A method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone"

Abstract

The present invention discloses a method for ultra-stable mineralization of beryllium in "artificial fragrant flower stone". The amounts of Ca 2+ , Li + , SiO3 2‑ and F ‑ in the beryllium-containing wastewater or beryllium-containing solid waste slurry are adjusted to an appropriate range for mineralization reaction, so that the free beryllium cations and anions are mineralized into a stable fragrant flower stone [Ca3Li2(BeSiO4)3F2] form, realizing the long-term stabilization of the toxic beryllium element, eliminating the beryllium pollution risk of beryllium-containing wastewater and solid waste, and being particularly suitable for the harmless treatment of beryllium-containing waste generated in the processes of mining, ore dressing, smelting and material processing of beryllium-containing ores such as beryllium ore, lithium ore and fluorite ore. It can make the beryllium content in the wastewater and the beryllium leaching toxicity in the solid waste lower than the national standard, and has the advantages of low cost, no toxicity, simple construction process, high stabilization efficiency, good long-term stability and no secondary pollution.

Description

Technical Field

[0001] The present invention relates to a method for ultra-stable mineralization of beryllium, and in particular to a method for long-term stabilization of beryllium-containing solid waste or wastewater generated during the mining, ore dressing, smelting and material processing of beryllium-containing ores such as beryllium ore, lithium ore and fluorite ore, and belongs to the technical field of beryllium pollution prevention and control. Background Art

[0002] Beryllium is increasingly valued as an emerging material. It is an indispensable and valuable material in atomic energy, rockets, missiles, aviation, space navigation and metallurgical industries. It is mainly used in atomic reactor materials, aerospace engineering materials, beryllium copper alloys, X-ray transmission windows, etc.

[0003] Beryllium compounds such as beryllium oxide, beryllium fluoride, beryllium chloride, beryllium sulfide, beryllium nitrate, etc. are highly toxic, while metallic beryllium is relatively less toxic. Generally speaking, soluble beryllium is highly toxic, while poorly soluble beryllium is less toxic; it is most toxic when injected intravenously, followed by the respiratory tract, and least toxic when injected orally and through the skin. Soluble beryllium compounds are mainly stored in bones, liver, kidneys, and lymph nodes. They can react with plasma proteins to form protein complexes, causing lesions in organs or tissues and causing cancer. Beryllium is listed as a Class I pollutant. Relevant national standards stipulate that the beryllium content in industrial wastewater discharge should be less than 0.005 mg / L, and the concentration in the toxic leaching test of solid waste should be less than 0.02 mg / L.

[0004] There are more than 30 known beryllium-containing minerals, including beryl, hydrous beryllite, chrysoberyl, etc., which are valuable for industrial mining and utilization. They are mainly produced in Brazil, Argentina, India, South Africa, the United States, China and other places. Due to the principle of affinity of earth elements, these industrial beryllium ores are highly dispersed and often co-exist in light element deposits such as lithium and fluorite. Therefore, in the mining, beneficiation, smelting and subsequent material processing of beryllium, lithium and fluorite, wastewater and solid waste containing beryllium are inevitably generated, and the content of free beryllium exceeds the requirements of national standards, resulting in strict restrictions on the discharge of industrial wastewater, storage or disposal of waste slag, which has become a bottleneck problem for the sustainable development of industries such as beryllium, lithium and fluorite. Summary of the invention

[0005] In view of the technical difficulties in the treatment of beryllium pollution in wastewater and solid waste generated in the process of development and utilization of beryllium, lithium and fluorine resources in the prior art, the present invention aims to provide a method for ultra-stable mineralization of beryllium, which can achieve the free beryllium element (including Be 2+ 、Be(OH) 4 2- and its beryllium complex ion), and mineralizes free beryllium into stable chrysanthemum stone [Ca 3 Li 2 (BeSiO 4 )3 F 2 ] minerals, achieving long-term ultra-stable mineralization of free beryllium, so that the beryllium content in the treated beryllium-containing wastewater is lower than 0.005 mg / L, and the beryllium leaching concentration in the leaching toxicity test of beryllium-containing solid waste is lower than 0.02 mg / L, both of which meet the requirements of relevant national standards to reduce beryllium pollution in the environment.

[0006] In order to achieve the above technical purpose, the present invention provides a method for ultra-stable mineralization of beryllium by "artificial fragrant flower stone", which comprises the following steps: 2+ , Li + 、SiO 3 2- and F - After the molar amount of the beryllium and the total molar amount of free beryllium anions and cations are adjusted to 1-4:1, 0.7-2:1, 1-8:1 and 0.7-1.5:1 respectively, a mineralization reaction is carried out. After the mineralization reaction is completed, solid-liquid separation is carried out to obtain beryllium mineralized slag.

[0007] The key to the ultra-stable mineralized beryllium of "artificial fragrant flower stone" provided by the technical solution of the present invention is to creatively adjust the Ca in the system according to the type and content of free ions contained in the beryllium-containing wastewater or beryllium-containing solid waste slurry. 2+ , Li + 、SiO 3 2- and F - The ratio of free anion and cation beryllium ions to control the Be content in the system 2+ 、Be(OH) 4 2- and its beryllium complex ions are highly selectively converted into a stable fragrant flower stone structure to achieve the fixation of free anionic and cationic beryllium ions. 3+ , Fe 2+ , Ca 2+ Mg 2+ , Mn 2+ Cations such as silicate and fluoride will consume externally added ions, and SiO 3 2- , CO 3 2- OH - Anions such as calcium and lithium will consume externally added calcium ions and lithium ions. During the mineralization reaction, soluble calcium salts, lithium salts, silicates and fluorides are added externally to adjust the Ca 2+ , Li + 、SiO 4 2- 、F - With free beryllium elements (including Be 2+ 、Be(OH) 42- The content ratios of beryllium and its beryllium complex ions are strictly controlled at 1-4:1, 0.7-2:1, 1-8:1 and 0.7-1.5:1, respectively, which can create the necessary ions and appropriate ion concentrations to form the structure of fragrant flower stone with free beryllium element, thereby converting free beryllium anions and cations into stable fragrant flower stone.

[0008] The beryllium-containing wastewater or beryllium-containing solid waste of the present invention often also contains Ca 2+ , Li + 、SiO 3 2- 、F - Ions, etc., can be supplemented or reduced according to actual conditions to create an environment that is conducive to the conversion of free beryllium anions and cations into fragrant flower stone structures.

[0009] As a preferred solution, the pH of the beryllium-containing wastewater or beryllium-containing solid waste slurry is controlled within the range of 8 to 10.5. Within the preferred pH range, it is beneficial to deeply purify and remove beryllium in the beryllium-containing wastewater or beryllium-containing solid waste slurry. The pH of the beryllium-containing wastewater or beryllium-containing solid waste slurry is further preferably controlled within the range of 8.5 to 9.5.

[0010] As a preferred solution, the conditions of the mineralization reaction are: the temperature is from room temperature to 80°C, and the time is 10 to 30 minutes. Properly increasing the temperature is conducive to promoting the transformation of free beryllium anions and cations in beryllium-containing wastewater or beryllium-containing solid waste slurry into the structure of chrysanthemum stone.

[0011] As a preferred solution, Ca 2+ , Li + 、SiO 3 2- and F - The adjustment is carried out with soluble calcium salts, lithium salts, silicates and fluorides respectively. The calcium salt is preferably a soluble or slightly soluble calcium salt such as calcium carbonate, calcium oxide, calcium hydroxide, calcium chloride. The lithium salt is preferably a soluble lithium salt such as lithium carbonate, lithium fluoride, lithium sulfate, lithium chloride, lithium nitrate. The silicate is preferably a soluble or slightly soluble silicate such as sodium silicate, potassium silicate, lithium silicate, sodium metasilicate, potassium metasilicate, and the fluoride is preferably a soluble or slightly soluble fluoride salt such as potassium fluoride, sodium fluoride, calcium fluoride, magnesium fluoride.

[0012] As a preferred solution, the soluble calcium salt, lithium salt, silicate and fluoride are pre-treated by slurrying. The slurrying pre-treatment can fully dissolve the calcium salt, lithium salt, silicate and fluoride, improve the subsequent mineralization efficiency and achieve better mineralization effect.

[0013] As a preferred solution, the liquid-to-solid ratio of the slope solid waste slurry is 0.8-3L:1kg.

[0014] As a preferred solution, the filtrate obtained from the solid-liquid separation contains reusable ions, which can be returned to the mineralization process for recycling.

[0015] The beryllium-containing wastewater or beryllium-containing solid waste involved in the present invention includes but is not limited to beryllium-containing wastewater and beryllium-containing solid waste generated during the mining, beneficiation, smelting and material processing of beryllium ore, lithium ore, fluorite ore, etc.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] 1) Aiming at the technical difficulties in the stabilization technology of hazardous free beryllium elements in beryllium-containing wastes (beryllium-containing solid wastes and beryllium-containing waste liquids) in the prior art, the present invention proposes for the first time a method for ultra-stable mineralization of beryllium based on "artificial fragrant flower stone", by adding common calcium salts, lithium salts, silicates and fluorides to beryllium-containing wastewater or beryllium-containing solid waste slurry to adjust the Ca in the system. 2+ , Li + 、SiO 3 2- and F - The ratio of free beryllium anions and cations can mineralize the free anionic and cationic beryllium ions into a stable fragrant flower stone structure, realizing the long-term ultra-stable mineralization of dangerous beryllium elements, which can effectively solve the practical problem of beryllium pollution in the process of resource utilization.

[0018] 2) The beryllium ultra-stable mineralizing agent proposed in the technical solution of the present invention is a conventional chemical product, which has the advantages of being cheap, easy to obtain, easy to store and use, and having no secondary pollution.

[0019] 3) The beryllium ultra-stable mineralization construction process proposed in the technical solution of the present invention is simple and efficient, does not require complex and expensive equipment and instruments, and the overall operation process has the advantages of being economical, efficient, and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the Raman spectrum of the beryllium-containing region of the mineralized product in Example 1. DETAILED DESCRIPTION

[0021] The following examples are provided to further illustrate the content of the present invention, but are not intended to limit the scope of protection of the claims of the present invention.

[0022] Example 1

[0023] The method of the present invention is used to treat beryllium-containing wastewater (Be 77.31 mg / L, Ca 2+ 215.34mg / L,Al 3+ 63.33mg / L, Mg 2+ 1252mg / L,Na + 2285mg / L,K+ 473mg / L,Fe 2+ / 3+ 23.41mg / L,F - 11.23mg / L,SO 4 2- 4~7g / L), the wastewater is weakly acidic (pH4~6), the beryllium ion concentration is 77mg / L, and there are about 22% of solid particles by mass. The ultra-stable mineralization treatment process of beryllium-containing wastewater is briefly described as follows: prepare a mineralizer solution with a mass fraction of 2% calcium carbonate, 0.8% lithium carbonate, 8% sodium silicate and 1% sodium fluoride, add 8L of mineralizer solution to each cubic meter of beryllium-containing wastewater, adjust the solution pH value to 6~10 with sodium hydroxide solution, the reaction temperature is 30℃, stir the reaction for 30min, and after the reaction is completed, perform solid-liquid separation, the filtrate is the beryllium removal purification solution, and the filter cake is the beryllium removal slag. The beryllium content in the beryllium removal purification solution was analyzed and tested, and the beryllium content in multiple batches of beryllium removal purification solutions was 0.001~0.004mg / L, which is lower than the national standard for industrial wastewater discharge.

[0024] Table 1 Beryllium fixation effect at different pH

[0025]

[0026] Example 2

[0027] The method of the present invention is used to treat lithium slag produced by a lithium smelting enterprise in Hunan, wherein the beryllium content of the lithium slag is 0.067%, the water content is 18.67%, and the soluble lithium content is 0.012%. The slag is subjected to leaching toxicity test according to the standards of "Identification Standard for Hazardous Waste Leaching Toxicity Identification (GB 5085.3-2007)" and "Leaching Toxicity of Solid Waste Leaching Method Sulfuric Acid and Nitric Acid Method (HJ / T 299-2007)", and the results show that the beryllium content in the leachate is 8.75 mg / L, which exceeds the national standard of 0.02 mg / L. The treatment process of ultra-stable mineralization of beryllium element in lithium slag is briefly described as follows: Calcium oxide, sodium silicate and sodium fluoride powders are mixed in a mass ratio of 3:12:1, and a 30% mineralizer liquid is pre-configured. The lithium slag is mixed with 1 times the mass of clean water for slurrying. 6L of mineralizer liquid is added to each cubic meter of lithium smelting slag slurry, and the pH of the slurry is controlled at about 6-10. The mineralization temperature is 45°C. After 15 minutes of mineralization reaction, it is filtered, and the filtrate is returned for lithium slag slurrying. The filter cake is the stabilized lithium smelting slag. The leaching toxicity of the stabilized lithium slag was tested and analyzed in multiple batches, and all met the national identification standards for general solid waste.

[0028] Table 2 Beryllium fixation effect at different pH

[0029]

[0030] Example 3

[0031] The method of the present invention is applied to treat mine wastewater containing beryllium fluorite, which contains 0.76-1.52 mg / L beryllium, 154 mg / L calcium, 47 mg / L fluorine, 53 mg / L iron, 1726 mg / L magnesium, 618 mg / L aluminum ions, and needs to be treated and discharged after reaching the standard. The ultra-stable mineralization treatment process of beryllium-containing mine wastewater is briefly described as follows: a mineralizer liquid with a mass fraction of 0.6% lithium carbonate and 15% sodium silicate is configured, 0.5L of mineralizer liquid is added to each cubic meter of beryllium-containing mine wastewater, the pH value of the solution is adjusted to about 7-10 by sodium hydroxide solution, the reaction temperature is room temperature, the reaction is stirred for 45 minutes, and a small amount of flocculant is added after the reaction is completed for dense sedimentation. The overflow is a beryllium-removing purified liquid that meets the industrial wastewater discharge standard; the dense underflow is a beryllium-removing slag, which is discharged into the tailings dam. The beryllium content in the beryllium removal purification liquid was analyzed and tested, and the beryllium content in multiple batches of beryllium removal purification liquid was 0.0004~0.0022 mg / L, which is lower than the national standard for industrial wastewater discharge.

[0032] Table 3 Beryllium fixation effect at different pH

[0033]

Claims

1. A method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone", characterized in that: The Ca in beryllium-containing wastewater or beryllium-containing solid waste slurry 2+ , Li + 、SiO3 2- and F - After the molar amount of beryllium to the total molar amount of free beryllium anions and cations is adjusted to 1-4:1, 0.7-2:1, 1-8:1 and 0.7-1.5:1 respectively, a mineralization reaction is carried out. After the mineralization reaction is completed, solid-liquid separation is carried out to obtain beryllium mineralized slag; the pH of the beryllium-containing wastewater or beryllium-containing solid waste slurry is controlled in the range of 8-10.

5.

2. The method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone" according to claim 1, characterized in that: The conditions of the mineralization reaction are: temperature ranging from room temperature to 80° C., and time ranging from 10 to 30 minutes.

3. The method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone" according to claim 1, characterized in that: Ca 2+ , Li + 、SiO3 2- and F - Adjustment is carried out with soluble calcium salts, lithium salts, silicates and fluorides respectively.

4. The method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone" according to claim 3, characterized in that: Soluble calcium salts, lithium salts, silicates and fluorides are pre-treated by slurrying.

5. The method for ultra-stable mineralization of beryllium using "artificial fragrant flower stone" according to claim 1, characterized in that: The liquid-to-solid ratio of the beryllium-containing solid waste slurry is 0.8~3L:1kg.

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