CN111876596A - A method for extracting molybdenum and radioactive 187Os - Google Patents

Abstract

The invention discloses a method for extracting molybdenum and radioactive 187Os, which belongs to the technical field of mineral extraction, and solves the problems that molybdenum and radioactive ^187Os cannot be recovered simultaneously in the prior art, and the recovery process seriously pollutes the environment. The extraction method includes the following steps: batching → roasting → water immersion → filtration to obtain a first liquid phase and a first solid phase, and the first solid phase enters the process of acid boiling molybdenum and osmium distillation to obtain volatile osmium tetroxide and slurry, and the volatile osmium tetroxide and slurry are obtained. The osmium tetroxide enters the subsequent process of extracting ¹⁸⁷ Os, and the slurry enters the subsequent process of extracting molybdenum. The molybdenum extraction process includes the following steps: filtration→precipitation of impurities→ion exchange to extract molybdenum→elution→crystallization to obtain ammonium molybdate. The present invention realizes the simultaneous extraction of molybdenum and ¹⁸⁷ Os by one process.

Description

A method for extracting molybdenum and radioactive 187Os

technical field

The invention relates to the technical field of mineral extraction, in particular to the extraction of molybdenum, rhenium and ¹⁸⁷ Os, a national emerging strategic resource, in particular to a method for extracting molybdenum and radiogenic ¹⁸⁷ Os from molybdenite.

Background technique

Osmium (Os) is a member of group VIII of the sixth period of the periodic table, one of the platinum group metals, and is the densest metal known so far. Os has 7 isotopes (184, 186, 187, 188, 189, 190, 192). It is generally believed that the radioactive decay of ¹⁸⁷ Re produces ¹⁸⁷ Os, and the relative ratios among several other non-radiogenic Os isotopes are unchanged. Compared with other natural isotopes of Os, ¹⁸⁷ Os is very little in the earth's crust, and radiogenic ¹⁸⁷ Os has special physical properties.

Experts from the former Soviet Union applied radioactive ¹⁸⁷ Os to special industries such as military industry, nuclear power plants, and high-end anti-counterfeiting. And ¹⁸⁷ Os is expensive. In early 2000, 1 gram of radioactive isotope ¹⁸⁷ Os was worth $26,000. Therefore, ¹⁸⁷ Os is also a precious national defense strategic resource, and the control of ¹⁸⁷ Os is related to the national energy security strategy.

The melting point of molybdenum is 2620°C. Due to the strong interatomic bonding force, its strength is very high at room temperature and high temperature. It has a small expansion coefficient, high electrical conductivity and good thermal conductivity. It does not react with hydrochloric acid, hydrofluoric acid and alkali solutions at room temperature, and is only soluble in nitric acid, aqua regia or concentrated sulfuric acid, and is also stable to most liquid metals, non-metal slag and molten glass.

In the aerospace field, the high vacuum in the high-altitude universe and the strong radiation of cosmic rays are simply unsuitable for conventional lubricating materials such as grease or graphite. Molybdenum disulfide is an important lubricant, which can be widely used in the lubrication of various types of machinery, and can meet the special requirements of lubricating materials in the aerospace field.

In addition, molybdenum metal is gradually used in nuclear power, new energy and other fields. Due to the importance of molybdenum, various governments regard it as a strategic metal. Molybdenum was widely used in the manufacture of weapons and equipment in the early 20th century. Vanadium alloys are used in the manufacture of alloy components and parts for warships, rockets and satellites. Therefore, molybdenum has become an important raw material and an irreplaceable strategic substance in the national economy.

The current extraction technology cannot recover molybdenum and radioactive ¹⁸⁷ Os at the same time, and the recovery process seriously pollutes the environment.

SUMMARY OF THE INVENTION

In view of the above analysis, the present invention aims to provide a method for simultaneously extracting molybdenum and radioactive ¹⁸⁷ Os, so as to solve the problem that molybdenum and radioactive ¹⁸⁷ Os cannot be recovered simultaneously in the prior art, and the recovery process seriously pollutes the environment.

The object of the present invention is mainly achieved through the following technical solutions:

The invention provides a method for extracting molybdenum and radioactive ¹⁸⁷ Os, the extraction raw material is molybdenite, and the extraction method comprises the following steps:

Step 1: Ingredients;

Step 2: roasting;

Step 3: water immersion;

Step 4: Filtration to obtain the first liquid phase and the first solid phase, the first solid phase enters the process of acid boiling molybdenum and distillation osmium to obtain volatile osmium tetroxide and slurry, and the volatile osmium tetroxide enters the subsequent extraction ¹⁸⁷ Os process ¹⁸⁷ Os metal powder is obtained, and the slurry enters the subsequent molybdenum extraction process to obtain ammonium molybdate;

The molybdenum extraction process includes the following steps:

Step 1: carry out solid-liquid separation with the slurry obtained in step 4, obtain the second solid phase and the second liquid phase, adjust the second liquid phase to neutrality, and filter to obtain the first filtrate;

Step II: the first filtrate in the precipitation step 1 is subjected to solid-liquid separation to obtain the second filtrate and the filter residue containing impurities;

Step III: the second filtrate in step II is adjusted to be acidic, and ion exchange and elution are carried out to obtain an eluent;

Step IV: Crystallize the eluate to obtain ammonium molybdate.

Further, in step 1, after the second liquid phase is adjusted to neutrality, filtration is carried out within 4 hours.

Further, step IV includes the following steps: heating and evaporating the eluent obtained in step III to crystallize ammonium paramolybdate; continuing to evaporate until the ammonium nitrate in the solution is nearly saturated, and filtering to obtain ammonium molybdate.

Further, in step III, elution is performed with a mixed solution of ammonium nitrate and ammonium hydroxide.

Further, step II includes the following steps: adding NaOH to the first filtrate, making it alkaline, adding hydrogen peroxide, standing, filtering, and washing to obtain a second filtrate and a filter residue containing impurities.

Further, the extraction ¹⁸⁷ Os process comprises the following steps:

Step i: absorption and concentration of volatile osmium tetroxide to obtain concentrated solution;

Step ii: add sodium sulfide to the concentrated solution of step i to obtain osmium sulfide precipitate;

Step iii: alkali-fusing the osmium sulfide precipitate to obtain an osmium sulfide frit;

Step iv: dissolving the osmium sulfide frit, adding cerium sulfate for distillation, to obtain an absorption solution;

Step v: liquid-separating the absorbing liquid, adding absolute ethanol to the lower extraction phase, and reducing osmium tetroxide to osmium dioxide by ethanol;

Step vi: reducing osmium dioxide with hydrogen to obtain ¹⁸⁷ Os metal powder.

Further, in step iii, the alkali-fused osmium sulfide precipitate includes the following steps: firstly adding sodium hydroxide to the crucible, melting and cooling, adding the osmium sulfide precipitate, then adding sodium hydroxide to cover the osmium sulfide precipitate, and then using Sodium peroxide overlay.

Further, in step vi, reducing osmium dioxide with hydrogen comprises the following steps:

Step A: feed hydrogen;

Step B: heating to 90-110°C, keeping warm;

Step C: heating to 190-210°C, keeping warm;

Step D: heating to 390-410°C, keeping warm;

Step E: Heating to 630-670°C and keeping warm.

Further, in step 2, the thickness of the roasting material is 10-20 cm, and the roasting time is 1-2 hours.

Further, the above-mentioned extraction method also comprises the following steps: extracting rhenium technology

Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

1) The extraction method of the present invention can process 40 tons of molybdenite per year, extract 20 grams of ¹⁸⁷ Os with a purity of up to 99.9%, and the target product yield is high;

2) The recovery process does not generate SO ₂ , and does not pollute the environment;

3) In the process of recovering molybdenum and rhenium, the radioactive ¹⁸⁷ Os can be recovered at the same time, realizing the simultaneous extraction of molybdenum, rhenium and ¹⁸⁷ Os by one process, filling the fact that the existing extraction technology in China cannot recover molybdenum, rhenium and radioactive ¹⁸⁷ at the same time. Blank for Os;

4) The equipment required by the present invention is relatively simple, easy to operate, and low in investment.

Other features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be considered limiting of the invention, and like reference numerals refer to like parts throughout the drawings.

1 is a flowchart of extracting ¹⁸⁷ Os according to an embodiment of the present invention;

2 is a flow chart of extracting rhenium and ¹⁸⁷ Os according to an embodiment of the present invention;

Fig. 3 is the flow chart of extracting molybdenum, rhenium and ¹⁸⁷ Os according to the embodiment of the present invention;

FIG. 4 is a flow chart of extracting molybdenum and ¹⁸⁷ Os according to an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention are described below in detail with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present application, and together with the embodiments of the present invention, serve to explain the principles of the present invention.

Example 1

A specific embodiment of the present invention provides an extraction method for extracting molybdenum and radioactive ¹⁸⁷ Os. As shown in FIGS. 1 to 4 , the extraction raw material is molybdenum concentrate, specifically molybdenite. This is because , the reducing ore-forming fluid when molybdenite is formed (for example, Mo in the positive hexavalent state and Mo in the positive heptavalent state are reduced to Mo in the positive tetravalent state), and the Os in the positive tetravalent state can also be reduced into the positive trivalent Os. Even 0 valence Os. The lower the ion valence state, the larger the ionic radius. After the reduction of Os in the positive tetravalent state, not only a larger Os ion is generated, but also the charge is unbalanced, so that it cannot be homogeneously replaced by Mo. In the formation environment of molybdenite, Os in the positive tetravalent state is reduced to low-valent Os ions with larger ionic radius, which is the main reason why molybdenite does not contain ordinary Os.

The lattice of Re is similar to that of Mo. When molybdenite crystallizes, Re can replace the position of Mo isomorphically. The radioactive decay of ¹⁸⁷ Re produces ¹⁸⁷ Os, so molybdenite contains only radioactive ¹⁸⁷ Os.

In this example, the extraction purity of ¹⁸⁷ Os is improved by selecting molybdenite as the extraction raw material. Specifically, the extraction purity of ¹⁸⁷ Os was as high as 99.9%.

Specifically, the extraction method of this embodiment includes the following steps:

Step 1: Ingredients. The quicklime is washed with water to make plaster, dried and pulverized to 100-200 mesh. The obtained slaked lime powder and the dry molybdenite powder are uniformly mixed in a ratio of 2:1. The equipment used includes pulverizers, drying units, mixers, scales and containers.

Step 2: Roasting. The prepared mixture is placed in a reverberatory furnace and calcined in air at 650-750°C.

The purpose of the roasting process is to oxidize the molybdenum, sulfur, rhenium and osmium in the raw materials to a high valence state. In order to prevent rhenium and osmium from generating volatile gas loss during high-temperature oxidation, and to prevent environmental pollution caused by the production of a large amount of sulfur dioxide gas, a certain proportion of quicklime powder is mixed into the raw materials, so that the above elements are in the process of roasting. Calcium molybdate, calcium sulfate, calcium rhenate and calcium osmate are respectively generated and coexist in calcine. The main reaction is:

MoS ₂ +3CaO+9/2O ₂ =CaMoO ₄ +2CaSO ₄ +Q

At the same time, rhenium and osmium in molybdenite are also oxidized to rhenate and osmium, which are retained in calcine. The sulfur in the ore sample is oxidized to sulfate radicals, which will not produce SO ₂ and will not pollute the environment.

A pilot test is needed to determine the optimal thickness of the covering and the firing time. This is because, if the paving material is too thick, the oxidation reaction will be insufficient; and if the paving material is too thin, the amount of ore sample will be small, which will affect the experimental efficiency. Therefore, this step is very important to ensure the recovery rate of osmium, and it is necessary to ensure that all components in the ore sample are fully oxidized. In the present invention, the thickness of the four-square-meter paving at the bottom is controlled to be 10-20 cm, the optimal thickness of the paving is 15 cm, and the roasting time is 1-2 hours.

In order to reduce costs, the equipment used for roasting is a reverberatory furnace. In order to ensure the ventilation volume, the flue part should have an induced draft fan and an air volume control valve.

Considering that about 10% of the osmium is burned out during the roasting process, in order to recover this part of the osmium, a circulating rinsing device or a dust removal device is installed in the appropriate part of the flue, thereby improving the recovery rate of osmium.

Step 3: Water immersion. Because calcium rhenate has a high solubility in water, while calcium molybdate and calcium osmate are almost insoluble in water, the purpose of separating osmium can be achieved by water immersion. Water immersion includes the first leaching and the second leaching.

The first leaching is specifically as follows: put the calcined calcined calcined into a leaching tank containing 400 liters of water while still hot, stir mechanically or manually for 2-3 hours, place and take out to obtain the first supernatant.

The second leaching is specifically as follows: adding 100 liters of water to the leaching tank from which the first supernatant was taken out, stirring for 1 hour, placing, and taking out to obtain the second supernatant, and combining the second supernatant and the first supernatant .

The combined supernatant is returned to leaching the next batch of calcine. The leaching solution after processing four batches of calcine is no longer used, and CO ₂ gas (the CO ₂ produced by neutralizing the sulfuric acid solution in the later boiling molybdenum process) can be used to neutralize the Ca(OH) ₂ to pH 8- 9. A white precipitate of CaCO ₃ is produced. After clarification, the rhenium can be separated directly on the ion exchange column.

The equipment used for water immersion in this embodiment is a rhenium immersion tank, preferably with mechanical stirring, and the number of rhenium immersion tanks is two, which are used alternately. The size of the dip tank is 700mm×700mm×1200mm, the volume is 600 liters, the liquid outlet is 300mm away from the bottom of the tank, and the tank material can be engineering plastics, glass fiber reinforced plastic or iron plate.

Step 4: Filter. In order to improve the recovery rate of rhenium, in this embodiment, filtration is also performed after the second leaching, and in this embodiment, centrifugal separation is used for filtration to reduce residual rhenium in the calcined mortar. Liquid and solid phases are obtained after filtration. The liquid phase enters the extraction rhenium process to obtain potassium rhenate crystals, and the solid phase enters the acid boiling molybdenum and osmium distillation processes.

The extraction process of rhenium includes the following steps:

Step a: extracting rhenium by ion exchange to obtain an eluent containing rhenium.

Step b: The eluate is concentrated.

Step c: One-time crystallization to obtain ammonium rhenate crystals.

Step d: secondary crystallization to obtain potassium rhenate crystals.

The process of acid boiling molybdenum and distilling osmium is as follows: adding potassium permanganate and water to the calcine wet material after rhenium dipping, stirring, adding concentrated sulfuric acid, heating to boiling, and keeping the temperature.

Preferably, 75 kilograms of calcined wet material after immersion (if not centrifuged, containing 100-150 kilograms of water) are put into the reactor, 0.8-0.85 kilograms of potassium permanganate are added, and 600 liters of water (should be deducted) calcine water content), close the reaction kettle, start the mixer, add 50 liters (90 kg) of concentrated sulfuric acid, heat to boiling, and keep for 1-2 hours (the optimum time is determined by experiments) to obtain a slurry.

The calcium molybdate in the calcined sand enters the slurry for the subsequent extraction of molybdenum. The hexavalent osmium is oxidized to octavalent to generate volatile osmium tetroxide, which enters the extraction process of osmium.

It should be noted that, in order to facilitate the entry of osmium tetroxide into the osmium absorber, during the cooking process, while heating and stirring, always use an air pump to introduce air under the liquid level in the reactor, and carry out the generated osmium tetroxide gas. The osmium absorber was sent through the catheter and absorbed by the ice-bath 10% sodium hydroxide solution therein.

The process of extracting osmium includes the following steps:

Step 1: Absorption and concentration of volatile osmium tetroxide to obtain concentrated solution. Volatile osmium tetroxide enters the osmium absorber for absorption.

It should be noted that, since a large amount of water vapor enters the osmium absorber with osmium tetroxide in the distillation process, the volume of the absorption liquid is continuously increased, and the increased absorption liquid is periodically transferred out and an appropriate amount of sodium hydroxide is added. After the transferred absorption liquid reaches 100 liters, it is placed in a 200-liter reactor for concentrated distillation. Neutralize with sulfuric acid, add an appropriate amount of potassium permanganate, add 6 liters of sulfuric acid, heat to boiling, and keep for more than 2 hours. After the reaction, the residual liquid is returned to the molybdenum boiling process for continuous utilization. After the absorption liquid is accumulated to a certain amount, it is distilled and concentrated again.

Step II: adding sodium sulfide to the concentrated solution in step I to obtain an osmium sulfide precipitate.

The osmium absorption solution obtained by concentration is brownish yellow, contains more than 100mg/L of osmium, and also contains a large amount of sodium carbonate, sodium chloride, sodium hypochlorite, sodium hydroxide, etc., transfer this solution to a beaker, add sodium sulfite and stir until the solution is brown. The yellow faded and turned into a very pale purple-red. At this time, the osmium in the solution had changed from 8 to 6, and other oxidizing substances in the solution were also reduced. Add analytically pure sodium sulfide to the solution, stir to fully dissolve, and immediately produce a large amount of dark black osmium sulfide.

It should be noted that the added sodium sulfide must be excessive to ensure sufficient precipitation of osmium. Generally, more than 5 grams of solid sodium sulfide should be added to a solution containing about 200 mg/L of osmium per 500 ml.

Heat the beaker in a water bath to make the osmium sulfide agglomerate and sink, remove it and cool it, let it stand, until the upper solution is clear and transparent, transfer the supernatant out, change the water to wash the precipitate to reduce the alkalinity and salt content, and then let it stand still. Set it until the upper solution is clear, transfer out the clear solution (place it separately to fully precipitate residual osmium sulfide), filter the thick slurry in the lower part on a negative pressure suction filtration system equipped with a 0.45μm alkali-resistant filter membrane, and pump it until the slurry dries quickly and does not crack. , washed twice with distilled water, and finally fully drained until the osmium sulfide filter cake cracked, transferred to a small beaker, and dried in an oven at 70-80 °C. Should not be crushed. After drying, weigh.

Step III: alkali-melting the osmium sulfide precipitate to obtain an osmium sulfide frit. First add sodium hydroxide to the crucible, melt, cool, add dry osmium sulfide powder, then add sodium hydroxide to cover the dry osmium sulfide powder, and then cover with sodium peroxide.

Specifically, prepare 6 corundum crucibles of 30 ml, add 2 grams of sodium hydroxide to each, put them in a muffle furnace at 200-300 ℃ to melt and make a bottom, take out and cool, weigh 0.4 grams of osmium sulfide dry powder into each, and cover them with finer pieces. 4 grams of sodium hydroxide, then cover with 12-15 grams of sodium peroxide, and shake the crucible to make it fully covered. Put the corundum crucible in a 50ml porcelain crucible, cover it, put it in a muffle furnace below 200°C, slowly heat up with a current of 16-18A, rise to 700°C after about an hour, keep it warm for 10-15 minutes, and turn it on. Furnace door, take out the crucible, and let it cool to obtain an osmium sulfide frit.

Step IV: Distillation. The osmium sulfide frit is dissolved, and cerium sulfate is added for distillation to obtain an absorption solution.

Extract the frit: put the cooled corundum crucible containing the osmium sulfide frit into a 200 ml beaker of ~70 ml of water (or alkaline raffinate), add a watch glass, and after the osmium sulfide frit is completely dissolved, Take out the corundum crucible, wash the crucible with water, and control not to make the volume too large.

Transfer about 250 ml of the extract from each three crucibles into a 1000-ml distillation flask, add about 5 grams of cerium sulfate, seal the mouth of the distillation flask with 1:1 sulfuric acid, and seal the absorption tube with distilled water.

The first absorber tube contained 25 mL of repurified carbon tetrachloride, overlaid with 2 mL of distilled water.

The second absorption tube was filled with 20 ml of 20% sodium hydroxide, and the mouth of the bottle was rinsed with water to ~40 ml. Both the primary and secondary absorption tubes were cooled in an ice-water bath.

Connect the outlet of the second absorption pipe to the negative pressure system.

Add sulfuric acid from the addition funnel at the top of the distiller to make the acidity of the distillate 4-5 mol/L.

It should be noted that the electric heating jacket is used for heating in the distillation process. Do not set the temperature adjustment knob too high to prevent excessive heating to generate a large amount of steam, and the negative pressure system will not be able to extract it in time, causing the distillate to be sprayed from the air inlet. . After the solution boils, most of the osmium has been evaporated when the volume of the absorption solution increases by 15-20 ml. Lower the temperature, keep the solution slightly boiling but the absorption volume increases very slowly, about 1.5 hours after boiling, then increase the temperature, and flush all the residual osmium attached to the wall of the vessel after steaming into the absorption tube, until When the absorption tube is almost full, stop heating and lower the temperature under negative pressure for about half an hour.

Step V: liquid-separating the absorption liquid, adding absolute ethanol to the lower extraction phase (organic phase), and reducing the osmium tetroxide to osmium dioxide by the ethanol.

Disconnect the connection port of the absorption bottle and the distillation bottle, transfer the absorption liquid in the first absorption tube into the PTFE separatory funnel, and fully wash the absorption tube to prevent the volatilization loss of high-concentration osmium in carbon tetrachloride. Separation funnel, shake for 2 minutes, after phase separation, put the lower organic phase into a conical flask that has been filled with 80 ml of high-grade pure absolute ethanol, and shake well. After the solution in the first absorption tube was transferred out, 5 ml of carbon tetrachloride was added immediately to clean the absorption tube. After the organic phase in the separatory funnel was released, the carbon tetrachloride in the absorption tube was transferred to the separatory funnel. The raffinate phase (aqueous phase) was washed for 2 minutes, and after the phases were separated, the organic phase was put into a conical flask, and then washed once with 5 ml of carbon tetrachloride. Finally, after washing the water phase again with 25 ml of carbon tetrachloride, the organic phase was not incorporated into the conical flask, and was put into the first absorption tube, covered with 2 ml of water, as the absorption liquid in the next distillation.

The raffinate phase also contains a certain amount of osmium (about 1%), which is combined in a 1000-ml bottle, and solid sodium hydroxide (about 1mol/L NaOH) is added at a ratio of 15-20g/400ml. At this time, the osmium in the residual organic phase also enters. In the aqueous phase, the solution was brown-red. The solution can be used as the extraction solution of alkali frit. During distillation, acid (10 ml concentrated sulfuric acid) can be added appropriately. The residual organic phase in the raffinate phase has accumulated too much, which can be transferred to a separatory funnel and washed with a small amount of 20% NaOH. phase until the lye solution is colorless, indicating that the organic phase has no osmium, and is discarded.

The secondary absorption liquid is brown-red after being used for the second time, and is also incorporated into the raffinate phase as the extraction liquid. Replace the new NaOH solution in the absorption tube.

The first-level absorption liquid obtained by each two distillations was combined in the same conical flask and placed with a cap.

During distillation operations, due to the handling of high concentration osmium solutions (up to 20-25 g/L), extra care should be taken to prevent osmium volatilization loss and contamination to ensure product recovery and purity. Specifically, the following aspects should be noted:

1. In the process of installation and disassembly, it is necessary to ensure that the first-stage absorbing liquid is absolutely not polluted by sodium, cerium, sulfate, etc. in the distillation flask and the second-stage absorbing liquid. Every time the operation of contacting sodium hydroxide (alkali melting, extraction, replacement of absorbing liquid, etc.) is carried out, you must wash your hands and ensure that the entire operating environment is not polluted by sodium. After the glass tube in the absorption tube is taken out, it should also be properly placed to prevent dust pollution.

2. The concentration of osmium in the first absorption tube reaches 20-30g/L, which can smell the special smell of osmium tetroxide. Therefore, preparations should be made before disassembly, and the operation should be fast. After disassembling the closed system of the catheter, immediately clean the inside and outside of the catheter with a small amount of distilled water, quickly transfer it to the separatory funnel, and use distilled water to remove the residual tetrachloride in the absorption tube. Wash with carbon, and transfer to a separatory funnel together to prevent the loss of osmium volatilization.

3. The distillation residue also contains 5-8mg/L osmium, which should be returned to the second concentration process for use.

4. After the first absorption liquid concentrated by this distillation, there will be no other purification steps. The impurities introduced after this operation will always be brought into the product. Therefore, be careful everywhere and pay attention to every detail so as not to cause pollution.

It is worth noting that the osmium tetroxide in the conical flask is reduced to osmium dioxide by ethanol, and the original clear and colorless solution turns black. Finish. In order to make the reaction sufficient, this solution is generally placed for three days. After the transformation is complete, open the conical bottle cap, place it in a water bath, heat at 80-90 °C to volatilize carbon tetrachloride and ethanol, and after thorough drying, transfer the solid osmium dioxide in the bottle to a weighing bottle Weigh.

Step VI: reducing osmium dioxide with hydrogen to obtain ¹⁸⁷ Os metal powder (abbreviated as "osmium powder").

Weigh the special quartz boat, then weigh in 1.5-2 grams of osmium dioxide, and spread it evenly. It is placed in the center of the quartz tube of the tube furnace, the outlet of the quartz tube is introduced into an open container filled with 5% NaOH solution, and the air inlet is sealed with water. The hydrogen flow is introduced first, and the outlet is adjusted to produce continuous bubbles. Adjust the heating current to 6A, slowly heat to 100°C, after 10 minutes, increase to 200°C at 10A, after another 10 minutes, increase to 400°C at 12A, after another 10 minutes, increase to 650°C at 16A. After reaching 650°C, hold for 30 minutes and stop heating, during which osmium dioxide is reduced to ¹⁸⁷ Os metal powder.

Continue to maintain the hydrogen flow, while slowly opening the nitrogen valve to maintain a certain nitrogen flow, and then close the hydrogen valve. After the reduction, the ¹⁸⁷ Os metal powder was gradually cooled under the protection of nitrogen flow. After about 30 minutes, the temperature was lowered to 200-300 ° C. The outlet of the quartz tube was disconnected from the conduit, and the quartz tube was removed from the tube furnace while maintaining the nitrogen flow. pull out.

In order to prevent the air from entering the quartz tube due to the gas contraction caused by the sudden temperature drop, the nitrogen flow should be slightly increased first.

When the temperature of the quartz tube drops to room temperature, close the nitrogen valve, and take out the quartz boat containing the osmium powder. After weighing, the osmium powder is transferred to the weighing bottle and packaged according to certain specifications. When the product glass tube is closed, it must be ensured that there is no air leakage, so as to prevent the air from entering and causing the osmium powder to be oxidized and volatilized.

The purity of the ¹⁸⁷ Os metal powder extracted by the rhenium and radioactive ¹⁸⁷ Os extraction method of the present embodiment was determined by the alkali fusion method, and the test process was as follows:

Weigh 5 mg of the prepared ¹⁸⁷ Os metal powder into a zirconium pot bottomed with NaOH 2 g, and then concentrate 15 mL of ordinary Os standard solution to 0.5 mL. A small amount of NaOH powder was added for neutralization, and the concentrated common Os standard solution was transferred to a zirconium pot, and finally covered with 1 g NaOH and 4 g Na ₂ O ₂ solid powder, and alkaline solution heating was performed in a muffle furnace at 700 °C for 1 h. After the zirconium pot was cooled, 20 ml of 1:1 H ₂ SO ₄ was added for neutralization, and 0.5 g of CeSO ₄ was added to separate Os by distillation. The value of ¹⁸⁷ Os/ ¹⁹⁰ Os was determined by thermal surface ionization mass spectrometry to 1.057, and then combined with the ordinary Os content (300ug/g) and the abundance of ¹⁸⁷ Os ¹⁸⁷ Os/ ¹⁸⁸ Os=0.1211, the obtained ¹⁸⁷ Os metal powder was calculated. The content is greater than 99.9%.

In the present embodiment, the extraction molybdenum process comprises the following steps:

Step i: Filter.

Step ii: Precipitation to remove impurities such as iron, copper, manganese, etc.

Step iii: Ion exchange extraction of molybdenum.

Step iv: Elution.

Step v: Crystallization to obtain ammonium molybdate.

Process equipment:

1) Two 1000-liter glass-lined reactors (steam heating or electric heating).

The reactor is required to meet the following requirements:

a. Controllable temperature (about 100℃)

b. Equipped with feeding ports (wet calcine, concentrated sulfuric acid, water, return immersion liquid, etc.), air inlet, air outlet, temperature measurement hole, (pressure measurement hole,) observation window, material outlet, etc.;

c. The system needs to be sealed to prevent osmium leakage, but the pressure is not large, less than 2 meters of water column;

d. Stir well, because the material is viscous, it is necessary to prevent the existence of dead corners or the formation of concentric circles, and prevent the agglomeration and sticking to the wall caused by insufficient stirring;

e. Outlet pipe, glass-lined or lined with Teflon to prevent osmium tetroxide from being reduced and adsorbed.

2) Quantitative sampling system - metering pump (concentrated sulfuric acid, acid filtrate, water, etc.), high level tank.

3) One 200-liter glass-lined reactor (steam heating or electric heating) for concentrating osmium absorbing liquid.

4) Osmium absorber: two stages in series, can be made of stainless steel, should be able to observe the liquid level.

5) Cooling tank for ice bath osmium absorber.

6) Compressed air pump to deliver air to the reactor, and the required air intake can be adjusted.

7) The filtration and separation device is required to effectively filter the viscous slurry and fully wash it to ensure the effective recovery of molybdenum.

8) The discharge receiving groove, 1400mm×1400mm×500mm, with a volume of 1000 liters, is made of engineering plastics or stainless steel, and there is a discharge port at the bottom.

9) Container, 10 plastic buckets of 200 liters, for receiving filtrate and washing water.

10) Freezer, used to make ice to cool the osmium absorption liquid.

Embodiment 2

As shown in Figure 2, the extraction rhenium process of embodiment one more specifically includes the following steps:

Step a: extracting rhenium by ion exchange to obtain an eluent containing rhenium.

The rhenium-containing immersion solution processed by water immersion flows through the ion exchange column at a flow rate of 500 ml/min, the rhenium in the immersion solution remains on the column, and impurities such as calcium and molybdenum flow out with the effluent. When rhenium can be detected in the effluent, it indicates that the column capacity is full, and the column loading is stopped. The effluent can be returned to the rhenium immersion process for further use. The column was washed with 50 liters of 10% NaOH solution (to remove molybdenum), and then washed with deionized water until neutral. The rhenium on the column was eluted with ₉ % NH4SCN solution. The flow rate of the eluent should be as slow as possible, and the specific conditions and the amount of eluent should be determined through experiments.

Step b: The eluate is concentrated. The eluate is carried out in stages, wherein the solution with a rhenium concentration higher than 10 g/L is concentrated at about 80° C. to a rhenium concentration of 50-100 g/L.

Step c: One-time crystallization to obtain ammonium rhenate crystals. The concentrated solution was placed in a refrigerator to cool overnight to precipitate ammonium rhenate crystals.

Step d: secondary crystallization to obtain potassium rhenate crystals. Dissolve ammonium rhenate crystals in a small amount of deionized water, add an appropriate amount of potassium chloride solution, and obtain potassium rhenate crystals through secondary crystallization, filter and dry at low temperature. The eluent with lower rhenium concentration can be returned to continue elution.

The ion exchange column used in this example is 201 strong basic anion exchange resin, the exchange capacity for rhenium is 130 g/kg resin, the number of ion exchange columns is two, and the volume of the high-level storage tank is 1200 liters. Pump the immersion liquid into the high level tank.

Embodiment 3

As shown in Figure 3, the molybdenum extraction process of Embodiment 1 more specifically includes the following steps:

Step i: the slurry is separated from solid and liquid, the main component of the solid phase is CaSO ₄ (gypsum), the liquid phase is adjusted to neutrality (pH is about 7) with calcium carbonate, filtered, and the filtrate is subjected to the subsequent molybdenum extraction process.

It should be noted that after the liquid phase is adjusted to neutrality, it must be filtered within four hours, otherwise the dissolved molybdenum will precipitate in the form of calcium molybdate, reducing the recovery rate of molybdenum.

After the reaction, put all the thick slurry in the kettle into a receiving tank with a volume of 1000 liters, and introduce it into a centrifuge in stages for solid-liquid separation, and collect the liquid phase. The filter residue is washed twice with a small amount of water (the degree of washing directly affects the recovery rate of molybdenum) and the washing solution is collected separately.

After the acidity of the direct filtrate is measured, the filtrate is returned to the reactor to continue the digestion of the next batch of calcine. Adjust the amount of potassium permanganate added according to the color of the filtrate, and add concentrated sulfuric acid (about 30 liters) to a total of 50 liters. By analogy, one filtrate can be used repeatedly to process more than four batches of calcine. After processing four batches of calcine, continue stirring after the reaction is completed, and slowly add calcium carbonate (limestone) fine powder from the feeding port to neutralize the sulfuric acid in the solution. At this time, a large amount of CO ₂ gas is generated, and the immersion liquid after four times of rhenium immersion is introduced through the gas outlet pipe to neutralize the calcium hydroxide in it. Then put the slurry into the receiving tank, continue to adjust the pH to about 7 with calcium carbonate, filter, and the molybdenum concentration in the filtrate is about 60 g/L, and then send to the molybdenum extraction process.

The collected water washing liquid is used for the treatment of a new batch of calcine after the acidity is determined.

Step ii: Precipitation to remove impurities such as iron, copper, manganese, etc. Add NaOH to the filtrate in step i, adjust the pH to about 10, add hydrogen peroxide, let stand for 1 hour, filter, wash to obtain a yellow filtrate, and impurities such as iron, copper, and manganese enter the filter residue.

Specifically, after the liquid phase after solid-liquid separation is removed sulfate radicals with calcium carbonate, a filtrate with a pH of about 7 is obtained, which contains a large amount of impurity elements, mainly including iron, copper, manganese, etc., which should be removed as much as possible before ion exchange. Add NaOH slowly and evenly to the filtrate (if it is a large particle, it needs to be made into a concentrated solution to prevent local excess), stir to ~ pH10, and then add a small amount of hydrogen peroxide until the purple-red solution turns yellow (the amount added depends on The content of manganese in the solution, generally 0.5% of the filtrate), indicates that manganese has been reduced to divalent. After standing for one hour, a large amount of precipitation was produced, centrifugal filtration, the precipitation was washed with water, and the filter residue was discarded. The removal rate of iron and manganese in the filtrate is 100%, and the removal rate of copper is >98%.

Step iii: Ion exchange extraction of molybdenum. The filtrate obtained in step ii is adjusted to be acidic, and ion exchange is carried out.

The filtrate (pH10) after the impurity removal was adjusted to pH2 with nitric acid. If the amount of hydrogen peroxide added during the precipitation and impurity removal was insufficient, add an appropriate amount of hydrogen peroxide until the solution was bright yellow. The exchange tank of the basic anion exchange resin is stirred intermittently and slowly. After one day, the yellow color of the solution disappears, indicating that the molybdenum in the solution has been adsorbed by the resin. The exchanged solution is released. If the molybdenum content is very low, it can be discarded. If the molybdenum content is high, leave the batch exchange or upper column to recover the residual molybdenum.

The resin saturated with molybdenum adsorption in the exchange tank is first washed with slightly acidic water containing a small amount of nitric acid, and the washing water can also be poured onto the column, and then washed several times with deionized water. If centrifugal separation can improve washing efficiency.

Step iv: Elution. The molybdenum adsorbed by the resin was eluted with a mixed solution of ammonium nitrate and ammonium hydroxide equal to the volume of the resin.

The molybdenum adsorbed by the resin was eluted with an equal volume (about 450 liters) of a mixed solution of ammonium nitrate and ammonium hydroxide (the ammonium nitrate concentration was 1 mol/L, and the ammonium hydroxide concentration was 12.5%). After stirring in the exchange tank for 20 minutes, the eluate was filtered off by centrifugation. The resin was washed in a centrifuge with 200 liters of deionized water, and the wash water was collected and used to prepare the next batch of eluent. The washed resin is washed with water containing nitric acid to pH 2, which can be used to continue exchanging molybdenum.

Step v: Crystallization to obtain ammonium molybdate.

The concentration of molybdenum in the eluate obtained by filtration is about 170 g/L, which can be heated and evaporated in a heating kettle to crystallize out ammonium paramolybdate. When the ammonium nitrate in the solution is evaporated to near saturation, the precipitated ammonium molybdate is filtered, and the mother liquor is replenished with ammonium hydroxide and used to elute the molybdenum in the resin. It is also possible to obtain ammonium tetramolybdate crystals by neutralization when evaporating to a molybdenum concentration of 200 g/L.

The precipitated ammonium molybdate was filtered and dried (<89° C.) to obtain ammonium molybdate product.

The equipment required for the molybdenum extraction process is:

1) Settling tank, used for precipitating impurities, 1000mm×1000mm×1500mm, can be stirred, and there is a liquid outlet at the bottom;

2) Exchange tank, used for ion exchange of molybdenum leaching solution, two are used alternately, the requirements are the same as 1);

3) Resin, D301 macroporous weakly basic anion exchange resin (produced by Tianjin Nankai University Chemical Plant), 200 kg per tank, 400 kg in total. The new resin is washed with water to remove impurities before use, soaked in 10% nitric acid for washing and transformation, and the water is selected to be weakly acidic for use;

4) Centrifugal filter, used for filtration and separation of precipitated impurities, resin washing, and ammonium molybdate crystallization;

5) Drying device, used for drying ammonium molybdate products, which requires controllable temperature;

6) Evaporation (neutralization) kettle, 500 liters, can be heated and stirred. It is best to realize the evaporation under reduced pressure. If there are no conditions for the time being, the evaporation is open. If the neutralization method is considered, acid resistance (pH2) is required;

7) ion exchange column, used to recover low-content molybdenum in the washing solution, the specification is the same as the ion exchange column for extracting rhenium;

8) Pumps for the transfer of large quantities of liquids.

By adopting the extraction method of the invention, 40 tons of molybdenite can be processed annually, and 20 grams of radioactive origin ¹⁸⁷ Os, 30 kilograms of potassium rhenate and 30 tons of ammonium molybdate can be extracted in total.

The extraction method of the invention can realize sufficient separation of molybdenum and rhenium, and obtain high-purity potassium rhenate and ammonium molybdate. The raw materials used in the recovery process are easily available, no waste gas such as SO ₂ is generated, and the impact on the environment is small. At the same time, the radioactive ¹⁸⁷ Os can be recovered. In addition, the equipment required by the present invention is relatively simple, easy to operate, and low in investment.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention.

Claims (10)

1. a method for extracting platinum and radioactive ¹⁸⁷ Os, is characterized in that, extracting raw material is molybdenite, and described extracting method comprises the steps: Step 1: Ingredients; Step 2: roasting; Step 3: water immersion; Step 4: Filtration to obtain the first liquid phase and the first solid phase, the first solid phase enters the process of acid boiling molybdenum and distillation osmium to obtain volatile osmium tetroxide and slurry, and the volatile osmium tetroxide enters the subsequent extraction ¹⁸⁷ Os process ¹⁸⁷ Os metal powder is obtained, and the slurry enters the subsequent molybdenum extraction process to obtain ammonium molybdate; The described molybdenum extraction process comprises the following steps: Step 1: carry out solid-liquid separation with the slurry obtained in step 4, obtain the second solid phase and the second liquid phase, adjust the second liquid phase to neutrality, filter, and obtain the first filtrate; Step II: the first filtrate in the precipitation step 1 is subjected to solid-liquid separation to obtain the second filtrate and the filter residue containing impurities; Step III: the second filtrate in step II is adjusted to be acidic, and ion exchange and elution are carried out to obtain an eluent; Step IV: Crystallize the eluate to obtain ammonium molybdate. 2. the method for extracting platinum and radioactive origin ¹⁸⁷ Os according to claim 1, is characterized in that, in step 1, after the second liquid phase is adjusted to neutrality, filter within 4 hours. 3. the method for extracting platinum and radioactive ¹⁸⁷ Os according to claim 1, is characterized in that, step IV comprises the following steps: the eluent obtained in step III is heated and evaporated, and crystallizes out ammonium paramolybdate; When the ammonium nitrate in the solution is nearly saturated, ammonium molybdate is obtained by filtration. 4. The method for extracting molybdenum and radioactive ¹⁸⁷ Os according to claim 1, characterized in that, in step III, elution is performed with a mixed solution of ammonium nitrate and ammonium hydroxide. 5. The method for extracting molybdenum and radioactive ¹⁸⁷ Os according to claim 1, wherein the step II comprises the steps of: adding NaOH to the first filtrate, adjusting to alkaline, adding hydrogen peroxide, Let stand, filter and wash to obtain the second filtrate and filter residue containing impurities. 6. The method for extracting platinum and radioactive ¹⁸⁷ Os according to any one of claims 1 to 5, wherein the extraction ¹⁸⁷ Os process comprises the following steps: Step i: absorption and concentration of volatile osmium tetroxide to obtain concentrated solution; Step ii: add sodium sulfide to the concentrated solution of step i to obtain osmium sulfide precipitate; Step iii: alkali-fusing the osmium sulfide precipitate to obtain an osmium sulfide frit; Step iv: dissolving the osmium sulfide frit, adding cerium sulfate for distillation, to obtain an absorption solution; Step v: liquid-separating the absorbing liquid, adding absolute ethanol to the lower extraction phase, and reducing osmium tetroxide to osmium dioxide by ethanol; Step vi: reducing osmium dioxide with hydrogen to obtain ¹⁸⁷ Os metal powder. 7. The method for extracting molybdenum and radioactive ¹⁸⁷ Os according to claim 6, characterized in that, in the step iii, the alkali-fused osmium sulfide precipitate comprises the steps of: first adding sodium hydroxide in the crucible, melting and Cool, add osmium sulfide precipitate, add sodium hydroxide to cover the osmium sulfide precipitate, and then cover with sodium peroxide. 8. The method for extracting platinum and radioactive ¹⁸⁷ Os according to claim 6 or 7, wherein in the step vi, reducing osmium dioxide with hydrogen comprises the steps: Step A: feed hydrogen; Step B: heating to 90-110°C, keeping warm; Step C: heating to 190-210°C, keeping warm; Step D: heating to 390-410°C, keeping warm; Step E: Heating to 630-670°C and keeping warm. 9. The method for extracting molybdenum and radioactive ¹⁸⁷ Os according to any one of claims 1 to 8, characterized in that, in the step 2, the thickness of the calcined paving is 10-20cm, and the calcination time is 1-2 hours . 10 . The method for extracting molybdenum and radioactive ¹⁸⁷ Os according to claim 1 , further comprising the steps of: extracting rhenium. 11 .

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