A method for clean smelting of beryllium oxide and beryllium oxide

Abstract

The present invention relates to the technical field of inorganic materials, and particularly to a method for clean smelting of beryllium oxide and beryllium oxide. The smelting method includes using iron powder to remove trivalent iron in the acid leaching solution of beryllium ore; using a non-saponified extraction system without sodium ions and ammonium cations, and the non-saponified extraction system exchanges hydrogen ions with itself when extracting beryllium ions. The present invention solves the problems existing in beryllium smelting preparation in the prior art, such as low beryllium recovery rate, easy interference by associated elements, large pollution, and difficult waste liquid treatment. An alkaline earth metal compound is used as a raffinate impurity removal reagent and a non-saponified extraction system, and the raffinate after impurity removal is recycled for beryllium ore leaching, improving the beryllium recovery rate and reducing the environmental pollution caused by waste liquid discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of beryllium industry, and in particular to a method for clean smelting of beryllium oxide and beryllium oxide. Background Art

[0002] Beryllium is an indispensable important material in the atomic energy, rocket, missile, aviation and metallurgical industries. However, beryllium is extremely harmful to the environment. The lethal concentration of beryllium in water for fish is 0.15 mg / L.

[0003] In the prior art, the acid leaching + extraction process is mainly used to treat beryllium ore. The existing process for extracting beryllium from beryllium ore has the following defects: on the one hand, acid leaching will introduce associated element ions of beryllium in the beryllium ore (such as ferric ion) into the leaching solution at the same time, and the associated element ions often undergo competitive extraction with beryllium ions, greatly reducing the extraction and separation effect of beryllium, resulting in the loss of beryllium, and the decrease in the recovery rate of beryllium will cause some beryllium to flow into the natural world, causing pollution; on the other hand, soluble alkaline substances (sodium hydroxide or ammonia water) need to be added during the extraction process to adjust the acidity of the solution during the extraction process, resulting in the introduction of cations of soluble alkalis into the leaching solution, greatly increasing the difficulty of subsequent wastewater treatment. Therefore, there is an urgent need in the market for a method for clean smelting of beryllium oxide that is efficient and environmentally friendly. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a method for clean smelting of beryllium oxide and beryllium oxide, which solves at least one of the problems existing in the smelting and preparation of beryllium in the prior art, such as low yield of beryllium element, easy interference by associated elements, large pollution and difficult waste liquid treatment.

[0005] The object of the present invention is mainly achieved through the following technical solutions:

[0006] A method for clean smelting of beryllium oxide, the clean smelting method includes using iron powder to remove ferric iron from the acidic beryllium ore leaching solution.

[0007] Preferably, the clean smelting method includes:

[0008] Step 1: After the beryllium ore is sulfated and matured, it is leached to obtain a leaching solution;

[0009] Step 2: Add iron powder to remove ferric iron ions in the leaching solution to obtain an extraction stock solution;

[0010] Step 3: Extract beryllium from the extraction stock solution to obtain a beryllium-loaded organic phase and a raffinate;

[0011] Step 4: The beryllium-loaded organic phase is subjected to back extraction to obtain a back extraction solution;

[0012] Step 5: The back extraction solution is hydrolyzed to prepare beryllium hydroxide, and the beryllium hydroxide is further prepared into beryllium oxide.

[0013] Preferably, the concentration of beryllium in the beryllium sulfate leaching solution described in step 1 is 1-3 g / L, preferably 2-3 g / L.

[0014] Preferably, the iron powder in step 2 is 0.6-1.5 times the molar amount of ferric iron in the leaching solution.

[0015] Preferably, before adding the iron powder in step 2, it also includes adjusting the pH value of the leaching solution of beryllium ore with an alkaline earth metal compound, and the atomic number N of the alkaline earth metal is ≥20.

[0016] For the raffinate described in step 3, the pH value of the leaching solution of beryllium ore is adjusted with an alkaline earth metal compound to remove impurities in the solution and return it to step 1 for recycling, and the atomic number N of the alkaline earth metal is ≥20;

[0017] Preferably, in step 3, a non-saponified extraction system without sodium ions and ammonium cations is used, and the non-saponified extraction system exchanges hydrogen ions with itself when extracting beryllium ions.

[0018] Preferably, the non-saponified extraction system includes: a cationic extractant, a synergistic extractant, and a diluent.

[0019] Preferably, the cationic extractant is one or more of P204, P507, or Cy272; and / or, the synergistic extractant is one or more of sec-octanol, n-octanol, or TBP; and / or, the diluent is kerosene.

[0020] Preferably, the cationic extractant is P204 and the synergistic extractant is TBP.

[0021] A kind of beryllium oxide is prepared by the above-mentioned clean smelting method of beryllium oxide, and the purity of beryllium oxide is ≥99%.

[0022] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0023] (1) In the present invention, by introducing iron powder, the original ferric iron in the leaching solution is reduced to ferrous iron with weaker extraction competitiveness, thereby improving the recovery rate of beryllium during extraction; at the same time, calcium salt is introduced to participate in the adjustment of the pH value of the leaching solution, avoiding the introduction of new cations, and thus improving the recovery rate of beryllium during extraction;

[0024] (2) The present invention uses iron powder reduction to cancel the traditional pre-extraction reduction with sodium sulfite and the washing step of the loaded phase with sodium sulfite, fundamentally solving the problem of the introduction of sodium ions in the beryllium smelting process; at the same time, the magnetic adsorption separation method of iron used in the present invention reduces the loss of residual beryllium ions on the filter cake layer, pipeline, and filtration equipment compared with the traditional iron removal by filtration, which helps to improve the recovery rate of beryllium in the extraction operation;

[0025] (3) The present invention uses alkaline earth metal compounds as impurity removal reagents for the raffinate, and recycles the raffinate after impurity removal for the leaching of beryllium ore. This can not only recover the residual beryllium in the raffinate, improve the beryllium recovery rate, and reduce the environmental pollution caused by beryllium emissions; at the same time, it can remove the associated toxic heavy metals in the beryllium ore, avoid their discharge in solution state, reduce the environmental toxicity, and avoid the accumulation of toxic heavy metals in the leaching solution and the interference with the beryllium extraction process; the hydrolysis precipitation under controlled conditions enables beryllium to be separated in solid state, and the simultaneously obtained hydrolysis mother liquor is recycled for stripping. This can not only recover the residual beryllium in the raffinate and hydrolysis mother liquor, improve the beryllium recovery rate, and reduce the environmental pollution caused by beryllium emissions; compared with the prior art, it realizes the internal circulation of by-product waste liquid and avoids the generation of waste liquid.

[0026] (4) The non-saponification system adopted by the present invention does not require saponification of the organic phase. The cationic extractant in the organic phase still exists in the H form during the extraction process. After mixing with the aqueous solution, the ion exchange speed is fast, which improves the beryllium recovery rate; while the organic phases of traditional sodium soap and ammonia soap transform the H-type cationic extractant into sodium-type or ammonium-type cationic extractants. The sodium-type or ammonium-type is organic sodium salt or organic ammonium salt, which is easy to emulsify when contacting with the aqueous solution and difficult to phase-separate.

[0027] Other features and advantages of the present invention will be described in the subsequent specification. Moreover, some advantages can be made obvious from the specification, or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the embodiments of the specification and the attached drawings. Brief Description of the Drawings

[0028] Figure 1 : Process flow chart of a clean smelting method of beryllium oxide according to the present invention. Detailed Embodiments

[0029] The following will specifically describe the preferred embodiments of the present invention in conjunction with the attached drawings. Among them, the attached drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention, and are not used to limit the scope of the present invention.

[0030] Regarding Technical Terms

[0031] Smelting: It is a pyrometallurgical process in which metal materials and other auxiliary materials are put into a heating furnace to be melted and conditioned. The furnace charge undergoes certain physical and chemical changes in the high-temperature (1300 - 1600K) furnace, removing impurities, producing crude metal or metal concentrate and slag.

[0032] Most beryllium ores must be decomposed by melting at high temperature (above 1400 °C) to convert beryllium into beryllium oxide that is easily soluble in acid. The smelting of beryllium ore is mainly a process of converting complex beryllium compounds into substances mainly composed of beryllium oxide.

[0033] Aging: Before acid or water leaching, the entire ore heap is completely penetrated with a higher concentration of acid, and then left to stand for a period of time.

[0034] Aging treatment can improve the mineral leaching rate. For minerals that are difficult to leach, the leaching rate can be increased by 20% - 50%.

[0035] Saponification: During the extraction reaction, H + is displaced, which increases the acidity of the solution, affects the distribution ratio, and reduces the distribution. Generally, saponification is carried out before extraction so that the hydrogen ions in the extractant are replaced by saponified cations, which helps to inhibit the increase in pH during extraction. Common methods include the sodium saponification method and the ammonium saponification method of adjusting the pH value using sodium hydroxide and ammonia water.

[0036] On the one hand, the present invention discloses a clean smelting method of beryllium oxide, including using iron powder to remove trivalent iron from the acidic leaching solution of beryllium ore.

[0037] It should be noted that using iron powder to remove trivalent iron from the leaching solution can reduce the interference of trivalent iron on beryllium extraction. This is because: Cation extractants such as P204 and P507 are very easy to extract trivalent iron ions. Reducing trivalent iron ions to divalent iron ions with iron powder can prevent the co-extraction of trivalent iron ions and does not introduce other impurity ions, which not only improves the selective extraction effect of beryllium but also facilitates the treatment of wastewater.

[0038] Preferably, the clean smelting method of beryllium oxide includes extracting beryllium from the beryllium leaching solution using a non-saponified extraction system; the non-saponified extraction includes not using sodium hydroxide or ammonia water to adjust the acidity of the leaching solution and saponifying the extractant.

[0039] It should be noted that using sodium hydroxide or ammonia water to adjust the acidity of the leaching solution introduces cation impurities. The cation impurities compete with beryllium extraction during the extraction of beryllium, which will reduce the separation effect of beryllium.

[0040] Compared with the prior art, the present invention reduces the original trivalent iron in the leaching solution to divalent iron with weaker extraction competitiveness by introducing iron powder, thereby improving the recovery rate of beryllium during extraction; at the same time, introducing calcium salt to participate in the adjustment of the pH value of the leaching solution avoids the introduction of new cations, thereby improving the recovery rate of beryllium during extraction.

[0041] Specifically, the clean smelting method of beryllium oxide includes:

[0042] Step 1: After the beryllium ore is aged with sulfuric acid, it is leached to obtain a leaching solution;

[0043] Step 2: Add iron powder to remove trivalent iron ions from the leaching solution to obtain an extraction stock solution;

[0044] Step 3: Extract beryllium from the extraction stock solution to obtain a beryllium-loaded organic phase and a raffinate;

[0045] Step 4: The beryllium-loaded organic phase is subjected to back extraction to obtain a back extraction solution;

[0046] Step 5: The back extraction solution is hydrolyzed to prepare beryllium hydroxide, and the beryllium hydroxide is further prepared into beryllium oxide.

[0047] Specifically, the concentration of beryllium in the beryllium sulfate leaching solution described in Step 1 is preferably 1-3 g / L, and more preferably 2-3 g / L.

[0048] It should be noted that the reason for selecting the beryllium concentration of 1-3 g / L is that in the non-saponified extraction system, when extracting beryllium into the beryllium-loaded organic phase, the hydrogen ions in the organic phase are exchanged into the aqueous solution, resulting in an increase in the acidity of the solution. However, too high acidity is not conducive to the extraction of beryllium ions. Therefore, it is necessary to control a certain range of beryllium ion concentration.

[0049] Specifically, in the ripening operation in Step 1, the dosage of beryllium ore and sulfuric acid satisfies: 1000 g / L - 2000 g / L; the ripening operation temperature satisfies: 200 °C - 300 °C; the ripening operation time satisfies: 6 h - 12 h.

[0050] It can be understood that the use of high-concentration sulfuric acid in the ripening treatment to completely penetrate the entire ore pile helps to improve the mineral leaching rate: on the one hand, concentrated sulfuric acid can convert aluminum, iron, and beryllium in the ore into soluble salts; on the other hand, the high-temperature environment generated by the large amount of heat released during the ripening process of concentrated sulfuric acid can accelerate the dissociation of beryllium ore.

[0051] Specifically, the median particle size of the beryllium ore in Step 1 satisfies: 100 mesh - 200 mesh.

[0052] Specifically, the leaching solvent for the beryllium ore in Step 1 can be water and / or dilute sulfuric acid.

[0053] Preferably, before the leaching of the beryllium ore in Step 1, it also includes smelting and sample preparation.

[0054] It should be noted that the smelting of beryllium ore converts complex beryllium compounds into substances mainly composed of beryllium oxide, which is beneficial to improving the leaching rate of subsequent leaching; sample preparation is to obtain beryllium ore particles with the target particle size by physical methods (such as crushing, ball milling, sieving).

[0055] Specifically, the iron powder in Step 2 is 0.6 - 1.5 times the molar amount of ferric iron in the leaching solution.

[0056] During implementation, keep a part of the unreacted surplus iron powder in the leaching solution all the time. The surplus iron powder can be separated by magnetic adsorption before the extraction of the leaching solution, and the separated iron powder is recycled and reused to remove ferric iron ions from the leaching solution.

[0057] Compared with the prior art, the traditional pre-extraction reduction with sodium sulfite and the washing step of the loaded phase with sodium sulfite are cancelled, fundamentally solving the problem of the introduction of sodium ions in the beryllium smelting process; at the same time, the method of magnetic adsorption separation of iron adopted in the present invention reduces the loss of residual beryllium ions on the filter cake layer, pipeline and filtration equipment compared with the traditional iron removal by filtration, which helps to improve the recovery rate of beryllium in the extraction operation.

[0058] Specifically, before adding iron powder in step 2, it also includes adjusting the pH value of the leaching solution of beryllium ore with an alkaline earth metal compound, and the atomic number N of the alkaline earth metal is ≥ 20.

[0059] Specifically, the alkaline earth metal compound is one or more of alkaline earth metal oxides, alkaline earth metal weak salts, alkaline earth metal dibasic weak acid hydrogen salts and alkaline earth metal hydroxides.

[0060] Specifically, the alkaline earth metal compound can be one or more of oxides of calcium, strontium, barium elements, carbonates of calcium, strontium, barium elements, bicarbonates of calcium, strontium, barium elements, calcium hydroxide, strontium hydroxide, barium hydroxide.

[0061] It can be understood that sulfates of alkaline earth metals with an atomic number ≥ 20 (alkaline earth metals after calcium) are precipitates or slightly soluble substances, and excessive alkaline earth metal ions can be removed in the form of precipitates.

[0062] During implementation, on the one hand, the alkaline earth metal compound consumes hydrogen ions in the leaching solution to adjust the pH value; on the other hand, the alkaline earth metal ions generated by the reaction of the alkaline earth metal compound with hydrogen ions are consumed by sulfate radicals in the leaching solution to form alkaline earth metal sulfate precipitates and separate from the leaching solution system, avoiding the introduction of new cations, and further avoiding competition with beryllium during cation extraction and reducing the recovery rate of beryllium during extraction.

[0063] Preferably, the pH value of the leaching solution of beryllium ore is adjusted to 1.5 - 2.5 so that divalent iron ions can stably exist without hydrolysis.

[0064] Exemplarily, as Figure 1 shown, using calcium oxide as the pH value adjustment reagent for the leaching solution of beryllium ore, calcium oxide consumes hydrogen ions in the leaching solution of beryllium ore, raises the pH value to the target range, and at the same time the generated calcium cations react with excessive sulfate radicals in the leaching solution to form calcium sulfate precipitates, which are relatively easy to separate from the liquid phase, avoiding the introduction of calcium ions into the leaching solution.

[0065] Preferably, in step 3, a non-saponified extraction system without sodium ions and ammonium cations is adopted, and the non-saponified extraction system exchanges with its own hydrogen ions when extracting beryllium ions.

[0066] Specifically, the non-saponified extraction system includes: a cationic extractant, a co-extractant and a diluent.

[0067] Specifically, the cation extractant is one or more of P204, P507 or Cy272; the co-extractant is one or more of sec-octanol, n-octanol, TBP; the diluent is kerosene.

[0068] Preferably, the cation extractant is P204 and the co-extractant is TBP.

[0069] Specifically, in the non-saponified extraction system, the mass percentage of the cation extractant is 30% - 50%; the mass percentage of the co-extractant is 5% - 25%, and the rest is kerosene.

[0070] Specifically, the mass percentages of the cation extractant are 30%, 32%, 33%, 35%, 37%, 39%, 40%, 41%, 43%, 45%, 47%, 49% and 50%.

[0071] Specifically, the mass percentages of the co-extractant are 5%, 7%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24% and 25%.

[0072] It should be noted that the reasons for choosing the above proportion ranges for the cation extractant, co-extractant and diluent are as follows:

[0073] 1. Compared with the extractant after saponification with sodium soap and ammonia soap, the non-saponified extraction system of the present invention will cause an increase in the acidity of the solution during the extraction process. Therefore, the concentration of the extractant (such as P204) needs to be higher than that of the traditional saponified extraction system to improve the extraction rate;

[0074] 2. The non-saponified extraction system needs to exchange hydrogen ions while extracting beryllium. Therefore, the separation effect of beryllium-aluminum and beryllium-iron is better during the extraction process, which can largely offset the problem of co-extraction of impurities caused by the increase in the concentration of the extractant;

[0075] 3. The co-extractant TBP is selected because TBP is a phosphonate extractant, which has a very similar molecular structure to cation extractants such as P204 and P507, has better compatibility, and can improve the phase separation effect during the extraction process.

[0076] Preferably, the mass percentage of the cation extractant is 30% - 40%, the mass percentage of the co-extractant is 10% - 20%, and the rest is kerosene.

[0077] Compared with the prior art, the non-saponified system adopted by the present invention does not need to saponify the organic phase. The cation extractant in the organic phase still exists in the H form during the extraction process. After mixing with the aqueous solution, the ion exchange speed is fast, which improves the recovery rate of beryllium; while the organic phases of traditional sodium soap and ammonia soap transform the H-type cation extractant into sodium-type or ammonium-type cation extractants. The sodium-type or ammonium-type is an organic sodium salt or organic ammonium salt, which is easy to emulsify and difficult to phase-separate when contacting with the aqueous solution.

[0078] Preferably, in step 3, countercurrent extraction is carried out at room temperature, and the phase ratio O / A can be selected from 1 / 1 to 4 / 1, and the number of stages can be selected from 3 to 6.

[0079] Preferably, step 3 also includes impurity removal treatment of the raffinate to remove toxic heavy metals in the raffinate, and separate them in the form of precipitation for deep burial treatment as waste residue.

[0080] Preferably, the impurity removal reagent for the raffinate can be an alkaline earth metal compound.

[0081] Preferably, the impurity removal reagent for the raffinate can be one or more of oxides of calcium, strontium, and barium elements, carbonates of calcium, strontium, and barium elements, bicarbonates of calcium, strontium, and barium elements, calcium hydroxide, strontium hydroxide, and barium hydroxide.

[0082] Preferably, the pH value after the impurity removal treatment of the raffinate is 5 - 6.

[0083] During implementation, within this pH range, trace beryllium elements in the raffinate after impurity removal treatment exist as soluble beryllate ions; the raffinate after impurity removal treatment is used for the leaching of beryllium ore in step 1.

[0084] Compared with the prior art, the present invention uses an alkaline earth metal compound as the impurity removal reagent for the raffinate, and recycles the raffinate after impurity removal for the leaching of beryllium ore. This not only can recover the residual beryllium in the raffinate, improve the beryllium recovery rate, and reduce the environmental pollution caused by beryllium emissions; at the same time, it can remove metal ion impurities such as iron, aluminum, copper, and calcium and anion impurities such as sulfur, phosphorus, and silicon associated with beryllium ore, avoid their emission in solution state, reduce environmental toxicity, and avoid the accumulation of toxic heavy metals in the leaching solution and the interference with the beryllium extraction process.

[0085] Exemplarily, as Figure 1 shown, using calcium oxide as the impurity removal reagent for the raffinate, solid waste residue and the liquid after impurity removal are obtained after treating the raffinate; the solid waste residue is buried deeply, and the liquid after impurity removal is recycled to step 1 as the leaching solvent for beryllium ore, realizing a production closed-loop and avoiding the generation of waste liquid.

[0086] Specifically, in step 4, the stripping agent is a soluble strong base, so that beryllium ions are desorbed from the extractant and dissolved in the form of beryllate ions to achieve stripping.

[0087] Specifically, the stripping agent can be sodium hydroxide or potassium hydroxide.

[0088] It can be understood that sodium hydroxide or potassium hydroxide reacts with beryllium ions to form soluble cations and beryllate ions, and beryllate ions can coexist with sodium and potassium cations. After adjusting the pH value, beryllate ions form beryllium hydroxide precipitate, which can be easily separated from sodium and potassium cations.

[0089] Compared with the prior art, the present invention uses soluble strong base to strip the beryllium-loaded organic phase, so that beryllium elements are further converted into soluble berylate ions, which is conducive to removing associated metal cations in the beryllium-loaded organic phase and separating them in the strong alkaline environment in the form of precipitation, which is conducive to improving the purity of berylate ions in the stripping solution.

[0090] Preferably, in step 4, countercurrent extraction is carried out at room temperature, the phase ratio O / A can be selected from 2.5 / 1 to 4 / 1, and the number of stages can be selected from 3 to 8.

[0091] Specifically, in step 5, the stripping solution is hydrolyzed to prepare beryllium hydroxide, and the specific operation is as follows: add water for dilution and heat to above 95 °C, and control the concentration of free alkali in the solution not to exceed 1 mol / L.

[0092] Preferably, step 5 further includes evaporating and concentrating the hydrolysis mother liquor and recycling it to step 4 to participate in the stripping.

[0093] Optionally, after the hydrolysis mother liquor is evaporated and concentrated, the stripping agent is supplemented and recycled to step 4 to participate in the stripping.

[0094] During implementation, for example, as Figure 1 shown, in step 4, a sodium hydroxide stripping agent is added to prepare a stripping solution rich in sodium berylate. After the stripping solution is hydrolyzed and precipitated, beryllium hydroxide precipitate and hydrolysis mother liquor are obtained. After the hydrolysis mother liquor is evaporated and concentrated, the stripping agent is supplemented and the back liquid is recycled to step 4 to participate in the stripping, realizing a production closed loop and avoiding the generation of waste liquid.

[0095] Compared with the prior art, the present invention uses hydrolysis precipitation under controlled conditions to separate beryllium in a solid state, and the simultaneously obtained hydrolysis mother liquor is recycled for stripping, so that the residual trace beryllium in the hydrolysis mother liquor can be recovered, the beryllium recovery rate is increased, and the environmental pollution caused by beryllium emission is reduced.

[0096] In step 5, beryllium hydroxide can be prepared into beryllium oxide by using the heating decomposition method in conventional technology to prepare beryllium oxide, and the specific method is not described in detail in the present invention.

[0097] The present invention discloses a clean smelting method of beryllium oxide. By adopting the above steps, the recovery rate of beryllium oxide in the solution is ≥98%.

[0098] On the other hand, the present invention discloses a high-purity beryllium oxide, which is prepared by the above clean smelting method, and the purity of beryllium oxide is ≥99%.

[0099] The present invention discloses a method for measuring the purity of beryllium oxide, which uses the prior art method to measure the content of typical impurities of trace beryllium oxide. The typical impurities include: Fe2O3, Al2O3, CaO, MgO and P.

[0100] In order to further illustrate the technical solution of the present invention, the following examples and comparative examples are further set:

[0101] Example 1

[0102] In this example, beryllium ore (beryllium oxide content 6.5%) is selected to prepare beryllium, including the following steps:

[0103] Step 1: The smelted and matured beryllium ore is leached with water to obtain a beryllium sulfate leaching solution containing 1 g / L of beryllium and 3 g / L of iron ions;

[0104] Step 2: Calcium oxide is added to the beryllium sulfate solution with a total volume of 1 liter to adjust the solution acidity to pH 1.5 and 2 grams of iron powder are added;

[0105] Step 3: 25% wt P204 + 10% wt sec-octanol + 65% wt kerosene is used as the extractant, with a phase ratio O / A = 1 / 1, and countercurrent 5-stage extraction is carried out at room temperature to obtain a loaded organic phase and a raffinate; the raffinate contains less than 0.02 g / L of beryllium and the extraction rate is greater than 98%;

[0106] Step 4: After washing, the loaded organic phase is stripped with an aqueous sodium hydroxide solution as the stripping agent, with a sodium hydroxide concentration of 2.5 mol / L and a stripping phase ratio O / A = 3 / 1, and countercurrent 3-stage stripping is carried out at room temperature to obtain a stripping solution (sodium beryllate solution) with a beryllium content of 2.92 g / L; the raffinate after beryllium extraction is neutralized with the addition of calcium oxide to remove the excess acid, and the solution acidity is adjusted to neutral. Metal ion impurities such as iron, aluminum, copper, and calcium, as well as anion impurities such as sulfur, phosphorus, and silicon, are also removed and sink into the slag, so that the raffinate is purified and can be directly returned to the beryllium ore water leaching process;

[0107] Step 5: The stripping solution obtained in Step 4 is diluted with pure water at a volume ratio of 1 / 1 to a free alkali concentration of 1 mol / L and heated to 98 °C. At this time, sodium beryllate hydrolyzes into beryllium hydroxide precipitate, and beryllium hydroxide product and hydrolysis mother liquor are obtained by filtration. The hydrolysis mother liquor is evaporated and concentrated to be reused as the stripping agent; after calcination at 950 °C, beryllium hydroxide is obtained as high-purity beryllium oxide.

[0108] After calculation, the beryllium recovery rate in the extraction section is 99.1%, and the purity of beryllium oxide is 99.91% (only calculating typical impurity contents).

[0109] Example 2

[0110] In this example, beryllium ore (beryllium oxide content 4.5%) is selected to prepare beryllium, including the following steps:

[0111] Step 1: The smelted and matured beryllium ore is leached with water to obtain a beryllium sulfate leaching solution containing 2 g / L of beryllium and 4.5 g / L of iron ions;

[0112] Step 2: Calcium carbonate is added to the beryllium sulfate solution with a total volume of 1 liter to adjust the solution acidity to pH 1.8 and 4.5 grams of iron powder are added;

[0113] Step 3: Use 35% wt P204 + 10% wt n-octanol + 65% wt kerosene as the extractant, with an O / A ratio of 2 / 1, and perform countercurrent 4-stage extraction at room temperature to obtain the loaded organic phase and the raffinate; the raffinate contains less than 0.03 g / L of beryllium, and the extraction rate is greater than 98.5%;

[0114] Step 4: After washing the loaded organic phase, use an aqueous sodium hydroxide solution as the stripping agent, with a sodium hydroxide concentration of 3 mol / L, and perform countercurrent 3-stage stripping at an O / A ratio of 2.5 / 1 and room temperature to obtain a stripping solution (sodium beryllate solution) with a beryllium content of 2.45 g / L; the raffinate after beryllium extraction is neutralized with the addition of calcium oxide to remove the excess acid, and the solution acidity is adjusted to neutral. Metal ion impurities such as iron, aluminum, copper, and calcium, as well as anion impurities such as sulfur, phosphorus, and silicon, will also be removed and sink into the slag, purifying the raffinate, which can be directly returned to the beryllium ore water leaching process;

[0115] Step 5: Dilute the stripping solution obtained in Step 4 with pure water in a volume ratio of 1 / 1 to a free alkali concentration of 0.8 mol / L, and heat it to 95 °C. At this time, sodium beryllate hydrolyzes to form beryllium hydroxide precipitate. Filter to obtain beryllium hydroxide product and hydrolysis mother liquor. The hydrolysis mother liquor is evaporated and concentrated to be reused as the stripping agent. Beryllium hydroxide is calcined at 950 °C to obtain high-purity beryllium oxide.

[0116] After calculation, the beryllium recovery rate in the extraction section is 99.2%, and the purity of beryllium oxide is 99.89%.

[0117] Example 3

[0118] This example uses beryllium ore (beryllium oxide content 5.6%) to prepare beryllium, including the following steps:

[0119] Step 1: Add water to leach the smelted and matured beryllium ore to obtain a beryllium sulfate leaching solution containing 3 g / L of beryllium and 5.4 g / L of iron ions;

[0120] Step 2: Add calcium oxide to a beryllium sulfate solution with a total volume of 1 liter to adjust the solution acidity to pH 2 and add 4.32 grams of iron powder;

[0121] Step 3: Use 45% wt P204 + 5% wt P507 + 10% wt TBP + 65% wt kerosene as the extractant, with an O / A ratio of 4 / 1, and perform countercurrent 6-stage extraction at room temperature to obtain the loaded organic phase and the raffinate; the raffinate contains less than 0.01 g / L of beryllium, and the extraction rate is greater than 99%;

[0122] Step 4: After washing, the loaded organic phase is subjected to countercurrent stripping with an aqueous sodium hydroxide solution as the stripping agent. The concentration of sodium hydroxide is 3.5 mol / L, the stripping phase ratio O / A is 4 / 1, and countercurrent stripping is carried out in 3 stages at room temperature to obtain a stripping solution (sodium beryllate solution) with a beryllium content of 2.95 g / L. The raffinate after beryllium extraction is neutralized with the addition of calcium oxide to adjust the solution acidity to neutral. Metal ion impurities such as iron, aluminum, copper, and calcium, as well as anion impurities such as sulfur, phosphorus, and silicon, will also be removed and sink into the slag, thus purifying the raffinate, which can be directly returned to the beryllium ore water leaching process.

[0123] Step 5: The stripping solution obtained in Step 4 is diluted with pure water at a volume ratio of 1 / 1 to a free alkali concentration of 0.5 mol / L and heated to 100 °C. At this time, sodium beryllate hydrolyzes to form beryllium hydroxide precipitate. After filtration, beryllium hydroxide product and hydrolysis mother liquor are obtained. The hydrolysis mother liquor is evaporated and concentrated to be recycled as the stripping agent. Beryllium hydroxide is calcined at 950 °C to obtain high-purity beryllium oxide.

[0124] After calculation, the beryllium recovery rate in the extraction section is 99.5%, and the purity of beryllium oxide is 99.9%.

[0125] Example 4

[0126] In this example, beryllium ore (beryllium oxide content 6.5%) is selected to prepare beryllium. The only difference compared with Example 1 is that the synergistic extractant is 10% TBP. After calculation, the beryllium recovery rate in the extraction section of the method in Example 4 is 99.6%, and the purity is 99.96% (only calculating the typical impurity content).

[0127] It can be understood that TBP has a similar structure to cationic extractants (such as P204), and can improve the separation coefficient during the extraction process, resulting in a higher product purity compared to Example 1.

[0128] Comparative Example 1

[0129] In this example, the same beryllium ore as in Example 1 (beryllium oxide content 6.5%) is selected to prepare beryllium oxide. The only difference compared with Example 1 is that iron powder is not added in Step 2. After calculation, the beryllium recovery rate in the extraction section of this method is 97%, and the purity of the prepared beryllium oxide is 98.63%. Due to the interference of Fe 3+ the beryllium recovery rate in the extraction section and the purity of beryllium oxide are significantly reduced, and the Fe2O3 content in Table 1 increases.

[0130] Comparative Example 2

[0131] In this example, the same beryllium ore as in Example 1 (with a beryllium oxide content of 6.5%) was selected to prepare beryllium oxide. The only difference compared with Example 1 is that in Step 2, iron powder was replaced with a sufficient amount of sodium sulfite. After calculation, the beryllium recovery rate in the extraction section of this method is 99.0%, and the purity of the prepared beryllium oxide is 98.93%. However, since it is difficult to remove sodium ions from the extraction solution after their introduction, if the extraction solution is recycled for leaching, it will lead to the accumulation of sodium ions, competing with beryllium, resulting in a decrease in the beryllium extraction rate and an increase in impurity ions in the product. Therefore, the extraction solution cannot be recycled after the replacement of iron powder with a sufficient amount of sodium sulfite, causing a significant increase in the amount of wastewater treatment.

[0132] Comparative Example 3

[0133] In this example, the same beryllium ore as in Example 1 (with a beryllium oxide content of 6.5%) was selected to prepare beryllium oxide. The only difference compared with Example 1 is that in Step 3, a typical sodium salt saponification extraction system was used, and the specific composition of the saponification extraction system is: 25% wt P204 / 10% wt sec-octanol / 65% wt kerosene.

[0134] The specific sodium salt saponification operation is as follows: Sodium hydroxide or ammonia water is used to react with the extractant to convert the H-type extractant into the sodium type, and the conversion rate is the saponification rate.

[0135] After calculation, the beryllium recovery rate in the extraction section is equivalent to that in Example 1, but the purity of beryllium oxide has decreased significantly, only being 98.46%. The main reason is that after sodium salt saponification, it is easy to emulsify when contacting with the aqueous solution, and phase separation is difficult, resulting in a decrease in the separation coefficient of beryllium-aluminum and beryllium-iron, and a large co-extraction of iron and aluminum. At the same time, the introduction of sodium ions makes the raffinate unable to be recycled, increasing the amount of wastewater treatment.

[0136] The typical impurity mass composition in the beryllium oxide product is shown in Table 1:

[0137] Table 1 Typical impurity components of beryllium oxide

[0138]

[0139] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for clean smelting of beryllium oxide, characterized in that, The described clean smelting method includes: Step 1: After the beryllium ore is sulfated and matured, it is leached to obtain a leaching solution; Step 2: Add iron powder to reduce ferric ions in the leaching solution to obtain a stock solution for extraction; Step 3: Extract beryllium from the stock solution for extraction to obtain a beryllium-loaded organic phase and a raffinate; Step 4: The beryllium-loaded organic phase is stripped to obtain a stripping solution; Step 5: The stripping solution is hydrolyzed to prepare beryllium hydroxide, and the beryllium hydroxide is further prepared into beryllium oxide; In the sulfation operation in Step 1, the dosages of the beryllium ore and sulfuric acid satisfy: 1000 g / L - 2000 g / L; the sulfation operation temperature satisfies: 200 °C - 300 °C; Before adding iron powder in Step 2, it also includes adjusting the pH value of the leaching solution of the beryllium ore with an alkaline earth metal compound, and adjusting the pH value of the leaching solution of the beryllium ore to 1.5 - 2.5; In Step 2, there is always a part of the unreacted surplus iron powder in the leaching solution. The surplus iron powder is separated by magnetic adsorption before the extraction of the leaching solution, and the separated iron powder is recycled and reused to remove ferric ions from the leaching solution; For the raffinate described in Step 3, use an alkaline earth metal compound to adjust the pH value of the leaching solution of the beryllium ore to remove impurities in the solution and return it to Step 1 for recycling; In Step 5, the stripping solution is hydrolyzed to prepare beryllium hydroxide. The specific operation is: dilute with water and heat to above 95 °C, and control the free alkali concentration in the solution not to exceed 1 mol / L; Step 5 also includes evaporating and concentrating the hydrolysis mother liquor and recycling it to Step 4 to participate in stripping.

2. The cleaning and smelting method of beryllium oxide according to claim 1, characterized in that, The concentration of beryllium in the beryllium sulfate leaching solution described in Step 1 is 1 - 3 g / L.

3. The method for clean smelting of beryllium oxide according to claim 2, wherein The concentration of beryllium in the beryllium sulfate leaching solution described in Step 1 is 2 - 3 g / L.

4. The method for clean smelting of beryllium oxide according to claim 1, characterized in that The iron powder in Step 2 is 0.6 - 1.5 times the molar amount of ferric ions in the leaching solution.

5. The method for clean smelting of beryllium oxide according to claim 1, characterized in that, The alkaline earth metal atom serial number N in the alkaline earth metal compound added in Step 2 is ≥20.

6. The method for clean smelting of beryllium oxide according to claim 1, characterized in that, In Step 3, a non-saponified extraction system without sodium ions and ammonium cations is used. When the non-saponified extraction system extracts beryllium ions, it exchanges with its own hydrogen ions; The alkaline earth metal atom serial number N in Step 3 is ≥20.

7. The method for clean smelting of beryllium oxide according to claim 6, characterized in that, The non-saponified extraction system includes: a cationic extractant, a co-extractant, and a diluent.

8. The method for clean smelting of beryllium oxide according to claim 7, characterized in that, The cationic extractant is one or more of P204, P507, or Cy272; and / or, the co-extractant is one or more of sec-octanol, n-octanol, or TBP; and / or, the diluent is kerosene.

9. The method for clean smelting of beryllium oxide according to claim 8, characterized in that, The cationic extractant is P204, and the co-extractant is TBP.

10. A beryllium oxide, characterized in that, Prepared by the clean smelting method of beryllium oxide described in any one of Claims 1 - 9, the purity of beryllium oxide ≥99%.

Images