CZ309484B6 - A method of obtaining concentrates of rare earth elements, niobium-tantalates, zircon and active substances by gradual gradient magnetic separation in a variable magnetic field - Google Patents

Abstract

The method of obtaining concentrates of rare earths (REE) and yttrium, niobium-tantalates, zircon and active concentrates containing Th, Hf, U, etc., including their distribution in the mixture by gradual gradient magnetic separation in a variable magnetic field, consists of gradually increasing the induction of the magnetic field in gradients of 0 to 0.25 T, 0.25 to 0.5 T, 0.5 to 0.75 T, 0.75 to 1.0 T, 1.0 to 1.25 Tesla and more, from the non-magnetic share, concentrates of niobium-tantalates, REE+yttrium, zircon and radioactive elements are formed. The weakest magnetic field (0 to 0.25 T) captures ballast ferromagnetic minerals and substances, including waste, in the magnetic portion. In the non-magnetic fraction niobotantalates, REE and zircon remain, including Th, Hf, U, etc. By applying a stronger or the same magnetic field (0.25 to 0.50 T), Nb-Ta concentrate (columbite) is obtained from this non-magnetic fraction in the magnetic fraction and in the non-magnetic fraction REE+Y and zircon. By magnetic separation under the induction of a magnetic field of 0.50 to 0.75 T, the REE+Y concentrate in the magnetic portion and the zircon concentrate in the non-magnetic portion are obtained from this non-magnetic portion. With this process, after pre-treatment by crushing, grinding and sorting, the inactive and active minerals can be separated and radioactive particles (Hf, Th, U, etc.) concentrated at higher magnetic field gradients.

Description

The method of obtaining concentrates of rare earth elements, niobium-tantalates, zircon and active substances by gradual gradient magnetic separation in a variable magnetic field

Field of technology

The field of application of the invention is the acquisition of inactive concentrates of rare earths REE and yttrium, niobotantalates, zircon and active substances such as thorium, hafnium and uranium compounds by gradual gradient magnetic separation after the separation of minerals containing REE and/or niobo tantalates and/or zircon and/or active substances according to the magnetic gradient in the created variable magnetic field.

Current state of the art

Minerals and substances are divided according to magnetic susceptibility (it is a physical quantity that describes the behavior of the material in an external magnetic field) to diamagnetic (they have low and negative values of magnetic susceptibility, for example, limestone, dolomite, quartz, graphite, galena, gypsum are included in this group , diamond, halite, kaolin, feldspar, etc.), which are not magnetizable, further to paramagnetic (they have small and positive magnetic susceptibility values, and this group includes, for example, minerals such as chlorite, pyrite, amphibole, pyroxene, olivine, biotite, etc.) and ferromagnetic, which are the most easily magnetized in a magnetic field (the best-known substances that exhibit ferromagnetism at room temperature are, for example, the elements iron, cobalt, nickel, gadolinium, and also a considerable number of alloys and non-metallic compounds). Ferromagnetic substances also include ferrimagnetic minerals, which are strongly magnetic, exhibit magnetic hysteresis, and retain remanent magnetization even when removed from a magnetic field. Such magnets include, for example, magnetite, titanomagnetite, maghemite, pyrrhotite, goethite, hematite, etc. However, the practical distribution of natural minerals and substances in the external magnetic field may not be clearly determined due to the influence of mixed minerals, inclusions and inclusions.

Dry or slurry magnetic separation is commonly used in industry to separate magnetizable materials from diamagnetic materials that do not respond to magnetic field strength. Industrially, for example, kaolins are purified from iron and titanium minerals, various metals (e.g. Li in the form of lithium mica) are obtained from ballast silicate minerals, etc. During magnetic separation, a so-called magnetic portion is always formed, where magnetized substances, elements, oxides are concentrated or minerals and the non-magnetic part, which contains non-magnetizable (diamagnetic) elements, oxides or minerals. When it comes to obtaining metals and rare elements, oxides or minerals that can be easily magnetized in an external magnetic field, the magnetic part is the main component and ballast, usually silicate or limestone minerals, are contained in the non-magnetic part. For example, patent CZ 306697 B6 "Method of obtaining concentrates of rare and strategic elements, oxides and minerals by selective magnetic separation" from 2018 describes the method of obtaining concentrates of rare and strategic elements, oxides and minerals by selective magnetic separation, when the processed material is first subjected to magnetic separation for dry in powder or wet in suspension with an induction of 1 to 5 T, characterized by the fact that after the formation of a magnetic and non-magnetic part, the magnetic part obtained in this way is selectively divided again by the action of a magnetic field weaker than 1 T (e.g. 0.1 to 0.35 T) into two parts, where in the first part there are more magnetizable substances, that is mainly ferro and ferrimagnetic substances or even mixed substances bound to them, containing substances selected from the group including mainly lithium Li, rubidium Rb, niobium Nb, etc. , and in the remaining part, as a rule, less magnetizable substances, i.e. steam and diamagnetic substances, which increases the concentration of the desired element by xide or mineral. Another example of the use of magnetic separation in the treatment of poor ores is a Japanese-Indian article from the journal Minerals (Ilhwan Park et al. (2021): Beneficiation of Low-Grade Rare Earth Ore from Khalzan Buregtei Deposit (Mongolia) by Magnetic Separation, 11-01432) , where the REE rare earths are obtained by combined magnetic separation in the fraction of 0.1 to 0.5 mm dry and in the fraction

- 1 CZ 309484 B6 up to 106 pm (0.075 to 0.106 mm) in suspension at the induction of a magnetic field of 0.8 Tesla, when REEs are obtained from low-quality raw material with a yield of up to 80%.

The essence of the invention

The subject of the invention is the process of treatment of mineral raw materials, minerals, compounds and waste products with the aim of obtaining a concentrate of rare earth elements (REE) and yttrium (Y), a concentrate of niobium tantalates, a concentrate of zircon and a concentrate of active minerals containing radioactive Th, Hf, U, etc. by gradual, gradient magnetic separation in a variable magnetic field. Using the mentioned procedure, it is possible to obtain separately or separate mineral concentrates containing these rare earths, Nb-Ta, zircon and active components carrying radioactive elements such as U, Th, Hf, etc. by the gradual effect of a selectively variable magnetic field with a gradient of 0.25 Tesla. The separated natural or waste material containing the mentioned minerals and elements of interest, after grinding and sorting to a suitable grain size, may (if the material contains light minerals such as quartz, feldspar, mica, etc.) or may not first be freed of light minerals with a density below 2.96 g/cm ³ and the heavy part with particles with a density above 2.96 g/cm ³ is then subjected to a weak effect of the magnetic field, e.g. with induction of 0 to 0.25 Tesla in dry conditions or in suspension, when the most is captured in the magnetic part (part) magnetizable particles of minerals or secondary waste (ferromagnetic and ferrimagnetic substances, e.g. magnetite, ilmenite, etc., but also in waste Fe, Ni, Co, etc.) and less magnetizable mineral particles in the "non-magnetic" part. This results in the first best magnetizable concentrate (G1), actually ballast minerals and elements in the magnetic portion. The resulting "non-magnetic" part is further, for example, in a cascade arrangement of magnetic fields from the lowest intensity (0.05 T) to the highest (up to 10 T) following a magnetic field gradient of 0.25 Tesla, subjected to magnetic separation at a higher or the same magnetic field induction ( e.g. 0.25 to 0.50 T), when a magnetic part containing less magnetizable minerals, requiring a greater strength of the external magnetic field (e.g. a concentrate of niobium-tantalate columbite is obtained) and a "non-magnetic" part containing REE+ minerals Y and zircon, which during this induction were not captured in the magnetic part in the originally "non-magnetic" portion. As can be seen, a part of the so-called originally non-magnetic part formed at a lower induction of the magnetic field can turn into a magnetic part during subsequent exposure in the same or higher selective magnetic field.

This "non-magnetic" fraction is then again subjected to magnetic separation at an even higher magnetic field strength (eg 0.50 to 0.75 Tesla). In that case, the magnetic part (with magnetizable REE minerals) will separate again, and in the "non-magnetic" part the minerals are originally non-magnetizable in a weaker field (e.g. zircon, cassiterite, etc.). By increasing the gradient of the magnetic field by 0.25 T (0.75 to 1.0 T), part of the magnetizable minerals (in the magnetic part) can be separated from this non-magnetic portion again from the resulting non-magnetic portion. Thus, per partes, it is possible to proceed further by increasing the gradient of the magnetic field with the selective separation of minerals and elements while simultaneously concentrating them.

By gradual (gradient) magnetization of the represented minerals or wastes in the mixture or separately bearing elements of rare earths and yttrium, Nb-Ta, Zr, Th, Hf, U, etc. in the resulting non-magnetic portion, the desired distribution of minerals and elements occurs and at the same time their concentration. The narrower the range of the magnetic induction gradient (0.25 T in our case), the more selectively it is possible to separate minerals and elements, including those from secondary wastes, and favorably increase their concentration. In the case of our proposal, the most magnetizable minerals (position G1) can be successfully separated from a mixture of minerals containing columbite, REE and zircon and gradually concentrated in a variable magnetic field in the described manner to obtain a niobium-tantalate columbite concentrate (at position G3), further at a higher or equal value of the magnetic field intensity, the rare earth elements REE + yttrium (G5) and at the strongest magnetic field, zircon remains in the non-magnetic portion, sometimes with inclusions of radioactive elements or even rare earths. By increasing the intensity of the magnetic field, even initially, according to the theory, non-magnetizable (diamagnetic) minerals can be magnetized and thereby converted

- 2 CZ 309484 B6 to the magnetic part (share). Even at the highest magnetic field strength, pure diamagnetic minerals remain in the non-magnetic fraction (e.g. pure zircon, quartz, feldspar, calcite, etc.). At the same time, it is clear that by gradient magnetic separation both dry and in suspension, the initially non-magnetic fraction of minerals containing niobium-tantalates and/or rare earths and/or zircon is divided into magnetic and non-magnetic parts, or also into an inactive and an active part, i.e., depending on the magnitude of the magnetic induction gradient, the minerals in the mixture can not only be divided, but also concentrated either in the magnetic or in the non-magnetic portion. Purification, and thus obtaining higher concentrations of REE+Y, niobium-tantalates and zircon, can be carried out with the same magnetic field induction by repeated magnetic separation.

Examples of implementation of the invention

Example 1 - Rare earths REE+Ya Ti minerals in quartz sand and loam.

A sample of Chlum nad Malší gravel sand with a grain size of 0 to 4 mm was gradually technologically modified to obtain a fine fraction from the hydrocyclone (overflow) with a content of about 6% mass, heavy minerals with a density above 2.96 g/cm ³ in fine dusty-sandy and clay fraction below approx. 0.50 mm. The heavy fraction in the granular fraction of approx. 0 to 0.50 mm contained ilmenite FcTiOí, rare earths REE + yttrium Y, zircon, radioactive U and Th, etc. Chemically, for example, about 41% by mass of titanium, 24% by mass of iron was found in the heavy fraction , but also about 0.24% mass. Ce, 0.12 wt%. La, 0.15 wt%. Nd, 0.04 wt%. Pr, 0.17 wt%. Y, 0.08 wt%. Zr, 0.09 wt%. V, 0.03 wt%. Sc, but also 0.009 wt%. Th, 0.008 wt%. U, etc. According to the proposed solution, the goal was to divide and concentrate ilmenite as a source for the production of titanium white (white filler) - concentrate No. 1, to further obtain concentrate No. 2 REE+Y and concentrate No. 3 zircon. After magnetization with the weakest magnetic induction gradient of 0 to 0.25 Tesla, a concentrate of Fe and Ti compounds, the best magnetized (ilmenite), was obtained in position G1 as a magnetic fraction. In the non-magnetic part (position G5), for example, the concentration of rare earth REEs (e.g. 0.58 wt.% Ce, 0.29 wt.% La, 0.28 wt.% Nd, 0.08 wt.% Pr) and 0.4% mass. Y, then 0.18% mass. Zr, 0.12 wt%. V, but also 0.04% by mass, radioactive Th, 0.02% by mass. U etc. After further dry magnetic separation of this non-magnetic part during the induction of mag. field of 0.25 to 0.50 T, a non-magnetic fraction was obtained in position G5 with a favorable extremely increased content of REE+Y (e.g. 2.2 wt.% Ce, 1.2 wt.% La, 0.94 wt.% Nd , 0.3% wt. Pr and 1.73% wt. Y), but also e.g. 0.44% wt. V, 0.92 wt%. Zr, 0.46 wt%. Th, 0.05 wt%. U, etc. Thus, titanium and REE+Y concentrates were obtained. In addition, the main product of the treatment of clay and dust-fine sandy overflow from the hydrocyclone is, after reducing the content of Fe and Ti compounds, high-quality fire-resistant earthenware clay. The results of the gradient magnetic separation adjustment procedure are presented in Table I.

Table I - Chemical analysis of the non-magnetic heavy fraction (above 2.96 g/cm ³ ) Chlum nad Malší after gradient SMS

Gradient mag. field (Tesla) non-magnetic heavy fraction ce % La% Nd % Pr % Sm % Gd% Y % Zr % IN % Th% at % 0 heavy share 0.24 0.12 0.15 0.04 0.17 0.08 0.09 0.009 0.008 0 to 0.25 0.58 0.29 0.28 0.08 0.39 0.18 0.12 0.04 0.02 0.25 to 0.50 2.21 1.22 0.94 0.44 1.73 0.92 0.44 0.46 0.05 0.50 to 0.75 5.00 2.42 2.23 0.60 0.43 0.39

Note Sm, Gd heavy rare earths

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Example 2- IB 2 Sierra Leone columbite, REE and zircon

A sample of natural niobium tantalate from Sierra Leone contained about 53% by weight. columbite mineral, 16 wt.% ilmenite, 12 wt.% zircon, 8 wt.% rutile, 3.5 wt.% monazite, garnet, quartz, etc. Chemically, for example, about 20 wt.% Fe2O3, 20 wt% T1O2, 8.5% wt. Ta2O3, 18.9 wt% Nb2O3, 11.5 wt% ZrO2, 1.7 wt% P, 0.7 wt% Nd2O3, 0.16 wt% Y, 0.69% wt. ThO2, etc. After inserting a natural material with a grain size of 0.1 to 2 mm into a device with a variable magnetic field of 0 to 0.25 T (positions G1 and G2), 0.25 to 0.5 T (positions G3 and G4) and 0 .50 to 0.75 T (position G5) concentrates were obtained: ilmenite FeTiOs (up to 60% by weight)/Gl+G2/ at a yield of about 25% by weight, columbite concentrate (up to 91% by weight)/G3+G4 / at a yield of about 53 wt.% and REE+Y rare earth and zircon concentrate (27.5 wt.% monazite, 56 wt.% zircon, etc.)/G5/ in an amount of about 22 wt.%. In addition, active minerals with a content of up to 1.68% by weight were concentrated in the non-magnetic part of G5. ThO2. Table II presents the results of a gradual, gradient dry magnetic separation of the non-magnetic portion of sample IB2. It is clear from it that even without gravity sorting and obtaining the heavy portion, it was possible to divide and concentrate natural niobium-tantalate into at least three usable products: ilmenite concentrate, niobium-tantalate concentrate with an increase in the columbite mineral from 53 wt.%. to 91% by weight, i.e. an increase of approx. 38% by weight and REE+Y concentrate (e.g. 5% by weight CeO2, 1.44% by weight Nd2O3, etc.), but also zircon (up to 48% by weight) with active mineral content (e.g. 1.32% by weight HfO2, 1.68 wt% ThO2, etc.). By further gradient magnetic separation, it is possible to further separate the non-magnetic portion of G5 into only REE+Y concentrate from the zircon concentrate with active minerals in the inclusions, and after further treatment and the action of a higher magnetic field gradient, separate the inactive part (zircon) from the active part (radioactive Th, U, Hf etc.).

Table II - Diffraction mineralogical analysis of selected minerals of interest obtained in fractions after gradient SMS (recalculation is not 100%)

Gradient mag. field (Tesla) yield % wt columbite zircon monazite ilmenite rutile 0 Original sample 100 53 12 3.5 16 8 0 to 0.25 G1+G2 Ilmenite strongly magnetic fraction 25 11 3 38 2 0.25 to 0.50 G3+G4 columbite weakly magnetic fraction 53 92 1.8 0.25 to 0.50 share of G5 REE+Y+zircon+active min. non-magnetic fraction 22 55.8 26.7 7.6

Example 3 - REE + Y in albitic rock Hűrka

A prospective deposit of rare earth elements REE and yttrium is the feldspar (albitic) rock of Hůrka near Rakovník. The task was to separate and concentrate minerals with REE+Y content in mineralogically and technologically complex raw material with a predominance of sodium feldspars. After crushing and sorting the 0.1 to 0.5 mm grain size fraction, a heavy portion of TM was obtained after separation in a heavy liquid with a density above 2.96 g/cm ³ , which was further subjected to gradient magnetic separation in narrow bands of a variable magnetic field from 0 to 0.25 T (G1 and G2 positions with the most magnetizable minerals), 0.25 to 0.50 T (G3 and G4 positions with less magnetizable minerals) and G5 positions with a non-magnetic fraction at the same magnetic field induction. Table III shows the results achieved. The table shows that the REE+Y rare earths obtained from the heavy fraction are concentrated in the non-magnetic fraction G5 (up to 0.96% by weight in total), after treatment in a selective magnetic field with a gradient of 0 to 0.25 Tesla, they were captured in the magnetic fraction the most magnetizable particles with a yield of about 44 wt.%, in the non-magnetic fraction

-4CZ 309484 B6 with a gradient of 0.25 to 0.50 Tesla, for example, the Ce content was increased from the original about 800 ppm (Ij. 0.08% by weight) to 0.45% by weight, lanthanum La from about 600 ppm (0 .06 wt.%) to almost 3000 ppm, Ij. 0.3 wt% By repeated gradient magnetic separation with the same induction of the magnetic field, the magnetic fractions G1 to G4 can also be "purified" and a further increase in REE+Y and zircon can be obtained, which can be separated from the REE after the application of a higher magnetic field gradient (e.g. 0.75 to 1 Tesla) +Y to obtain a zirconium concentrate (see example no. 4).

Table III - Chemical analysis of the mixture of heavy minerals with a density above 2.96 g/cm3 of well JK-1 after gradient magnetic separation (R+Y is REE+Y).

Sample wt% share Zr Y La Ce Pr Nd REE+Y PPm PPm PPm PPm PPm PPm PPm Well JK-1 mixture TM G1 19.7 4984 79 <LOD 405 <LOD <LOD 484 Well JK-1 mixture TM G2 24.2 2674 228 361 575 <LOD <LOD 1164 Well JK-1 mixture TM G3 33.3 2936 428 1287 2053 <LOD <LOD 3768 Well JK-1 mixture TM G4 9.1 9355 727 2207 3190 <LOD <LOD 6124 Well JK-1 mixture TM G5 13.7 99050 833 2997 4517 415 813 9575

Note: <LOD below detection limit

Example 4 - Obtaining Zr zirconium concentrate, or ZrSiCE

An increased Zr zirconium content was found in the Hůrka raw material, which can be significantly increased by gradient magnetic separation in a selective, variable magnetic field to obtain a Zr concentrate (see example and 3). After repeated dry magnetic separation of G1-G4 fractions at the same induction gradient of 0.25 to 0.50 Tesla, the REE+Y concentration increased to 1.96% by weight. and the concentration of Zr at about 115,000 ppm, i.e. 11.5% by weight. Zr. Our next task was to separate the REE+Y rare earth elements from each other and concentrate zircon separately. For this, a gradient magnetic separation of the non-magnetic portion of G5 was used at a magnetic field strength of 0.50 to 0.75 Tesla. In this way, a concentrate of rare earths and yttrium was obtained in the magnetic part and a concentrate of zircon in the non-magnetic part. Table IV presents the results.

Table IV - Chemical analysis of the non-magnetic heavy fraction (above 3.3 g/cm ³ ) after dry gradient magnetic separation (SMS)

Gradient mag. Field (Tesla) non-magnetic heavy fraction G5 ce % La % Nd % Pr % Y % Zr % IN % G5 after repeated SMS 0.98 0.65 0.08 0.04 0.2 11.5 0.23 0.50 to 0.75 G3 magnetic fraction 1.55 0.88 0.35 0.12 0.54 0.25 0.55 0.50 to 0.75 G5 non-magnetic p. 0.1 0.03 25.8 REE+Y concentrate 3.4 4% wt. concentrate Zr 25.8 wt%

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Example 5 - Separation of rare earths REE, zircon and radioactive elements Ef U and Th

Raw material IB 2 from Sierra Leone rich in rare earth elements, zircon and active elements such as hafnium, uranium and thorium was subjected to gradient magnetic separation in a selective magnetic field and after removing the magnetic part G1+G2 at induction of 0 to 0.25 Tesla, it was after applying gradient of 0.25 to 0.50 Tesla obtained a concentrate of niobium-tantalate columbite with a content of 17.5 wt.%. Ta2O3 and almost 40 wt.% Nb2O3 (position G3+G4). In the non-magnetic portion, a concentrate of zircon, rare earth REE and active minerals containing U, Th, Hf, etc. was obtained in position G5. By applying a higher magnetic field gradient of 0.50 to 0.75 Tesla, this non-magnetic portion was divided into a magnetic part with REE+Y concentrate and a non-magnetic part with zircon and radioactive elements concentrate.

The effect of a higher magnetic field gradient of 0.75 to 1.0 Tesla on the resulting non-magnetic fraction led to selective separation and the formation of almost a zircon concentrate with a content of about 68.5% by weight. ZrO2 mixed with active minerals (e.g. content of radioactive ThO2 up to 3.6% by weight, 2.3% by weight HfO2) in the non-magnetic portion and concentrate of rare earths and yttrium REE+Y in the magnetic portion G3 with a high content of cerium compounds ( 8.55 wt% CeO2) and neodymium (2.65 wt% Nd2O3). Active minerals from inclusions in zircon in the non-magnetic part were separated from the zircon in suspension after treatment by crushing, grinding and sorting after applying an even higher magnetic gradient of 1.0 to 1.2 Tesla. In the non-magnetic part there is a concentrate of zircon and in the magnetic part there is a concentrate of radioactive elements.

Table V shows the composition of the almost inactive zircon concentrate in the non-magnetic portion (up to 68.5 wt.% ZrO2) and the active mineral concentrate with a high content of thorium, hafnium and uranium minerals.

Table V - Chemical analysis of the non-magnetic fraction (above 3.3 g/cm ³ ) of IB2 (Sierra Leone) after gradient SMS and obtaining the inactive part (zircon) and the active part (Hf, Th, U)

Gradient mag. field (Tesla) non-magnetic fraction ZrO ₂ % Ta2O3% Nb2O3 % ThO ₂ % HfO ₂ % at % CeO ₂ % Nd2O3% IB2 original 11.40 8.49 18.89 0.69 0.049 0.71 0 to 0.25 G1+G2 0.92 5.15 10.65 0.85 0.049 0.93 0.25 to 0.50 G3+G4 1.76 17.47 39.48 1.13 0.112 1.29 0.35 0.50 to 0.75 G5 REE+zircon+active 47.98 0.28 0.36 1.68 1.32 0.100 5.03 1.44 0.75 to 1.0 G3 REE+Y 0.52 0.05 0.20 0.21 0.33 8.55 2.65 0.75 to 1.0 G5 zircon+active min. 68.52 0.02 0.08 3.55 2.34 0.25 0.32 0.12

By combining gradient magnetic separation in a variable magnetic field in the dry state in fractions of 0.1 to 0.5 mm and after breaking the zircon inclusions in the wet state in suspension, the separation of individual concentrates of ilmenite FcTiOí, REE+Y, zircon and active minerals was achieved. The method of obtaining them is elegant and environmentally sound.

Example 6 - Columbite in South Bohemian granite of the Nakolice deposit

The extraction of niobium-tantalates (columbite) from South Bohemian granite deposits (e.g. Nakolice, Homolka) was carried out from a crushed and coarsely ground sample of sodium feldspar Nakolice TBN 085 after obtaining a heavy fraction with a mineral density above 2.96 g/cm ³ in the granular fraction 0 up to 1 mm. The heavy portion in the amount of about 0.17% by weight. (see table VI properties) was subjected to a magnetic gradient

-6CZ 309484 B6 separation in a variable, selective magnetic field of 0 to 0.80 Tesla. In the field with the lowest magnetic gradient of 0 to 0.25 T (weak magnet), a strongly magnetic fraction of G1 and G2 with a high content of Fe and Mn minerals was captured. Niobium-tantalate columbite concentrate was obtained in the weakly magnetic part G3 with a gradient of 0.25 to 0.50 T (stronger magnet) and in the non-magnetic part an apatite concentrate accompanied by REE+Y minerals was obtained.

Table VI - Chemical and mineralogical analysis of the heavy fraction (above 2.96 g/cm ³ ) before and after gradient SMS

Gradient mag. field (Tesla) Heavy share Yield % Nb % that % Colombia % Apaiiii % CH % Fe% Mn% Note 0ΤΡ 0.17 0.27 0.22 0.5 79 6.5 35.6 4.88 Gradient magnetic separation Nb % that % Colombia % Apaiiii % CH % 0 to 0.25 T G1 0.016 53 66.5 8.62 Magnesium content 0.25 to 0.5 G3 4.12 3.10 4.5 Magnesium fraction 0.25 to 0.5 G5 0.043 90.5 Non-Magneic p.

Note: CH-childrenite

Example 7 - Zircon and REE+Y in decay sediments (sands, clays)

In Chlum nad Malší in South Bohemia, in the locality of Ločenice, rare earths and ilmenite were found in fine, disintegrating quartz and clay fractions falling off during the production of gravel, sand and sand. After obtaining the overflow fraction from the hydrocyclone under the trademark sand 0/1 mm, the overflow fraction in the grain size of about 0 to 0.50 mm was first subjected to the removal of clay in the fraction below 0.063 mm. A fine sandy fraction of 0.063 to 0.50 mm was then separated in a heavy liquid with a density of 2.96 g/cm ³ with a yield of about 5.6% mass. Then, a gradient magnetic separation in a variable magnetic field was performed on the heavy portion with mineral density greater than 2.96 g/cm ³ . Table VII shows the results achieved. First, ilmenite FeTiOs concentrate was obtained from the heavy portion in the magnetic portion at a magnetic field gradient of 0 to 0.25 Tesla in the G1 portion. At a gradient of 0.25 to 0.50 Tesla, a concentrate of rare earths REE and yttrium Y under the designation G5 with a content of about 0.58% mass was obtained in the non-magnetic fraction. Ce, 0.29 wt%. La, 0.28 wt%. Nd, 0.41 wt%. Y, etc. After repeated gradient magnetic separation of the non-magnetic fraction at the same magnetic field gradient of 0.25 to 0.50 Tesla, a concentrate of rare earths and yttrium G5* with an increased content of Ce, La, Nd and Pr was obtained with a total amount of REE+Y up to 6 .2% mass.

Table VII - Chemical analysis of the heavy fraction with mineral density above 2.96 g/cm ³ (Chlum nad Malší, Ločenice location) and after gradient magnetic separation in suspension in the 0.063 to 0.50 mm fraction

Grading mag. field (Tesla) non-magnesium heavy fraction ce % La % Nd % Y% IN% sc % Zr % Fe % Ti% 0 heavy share 0.243 0.123 0.146 0.172 0.085 0.034 0.077 23.52 40.96 0 light share 0.006 0.002 0.002 0.002 0.480 0 to 0.25 G1 0.051 0.025 0.034 0.091 0.043 0.051 25.67 40.10 0.25 to 0.5 G5 0.583 0.287 0.280 0.405 0.119 0.041 0.172 0.25 to 0.5 Gl* 0.046 0.018 0.176 0.089 0.039 0.042 24,21 43.51 0.25 to 0.50 G5* 2,121 1,131 0.935 1,728 0.447 0.066 0.922

* repeated magnetic separation at the same magnetic field gradient

G5* Pr content is 0.294% by weight.

Example 8 - REE+Y in elm sediments of Čavyn, wet treatment in suspension

The rare earth elements REE and yttrium Y, as well as zircon Zr, are found in fine sands and clays in South Bohemian gravel-sand sediments. The sample from Čavyn near the Blaníce river was first chemically analyzed according to grain size fractions and subsequently freed of clay below 0.063 mm. The rest above 0.063 mm consisting of fine, dusty to sandy quartz and feldspar was stripped of the light fraction in a heavy liquid with a density of 2.96 g/cm ³ . On the heavy portion with a density above 2.96 g/cm ³ , a gradual gradient magnetic separation was carried out in suspension in the particle size fraction of 0.063 to 2.0 mm. When a magnetic field of 0 to 0.25 Tesla was induced, the most magnetizable particles with a high Fe content were removed in the magnetic fraction.

Table VIII - Chemical analysis of the original fractions of Čavyné gravel-sand clay and heavy 15 minerals with a density above 2.96 g/cm ³ after gradient magnetic separation.

Sample AI Fe Approx Zr Y La Ce Pr Nd REE+Y % % % ppm PPm PPm PPm PPm PPm PPm original sample 11.73 1.69 505 25 fraction 0.25 to 2.0 mm 4.09 0.75 44 0.10 to 0.25 6.86 0.60 111 8 0.063 to 0.1 7.84 0.81 332 19 62 81 0.045 to 0.063 7.54 0.92 1139 60 83 138 281 Fraction below 0.045 13.10 2.80 0.09 677 34 53 136 223 0 to 0.25 T Share G1 5.19 23.03 0.57 273 259 259 0.25 to 0.5T Mag.p.G3 7.50 26,24 5.35 476 3910 957 1800 749 7416 0.25 to 0.5T Non-mag.p. G5 12.00 3.5 0.88 61,235 96 1437 2595 556 5584 0.25 to 0.5T Mag. share of G3 bear. bear. 10.2 22 5698 2566 4588 455 1277 14,584 0.25 to 0.5T Non-Mag. share G5** bear. bear. bear 122,344 66 45 122 32 265 0.25 to 0.5T Magnet, proportion G3** bear. bear. bear 322 2557 4277 344 1155 8656

* from the magnetic part of G3 ** from the non-magnetic part of G5 not available - not determined

-8CZ 309484 B6

The obtained non-magnetic portion was subjected to a higher magnetic field gradient of 0.25 to 0.50 Tesla to obtain the first concentrate of rare earths and yttrium REE+Y G3 with a total amount of REE+Y of about 0.74 wt%. (of which up to 0.39 wt.% Y) and non-magnetic concentrate G5 with a high zircon content (up to 6.1 wt.%) with remnants of unseparated REE particles (still about 0.56 wt.% in total). In order to obtain even this amount of rare earths, the non-magnetic portion was repeatedly subjected to gradient magnetic separation at the same induction of 0.25 to 0.50 Tesla. This resulted in a second REE+Y concentrate with a content of up to 0.87% by weight in the magnetic fraction G3**. rare earths and in the non-magnetic portion G5** zircon concentrate with a content of up to 12.2 wt.% Zr. By gradient magnetic separation of the first magnetic fraction as a concentrate of rare earths and yttrium (see 0.74% by weight) in a variable magnetic field at the same induction of 0.25 to 0.50 Tesla, the highest REE+Y G3* concentrate with a content of up to 1, 46 wt% REE+Y. By merging the G3* and G3** concentrates, a total concentrate of rare earths and yttrium was obtained with a content of up to (0.87 + 1.46% by weight) 2.33% by weight. REE+Y. By processing the Čavyně gravel-sand clay, in addition to the main product of washed gravel-sand and sand 0/4 and 0/1 mm and waste, further usable ceramic clay in the fraction below 0.063 mm, two rare concentrates were obtained: the first REE rare earth concentrate (e.g. 0.88% cerium by weight Ce, over 0.5% by weight of lathane La, about 0.24% by weight of neodymium Nd, etc.) and yttrium (e.g. up to 0.57% by weight of Y) and zirconium concentrate (12.2% by weight .Zr).

Example 9 - Combined, dry and wet treatment of rock with REE+Y

The various sources of rare earths in Hůrka's albitic rock (fluorocarbonates such as bastnaesite, monazite, zircon, apatite, xenotime, etc.) enable their extraction and concentration by a combination of dry and wet magnetic separation in a variable magnetic field using a selective, gradient method. Well-releasable minerals bearing REE+Y are obtained after crushing and sorting the grain fraction of 0.1 to 0.5 mm after separation of the heavy, but also the light fraction by dry gradient magnetic separation, when the magnetic fraction of heavy minerals is first removed in the weakest magnetic field with a gradient of 0 to 0.25 Tesla ballast minerals with a high content of Fe, Mn, Co, Ni, W, etc. The non-magnetic heavy fraction is then subjected to gradient magnetic separation at a higher value of magnetic induction (0.25 to 0.50 T). This results in a REE+Y concentrate in the magnetic part, and in the resulting non-magnetic part, e.g. diamagnetic minerals such as zircon (if it does not contain inclusions), cassiterite, etc. are concentrated. A fine portion of REE+Y or a finely ground or otherwise delaminated portion (due to heat, ultrasound, etc. .) formed after treatment of the grain size fraction of 0.1 to 0.5 mm in the grain size fraction of 0 to 0.1 mm (0 to 100 μm) is subjected to wet gradient magnetic separation in suspension. The resulting fine fraction below 0.1 mm no longer contains REE+Y conglomerates with magnetizable and non-magnetic minerals in both heavy and light proportions, and in the liquid state it can be magnetically divided in a suitably chosen magnetic field gradient. In a weak field (0 to 0.25 T), for example, ilmenite, magnetite, childrenite and other metallic minerals are removed from the mixture. By further increasing the gradient of the magnetic field between 0.25 and 0.50 T, resp. even 0.5 to 0.75 T and even 0.75 to 1.0 T or up to 1 to 1.25 Tesla after the action on the always arising non-magnetic part accumulates REE+Y in the magnetic part or when applying the same magnetic field induction to the concentration of RE+Y in the non-magnetic fraction.

Example 10 - Secondary waste material - ash and fly ash after combustion or gasification of coal containing REE+Y

By air sorting ash or ash formed after gasification of coal at a temperature of 700 °C, containing rare earths and yttrium, a REE+Y concentrate in a particle size fraction of 40 to 100 μm was obtained by air sorting, which was further subjected to gradient magnetic separation in a variable magnetic field with a gradient of 0 .25 Tesla. At an induction of 0 to 0.25 Tesla, a REE+Y concentrate with a content of 567 ppm (350 ppm Ce, 137 ppm La and 80 ppm Y) was obtained in the magnetic part G1 and a silicate residue in the non-magnetic part. After burning brown coal at a temperature of up to 1350 °C to 1400 °C, a REE+Y concentrate was obtained in suspension from the resulting ash in the magnetic fraction G1 after performing magnetic separation at a gradient of 0.25 Tesla and in the non-magnetic fraction

- 9 CZ 309484 B6 a concentrate of refractory sillimanite AI2SÍO5 was obtained. After repeated gradient magnetic separation of the non-magnetic portion at an induction of 0.25 to 0.5 Tesla, a concentrate with a content of up to 50% by weight was obtained. sillimanite in the non-magnetic part of the sample and the secondary REE+Y concentrate in the magnetic part of the sample.

Claims (1)

PATENT CLAIMS 1. A method of obtaining inactive concentrates of minerals, oxides and rare earth elements (REE) and yttrium, niobium-tantalates, zircon and active concentrates by gradual gradient magnetic separation in a variable magnetic field, when first the processed natural or secondary waste material is crushed and sorted into a suitable grain size is first removed from light minerals and the heavy part with particles with a density above 2.96 g/cm ³ is then subjected to a weak effect of a magnetic field, e.g. with induction of 0 to 0.25 Tesla in dry conditions or in suspension, and the resulting non-magnetic part is subjected to gradual magnetic separation in a gradient of 0.25 Tesla at induction 0 to 0.25 T, 0.25 to 0.5 T, 0.5 to 0.75 T, 0.75 to 1.0 T dry and/or wet in suspension at the same and/or increasing magnetic field induction of up to 1 T, characterized by the fact that after the formation of the magnetic and non-magnetic portion, the non-magnetic and/or i the magnetic part is selectively divided again by the action of a stronger or the same gradient of the magnetic field into two parts, where the first part contains more magnetizable substances and the remaining part usually less magnetizable substances.