Method for processing of loparite concentrate

 

(57) Abstract:

The method relates to metallurgy and is the grinding of the concentrate to the size of particles of at least 0.075 mm classification, the opening of loparite concentrate weak 47 - 55% nitric acid at 115 - 118C and continuous movement of the pulp through a number of series-connected reactor volumes. Obtained at autopsy concentrate hydrated cake oxides of refractory metals washed with water to obtain pure hydrate cake and combined nitrate solution of rare earth elements with impurities and activity, which neutralize and inactivate with translation in the sediment of all impurities, including thorium, mesochori. Net nitrate solution of rare earth elements is treated with soda and the amount of precipitated carbonates of rare earth elements. Recycling of the filtrate carry parcoy to a concentration of 500 - 600 g/l and subsequent hydrolysis at 600 - 800C To produce elemental nitrogen, oxygen and carbon dioxide in the exhaust gases, and ash, which serves to neutralize the nitric acid solution and the precipitation of the carbonate of rare earth elements, while the exhaust gas is subjected to scrubbing with water, after che is 2">

The invention relates to hydrometallurgical processing ore concentrates, and more particularly to the processing of loparite concentrate.

Loparite concentrate is a complex raw material containing oxides of a large number of chemical elements. Used for processing of loparite concentrate brand CL-1 with the contents of loparite at least 95% in accordance with the applicable specifications contains, wt%:

The oxide of tantalum (Ta2O5) - 0,57

The oxide of niobium (Nb2O5) - 8,14

The titanium oxide (TiO2) of 38.1

The oxides of rare earth metals cerium group, mainly oxides of lanthanum (La2O3), cerium oxide (Ce2O3) oxide, praseodymium (Pr2O3), neodymium oxide (Nd2O3) - 32

The sodium oxide (Na2O) - 7,9 - 9,06

Calcium oxide (CaO) - 4,2 - 5,7

The strontium oxide (SrO) - 2,3 - 3,0

Iron oxide (Fe2O3) - 2,0 - 2,5

Silicon oxide (SiO2) - 1,95 - 2,5

Aluminum oxide (Al2O3) - 0,6-0,7

The oxide of potassium (K2O) - 0,26 - 0,75

The oxide of phosphorus (P2O5) - 0,15-0,22

The source of alpha radiation - thorium oxide (ThO2) - 0,54

From loparite concentrate extract the most cenestin method for processing of loparite concentrate using concentrated sulfuric acid for the opening of loparite (see A. N. Zelikman and other metallurgy of rare metals, M.: metallurgy, 1991, S. 101, 103-105).

Sulfuric acid method is based on the decomposition of loparite concentrate with sulfuric acid and separating valuable components using differences in solubility of double sulfates of titanium, niobium and tantalum, rare earth elements with sulfates of alkali metals or ammonium. Source loparite concentrate is ground to a particle size of not less than 0.075 mm and subjected to classification. The opening of the concentrate is carried out using 95% sulfuric acid, spent based 2,78 t 1 t powdered concentrate. To prevent sintering of the reacting mass and improve recovery solution of niobium and tantalum to sulfuric acid is added ammonium sulfate (0.2 tons per 1 ton of concentrate). In the opening, occurring at a range of temperatures up to 270-280oC, niobium and tantalum in the presence of large quantities of titanium are part of the double sulfates of titanium in the form of isomorphic admixture. Rare earth elements are part of the double sulphates REE-R2(SO4)3(NH4)2SO4. Product sulfatization - sulfate spec subjected to water leaching. As a result, in the solid phase remain off Bukovina presence in poprice source of alpha-emitting thorium Th, divided between the solid and liquid phases by 50%.

For the separation of titanium from niobium and tantalum using precipitation with ammonium sulfate insoluble titanium salt (NH4)2TiO(SiO4)2H2O. In the sediment stands out 70-80% of the titanium content in the solution. Double sulfate of titanium is used as an effective tanning agent in the leather industry. Thermal him decomposition receive technical titanium dioxide. Remaining after separation of the titanium salt solution, referred to as the sulfuric acid mother liquor contains tantalum and niobium. This solution is subjected to fluorination 40% HF. Then for the extraction of tantalum and niobium in the process of dividing extraction 100% tributyl phosphate TBP. To enable subsequent extraction of rare earth metals conduct additional independent technological cycle of conversion of double sulfates of REE carbonates.

This method of processing of loparite concentrate has a number of significant drawbacks. The main of them is immediately at the first stage of processing - the showdown concentrate showdown and the release of the most valuable tantalum and niobium, go into solution, which again is from the most valuable components of the less valuable the double sulphate REE, which takes in various forms up to 25-30% of tantalum and niobium. To return tantalum and niobium is necessary to carry out additional processing of the dump cake remaining after the processing of double sulphates REE. In addition, there irretrievable loss of tantalum and niobium with crystals of titanium salt when salting out from sulfuric acid solution of tantalum, niobium and titanium. Furthermore, the method is sequential, consisting of separate periodic stages that cannot be automatically combined into a single control circuit. All this makes the method complicated and expensive.

All these drawbacks are eliminated in the method for processing of loparite concentrate on the patent of Russia No. 2145980 from 27.07.99 by M. CL.7C 22 B 59/00, which was developed by the applicant and is the prototype of the claimed invention.

In accordance with this method the original loparite concentrate is ground to particle sizes of not more than 0.075 mm by wet grinding with the classification of the particles and the thickening of the pulp loparite concentrate to paste with a moisture content of about 33%.

Opening loparite concentrate implement special 70-75% nitric acid when the source is ramadani pulp through a number of series-connected reactor volumes. In the opening of concentrate nitric acid is produced nitrate slurry of hydrated oxide oxides of refractory metals (GCP) and the United nitric acid solution of rare earth elements (REE) with impurities and activity. Then nitrate hydrate slurry cake is diluted with water to 1.5-2.0 times and cooled to a temperature of t=40-50oC. After cooling are filtered solution of nitrate slurry of hydrated oxide and its subsequent washing with clean water from nitrate solutions of nitrates of rare-earth elements and impurities.

Pure hydrated cake is the starting product for the production of a refractory oxides of metals. Methods for producing oxides of refractory metals from hydrate cake is protected by a separate patent, and therefore in this application will not be considered. United nitric acid solution of rare earth elements with all the impurities (Na, Ca, Sr, Fe, Si, Al, K, P) and activity (thorium Th, mesochori MsTh or that the same isotope of radium Ra228) is subjected to decontamination, which is not difficult. For this first solution serves soda solution to neutralize the nitric acid. Then served ammonium sulfate (NH4)2SO4and barium nitrate Ba(NO3Satori. The process of neutralization and decontamination is performed at a temperature of t=70-80oC and a pH of 4.5-5.0 for 6-8 hours Followed by filtration of the solution are removed telesotherapy cake containing all the activity, all the iron, calcium and strontium. Selected active telesotherapy cake is subjected to processing and subsequent disposal in the workings of the mine. Remaining in the filtering net nitrate solution REE is the initial product to extract the carbonates of rare earth elements. This rare earth elements collectively precipitated with a solution of soda in the form of the sum of REE carbonates and filtered. The filtered wet carbonates of rare earth elements are finished products. Their processing is carried out by well-known specialists principles, and therefore is not considered here. The remaining filtrate is a solution of sodium nitrate mixed with nitrates of alkaline earth elements (Ca, Sr) are subject to mandatory recycling due to its extreme danger to the environment. The solution is disposed of by obtaining from it by the method of residues acute ferry low nitrogen fertilizer with impurities.

Compared to sulfuric acid technology periradicular stage of dissection provides a complete single branch of the most valuable components of tantalum, niobium and titanium, from less valuable rare earth elements and impurities. The most valuable components remain almost immediately clean from radioactivity. The obtained hydrated cake GCP and nitrates REE are suitable for further processing. The method is compared with the prototype significantly reduced number of technological operations, which form a continuous chain that permits them to be in continuous operation with full automation and control.

For all its advantages prototype method has one disadvantage. It is that opening loparite concentrate, crushed wet grinding and being in the form of paste with a moisture content of about 30%, is possible only special 70-75% nitric acid. This is because only such concentrated acid diluted with water present in the paste-like concentrate, provides the initial concentration of acid in the pulp C=600-700 g/l, required for dissection. This special 70-75% nitric acid belongs to the category of highly toxic substances (VP) with all the ensuing consequences, for example:

- difficult and expensive is ivemy warehouses limited capacity not exceeding 500 tons, with ventilation, etc.;

danger when working with the acid of such concentration.

The present invention was used to develop the method for processing of loparite concentrate, in which an autopsy would be carried out under such conditions as to ensure the possibility of reducing the concentration of nitric acid, and the remaining filtrate was disposed of would be suitable for use in the method, providing the technical result - the reduction of processing costs loparite concentrate, reducing cost and increasing efficiency of the production as a whole.

The technical result is achieved in that in the method for processing of loparite concentrate, including the grinding of the concentrate to the size of particles of at least 0.075 mm classification, opening loparite concentrate nitric acid at a temperature 115-118oC and continuous movement of the pulp through a number of series-connected reactor volumes, washing with water hydrated oxide oxides of refractory metals, obtained at autopsy of concentrate to produce pure hydrate cake, used for further processing, and United is vazio transfer to precipitate the impurities, including thorium and mesochori, separating the solution by filtration on telesotherapy cake with all the impurities, recycle and disposal, and net nitrate solution of rare earth elements, their deposition soda as the sum of carbonates of rare earth elements and separating by filtration the quality of the finished product, the subsequent processing for disposal of the remaining filtrate, representing a solution of sodium nitrate mixed with nitrates of rare-earth elements, it is new that the loparite concentrate crushed dry grinding, air classification, and his autopsy carried out weak 47-55% nitric acid, recycling of the filtrate carry parcoy to the concentration of 500-600 g/l and subsequent hydropyrolysis at a temperature of 600-800oC to produce elementary nitrogen, oxygen and carbon dioxide in the exhaust gas, and ash, which serves to neutralize the nitric acid solution and the precipitation of the carbonate of rare earth elements, while the exhaust gas is subjected to scrubbing with water, and then discharged into the atmosphere.

Thanks to this solution is the possibility of using for opening loparite concentrate nitric acid all of this and provides a sharp decline in consumption of chemicals for the processing of loparite concentrate, reducing cost and increasing efficiency of the production as a whole.

The inventive method of processing of loparite concentrate is carried out as follows. Source loparite concentrate is ground to a particle size at least 95% of particles of not more than 0.075 mm dry grinding, for example in a ball mill, dry grinding, air classification of particles and cleaning the transport of dust from air after the cyclone. Then carry out attackone opening of the pulp loparite at atmospheric pressure weak 47-55% nitric acid HNO3at temperature t=115-118oC. the initial concentration of nitric acid in the pulp, prepared for dissection, which would in this case is the same as in the method prototype, namely C=650-700 g/l, due to the fact that the crushed dry grinding loparite concentrate does not carry moisture and water in the slurry supplied to the autopsy, not added. In this temperature range at atmospheric pressure the same way as in the method prototype is opening under the influence of nitric acid of all particles loparite concentrate. When this temperature range is as close to the point of the azeotrope mixture of nitric acid with vlname opening of particles of loparite, and maintain process temperatures above 118oC is not advisable from an economic point of view and a sharp increase in the evaporation of nitric acid.

To increase the residence time of particles loparite in nitric acid and increase the likelihood of their opening processing is carried out in a so-called cascade option. This large volume is divided into a number of small volumes and consistently connect them. This increases the residence time of the particles in the reaction volume to a predetermined value, for example 40 hours, which reduces the removal of undiscovered particles from the reaction zone. After azotnokislogo opening receive the pulp opening - nitrate slurry of hydrated oxide oxides of refractory metals (GCP). In the opening in the solution passed all the oxides of rare earth metals lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide into soluble form nitrates of rare-earth elements R(NO3)3.

At the same time in the process of opening under the influence of nitric acid in the solution is passed in the form of nitrates and all impurities loparite, including the source of the alpha-activity of the thorium oxide. The most valuable of allocated components of loparite - oxides of tantalum, niobium and the dust, becoming hydrated oxides of refractory metals - hydrate cake oxides of refractory metals. In the KEK these components are in the mixture, the same as they were in will poprice.

Thus in the opening loparite concentrate nitric acid is full of single branch of the most valuable components (tantalum, niobium), remaining hydrated Keke without any losses from the less valuable components that have fallen into the solution. When hydrated, the cake is almost free from activity, since ~95% of thorium oxide is nitric acid solution of nitrates of rare-earth elements and impurities, and therefore, if further processing is not required, a special process of decontamination cake ELEVATION. Then nitrate hydrate slurry cake is diluted with water to 1.5-2.0 times and cooled to a temperature of t=40-50oC. After cooling are filtered solution of nitrate slurry of hydrated oxide and its subsequent washing from nitric acid solutions of nitrates of rare-earth elements and impurities. Washing is carried out in a countercurrent slurry and wash water. In the hillshade get pure hydrated cake MARK in the form of a slurry with a concentration of nitrates NO3~ 2 g/l and the end of the blowing extract the oxides of refractory metals, thanks to the present method completely left in him. The process of obtaining the oxides of tantalum and niobium from hydrate cake ELEVATION patented separately, and therefore is not considered here. In addition to pure cake after washing get United nitrate solution REE with all the impurities (Na, Ca, Sr, Fe, Si, Al, K, P) and activity (thorium Th, mesochori MsTh or what is the same, the isotope of radium Ra228). Then carry out decontamination nitrate solution REE, which is not difficult. For this first solution serves soda solution of Na2CO3for neutralization of nitric acid. Then served sodium sulfate Na2SO4not to add excess cation and barium nitrate Ba(NO3)2that the result of the reaction between a form barium sulfate BaSO4precipitated. Mesochori has the same chemical properties with radium, are in the same chemical group with barium, and therefore the reaction they form sulfates, which have the same crystal lattice. As a result, radium sulfate RaSO4is introduced into the crystal lattice of barium sulfate BaSO4and falls with him in the sediment. Neutralization along the way leads to the fact that thorium is present in the region of the SUB>2CO3+2H2O=Th(OH)4+ 4NaNO3+2CO2< / BR>
Simultaneously with the deactivation occurs a partial exemption of the solution from impurities (Ca, Sr), which has wiselogel nitric acid. As a result of ash in the sediment fell in the form of hydroxide Fe(OH)3all ferric iron, resulting in a nitric acid environment. Under the influence of an excess of sodium sulfate was a partial binding of calcium and strontium in soluble sulphate CaSO4, SrSO4as well precipitating. The process of neutralization and decontamination is performed at a temperature of t=70-80oC and a pH of 4.5-5.0 for 6-8 hours

Subsequent filtering of the solution are removed telesotherapy cake containing all activity, all of the iron, part of the calcium and strontium. Selected active telesotherapy cake is subjected to processing and subsequent disposal in the workings of the mine. Remaining in the filter clean without activity nitrate solution REE is the initial product to extract the carbonates of rare earth elements. This rare earth elements collectively precipitated with a solution of soda in the form of the sum of REE carbonates and filtered. The filtered wet carbonates of rare earth elements, is therefore not considered here. The remaining filtrate is a solution of sodium nitrate mixed with nitrates of alkaline earth elements (Ca, Sr) and is subject to mandatory recycling due to its extreme danger to the environment.

Recycling of the filtrate in the claimed method differs fundamentally from the processing carried out in the method prototype. The solution is evaporated to a concentration of 500-600 g/l, and then subjected to hydropyrolysis at a temperature of t= 600-800oC. Hydropolis perform in the famous tower spray pyrolysis furnaces operating on a mixture of propane and butane or natural gas. At hydropyrolysis concentrated solution of sodium nitrate spray nozzles in the upper part of the furnace. In the process of hydropyrolysis there is a thermal decomposition of nitrates with the formation of elemental nitrogen and oxygen, and sodium oxide Na2O connecting with carbon dioxide from the flue gases. The resulting soda ash, Na2CO3in the form of fine powder falls on the oven hearth. Flue gases are sent to a scrubber for wet cleaning of dust and traces of nitrogen oxides. As a result of contact with water flue gases completely is the liberalization of the excess nitric acid and precipitation of the carbonate of rare earth elements.

Processing nitrate solution is carried out so, can dramatically reduce the consumption of neutralizing reagent in the present method. The need for imported soda is eliminated entirely, because of losses soda will always be compensated for those of sodium, which will vydeliajutsia of loparite when anatomisation autopsy.

This leads to a significant reduction in processing costs loparite concentrate, reduces production cost and increases the efficiency of production in General.

Below, the inventive method is illustrated by a concrete example of its implementation.

Reworked the way the nitrate opening 1000 kg loparite concentrate brand CL-1 of the above structure.

The opening of the concentrate was carried out under the following conditions:

after the initial dry grinding concentrate > 95% of the particles have a particle size of not more than 0,074 mm;

the solid content in the pulp opening - 600 g/l;

initial concentration of nitric acid - 700 g/l;

temperature autopsy - 115-118oC;

autopsy - 40 hours;

intensive mixing mechanical stirrer (speed n = 200 to 220 rpm).

On opening laparotomy pairs (deaf) - 550

Water for washing hydrate cake OTM - 3000

In the nitrate processing reached the opening of loparite concentrate (total rare earth elements) - 95%.

Received the washed hydrate cake GCP - 575 kg (dry) of the following composition, %:

Ta2O5- 0,99

Nb2O5- 14,5

TiO2- 66,2

The amount of oxides REE - 2,78

ThO2- 0,05

CaO - 0,4

Na2O - 0,75

Fe2O3- 0,35

SiO2- 3,5

NO3- 0,1

Also received 5430 l decontaminated solutions of nitrates of rare-earth elements the following composition, g/l:

The amount of oxides REE - 55

The concentration of CaO - 4,0

The concentration of SrO - 1,5

Concentration ThO2- <0.003
The output amounts of rare earth elements in the deactivated solution was 93%. In our example of the decontaminated solution were precipitated carbonates REE. On receipt of the deactivated REE carbonates was consumed, kg:

Soda ash - 520

Nitrate barium - 16

The sodium sulfate - 70

Process water for the preparation of solutions and flushing of sediment - 5000

Heating steam (deaf) - 800

Received carbonates redcatch oxides REE.

From the specific embodiments of the claimed invention for any specialist in this field are obvious possibilities for its realization with the simultaneous solution of the set task. It is also obvious that the invention can be made small changes, but which will not exceed the scope of the invention defined by the following claims.

The inventive method of processing of loparite concentrate saves compared to sulfuric acid technology all the advantages azotnokislogo opening loparite concentrate. Thus it provides a possibility for opening loparite concentrate nitric acid. The method is compared with the prototype of the much lower consumption of imported used reagents. This creates higher economic efficiency and profitability of the processing of loparite concentrate.

Method for processing of loparite concentrate, including the grinding of the concentrate to the size of particles of at least 0.075 mm classification, opening loparite concentrate nitric acid at 115 - 118oC and continuous periomenopause metals, obtained at autopsy concentrate, to obtain the pure hydrate cake, used for further processing, and the United nitrate solution of rare earth elements with impurities and activity, its neutralization and decontamination of translation in the sediment of all impurities, including thorium, mesochori, separating the solution by filtration on iron-thorium cake with all the impurities, recycle and disposal, and net nitrate solution of rare earth elements, their deposition soda as the sum of carbonates of rare earth elements and separating by filtration the quality of the finished product, the subsequent processing for disposal of the remaining filtrate, representing a solution of sodium nitrate mixed with nitrates of rare-earth elements, characterized in that the loparite concentrate crushed dry grinding, air classification, and his autopsy carried out weak 47-55% nitric acid, and recycling the filtrate is carried parcoy to a concentration of 500 - 600 g/l and subsequent hydropyrolysis at 600 - 800oC to produce elementary nitrogen, oxygen and carbon dioxide in the flue gas and ash, which serves to neutralize the nitric acid solution and the precipitation of the carb is up in the atmosphere.

 

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