denver (Fig. 2): first float mica with an amine acetate and a foaming agent in an acidic medium, and then add hydrofluoric acid to activate feldspar and beryl, and collect it with cations. Jing mixed flotation feldspar-beryl, mixed concentrate after washing (plus calcium hypochlorite), after drug removal, flotation of beryl with petroleum sulfonate. Denver Company treated the ore containing 0.95% of BeO to obtain a beryl concentrate containing BeO8.61% with a recovery rate of 87.8%. The acid method preferential flotation process is to adjust the slurry with sulfuric acid, add the cationic collector to float the mica, then wash the mineral, concentrate, and then add the hydrofluoric acid treatment, and float the beryl with the fatty acid collector in the soda medium. . The ore of a deposit in the United States contains BeO 0.14%, and is ground to -0.85 mm. After de-muding, sulfuric acid and cations are added to collect the mica, and then hydrofluoric acid is added to the captive ore to activate the green living stone in soda. The medium is filled with oleic acid and neutral oil to float green living stone. The beryl concentrate obtained by flotation is magnetically removed to remove magnetic minerals, and finally the beryl concentrate containing BeO8% or more is obtained. The recovery rate is 89%, and mica, feldspar and quartz with purity of 93% to 98% are also selected respectively. The product, principle flow is shown in Figure 3.

Figure 2 Denver's recommended acid mixing flotation process

Figure 3 The acid preferential flotation principle process for selecting a beryl ore in the United States

It should be pointed out that the grade of beryl concentrate obtained by the above flotation method is not too high, and it is often required to be selected by magnetic separation, heating flotation or other methods.

When the ore contains sulfide, it can be first floated out with xanthate. If there are more fluorite , it can be floated out with a small amount of water glass and an anionic collector after the mica flotation. If the ore contains more strongly weathered feldspar, it is usually preferred to use preferential flotation.

Flotation practice green living abroad Description: beryl ore associated with certain heavy minerals (or buoyant minerals) as garnet, hornblende, tourmaline, apatite, etc. of the final concentrate beryl The quality of the film is quite large and should be eliminated as soon as possible. In 1983, Moir et al. proposed in their papers that the grade of the green living stone concentrate depends on the heavy mineral content in the ore, emphasizing the necessity of pre-excluding heavy minerals and formulating the first selection of heavy minerals. Acid beryl preferred flotation process. The raw ore of Moyle et al. with 0.2% BeO successfully completed the continuous test and obtained the green living stone concentrate with a grade of 10.9% Be0. The recovery rate was higher than 75%. The continuous test procedure is shown in Fig. 4.

Figure 4 Moyle continuous test process

Alkaline flotation process

The alkali flotation process is that the ore is treated with alkali and washed and de-sludged before grinding or flotation, and then the fatty acid collector and the foaming agent flotation beryl are added. Ram developed an alkali process and tested a pegmatite beryl mine. A beryl concentrate with a grade of 12.2% BeO was selected from the ore containing 1.3% BeO. The recovery rate was 74.7%. In Figure 5.

Figure 5 Ramine process

China's election workers started the research on the green-salt-salt flotation process as early as 1960. After adjusting the slurry with NaOH-Na ₂ S-Na ₂ CO ₃ or NBOH-Na ₂ CO _{3 ,} they rushed to the flotation green habitat. The simple process of flotation of the stone without de-mudging and non-washing is successful in industrial trials. The outstanding advantage of this process is the elimination of the complicated process of slurry removal and washing before the flocculation of foreign beryl flotation. The production process of the 可 series of the Cocoa Sea Concentrator in Xinjiang is the alkali process successfully developed in China, and the details will be described in the examples.

Agris developed a green living stone flotation process, which is characterized by the treatment of demineralized pulp with Na ₂ S and the addition of hot oleic acid flotation beryl. A semi-industrial test was carried out on the ore with 0.091% Be0, and a beryl concentrate containing 4.34% Be0 was obtained. The recovery rate was 81.2%. The test procedure is shown in Fig. 6.

Figure 6 Aegles test process

Third, other mineral processing methods

Radioactive beneficiation

Radioactive beneficiation is also a method for selecting green living stones. The method is based on the green radioactive stone, which is induced by r-rays. The counter will record its well-operated actuators and collect the beryl nuggets into the concentrate. Inside the slot. In 1958, the California-based plant selected this method instead of hand-selecting to produce green living stone concentrate, which is 100 tons/day.

Granular flotation

Particle floatation, also known as platform floating or floating re-election, is based on the difference in physical and chemical properties of the mineral surface. The surface of the hydrophobic mineral is concentrated by the action of surface tension. Many small bubbles form agglomerates and float on the surface. Hydrophilic minerals Sink at the bottom of the water and sort by re-election principle. Granular floatation is widely used in China's tungsten- tin- selection plant, and its main equipment is a granular floating shaker or chute.

The particle floatation method has also been applied in the selection of beryl ore. Since the 1950s, the Jiangxi Thrush, Dangping and Pangushan tungsten mines have been tested and used to select low-grade beryl concentrates obtained by hand selection. Its general process is: selected from low-grade ore closed hand crushed less than 2 mm, was added after desliming sodium oleate, coal oil collector slurried, and then allowed to stand for about two hours, and finally with a floating grain chute. Usually, the beryl fines with a grade of about 9% Be0 can be obtained by the coarse-sweeping, and the recovery rate is 85% to 90%. Figure 7 shows the granulation process of a low-grade concentrate of Green Residence Stone in a factory in Jiangxi. The final concentrate grade is 9.28% BeO, and the recovery rate is 90%. This method has limited application due to its high labor intensity and high drug consumption.

Figure 7 Granulation flotation process

Magnetic separation

Magnetic separation is an auxiliary method for removing magnetic impurities from beryl concentrates to improve concentrate grade. As mentioned earlier, some of the minerals associated with beryl, such as garnet, tourmaline, hornblende and biotite, have similar planktonic properties to beryl, and some flotation processes often fail to reach them with beryl. Effective separation, however, these minerals are weakly toxic, and they can be selected from the beryl concentrate to improve the quality of the beryl concentrate.

Grinding method

According to the high hardness (7.5-8) of beryl, when it is together with softer (such as mica schist, talc ), using the hardness between them, the selective grinding is used to make the fragile gangue mineral fine. While the beryl is coarsely divided, the initial separation can be achieved by means of sieving. The process is shown in Figure 8. Figure 8 shows the principle of selective grinding.

Figure 8 Selective grinding principle process

In addition, many mineral processing workers have carried out a lot of other research work on beryl beneficiation. For example, electrostatic beneficiation tests have been carried out with beryl ore with a particle size of 0.4 to 1.6 mm: sodium hydroxide, hydrofluoric acid and fatty acids have been used successively. The ore was processed, then subjected to low-temperature roasting, and finally subjected to electrostatic beneficiation rough selection and selection. The result was selected from the ore containing 0.46% BeO, and the beryl concentrate with a grade of 11.4% BeO was recovered, and the recovery rate was 88%. There is a lot of information about such small trials, and I won’t comment here.