Method for extracting and preparing basic magnesium carbonate from P507 raffinate
Through P507 organic magnesium extraction and metathesis-pyrolysis method, the problem of excessive magnesium content in wastewater in the cobalt extraction process is solved, and the resource recycling of magnesium and efficient wastewater treatment are realized, reducing the treatment cost.
Patent Information
- Application Number
- CN202411961483.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-05-02
AI Technical Summary
In the cobalt extraction process, the magnesium content in the wastewater is too high, resulting in the high cost of treatment of high-salt wastewater. The prior art requires the consumption of a large amount of chemical reagents to precipitate magnesium and soften the water quality.
By organically extracting magnesium in P507, the magnesium in the wastewater was enriched in the P507 raffinate, and alkaline magnesium carbonate was prepared by metathesis-pyrolysis method to realize the open circuit and resource recycling of magnesium in the wastewater.
It effectively reduces the magnesium content in wastewater treatment, avoids the high cost of subsequent magnesium precipitation treatment, realizes resource recycling of magnesium, and produces good quality alkaline magnesium carbonate products.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of hydrometallurgy and wastewater treatment, and provides a method for extracting and preparing basic magnesium carbonate from P507 raffinate. Background Art
[0002] In the field of hydrometallurgy and wastewater treatment technology, relevant enterprises that discharge industrial wastewater should take effective measures to treat the wastewater generated in the production process and recycle it. At present, in the cobalt extraction process, the crude cobalt hydroxide raw material generally contains 4-6% magnesium. This part of magnesium is circulated and enriched in the entire production process of the cobalt salt solution, and finally discharged in the form of wastewater (containing 3-5g / l of magnesium). The wastewater also contains impurities such as Ca, Fe, Co, Ni, Cu, organic matter, TDS, etc. The mass fraction of total salt is above 1% (ion concentration 10000mg / l), which meets the standard of high-salt wastewater.
[0003] At present, the main technologies for treating high-salt wastewater in the industry are: chemical precipitation, membrane separation technology, thermal evaporation technology, freezing nitration, advanced oxidation, etc. When treating high-salt wastewater, the above technologies all require pre-softening of the water. The excessively high magnesium content in the wastewater will consume a large amount of chemical reagents, resulting in high costs for high-salt wastewater treatment.
[0004] The method of the present invention uses P507 organic magnesium extraction to enrich the magnesium in the wastewater in the P507 raffinate, and prepares basic magnesium carbonate by double decomposition-pyrolysis method to realize the open circuit of magnesium in the wastewater. Basic magnesium carbonate can be used in industries such as refractory thermal insulation materials, fire retardant coatings, and medicine to realize the resource recycling of magnesium in the wastewater. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a method for extracting and preparing basic magnesium carbonate from P507 raffinate with good treatment effect, low cost and environmental friendliness.
[0006] To this end, the present invention provides the following technical solutions: The method for extracting and preparing basic magnesium carbonate from P507 raffinate of the present invention comprises the following steps: (1) P204 extraction: P204 extractant and light white oil are mixed at a volume ratio of 1:4-1:5 to obtain an organic extract, and the mixed organic extract is saponified with a 30% sodium hydroxide solution to control the saponification rate to be 50%-60%. Crude cobalt sulfate solution is used as the P204 extraction liquid to perform 7-stage countercurrent extraction and impurity removal at a volume ratio of 1-3:1 to obtain a P204 raffinate; At present, most of the cobalt raw materials used in the hydrometallurgical industry are crude cobalt hydroxide and cobalt carbonate solids. After leaching the raw materials with 98% sulfuric acid, crude cobalt sulfate solution can be obtained. The cobalt sulfate solution is extracted with P204 to remove the impurities of Fe, Mn, Cu, and Zn in the solution to obtain P204 raffinate. The main components of the P204 raffinate are Co, Mg, and Ni elements. The pH value of the P204 raffinate is 3.5.
[0007] (2) P507 extraction: P507 extractant is mixed with light white oil as the extracted organic phase, and the mixed organic phase is saponified with 30% sodium hydroxide solution, and the saponification rate is controlled to be 60%~75%; the soaped P507 organic phase and P204 raffinate are subjected to 7-stage countercurrent extraction at a volume ratio of 3~6:1 to obtain cobalt-loaded organic phase and P507 raffinate.
[0008] The volume ratio of the P507 extractant to the light white oil is 1:5-1:4. The P507 raffinate contains 2-8 g / L Mg, 30-50 g / L Na, and <0.001 g / L Co.
[0009] (3) P507 organic magnesium extraction: P507 extractant is mixed with light white oil as an organic extract, and the mixed organic is saponified with 30% sodium hydroxide solution, with a saponification rate of 60% to 75%; the soaped P507 organic phase and the P507 raffinate obtained in step (2) are subjected to 9-stage countercurrent extraction at a volume ratio of 2 to 3:1 to obtain magnesium-loaded organic and magnesium extraction raffinate; The volume ratio of P507 extractant to light white oil is 1:5-1:4. The magnesium extraction residual solution contains Mg<0.001g / L, Na40-60g / L, and Co<0.001g / L. The magnesium extraction residual solution is extraction wastewater. After adopting the method of the present invention, the magnesium content in the extraction wastewater is greatly reduced, and the subsequent magnesium precipitation treatment cost is greatly reduced.
[0010] (4) preparing a high-magnesium raffinate: subjecting the magnesium-loaded organic obtained in step (3) to 7-stage countercurrent extraction with the P204 raffinate at a volume ratio of 3 to 6:1 to obtain a cobalt-loaded organic and a high-magnesium raffinate; During the preparation of high-magnesium raffinate, if the raffinate contains less than 20 g / L of Mg, the raffinate is returned to the P507 organic magnesium extraction step for secondary enrichment until a high-magnesium raffinate containing 20-30 g / L of Mg is prepared. After adopting the method of the present invention, magnesium enrichment is effectively achieved.
[0011] (5) Deoiling: The high-magnesium raffinate obtained in step (4) is deoiled by passing it through a deoiler to reduce the oil content therein, thereby ensuring the quality of the product produced in the subsequent steps, and obtaining a high-magnesium raffinate after deoiling; (6) Preparation of basic magnesium carbonate: adding solid sodium carbonate to the deoiled high-magnesium extract obtained in step (5), using a double decomposition-pyrolysis method, wherein the double decomposition reaction temperature is controlled at 50-60°C, the reaction time is 1-2 hours, and the pyrolysis reaction temperature is controlled at 75-85°C, the reaction time is 1-2 hours, to obtain a mixture containing basic magnesium carbonate; the amount of solid sodium carbonate added is such that all magnesium ions in the solution are reacted to MgSO 4 ·3H 2 O is 1.1~1.5 times the theoretical amount required.
[0012] (7) Producing a basic magnesium carbonate product: The mixture containing basic magnesium carbonate obtained in step (6) is filtered, washed three times with water, and dried to obtain a basic magnesium carbonate product, and the washing water is reused. The basic magnesium carbonate product can be used in the fields of refractory thermal insulation materials, fire retardant coatings, etc.
[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) P507 organic magnesium extraction is adopted, and the feed liquid itself is the P507 raffinate produced by the fixed extraction of P507. The whole process has no additional costs except the equipment operation cost, and the obtained magnesium-loaded organic can be directly injected into the P507 production line for extraction, changing the traditional Na and Co replacement into Mg and Co replacement, which does not affect the normal operation of the P507 extraction process; (2) Before the method of the present invention is adopted, the P507 raffinate is extraction wastewater, which contains 2 to 8 g / L of Mg. When performing subsequent wastewater treatment, a large amount of chemical reagents are consumed to precipitate magnesium to soften the water quality, which is costly. After the method of the present invention is adopted, the magnesium extraction raffinate is extraction wastewater, in which the Mg content is reduced to below 0.001 g / L. Compared with directly softening the water quality, the cost is greatly reduced; (3) After the magnesium-loaded organic matter enters the P507 production line, the high-magnesium raffinate is produced as a magnesium sulfate solution. After enrichment, the Mg content can reach 20-30 g / L, effectively realizing the enrichment of magnesium in wastewater; (4) The basic magnesium carbonate product prepared by the present invention has good quality and can be used in the industrial production of refractory thermal insulation materials and fire retardant coatings, effectively realizing the resource recycling of magnesium. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is a process flow chart of the present invention; Figure 2 Schematic diagram of the extraction section of the P204 countercurrent extraction box; Figure 3 Schematic diagram of the extraction section of the P507 countercurrent extraction box; Figure 4 Schematic diagram of the magnesium extraction section and extraction section of the P507 countercurrent extraction box. DETAILED DESCRIPTION
[0015] The process and effects of the present invention are described in detail below in conjunction with the accompanying drawings and specific embodiments. Example
[0016] The embodiment of the present invention is implemented and studied on an actual production line with one set of P204 extraction boxes and two sets of P507 extraction boxes. For the convenience of description, one set of P204 extraction boxes is numbered as 1#P204 extraction box, and two sets of P507 extraction boxes are numbered as 1#P507 extraction box and 2#P507 extraction box, respectively. The number of extraction stages of the 1#P507 extraction box is 7, and the 2#P507 extraction box has 9-stage magnesium extraction stages and 7-stage extraction stages. Figure 2 .
[0017] (1) P204 extractant and light white oil were mixed in a volume ratio of 1:5-1:4 to obtain an organic extract, and the mixed organic extract was saponified with a 30% sodium hydroxide solution to control the saponification rate to 50%-60%. The soaped P204 organic extract was injected into the 1# P204 extraction box, and the crude cobalt sulfate solution leached with 98% sulfuric acid was used as the P204 extraction feed liquid to perform 7-stage countercurrent extraction in a volume ratio of 1-3:1 to obtain a P204 raffinate. The composition of the P204 raffinate is shown in Table 1.
[0018] The principle of P204 extraction and impurity removal reaction is as follows: ①30% liquid alkali saponification: OH - +Na + +HA(Org)→NaA(Org)+H 2 0; ②Extraction and impurity removal: X 2+ +2NaA (Org) → XA 2 (Org)+2Na + or X 3+ +3NaA (Org) → XA 3 (Org)+3Na + (X 2 + , X 3+ Impurity metal ions and a small amount of Co 2+ ).
[0019] (2) Mix the P507 extractant and light white oil in a volume ratio of 1:5-1:4 as the extraction organic phase, and saponify the mixed organic phase with 30% liquid alkali to control the saponification rate to 60%-75%; inject the soaped P507 organic phase into the 1# P507 extraction box and perform 7-stage countercurrent extraction with the P204 raffinate in a volume ratio of 3-6:1 (such as Figure 3 ), control the organic flow of each P507 production line 40m3 / h, P204 raffinate flow rate 10m 3 / h, and the produced P507 raffinate is stored centrally. The composition of P507 raffinate is shown in Table 2.
[0020] The principle of P507 extraction reaction is as follows: ①30% liquid alkali saponification: OH - +Na + +HA(Org)→NaA(Org)+H 2 0; ②Extraction: NaA 2 (Org)+X 2+ →XA 2 (Org)+Na 2+ (X 2+ For Co 2+ 、Ni 2+ and other metal ions).
[0021] (3) Mix the P507 extractant with light white oil as the extracted organic phase, and saponify the mixed organic phase with 30% liquid alkali, with the saponification rate of 60% to 75%; inject the soaped P507 organic phase into the magnesium extraction section of the 2# P507 extraction box and carry out 9-stage countercurrent extraction with the P507 raffinate obtained in step (2) at a volume ratio of 2 to 3:1 (such as Figure 4 ), control organic flow 50m 3 / h, P507 raffinate flow rate 20~25m 3 / h. Magnesium extraction residual solution and magnesium-containing organic load are produced. The composition of magnesium extraction residual solution is shown in Table 3. The magnesium extraction residual solution is returned to the wastewater treatment process, and the magnesium-containing organic load flows to the subsequent stages of the 2#P507 extraction box to continue the extraction operation.
[0022] Comparing the data in Table 2 and Table 3, the extraction rate of Mg in P507 raffinate by organic solvent after P507 soap can reach 99.98%, and the Mg content in the raffinate is less than 0.001 g / L.
[0023] The reaction principle of P507 magnesium extraction is as follows: ①30% liquid alkali saponification: OH - +Na + +HA(Org)→NaA(Org)+H 2 0; ②Magnesium soap: 2NaA (Org) + Mg 2+ →MgA 2 (Org)+2Na + (3) The magnesium-containing organic matter produced by the magnesium extraction of P507 in step (2) flows into the extraction section of the 2#P507 extraction box and is subjected to 7-stage countercurrent extraction with the P204 raffinate at a volume ratio of 3 to 6:1 (e.g. Figure 4 ), control organic flow 40m 3 / h, P204 raffinate flow rate 10m 3 / h, producing a magnesium-enriched raffinate. The composition of the solution after the primary enrichment is shown in Table 4. In order to make the Mg content in the magnesium-enriched raffinate greater than 20g / L, 5m 3 After the first enrichment, the raffinate is returned to the magnesium extraction section of the 2#P507 extraction box for secondary enrichment, so that the magnesium-containing loaded organic matter can load more Mg ions, and the extraction section of the 2#P507 extraction box can produce a high-magnesium raffinate with a Mg content greater than 20 g / L. The composition of the high-magnesium raffinate solution is shown in Table 5.
[0024] The principle of magnesium-loaded organic extraction is as follows: MgA 2 (Org)+X 2+ →XA 2 (Org)+Mg 2+ (X 2+ For Co 2+ 、Ni 2+ Metal ions (4) The high magnesium raffinate was deoiled to obtain the deoiled high magnesium raffinate, and the deoiling effect was observed. The results are shown in Table 6. The results show that the high magnesium raffinate has a good deoiling effect after deoiling treatment and can meet the preparation of basic magnesium carbonate.
[0025] (5) The forward volume is 30m 3 20m3 of titanium was injected into the titanium reactor 3 After degreasing, the high-magnesium extract was stirred, and after the solution temperature was raised to 55°C, 0.62t of sodium carbonate solid was added and the reaction was continued for 1h to carry out double decomposition reaction. The reaction equation is as follows.
[0026] Double decomposition reaction: MgSO 4 +Na 2 CO 3 +3H 2 O→MgCO 3 ·3H 2 O+Na 2 SO 4 The mixture after the double decomposition reaction in the titanium reactor was further heated to 80°C and stirred for 2 hours to perform a thermal decomposition reaction. The reaction equation is as follows.
[0027] Pyrolysis reaction: 5MgCO 3 ·3H 2 O+2H 2 O→4MgCO 3 Mg(OH) 2 +4H 2 O+CO 2 ↑ After the pyrolysis reaction is completed, the stirring of the titanium reactor is stopped, and the temperature is kept at 85°C for 0.5h. The heating is stopped, and the reaction mixture is filtered to obtain a filtrate and a filter residue. The filtrate is returned to the titanium reactor for a second round of preparation.
[0028] (6) The three-wash filter press process adopts a washing process with recycled washing water, that is, the first wash uses the second wash water for slurry washing, the second wash uses the third wash water for slurry washing, the third wash uses pure water for slurry washing, and the first wash water is returned to the basic magnesium carbonate preparation process to continue the reaction.
[0029] The specific process is as follows: the filter residue obtained after the filter press is placed in a slurry tank, slurried and washed with secondary washing water, and then filtered once, the filtrate is returned to the titanium reactor for the preparation of basic magnesium carbonate, the first filter residue is further placed in a slurry tank, slurried and washed with secondary washing water, and then filtered twice, the second filter residue is further placed in a slurry tank, slurried and washed with pure water, and the tertiary filter residue is dried to obtain basic magnesium carbonate solid.
[0030] The present invention firstly uses P507 post-soap organic and P507 raffinate to extract magnesium, replaces the Na ions loaded on the post-soap organic with Mg ions, produces magnesium-containing loaded organic and low-magnesium wastewater (sodium sulfate), reduces the cost of wastewater treatment, and then extracts the magnesium-containing loaded organic with P204 raffinate to produce high-magnesium raffinate (magnesium sulfate), removes oil from the magnesium sulfate and then adds sodium carbonate solid, adopts double decomposition-pyrolysis method to prepare basic magnesium carbonate. Compared with the prior art, the process of using P507 organic magnesium extraction effectively reduces the magnesium content in the wastewater, avoids the consumption of a large amount of chemical reagents when the wastewater is subsequently treated with magnesium precipitation, and has good economic and environmental benefits. At the same time, there is only equipment operation cost in the P507 organic magnesium extraction process, and the P507 organic and P507 raffinate used are all produced by normal production of the production line. Only the process trend is adjusted, which does not affect the operation of the original system and has the characteristics of low operation cost. The basic magnesium carbonate product produced has good quality indicators and can be used for the industrial production of refractory thermal insulation materials and fire retardant coatings.
[0031] The above are preferred embodiments of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. A method for extracting and preparing basic magnesium carbonate from P507 raffinate, characterized in that: The following steps are involved: (1) P204 extraction: P204 extractant and light white oil are mixed at a volume ratio of 1:4-1:5 to use as the extracted organic matter, and the mixed organic matter is saponified with a sodium hydroxide solution, with the saponification rate controlled to be 50%-60%. Crude cobalt sulfate solution is used as the P204 extraction feed liquid, and 7-stage countercurrent extraction is performed to remove impurities at a volume ratio of 1-3:1 to obtain a P204 raffinate; (2) P507 extraction: P507 extractant and light white oil are mixed in a volume ratio of 1:4-1:5 to form an organic extract, and the mixed organic is saponified with sodium hydroxide solution to control the saponification rate to 60%-75%. The soaped P507 organic phase and P204 raffinate are subjected to 7-stage countercurrent extraction in a volume ratio of 3-6:1 to obtain a cobalt-loaded organic and a P507 raffinate; (3) P507 organic magnesium extraction: P507 extractant is mixed with light white oil as an organic extract, and the mixed organic is saponified with sodium hydroxide solution, with a saponification rate of 60% to 75%; the soaped P507 organic phase and the P507 raffinate obtained in step (1) are subjected to 9-stage countercurrent extraction at a volume ratio of 2 to 3:1 to obtain magnesium-loaded organic and magnesium extraction raffinate; (4) preparing a high-magnesium raffinate: subjecting the magnesium-loaded organic obtained in step (2) to 7-stage countercurrent extraction with the P204 raffinate at a volume ratio of 3 to 6:1 to obtain a cobalt-loaded organic and a high-magnesium raffinate; (5) Deoiling: The high-magnesium raffinate obtained in step (3) is deoiled by passing it through a deoiler to reduce the oil content therein, thereby ensuring the quality of the product produced in the subsequent steps, and obtaining a high-magnesium raffinate after deoiling; (6) Preparation of basic magnesium carbonate: adding solid sodium carbonate to the deoiled high-magnesium raffinate obtained in step (4), using a double decomposition-pyrolysis method, wherein the double decomposition reaction temperature is controlled at 50-60° C. for a reaction time of 1-2 h, and the pyrolysis reaction temperature is controlled at 75-85° C. for a reaction time of 1-2 h, to obtain a mixture containing basic magnesium carbonate; (7) Producing a basic magnesium carbonate product: The mixture containing basic magnesium carbonate obtained in step (5) is filtered, washed three times with water, and dried to obtain a basic magnesium carbonate product, and the washing water is reused.
2. The method for extracting and preparing basic magnesium carbonate from P507 raffinate according to claim 1, characterized in that: In step (1), the crude cobalt sulfate solution is obtained by leaching crude cobalt hydroxide and cobalt carbonate with 98% sulfuric acid, and the crude cobalt sulfate solution is extracted with P204 to remove Fe, Mn, Cu and Zn impurities in the solution to obtain P204 raffinate, wherein the main components of the P204 raffinate are Co, Mg and Ni elements, and the pH value of the P204 raffinate is 3.
5.
3. The method for extracting and preparing basic magnesium carbonate from P507 raffinate according to claim 1, characterized in that: In step (2), the P507 raffinate contains Mg2-8 g / L, Na30-50 g / L, and Co<0.001 g / L.
4. The method for preparing basic magnesium carbonate by extracting from P507 raffinate according to claim 1, characterized in that: In steps (1), (2) and (3), the concentration of the sodium hydroxide solution is 30%.
5. The method for extracting and preparing basic magnesium carbonate from P507 raffinate according to claim 1, characterized in that: In step (3), the magnesium extraction residual solution contains Mg<0.001g / L, Na40~60g / L, and Co<0.001g / L.
6. The method for preparing basic magnesium carbonate by extracting from P507 raffinate according to claim 1, characterized in that: In the process of preparing the high-magnesium raffinate in step (4), if the raffinate contains less than 20 g / L of Mg, the raffinate is returned to the P507 organic magnesium extraction step for secondary enrichment until a high-magnesium raffinate containing 20-30 g / L of Mg is prepared. After adopting the method of the present invention, magnesium enrichment is effectively achieved.
7. The method for preparing basic magnesium carbonate by extracting from P507 raffinate according to claim 1, characterized in that: In the process of preparing basic magnesium carbonate in step (6), the amount of sodium carbonate solid added is 1.1 to 1.5 times the theoretical amount required for all magnesium ions in the solution to react into MgSO4·3H2O.