The tantalum and niobium ore dressing and roughing generally adopts the gravity separation method, and the selection adopts the gravity separation, flotation, electromagnetic separation or combined process of dressing and smelting. When dealing with ores with a high content of powder or primary mud, washing operations are essential. Efficient grinding and grading equipment to reduce tantalum and niobium mineral mud.

Technical characteristics of tantalum-niobium ore beneficiation

The general chemical formula of niobium tantalite is AB2O6, and the two are collectively referred to as niobium tantalite. A is iron and manganese, and B is niobium and tantalum. The magnetic susceptibility of niobium tantalite is (22.1～37.2)×10-6. The dielectric constant of ferroniobium is 10-12, and the dielectric constant of tantalite is 7-8. The density of the mineral is 5.15 to 8.20 (increasing with the increase of tantalum content).

The beneficiation technology of tantalum and niobium ore

Gravity separation is generally used in the beneficiation of tantalum and niobium ore, and most of the gangue minerals are discarded to obtain low-grade mixed rough concentrate. Various beneficiation methods such as gravity separation, flotation, electromagnetic separation or combined beneficiation and smelting process are used for selection to realize the separation of various useful minerals.

Foreign tantalum and niobium beneficiation

When processing fine ores with high content of primary mud, washing operation is essential. The weathered pegmatite alluvial clay rougher at the Greenbush Mine in Australia has two scrubbing systems. The raw ore is washed twice with a cylindrical sieve with a diameter of 1.5m and an aperture of 10mm. The clay balls enter the self-grinding machine to grind about 4mm, and then sieve with a cylindrical sieve with an aperture of 10mm. The water consumption for ore washing is 5m3/t, and the processing capacity of the cylindrical screen reaches 350 tons/hour. Foreign tantalum and niobium concentrators attach great importance to the use of high-efficiency grinding and classification equipment to reduce tantalum and niobium mineral mud. The pegmatite primary selection plant of Greenbush Mine adopts closed-circuit circulation of peripheral discharge rod mill and vibrating screen, and has achieved good results. Canada’s Bernick Lake tantalum mine is constantly improving, and the grinding process currently used is very distinctive. The mine adopts Ф2.4m×3.6m Messi-type grid ball mill AC horizontal vibrating screen (linear screen) closed circuit, screening particle size 2.5mm, screening 0.2mm using Derek sieve, -2.5+0.2mm particle grade by screw The concentrator is sorted, and the tailings are dehydrated by the arc screen and then returned to be ground again. The ball mill has two products to form a cycle, that is, two-stage closed-circuit grinding is realized with one mill. The cyclic load rate after adjustment of the grinding circuit is generally about 180%, and a small cyclic load may easily cause over-grinding. The roughing of tantalum and niobium iron ore in foreign countries is still dominated by gravity separation, and high-efficiency gravity separation equipment is used, and the process is simple. For example, Greenbush Mine roughs -10mm raw ore directly using the jigs. In the 1980s, the gravity separation-flotation-gravity separation process formed at the Bernick Lake tantalum mine in Canada became more and more perfect. The process is still dominated by re-election, and flotation is only used to treat fine mud. The gravity separation equipment adopts GEC spiral concentrator, three-layer suspension Dyster vibrating screen, Holman vibrating screen, and cross-flow belt concentrator. In the former Soviet Union, flotation was used to separate tantalite, fine spar and topaz from gravity concentrates. The collector is hydroxamic acid, and the regulator is oxalic acid. When the Ta2O5 content is 2.52%, the concentrate grade is 27% and the recovery rate is 90%.

Domestic tantalum and niobium beneficiation (China)

1. Rough processing of tantalum-niobium ore

The grade of tantalum-niobium ore in my country is generally very low, and the minerals are brittle and dense. In order to ensure the grinding particle size and avoid over-grinding, the staged grinding stage separation process is generally adopted. Jiangxi Yichun Tantalum and Niobium Concentrator adopts horizontal arc screen instead of linear vibrating screen for screening. On-site investigation and test results show that the fineness of the upper sieve can be reduced by 14.70%, the thickness of the lower sieve can be reduced by 4.3%, and the screening efficiency can be increased by 17.72%. The successful test run of the equipment provides a new way for the on-site reconstruction of the first phase of the mill and screen. Nanping, Fujian is a large granite pegmatite deposit. In 1998, the Guangzhou Institute of Nonferrous Metals conducted a beneficiation test study on the ore, which provided a design basis for the construction of the plant. Grinding and stage sorting process. The first section uses a rod mill and forms a closed loop with a sieve to reduce over-grinding. The second-stage grinding adopts a ball mill, which forms a closed circuit with a high-frequency vibrating fine screen. In addition to strictly controlling the particle size, it can also increase the processing capacity and improve the grinding efficiency. Ore roughing adopts a single gravity separation process. Gravity separation equipment includes GL spiral concentrator, spiral chute and vibrating table. The selected raw ore contains (TaNb)2O5 0.0499%, Sn 0.0598%, the rough concentrate obtained after roughing is 0.248%, contains (TaNb)2O5 14.94% (including Ta2O5 10.79%), and the raw ore recovery rate is 0.248%. It is 74.30% (the recovery rate of Ta2O5 is 74.96%); the content of Sn is 15.71%, and the recovery rate of raw ore is 65.11%.

2. Tantalum-niobium ore beneficiation

The rough concentrate obtained by the roughing process is generally mixed rough concentrate, which needs to be further screened to separate out a variety of useful minerals. For example, Fujian Nanping tantalum and niobium first use 6% hydrochloric acid solution to clean the mineral surface, and then use weak magnetic separation to remove strong magnetic minerals and iron filings. The tantalum-niobium concentrate is obtained by a dry high-intensity magnetic separator after a rough sweep. 69.92% (Ta2O5 recovery rate 69.071%), select operation recovery rate 94.11%.

3. Flotation of fine-grained tantalum-niobium ore

Jiangxi Dajishan Tungsten Mine No. 69 ore body is a large tantalum-niobium-tungsten-tungsten granite ore body. The tantalum niobium minerals in this ore are embedded with very fine grain sizes, mostly in the 40-74 μm range. According to the beneficiation method, the recovery rate of ore dressing is relatively low, and the recovery rate of tantalum is only 25% to 33%. Guangzhou Nonferrous Metals Research Institute adopts the combined heavy flotation process to recover tantalum and niobium minerals. When the flotation feed Ta2O5 is 0.0145%, the flotation concentrate rate is 0.7%, and the concentration of Ta2O5 in the concentrate is 1.8%. The recovery rate of tantalum was 87%. The ore enrichment ratio is more than 100 times. Then re-selection enrichment, wet separation of tantalum and tungsten. The recovery rate of tantalum dressing and smelting reached 44%. The ore properties of Baotou Bayan Obo Mine are very complex, especially the niobium minerals are famous for their poor, fine and miscellaneous properties. NO3)2 is an activator, D-1 is a calcium mineral inhibitor, and the composite collector is mainly hydroxamic acid. Niobium flotation is carried out in a medium with a pH of 6, and the flotation-enriched niobium coarse concentrate is subjected to desulfurization treatment. After that, the weak magnetic vibration table process is used for beneficiation to obtain rich niobium iron ore and iron ore concentrate. The rich ferroniobium concentrate 1 contains 1.66% Nb2O5, and the concentrate 2 contains 0.59% Nb2O5, and the total recovery rate of niobium is 35.58%. After studying the rare earth flotation tailings in Bayan Obo Mine, Chen Quanyuan et al. proposed that after the rare earth flotation tailings were concentrated and deslimed, oxidized paraffin soap, water glass reverse flotation fluorite and residual rare earth minerals were added to concentrate the products in the tank. Then, ammonium fluorosilicate and paraffin soap are added to the float iron ore to obtain iron concentrate, and sulfuric acid, carboxymethyl cellulose, salicylic acid hydroxamic acid, C5-9 hydroxime are added to the iron tailings acid, oxalic acid. After roughing and three beneficiation, the niobium flotation concentrate with Nb2O5 content of 1.67% and recovery rate of 40.14% was obtained. The concentrate is then strongly magnetized to separate iron and niobium, resulting in a niobium concentrate as a non-magnetic product and a secondary niobium concentrate as a magnetic product.