WO2016188387A1 - 含镁的冶炼废水综合回收的方法 - Google Patents

含镁的冶炼废水综合回收的方法 Download PDF

Info

Publication number
WO2016188387A1
WO2016188387A1 PCT/CN2016/082987 CN2016082987W WO2016188387A1 WO 2016188387 A1 WO2016188387 A1 WO 2016188387A1 CN 2016082987 W CN2016082987 W CN 2016082987W WO 2016188387 A1 WO2016188387 A1 WO 2016188387A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnesium
calcium
slurry
wastewater
solution
Prior art date
Application number
PCT/CN2016/082987
Other languages
English (en)
French (fr)
Inventor
冯宗玉
黄小卫
徐旸
王猛
孙旭
易帅
彭新林
王良士
赵娜
Original Assignee
有研稀土新材料股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 有研稀土新材料股份有限公司 filed Critical 有研稀土新材料股份有限公司
Priority to AU2016266463A priority Critical patent/AU2016266463B2/en
Priority to KR1020177034166A priority patent/KR102093004B1/ko
Publication of WO2016188387A1 publication Critical patent/WO2016188387A1/zh

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds

Definitions

  • the invention relates to the field of smelting and separation, in particular to a method for comprehensive recovery of smelting wastewater containing magnesium.
  • the Baotou mixed rare earth ore mainly adopts the sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction separation process.
  • the wastewater generated in the process is mainly extracted by rare earth sulfate solution.
  • the magnesium sulfate-containing acidic wastewater produced during the transformation process is mainly composed of sulfuric acid, hydrochloric acid, Mg ions, Ca ions, Al ions, F ions and heavy metal ions (such as Pb, Cd and As).
  • the traditional chemical neutralization method uses neutralization treatment by adding lime or calcium carbide slag to produce a large amount of calcium sulfate, calcium fluoride, magnesium hydroxide, etc.
  • the sediment is discharged after the clarification treatment.
  • the treatment process mainly consumes neutralizing agents such as lime and calcium carbide slag, the sedimentation amount is large, the sediment is complicated, and the operating environment is bad. The most important thing is that the recycling of the wastewater obtained after the treatment is limited.
  • the calcium, magnesium and sulfate content in the wastewater treated by this process is saturated, and when used in circulation, calcium sulfate scale is formed in the pipeline, the transfer pump and the storage tank as the temperature changes, and then the continuous Production has had a major impact.
  • the wastewater treated by this process has a very high salt content, and direct efflux will lead to an increase in the salinity of river water, causing serious pollution to soil, surface water and groundwater, leading to further deterioration of the ecological environment.
  • the promulgation and implementation of the new environmental protection law solving the problem of high-salt wastewater and making the near-zero discharge of wastewater will be the ultimate goal.
  • the membrane separation method utilizes selective separation of ions, molecules or particles in water, and the treatment effect is good, but it is easy to cause membrane fouling.
  • the evaporation crystallization method refers to the salty wastewater being concentrated by evaporation to reach a supersaturated state, so that the salt forms a crystal nucleus in the wastewater, and then gradually forms a crystalline solid to realize separation. This method is suitable for the treatment of high salt wastewater.
  • the stripping method refers to the direct contact between the wastewater and the water vapor, so that the volatile substances in the wastewater are diffused into the gas phase in a certain proportion, thereby achieving the purpose of separating the pollutants from the wastewater, and is mainly used for the treatment of volatile pollutants.
  • the chlorination method is to add a certain amount of chlorine gas or sodium hypochlorite to the waste water, so that the ammonia nitrogen is oxidized to N 2 , thereby achieving the purpose of removing ammonia nitrogen.
  • the main object of the present invention is to provide a method for comprehensively recovering magnesium-containing smelting wastewater to provide a wastewater treatment process which is inexpensive, environmentally friendly, and can be recycled after being treated.
  • a method for comprehensively recovering a magnesium-containing smelting wastewater comprising: step S1, adjusting a pH of a magnesium-containing smelting wastewater with a basic substance as a neutralizing agent And a slurry containing magnesium hydroxide and calcium sulfate; wherein the magnesium-containing smelting wastewater is magnesium sulfate-containing wastewater; the alkaline substance is a calcium-containing alkaline substance; and step S2, to magnesium hydroxide-containing Carbon dioxide gas is introduced into the slurry of calcium sulfate to carbonize, and the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the magnesium-containing smelting wastewater is a magnesium sulfate-containing wastewater produced by smelting and separating, sulfuric acid roasting, water immersion, magnesium oxide neutralization and impurity removal, and an extraction and transformation process.
  • step S1 includes: step S11, adjusting the pH of the magnesium-containing smelting wastewater to 4.0 to 10.0 with a calcium-containing alkaline substance to obtain a solid The liquid mixture; step S12, filtering the solid-liquid mixture to obtain a filtrate; and step S13, adjusting the pH of the filtrate to 10.0 to 12.5 with a calcium-containing alkaline substance to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • step S11 a step of adding calcium sulfate seed crystals to the magnesium-containing smelting wastewater; and/or a step of aging the slurry containing magnesium hydroxide and calcium sulfate is further included.
  • the aging time is 0.5 to 6 hours.
  • the step S2 comprises: carbonizing a carbon dioxide gas into the slurry, controlling the pH of the slurry in the range of 6.5 to 8.0 during the carbonization process to obtain a carbonized slurry; and performing solid-liquid separation on the carbonized slurry. , a solid residue and a magnesium hydrogencarbonate solution were obtained.
  • the calcium ion concentration in the magnesium hydrogencarbonate solution is from 0.01 g/L to 0.7 g/L, preferably from 0.01 g/L to 0.4 g/L.
  • the solid slag is purified to obtain calcium sulfate, or is returned to the acidic wastewater generated by the smelting separation to be neutralized to prepare calcium sulfate.
  • the carbon dioxide gas is prepared from the process waste gas, and the process waste gas includes one or more of boiler flue gas, oxalate precipitation and carbonate precipitation roasting kiln gas, and gas generated by saponification extraction of magnesium hydrogencarbonate solution.
  • the magnesium hydrogencarbonate solution is used in a wet smelting process, and the smelting process is a mineral sulfuric acid roasting-water immersion-neutralization impurity removal process, an acid leaching-neutralization impurity removal process, a solution extraction transformation or a precipitation transformation.
  • the smelting process is a mineral sulfuric acid roasting-water immersion-neutralization impurity removal process, an acid leaching-neutralization impurity removal process, a solution extraction transformation or a precipitation transformation.
  • the process by adding a basic substance to adjust the pH to 10.0 to 12.5 magnesium refining wastewater the wastewater is converted to magnesium hydroxide Mg 2+, while a large amount of Ca 2+ It is converted into calcium sulfate precipitate, and after carbonization, the magnesium hydroxide is converted into soluble magnesium hydrogencarbonate, and a small amount of calcium ions are further removed by the precipitation of calcium carbonate, thereby achieving complete separation of calcium and magnesium ions, thereby recovering the recovered
  • the low concentration of calcium ions in the aqueous solution of magnesium bicarbonate effectively solves the scaling problems of pipes, pumps and storage tanks when water is reused.
  • Fig. 1 is a flow chart showing a method for comprehensively recovering magnesium-containing smelting wastewater according to a preferred embodiment of the present invention.
  • the treatment method of the magnesium-containing smelting wastewater in the prior art is either too high in treatment cost or the treated wastewater is limited in recycling due to excessive salt content.
  • the treatment method of the magnesium-containing smelting wastewater in the prior art is either too high in treatment cost or the treated wastewater is limited in recycling due to excessive salt content.
  • a method for comprehensively recycling and recycling a magnesium-containing smelting wastewater comprising: using a basic substance As a neutralizing agent, the pH of the magnesium-containing smelting wastewater is adjusted to 10.0 to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate; wherein the magnesium-containing smelting wastewater is magnesium sulfate-containing wastewater; the alkaline substance is calcium-containing The alkaline substance; and the step S2, carbon dioxide gas is introduced into the slurry containing magnesium hydroxide and calcium sulfate to carbonize, and the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the above method is directed to magnesium-containing smelting wastewater, and the pH of the wastewater is adjusted to 10.0 to 12.5 by adding a calcium-containing alkaline substance (including a basic substance containing calcium and magnesium) as a neutralizing agent to the smelting wastewater. While the Mg 2+ is converted into magnesium hydroxide in the smelting wastewater, the calcium-containing alkaline substance is removed by the formation of calcium sulfate precipitated by the action of H + and SO 4 2- in the smelting wastewater.
  • a calcium-containing alkaline substance including a basic substance containing calcium and magnesium
  • magnesium hydroxide in the wastewater is converted into soluble magnesium hydrogencarbonate, and at the same time, a small amount of free Ca 2+ remaining in the wastewater is converted into carbonic acid.
  • the calcium and magnesium ions are further separated, so that the calcium ions in the recovered magnesium hydrogencarbonate solution are completely separated, and the content of CaSO 4 in the recycled circulating water is greatly reduced, thereby effectively solving the scaling problems of pipes, pumps and storage tanks, and at the same time
  • the obtained magnesium hydrogencarbonate solution is used in the smelting and separating process to realize the recycling of the production wastewater and realize the zero discharge of the wastewater.
  • the magnesium sulfate-containing wastewater treated in the above method includes, but is not limited to, sulfuric acid roasting, water immersion, magnesium oxide neutralization and impurity removal in the smelting and separation process of monazite, xenotime, bastnasite, nickel-cobalt ore. And the magnesium sulfate-containing wastewater produced after the extraction and transformation process, the magnesium sulfate-containing wastewater generated during the separation of any ore can be recycled by the above method of the present invention.
  • the above step S1 includes: step S11, using a calcium-containing alkaline substance to adjust the pH of the magnesium-containing smelting wastewater Adjusting to 4.0 to 10.0 to obtain a solid-liquid mixture; step S12, filtering the solid-liquid mixture to obtain a filtrate; and step S13, adjusting the pH of the filtrate to 10.0 to 12.5 with a basic substance containing calcium to obtain the above-mentioned hydroxide-containing A slurry of magnesium and calcium sulphate.
  • the pH of the magnesium-refining wastewater was adjusted with an alkaline substance to a calcium-containing 4.0 to 10.0, to give the desired solid-liquid mixture is mainly in the refining wastewater and H +, while the reduction process of The calcium sulphate content in the circulating water, thereby minimizing the problem of pipe fouling that is likely to occur when recycled water is reused.
  • all calcium-containing alkaline materials capable of providing an alkaline environment and easily converting calcium into calcium sulfate are suitable for use in the present invention.
  • Calcium hydroxide is preferably used.
  • the source of calcium hydroxide is not limited to a solid powder of calcium hydroxide, but may be an alkaline calcium hydroxide obtained by reacting calcium oxide obtained by calcining calcium oxide or calcium carbonate with water.
  • the calcium-containing alkaline substance is preferably a calcium hydroxide-containing alkaline substance which is rich in natural and inexpensive limestone (or dolomite).
  • the alkaline substance containing calcium and magnesium refers to a mixture containing both calcium hydroxide and magnesium hydroxide
  • the mixture may be a calcium or magnesium containing mineral or an industrial waste containing calcium and magnesium, and the calcined product is reacted with water to obtain
  • the mixture containing calcium hydroxide and magnesium hydroxide may also be a mixture containing calcium hydroxide and magnesium hydroxide obtained after light burning of dolomite.
  • the pH of the smelting wastewater is adjusted to 4.0 to 10.0 by using the calcium-containing alkaline substance, which can neutralize a large amount of H + in the smelting wastewater, and can form calcium as calcium sulfate. Separated from the wastewater. After adjusting the pH of the smelting wastewater to 4.0 to 10.0 with a calcium-containing alkaline substance to obtain a solid-liquid mixture, the solid-liquid mixture is filtered, and the precipitated calcium sulfate is removed to obtain a filtrate, followed by calcium and magnesium.
  • the alkaline substance or the alkaline substance containing calcium adjusts the pH of the filtrate to 10.0 to 12.5.
  • the calcium and magnesium ions in the wastewater are precipitated stepwise, and then the pH of the filtrate after removing the calcium sulfate is controlled in the range of 10.0 to 12.5.
  • the Mg 2+ in the smelting wastewater is converted into magnesium hydroxide under alkaline conditions with calcium and/or magnesium to obtain a slurry containing magnesium hydroxide and calcium sulfate precipitate.
  • the specific reaction pattern is as follows:
  • the pH of the magnesium-containing smelting wastewater is adjusted to 4.0 to 10.0 with a calcium-containing alkaline substance, and the purpose of precipitating calcium sulfate is achieved, in order to make the precipitation easier or more complete.
  • the step of adding calcium sulfate seed crystals to the magnesium-containing smelting wastewater, and/or the slurry containing magnesium hydroxide and magnesium sulfate is further included. The steps of the process. The addition of calcium sulfate seed crystals facilitates the precipitation of calcium sulfate and the precipitation reaction is relatively thorough. The aging treatment can also make the precipitation relatively complete.
  • the specific aging time can be appropriately adjusted according to the amount of the smelting wastewater to be treated.
  • the aging treatment time is 6 hours or less. Controlling the aging time within 6 hours has enabled the calcium sulphate to be precipitated thoroughly enough to facilitate reuse of the treated water. Continued aging time will delay the overall process operation and is not conducive to the overall process flow.
  • the smelting wastewater recovered by the present invention is wastewater containing magnesium sulfate, and the wastewater is mainly Mg 2+ , H + and SO 4 2- , and may also include one or more of Na + , Cl - and NO 3 -
  • the system is complex and there are many kinds of impurity ions.
  • calcium ions are formed in the sulfate ion system by precipitation of calcium sulfate, forming a solid mixture with magnesium hydroxide, and entering the carbonization step.
  • the present invention produces a low activity stable crystalline calcium sulfate precipitate by rationally controlling the pH value during the alkali transfer process, so that the concentration of calcium ions in the aqueous phase is lowered after the alkali rotation, and the low activity calcium sulfate is difficult to be used. Re-dissolving into calcium ions reduces the carbonization rate.
  • the segmental alkali transfer of calcium ions and magnesium ions is achieved by segmental control of the pH value, and then the solid calcium separation is performed to achieve the purpose of removing part of the calcium first, so that the calcium ions in the aqueous phase at the initial carbonization stage. The concentration is lowered.
  • the calcium ions are precipitated more thoroughly during the split alkali transfer, so that the initial concentration of calcium ions in the aqueous phase is lower, and the carbonization effect is better. .
  • the purpose of carbonization is to convert the magnesium hydroxide in the slurry into soluble magnesium hydrogencarbonate while further removing the remaining calcium ions in the slurry to form calcium carbonate.
  • the amount of carbon dioxide introduced in the carbonization step can be reasonably adjusted depending on the amount of wastewater treated.
  • the step S2 includes: carbonizing a carbon dioxide gas into the slurry, and controlling the pH of the slurry in the range of 6.5 to 8.0 during the carbonization process to obtain a carbonized slurry; The carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the wastewater treated by the above neutralization precipitation is a mixed slurry containing Mg(OH) 2 and CaSO 4 , and contains a small amount of free Ca 2+ , OH - and SO 4 2- due to the sparingly soluble nature of CaSO 4 .
  • Carbonization with CO 2 gas converts solid Mg(OH) 2 into Mg(HCO 3 ) 2 solution; due to the presence of a large amount of HCO 3 - ions, the free Ca 2+ in the aqueous phase is converted into CaCO 3 precipitation, which is promoted again Calcium solidification transformation, to achieve the purpose of further water phase calcium removal.
  • the specific reaction formula of the carbonization process is as follows:
  • the amount of carbon dioxide introduced can be controlled by controlling the pH of the slurry in the range of 6.5 to 8.0, so that the calcium ions in the slurry can be precipitated and removed as much as possible in the form of calcium carbonate to achieve calcium.
  • the magnesium is separated so that the concentration of calcium ions in the obtained magnesium hydrogencarbonate solution is as low as possible.
  • the calcium ion concentration in the magnesium hydrogencarbonate solution obtained by solid-liquid separation is from 0.01 g/L to 0.7 g/L, preferably from 0.01 g/L to 0.4 g/L. The lower the calcium ion concentration in the magnesium hydrogencarbonate solution, the less likely it is to cause fouling of the pipe when recycled water is reused, and the recycling of the smelting wastewater is realized.
  • the time of carbonization can be reasonably adjusted according to the concentration of calcium ions in the slurry containing magnesium hydroxide.
  • the carbonization time of the carbonization step is from 10 min to 120 min, more preferably from 20 min to 60 min. Controlling the carbonization treatment time from 10 min to 120 min can not only remove the residual calcium ions in the slurry containing magnesium hydroxide, but also prevent the treatment time of the entire wastewater treatment process from being too long, which also affects the cycle operation cycle and reduces the treatment. effectiveness.
  • the carbonization time is too long, it is possible to cause the calcium ions precipitated as calcium carbonate to be converted into calcium hydrogencarbonate due to excessive carbon dioxide, which is difficult to remove, and it is easy to cause a long treatment cycle, which affects the processing efficiency of the smelting wastewater.
  • the carbonization time is shorter than 10 min, it is very likely that the precipitation of calcium ions is not thorough enough, so that the treated water has a high concentration of calcium ions, which is not conducive to the recycling of water after treatment.
  • the carbonization time is controlled within 20 min to 60 min, so that the concentration of calcium ions in the treated magnesium hydrogencarbonate solution is lower, and the treatment time is relatively short, which is beneficial to the efficient recycling of enterprise wastewater.
  • the above method provided by the present invention embodies the rational use of energy from various aspects, and the above step S2 is no exception.
  • the solid residue obtained in the above step S2 is subjected to purification treatment to obtain calcium sulfate, and the specific purification treatment method includes a sulfuric acid acidification method, as shown in FIG. .
  • the specific method of purification can be selected according to specific production conditions and equipment.
  • the calcium sulfate obtained after purification can be sold as a product to maximize its value.
  • the solid slag is returned to the wastewater produced by the smelting separation for neutralization.
  • the source of the carbon dioxide gas to be introduced may be boiler flue gas, oxalate precipitation and carbonate precipitation roasting kiln gas, and magnesium hydrogencarbonate solution.
  • the gases produced by saponification extraction may be boiler flue gas, oxalate precipitation and carbonate precipitation roasting kiln gas, and magnesium hydrogencarbonate solution.
  • the present invention preferably uses a gas generated in the above several processes as a raw material, and a gas containing carbon dioxide can be obtained by compression, purification or other treatment steps, that is, carbonation containing magnesium hydroxide can be achieved by carbon dioxide.
  • the solution obtains the purpose of the magnesium hydrogencarbonate solution, and can rationally utilize the above process gas, reduce carbon emissions, and meet environmental protection requirements.
  • the magnesium hydrogencarbonate solution obtained after the treatment of the magnesium-containing smelting wastewater can be reused as circulating water (as shown in Fig. 1). Therefore, the step of using water in the separation and smelting process of all the ore, or the step of using the weakly alkaline solution, can use the magnesium hydrogencarbonate solution provided by the above method of the present invention. That is, the magnesium hydrogencarbonate solution obtained by the above method can be used for the ore sulfuric acid roasting-water immersion-neutralization and impurity removal process, the acid leaching-neutralization and impurity removal process, the solution extraction transformation or the precipitation transformation process, the solution extraction separation process and/or One or several of the solution precipitation processes.
  • Baotou rare earth concentrate sulfuric acid roasting water immersion neutralization and impurity removal process Baotou mine rare earth transformation extraction process, Sichuan fluorocarbon antimony ore and ionic rare earth mineral acid leaching neutralization and impurity removal process, and rare earth extraction separation process and rare earth
  • the solution precipitation process is used for recycling.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is used as a treatment object, and calcium hydroxide is added to the wastewater (where calcium hydroxide is quicklime and water)
  • the reaction is carried out to carry out a reaction to bring the pH of the wastewater to 10.0 to obtain a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry containing magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium hydrogencarbonate solution), and the pH of the slurry after the carbonization was controlled to be 7.3.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate.
  • the calcium hydroxide concentration in the solution of magnesium bicarbonate was 0.7 g/L, and was returned to the rare earth solution extraction and separation process for the Baotou rare earth concentrate.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and a mixture containing calcium hydroxide and magnesium hydroxide is added to the wastewater (by light
  • the reaction of burning dolomite with water is carried out to make the pH of the wastewater reach 11.0, and a slurry containing magnesium hydroxide and calcium sulfate is obtained;
  • Carbon dioxide was introduced into the slurry containing magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium hydrogencarbonate solution), and the pH of the slurry after the carbonization was controlled to be 7.3.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate.
  • the concentration of calcium ions in the solution of magnesium bicarbonate was 0.62 g/L, and was returned to the rare earth solution extraction and separation process for the rare earth concentrate of Baotou.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is used as a treatment object, and calcium hydroxide is added to the wastewater (where calcium hydroxide is quicklime and water) The reaction is carried out), the pH of the wastewater is brought to 11.5, and a slurry containing magnesium hydroxide and calcium sulfate is obtained, and the alkalinity of the slurry is 0.24 mol/L;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), carbonized for 60 minutes, and the pH of the slurry after controlling carbonization was 7.3.
  • the carbonized slurry was subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution, and the concentration of magnesium hydrogencarbonate was 3.15 g/L (in terms of MgO), and the carbonization rate was 65.7%.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ions in the solution of magnesium hydrogencarbonate was 0.56 g/L, and was returned to the rare earth solution extraction and separation process for the rare earth concentrate of Baotou.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated as a treatment object, and a mixture containing calcium hydroxide and magnesium hydroxide is added to the wastewater (by light).
  • the reaction of burning dolomite with water is carried out to make the pH of the wastewater reach 12.5, and a slurry containing magnesium hydroxide and calcium sulfate is obtained, and the alkalinity of the slurry is 0.37 mol/L;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.3.
  • the carbonized slurry was subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution having a magnesium hydrogencarbonate concentration of 5.55 g/L (as MgO) and a carbonization ratio of 75.5%.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the calcium hydroxide concentration in the solution of magnesium bicarbonate was 0.45 g/L, and was returned to the rare earth solution extraction and separation process for the Baotou rare earth concentrate.
  • the magnesium sulfate-containing acidic wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is used as a treatment object, and calcium hydroxide is added to the wastewater (where calcium hydroxide is quicklime and The water reaction is carried out to carry out a reaction to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 0.4g/L, and is returned to the rare earth solution extraction and transformation process for the Baotou rare earth concentrate, the extraction and separation of the rare earth solution, and the precipitation process.
  • the magnesium sulfate-containing acidic wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is used as a treatment object, and calcium hydroxide is added to the wastewater (where calcium hydroxide is quicklime and The water reaction is carried out to carry out a reaction to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), carbonized for 120 minutes, and the pH of the slurry after controlling carbonization was 6.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 0.58 g/L, and is returned to the leaching and impurity removal treatment of the rare earth concentrate of Baotou, the extraction process of the rare earth solution, and the extraction and separation process of the rare earth solution.
  • the magnesium sulfate-containing wastewater extracted by the nickel sulfate cobalt solution is treated as a treatment object, and calcium hydroxide (in which calcium hydroxide is obtained by reacting quicklime with water) is reacted to make the pH of the wastewater reach 12.5.
  • calcium hydroxide in which calcium hydroxide is obtained by reacting quicklime with water
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), carbonized for 40 minutes, and the pH of the slurry after controlling carbonization was 8.0.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and calcium hydroxide is added to the wastewater to react to make the pH value of the wastewater reach 12.5. , obtaining a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.0.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 0.49 g/L, and is returned to the rare earth solution precipitation transformation process for the Baotou rare earth concentrate, the extraction and separation of the rare earth solution, and the solution precipitation process.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and calcium hydroxide is added to the wastewater to react to make the pH of the wastewater reach 9.5. , obtaining a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.3.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 1.0g/L, and is returned to the rare earth solution extraction and transformation process for the rare earth concentrate of Baotou, and the extraction and separation process of the rare earth solution.
  • the magnesium sulfate-containing wastewater produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and calcium hydroxide is added to the wastewater to react, so that the pH value of the wastewater reaches 13.0. , obtaining a slurry containing magnesium hydroxide and calcium sulfate;
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.3.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the solid residue is purified by a sulfuric acid acidification method to obtain calcium sulfate for the preparation of cement.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 1.1g/L, and is returned to the rare earth solution extraction and transformation process for the rare earth concentrate of Baotou, and the extraction and separation process of the rare earth solution.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and quicklime is added to the wastewater for reaction, and the pH is adjusted to 5.0 to obtain solid.
  • the liquid mixture was subjected to solid-liquid separation to obtain a filtrate; the pH of the filtrate was adjusted to 12.5 with quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the concentration of calcium ion in the solution of magnesium bicarbonate is 0.3g/L, which is reused in the acid leaching-neutralization and impurity removal process of Baotou rare earth concentrate and the rare earth solution precipitation process of Baotou rare earth concentrate.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated.
  • the pH value of the wastewater is adjusted to 5.0 to obtain a solid-liquid mixture.
  • the filtrate was separated by solid-liquid separation for 6 hours; after the lime was digested, the pH of the filtrate was adjusted to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the concentration of calcium ion in the solution of magnesium bicarbonate was 0.22 g/L, which was reused in the acid leaching-neutralization and impurity removal process of Baotou rare earth concentrate and the rare earth solution precipitation process of Baotou rare earth concentrate.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated.
  • the pH value of the wastewater is adjusted to 5.0 to obtain a solid-liquid mixture.
  • the filtrate was separated by solid-liquid separation for 2 hours; after the lime was digested, the pH of the filtrate was adjusted to 7.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide was introduced into the slurry of magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after controlling the carbonization was 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the concentration of calcium ion in the solution of magnesium bicarbonate was 0.24 g/L, which was reused in the acid leaching-neutralization and impurity removal process of Baotou rare earth concentrate and the rare earth solution precipitation process of Baotou rare earth concentrate.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated.
  • the pH value of the wastewater is adjusted to 5.0 to obtain a solid-liquid mixture.
  • the filtrate was separated by solid-liquid separation for 0.5 h; after the lime was digested, the pH of the filtrate was adjusted to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide was introduced into the above slurry containing magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after the carbonization was controlled to be 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the concentration of calcium ion in the solution of magnesium bicarbonate was 0.27 g/L, which was reused in the acid leaching-neutralization and impurity removal process of Baotou rare earth concentrate and the rare earth solution precipitation process of Baotou rare earth concentrate.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and quicklime is added to the wastewater to react, and calcium sulfate seed crystal is added during the reaction.
  • the pH was adjusted to 5.0 to obtain a solid-liquid mixture, and the solid-liquid separation was carried out to obtain a filtrate; after the lime was digested, the pH of the filtrate was adjusted to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide was introduced into the above slurry containing magnesium hydroxide and calcium sulfate (the carbon dioxide was obtained by treating the gas produced by saponification extraction of magnesium hydrogencarbonate solution), and the pH of the slurry after the carbonization was controlled to be 7.5.
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solid residue and a magnesium hydrogencarbonate solution.
  • the concentration of calcium ion in the solution of magnesium hydrogencarbonate is 0.25g/L, which is reused in the acid leaching-neutralization and impurity removal process of Baotou rare earth concentrate and the rare earth solution precipitation process of Baotou rare earth concentrate.
  • the acidic wastewater containing magnesium sulfate produced by the monazite concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and the pH of the wastewater is adjusted to 4.0 after the lime is digested to obtain a solid-liquid mixture.
  • the liquid was separated to obtain a filtrate; after light burning of dolomite, the pH of the filtrate was adjusted to 11.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.3, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a magnesium hydrogencarbonate solution and a solid residue containing calcium sulfate and calcium carbonate precipitated;
  • the calcium ion concentration in the solution of magnesium hydrogencarbonate is 0.33 g/L, and the solution is returned to the rare earth solution extraction and separation process of the monazite concentrate and the rare earth solution precipitation process.
  • the solid slag is returned for neutralization of acidic wastewater in rare earth ore smelting separation.
  • the acidic wastewater containing magnesium sulfate produced by the monazite concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and the pH of the wastewater is adjusted to 6.0 after the lime is digested to obtain a solid-liquid mixture.
  • the filtrate was separated by liquid; the pH of the filtrate was adjusted to 11.5 with digested light burnt dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.3, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue containing calcium sulfate and calcium carbonate precipitate;
  • the concentration of calcium ions in the solution of magnesium hydrogencarbonate is 0.3 g/L, and the solution is returned to the rare earth solution extraction and separation process of the monazite concentrate and the rare earth solution precipitation process.
  • the acidic wastewater containing magnesium sulfate produced by the extraction and separation of rare earth sulfate solution is treated.
  • the pH value of the wastewater is adjusted to 9.0 to obtain a solid-liquid mixture, and the filtrate is obtained by solid-liquid separation; the pH of the filtrate is determined after light burning of dolomite The value was adjusted to 11.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate, and the slurry had a basicity of 0.67 mol/L.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.3, to obtain carbonized slurry, carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution, magnesium bicarbonate concentration of 12.2g / L (in terms of MgO), carbonization rate of 91.5%;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue containing calcium sulfate and calcium carbonate precipitated;
  • the calcium ion concentration in the solution of magnesium hydrogencarbonate is 0.18 g/L, and the solution is returned to the extraction and separation process of the rare earth sulfate solution and the precipitation process of the rare earth solution.
  • the acidic wastewater containing magnesium sulfate produced by extraction and transformation of rare earth sulfate solution is treated as the treatment object.
  • the pH value of the wastewater is adjusted to 10.0 to obtain a solid-liquid mixture, and the filtrate is obtained by solid-liquid separation; the filtrate is separated by light burning dolomite.
  • the pH was adjusted to 11.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.3, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue containing calcium sulfate and calcium carbonate precipitated;
  • the calcium ion concentration in the solution of magnesium hydrogencarbonate is 0.08 g/L, and the solution is returned to the smelting separation process cycle of the rare earth sulfate solution.
  • the acidic wastewater containing magnesium sulfate extracted by the rare earth sulfate solution is treated as the treatment object.
  • the pH value of the wastewater is adjusted to 4.0 to obtain a solid-liquid mixture, and the filtrate is obtained by solid-liquid separation; the pH of the filtrate is adjusted to 10.0 after the lime is digested.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (from the kiln gas of the rare earth oxalate and carbonate, and the sodium hydrogencarbonate solution is saponified and extracted to produce a gas comprehensively recovered) to carry out carbonization treatment to control the pH.
  • a value of 7.5 a carbonized slurry is obtained, the carbonized slurry contains calcium sulfate and calcium carbonate precipitates, and a magnesium hydrogencarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue containing calcium sulfate and calcium carbonate precipitate;
  • the calcium ion concentration in the solution of magnesium hydrogencarbonate is 0.65 g/L, and the solution is returned to the smelting separation process cycle of the rare earth sulfate solution.
  • the acidic wastewater containing magnesium sulfate produced by the extraction and separation process of the rare earth sulfate solution is treated. After the lime is digested, the pH value of the wastewater is adjusted to 4.0, and a solid-liquid mixture is obtained, and the filtrate is obtained by solid-liquid separation; the pH of the filtrate is adjusted after the lime is digested. At 11.0, a slurry containing magnesium hydroxide and calcium sulfate was obtained.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.5, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue precipitated by calcium sulfate and calcium carbonate;
  • the calcium ion concentration in the solution of magnesium hydrogencarbonate is 0.58 g/L, and the solution is returned to the smelting separation process cycle of the rare earth sulfate solution.
  • the acidic wastewater containing magnesium sulfate produced by the extraction and separation process is treated with lime sulfate, and the pH of the wastewater is adjusted to 4.0 after the lime is digested to obtain a solid-liquid mixture, and the filtrate is obtained by solid-liquid separation; the pH of the filtrate is determined after the lime is digested. Adjusted to 12.0 to give a slurry containing magnesium hydroxide and calcium sulfate.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 7.5, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue precipitated by calcium sulfate and calcium carbonate;
  • the mixed concentrate of monazite ore and xenotime is treated with sulfuric acid roasting-water immersion-magnesia neutralization and impurity-extraction process to produce acidic wastewater containing magnesium sulfate as the treatment object.
  • the pH value of the wastewater is adjusted to 10.0.
  • the solid-liquid mixture was obtained, and the filtrate was obtained by solid-liquid separation; after the light burned dolomite was digested, the pH of the filtrate was adjusted to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • a slurry containing magnesium hydroxide and calcium sulfate is obtained, and carbon dioxide is introduced into the slurry (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize Treatment, control pH value of 6.5, to obtain a carbonized slurry, the carbonized slurry contains calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate and a solid residue containing calcium sulfate and calcium carbonate precipitate;
  • the concentration of calcium ions in the solution of magnesium bicarbonate is 0.5 g/L, and the solution is returned to the cycle of the rare earth smelting separation process of the mixed concentrate of monazite and xenotime.
  • the acidic concentrate containing magnesium sulfate produced by the mixed concentrate of xenotime by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated, and the pH of the wastewater is adjusted to 3.5 after the lime is digested, and a small amount of solid is obtained.
  • the liquid mixture was subjected to solid-liquid separation to obtain a filtrate; after light burning of dolomite, the pH of the filtrate was adjusted to 11.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide is introduced into the slurry containing magnesium hydroxide and calcium sulfate (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize and control a pH of 8.0, a carbonized slurry is obtained, the carbonized slurry contains calcium sulfate and calcium carbonate precipitates, and a magnesium hydrogencarbonate solution;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate, and a solid residue containing calcium sulfate and calcium carbonate precipitated;
  • the concentration of calcium ions in the solution of magnesium bicarbonate is 0.36 g/L, and the solution is returned to the mixed rare earth separation process cycle of the xenotime.
  • the mixed concentrate of xenotime ore is treated with sulfuric acid roasting-water immersion-magnesia neutralization and impurity-extraction process to produce acidic wastewater containing magnesium sulfate.
  • the limestone is added to the wastewater for reaction, and the pH is adjusted to 11.0.
  • a large amount of solid-liquid mixture is obtained, and most of the magnesium forms a precipitate, and the filtrate is obtained by solid-liquid separation; after the light burned dolomite is digested, the pH of the filtrate is adjusted to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
  • Carbon dioxide is introduced into the slurry containing magnesium hydroxide and calcium sulfate (calculated by the kiln gas of boiler flue gas, rare earth oxalate and carbonate, and saponification extraction of magnesium hydrogencarbonate solution) to carbonize and control
  • the pH value is 8.0, the carbonized slurry is obtained, the carbonized slurry contains calcium sulfate and calcium carbonate precipitate, and the magnesium hydrogencarbonate solution is tested, and the concentration of magnesium hydrogencarbonate is 0.54 g/L;
  • the carbonized slurry is subjected to solid-liquid separation to obtain a solution of magnesium hydrogencarbonate, and a solid residue containing calcium sulfate and calcium carbonate precipitated;
  • the concentration of calcium ions in the solution of magnesium hydrogencarbonate is 0.14 g/L, and the solution is returned to the mixed rare earth separation process cycle of the xenotime.
  • the acidic wastewater containing magnesium sulfate produced by the Baotou rare earth concentrate by sulfuric acid roasting-water immersion-magnesia neutralization and impurity removal-extraction transformation process is treated with lime and magnesium-containing wastewater, and the pH is adjusted to 6.0 ⁇ 9.0, solid-liquid separation to obtain filtrate and waste residue, the calcium ion concentration in the filtrate was 1.1g / L.
  • the temperature changes with the pipe and the pump.
  • the storage tank is easy to form scales such as calcium sulfate, which seriously affects the recycling of wastewater, which has a great impact on continuous production.
  • the magnesium bicarbonate solution prepared by carbonization can be used for processes such as water immersion, neutralization, impurity removal, saponification and extraction separation, and can realize closed-circuit recycling of wastewater, achieve near-zero emission, and save a lot of water resources.
  • the present invention can prepare a magnesium hydrogencarbonate solution after performing a precipitation transformation and a carbonization purification step on the magnesium-containing smelting wastewater, and then return to the rare earth smelting and separating process. It not only realizes the comprehensive recycling of wastewater in the process of rare earth smelting, but also realizes zero discharge of production sewage. The utilization rate of the whole technical route is high, and its economic and social benefits are very obvious.
  • the magnesium-containing and calcium-acidic waste water discharged from the rare earth enterprise is comprehensively recycled by the alkali-to-carbonization method of the present invention, which can not only reduce the sewage discharge cost, but also obtain a pure magnesium hydrogencarbonate solution, return to the application of the rare earth solution, and remove impurities and saponify organic
  • the alkali-to-carbonization method of the present invention can not only reduce the sewage discharge cost, but also obtain a pure magnesium hydrogencarbonate solution, return to the application of the rare earth solution, and remove impurities and saponify organic

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Removal Of Specific Substances (AREA)

Abstract

一种含镁的冶炼废水综合回收的方法，包括用碱性物质调节含硫酸镁的酸性冶炼废水的pH值，得到含氢氧化镁和硫酸钙的浆液；碱性物质为含钙的碱性物质；以及向浆液中通入二氧化碳气体进行碳化，然后进行固液分离得到固体渣和碳酸氢镁溶液。通过中和沉淀和碳化提纯等关键工序，将钙离子转化为硫酸钙和少量碳酸钙沉淀回收利用，降低回用水中硫酸钙含量，从而有效解决管道、输送泵及储槽等结垢问题；同时将含镁的冶炼废水中的镁离子转化为碳酸氢镁溶液，可以返回用于冶炼分离，既实现生产过程中物料的循环利用，又实现废水的零排放。

Description

含镁的冶炼废水综合回收的方法 技术领域
本发明涉及冶炼分离领域，具体而言，涉及一种含镁的冶炼废水综合回收的方法。
背景技术
湿法冶炼分离生产过程中，产生了大量废水，如包头混合型稀土矿主要采用硫酸焙烧-水浸-氧化镁中和除杂—萃取转型分离工艺，过程中产生的废水主要为硫酸稀土溶液萃取转型过程产生的含硫酸镁酸性废水，废水中的主要成分为硫酸、盐酸、Mg离子、Ca离子、Al离子、F离子以及重金属离子(如Pb、Cd和As)等。
在湿法冶炼厂废水处理过程中，为中和大量的酸性废水，传统的化学中和法是采用加入石灰或电石渣等进行中和处理，产生大量硫酸钙、氟化钙、氢氧化镁等沉淀物，澄清处理后废水达标排放。该处理工艺虽然消耗的主要是石灰、电石渣等中和剂，但沉淀量大、沉淀物复杂且操作环境恶劣，最主要的是，处理后得到的废水的循环利用受到限制。因而这种工艺处理后的废水中钙、镁以及硫酸根含量饱和，在循环使用时，会随着温度的变化在管道、输送泵以及储槽等器件中形成硫酸钙结垢，进而对连续化生产造成了较大影响。此外，这种工艺处理后的废水含盐量极高，直接外排将导致江河水质矿化度提高，给土壤、地表水以及地下水带来严重的污染，进而导致生态环境的进一步恶化。随着新的环保法颁布实施，解决高盐废水问题并使得废水近零排放将是最终目标。
在冶炼废水的循环回收处理的研究和应用上，目前研究较多的是采用膜分离法、蒸发结晶法、汽提法和折点氯化法等。膜分离法是利用选择透过性分离水中的离子、分子或者微粒，处理效果较好，但易造成膜污染。蒸发结晶方法是指含盐废水经蒸发浓缩，达到过饱和状态，使盐在废水中形成晶核，继而逐步生成晶状固体进而实现分离。此方法适用于高盐废水的处理。汽提法是指让废水与水蒸汽直接接触，使废水中的挥发性物质按一定比例扩散到气相中去，从而达到从废水中分离污染物的目的，主要用于易挥发性污染物的处理。折点氯化法是将一定量的氯气或次氯酸钠加入到废水中，使氨氮被氧化为N2，从而达到去除氨氮的目的。这些方法均具有运行费用较高且投资费用大的缺点，因而在工业上的应用受到了限制。
因此，在冶炼废水的综合回收利用方面，仍需要对现有技术进行改进，以提供一种廉价、环保且处理后的废水能够进行循环利用的废水处理工艺。
发明内容
本发明的主要目的在于提供一种含镁的冶炼废水综合回收的方法，以提供一种廉价、环保且处理后的废水能够进行循环利用的废水处理工艺。
为了实现上述目的，根据本发明的一个方面，提供了一种含镁的冶炼废水综合回收的方法，该方法包括：步骤S1，用碱性物质作为中和剂将含镁的冶炼废水的pH调节至10.0～12.5，得到含氢氧化镁和硫酸钙的浆液；其中，含镁的冶炼废水为含硫酸镁的废水；碱性物质为含钙的碱性物质；以及步骤S2，向含氢氧化镁和硫酸钙的浆液中通入二氧化碳气体进行碳化，并对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
进一步地，含镁的冶炼废水为冶炼分离中经硫酸焙烧、水浸、氧化镁中和除杂以及萃取转型工艺处理后所产生的含硫酸镁的废水。
进一步地，所述含镁的冶炼废水为含硫酸镁的酸性废水时，步骤S1包括：步骤S11，用含钙的碱性物质将含镁的冶炼废水的pH值调节至4.0～10.0，得到固液混合物；步骤S12，对固液混合物进行过滤，得到滤液；以及步骤S13，用含钙的碱性物质将滤液的pH值调节至10.0～12.5，得到含氢氧化镁和硫酸钙的浆液。
进一步地，在步骤S11中，还包括向含镁的冶炼废水中加入硫酸钙晶种的步骤；和/或对含氢氧化镁和硫酸钙的浆液进行陈化处理的步骤。
进一步地，对含氢氧化镁和硫酸钙的浆液进行陈化处理的步骤中，陈化的时间为0.5～6h。
进一步地，步骤S2包括：向浆液中通入二氧化碳气体进行碳化，并在碳化过程中控制浆液的pH值在6.5～8.0范围内，得到碳化后的浆液；以及对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
进一步地，碳酸氢镁溶液中的钙离子浓度为0.01g/L-0.7g/L，优选为0.01g/L-0.4g/L。
进一步地，固体渣经纯化处理得到硫酸钙，或者返回对冶炼分离产生的酸性废水进行中和处理制备得到硫酸钙。
进一步地，二氧化碳气体由工艺废气制备得到，工艺废气包括锅炉烟气、草酸盐沉淀和碳酸盐沉淀的焙烧窑气以及碳酸氢镁溶液皂化萃取产生的气体中的一种或几种。
进一步地，在步骤S2中，碳酸氢镁溶液用于湿法冶炼工序，冶炼工序为矿硫酸焙烧-水浸-中和除杂工序、酸浸-中和除杂工序、溶液萃取转型或沉淀转型工序、溶液萃取分离工序和溶液沉淀工序中的一种或几种。
应用本发明的技术方案，该方法通过向含镁的冶炼废水中加入碱性物质调节pH至10.0～12.5，在将废水中的Mg2+转化为氢氧化镁的同时，将大量的Ca2+转化为硫酸钙沉淀，而经过碳化处理将氢氧化镁转化为可溶性的碳酸氢镁，少量的钙离子进一步的以碳酸钙沉淀形式被去除，实现钙镁离子较为彻底的分离，从而使回收得到的碳酸氢镁水溶液中钙离子浓度低，有效解决了水再利用时管道、输送泵及储槽等结垢问题。
附图说明
构成本申请的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。在附图中：
图1示出了根据本发明的一种优选的实施例中含镁的冶炼废水综合回收的方法的流程示意图。
具体实施方式
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。下面将结合实施例来详细说明本发明。
如背景技术部分所提到的，现有技术中的含镁的冶炼废水的处理方法要么处理成本太高，要么处理后的废水因含盐量过高而使得循环利用受到限制。为了改善现有技术中的上述状况，在本发明一种典型的实施方式中，如图1所示，提供了一种含镁的冶炼废水综合回收循环利用方法，该方法包括：用碱性物质作为中和剂将含镁的冶炼废水的pH调节至10.0～12.5，得到含氢氧化镁和硫酸钙的浆液；其中，含镁的冶炼废水为含硫酸镁的废水；碱性物质为含钙的碱性物质；以及步骤S2，向含氢氧化镁和硫酸钙的浆液中通入二氧化碳气体进行碳化，并对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
上述方法针对含镁的冶炼废水，通过向冶炼废水中加入用含钙的碱性物质(包括含钙和镁的碱性物质)作为中和剂调节废水的pH至10.0～12.5，在将含镁的冶炼废水中Mg2+转化为氢氧化镁的同时，所加入的含钙的碱性物质在冶炼废水中的H+和SO4 2-的作用下，生成硫酸钙沉淀而被去除。然后向上述含有氢氧化镁和硫酸钙的浆液中通入二氧化碳气体进行碳化处理，使得废水中的氢氧化镁转化为可溶性的碳酸氢镁，而同时废水剩余的少量游离的Ca2+转化为碳酸钙与镁离子进一步分离，进而使得回收得到的碳酸氢镁溶液中钙离子分离较为彻底，大幅度降低回收循环水中CaSO4的含量，从而有效解决管道、输送泵及储槽等结垢问题，同时所得碳酸氢镁溶液用于冶炼分离工序，既实现生产废水的循环利用，又实现废水的零排放。
上述方法中所处理的含硫酸镁的废水包括但不仅限于独居石、磷钇矿、氟碳铈矿、镍钴矿等矿的冶炼分离过程中经硫酸焙烧、水浸、氧化镁中和除杂以及萃取转型工艺处理后产生的含硫酸镁废水，任何矿的分离过程中产生的含硫酸镁的废水都可采用本发明的上述方法进行回收利用。
上述步骤S1中，加入碱性物质作为中和剂调节废水的pH至10.0～12.5的方式有多种，具体调节方式可根据实际生产需要进行合理调整。在本发明一种优选的实施例中，当含镁的冶炼废水为含硫酸镁的酸性废水时，上述步骤S1包括：步骤S11，用含钙的碱性物质将含镁的冶炼废水的pH值调节至4.0～10.0，得到固液混合物；步骤S12，对固液混合物进行过滤，得到滤液；步骤S13，用含钙的碱性物质将滤液的pH值调节为10.0～12.5，得到上述含氢氧化镁和硫酸钙的浆液。
上述优选实施例中，用含钙的碱性物质将含镁的冶炼废水的pH值调节至4.0～10.0，得到固液混合物的目的主要是中和冶炼废水中的H+，同时为减少处理后的循环水中的硫酸钙含量， 从而尽量减少回收水再利用时易出现的管道结垢问题。因而，所有能够提供碱性环境且易于使其中的钙转化成硫酸钙被除去的含钙的碱性物质均适用于本发明。优选使用氢氧化钙，氢氧化钙的来源不仅限于氢氧化钙的固体粉末，也可以是氧化钙或碳酸钙焙烧后得到的氧化钙与水反应后得到的碱性氢氧化钙。从冶炼废水的处理成本及原料的循环利用角度考虑，含钙的碱性物质优选以自然界丰富而廉价的石灰石(或白云石)等为原料制备含氢氧化钙的碱性物质。
同样，含钙和镁的碱性物质指同时含有氢氧化钙和氢氧化镁的混合物，该混合物可以是含钙和镁的矿物或含钙和镁的工业废渣经焙烧后的产物与水反应得到的含氢氧化钙和氢氧化镁的混合物，也可以是轻烧白云石消化后得到的含氢氧化钙和氢氧化镁的混合物。
上述优选实施例中，用上述含钙的碱性物质将冶炼废水的pH值调节至4.0～10.0，既能将冶炼废水中大量的H+进行中和，又能使钙以硫酸钙的形成从废水中分离出来。在用含钙的碱性物质将冶炼废水的pH值调节至4.0～10.0得到固液混合物后，对固液混合物进行过滤，将其中的沉淀硫酸钙除去得到滤液，接着再用含钙和镁的碱性物质或含钙的碱性物质将滤液的pH值调节为10.0～12.5。通过控制加入的含钙的碱性物质中和剂的加入量及pH值，使得废水中的钙镁离子得到分步沉淀，然后将除去硫酸钙后的滤液的pH值控制在10.0～12.5的范围内，使冶炼废水中的Mg2+在有钙和/或镁的碱性条件下转化成氢氧化镁，得到含氢氧化镁和硫酸钙沉淀的浆液。具体发生的反应式如下：
2H+(液)+SO4 2-(液)+Ca(OH)2(固)→CaSO4(固)+H2O(液)
Mg2+(液)+SO4 2-(液)+Ca(OH)2(固)→Mg(OH)2(固)+CaSO4(固)
在上述优选的实施例中，用含钙的碱性物质将含镁的冶炼废水的pH值调节至4.0～10.0已经能够实现使硫酸钙沉淀的目的，为了使沉淀更容易发生或者沉淀更彻底，在本发明另一种优选的实施例中，在上述步骤S1中，还包括向含镁的冶炼废水中加入硫酸钙晶种的步骤，和/或对含氢氧化镁和硫酸镁的浆液进行陈化处理的步骤。加入硫酸钙晶种便于硫酸钙沉淀更易发生且沉淀反应相对彻底。而陈化处理同样能够使沉淀相对完全。具体陈化的时间可以根据所处理的冶炼废水的量进行适当调整，本发明一种优选的实施例中，陈化处理的时间为小于等于6h。将陈化时间控制在6h内，已能够使硫酸钙沉淀的足够彻底，利于处理后的水再次利用，继续延长陈化时间会导致整体工艺流程操作上的延缓，不利于工艺整体流程的进行。
本发明所回收处理的冶炼废水是含硫酸镁的废水，废水中主要为Mg2+、H+和SO4 2-，还可能包括Na+、Cl-、NO3 -中的一种或几种，体系复杂，杂质离子种类繁多。采用含钙的碱性物质进行处理时，钙离子在硫酸根离子的体系中会以硫酸钙的沉淀形成存在，与氢氧化镁形成固体混合物，共同进入碳化步骤中。在碳化过程中，如果体系中存在大量钙离子会诱导碳酸氢根生成碳酸钙晶体，降低碳酸氢镁的生成率，并导致碳酸氢镁分解为碳酸镁固体析出，大量结垢对连续化生产造成了较大影响。
因此，本发明通过对碱转过程中pH值的合理控制，产生低活度的稳定的晶型硫酸钙沉淀，使碱转后水相中钙离子的浓度降低，且低活度的硫酸钙不易再溶解为钙离子降低碳化率。上 述优选实施例中通过对pH值的分段控制，实现了钙离子和镁离子的分段碱转，然后通过固液分离达到先去除部分钙的目的，从而使碳化初始时水相中钙离子的浓度降低。而通过进一步地加入晶种和/或进行陈化处理，使钙离子在分段碱转沉淀时，沉淀的更彻底，从而使碳化初始时水相中钙离子的浓度更低，碳化效果更好。
在上述碳化步骤中，碳化的目的是将浆液中的氢氧化镁转化为可溶性的碳酸氢镁，同时将浆液中剩余的钙离子以形成碳酸钙进一步除去。因而碳化的步骤中通入的二氧化碳的量可根据所处理的废水量进行合理调整。在本发明一种优选的实施例中，上述步骤S2包括：向浆液中通入二氧化碳气体进行碳化，并在碳化过程中控制浆液的pH值在6.5～8.0范围内，得到碳化后的浆液；以及对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经上述中和沉淀处理后的废水为含Mg(OH)2和CaSO4的混合浆液，由于CaSO4的微溶特性，因此还含有少量游离的Ca2+、OH-和SO4 2-。利用CO2气体进行碳化，使固态Mg(OH)2转化为Mg(HCO3)2溶液；由于大量HCO3 -离子的存在，使水相中游离Ca2+转化为CaCO3沉淀，即再次促进钙的固化转型，达到进一步水相除钙的目的。碳化过程的具体反应式如下：
Mg(OH)2(固)+2CO2(气)→Mg(HCO3)2(液)
Ca2++2HCO3 --→CaCO3(固)+H2O(液)+CO2(气)
在此碳化反应过程中可能发生如下副反应：
Mg(OH)2(固)+CO2(固)+H2O→MgCO3·3H2O(固)
上述优选实施例中，通过控制浆液的pH值在6.5～8.0范围内的方式控制通入的二氧化碳的量，能使浆液中的钙离子够尽可能地以碳酸钙的形式进行沉淀去除，达到钙镁分离，使得到的碳酸氢镁溶液中钙离子的浓度尽量降低。采用上述实施例碳化步骤，在固液分离得到的碳酸氢镁溶液中钙离子浓度为0.01g/L-0.7g/L，优选0.01g/L-0.4g/L。碳酸氢镁溶液中的钙离子浓度越低，作为循环水再利用的时候也越不容易引起管道结垢，实现冶炼废水的循环利用。
在上述优选的实施例中，碳化的时间可以根据含氢氧化镁的浆液中钙离子浓度的多少进行合理调整。在本发明又一种优选的实施例中，优选上述碳化步骤的碳化的时间为10min～120min，更优选为20min～60min。将碳化处理的时间控制在10min～120min，既能实现对含氢氧化镁的浆液中残留的钙离子的去除，又不至于使整个废水处理工艺的处理时间过长也影响循环运转周期，降低处理效率。若碳化时间过长，既有可能使沉淀为碳酸钙的钙离子因二氧化碳过多又转化成碳酸氢钙而难以除去，而且还容易导致处理周期变长，影响企业对冶炼废水的处理效率。而碳化时间短于10min，则极有可能是钙离子沉淀的不够彻底，使得处理后的循环水中含有的钙离子浓度较高，不利于处理后水的循环利用。而将碳化的时间控制在20min～60min内，使处理后的碳酸氢镁溶液中钙离子的浓度更低，且处理时间也相对较短，利于企业废水的高效循环利用。
本发明所提供的上述方法从各方面都体现了对能源的合理利用，上述步骤S2也不例外。在本发明又一种优选的实施例中，如图1所示，上述步骤S2中得到的固体渣经纯化处理得到硫酸钙，具体纯化处理的方式包括硫酸酸化法，如图1所示。。实际应用中，可以根据具体生产条件和设备，选择纯化的具体方式。纯化后得到的硫酸钙可以作为产品进行售卖，从而实现其价值的最大化。在另一种具体的实施例中，将上述固体渣返回对冶炼分离产生的废水进行中和处理。
在上述通入二氧化碳气体进行碳化的步骤中(如图1所示)，通入的二氧化碳气体的来源可以为锅炉烟气、草酸盐沉淀和碳酸盐沉淀的焙烧窑气以及碳酸氢镁溶液皂化萃取产生的气体中的一种或几种。如图1所示，本发明优选以上述几种工艺过程中产生的气体为原料，通过压缩、纯化或其他处理步骤后即可得到含有二氧化碳的气体，即能达到利用二氧化碳碳化含氢氧化镁的溶液得到碳酸氢镁溶液的目的，又能将上述工艺气进行合理利用，低碳减排，符合环保要求。
本发明的上述在步骤S2中，含镁的冶炼废水处理后得到的碳酸氢镁溶液可以作为循环水进行再次利用(如图1所示)。因而，所有矿的分离冶炼工序中用到水的步骤，或者用到弱碱性溶液的步骤均可使用本发明的上述方法所提供的碳酸氢镁溶液。即上述方法处理后得到的碳酸氢镁溶液可用于矿硫酸焙烧-水浸-中和除杂工序、酸浸-中和除杂工序、溶液萃取转型或沉淀转型工序、溶液萃取分离工序和/或溶液沉淀工序的一种或几种。比如，可以用于包头稀土精矿硫酸焙烧水浸中和除杂工序、包头矿稀土转型萃取工序、四川氟碳铈矿和离子型稀土矿酸浸中和除杂工序以及稀土萃取分离工序和稀土溶液沉淀工序，实现循环利用。
下面将结合具体的实施例进一步说明本发明的有益效果。
实施例1
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙(其中，氢氧化钙是生石灰与水反应得到)进行反应，使废水的pH值达到10.0，得到含氢氧化镁和硫酸钙的浆液；
向含氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙。
经检测，碳酸氢镁的溶液中钙离子浓度为0.7g/L，返回用于包头稀土精矿的稀土溶液萃取分离工序中。
实施例2
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加入含氢氧化钙和氢氧化镁的混合物(由轻烧白云石与水反应得到)进行反应，使废水的pH值达到11.0，得到含氢氧化镁和硫酸钙的浆液；
向含氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙。
经检测，碳酸氢镁的溶液中钙离子浓度为0.62g/L，返回用于包头稀土精矿的稀土溶液萃取分离工序中。
实施例3
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙(其中，氢氧化钙是生石灰与水反应得到)进行反应，使废水的pH值达到11.5，得到含氢氧化镁和硫酸钙的浆液，浆液碱度为0.24mol/L；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，碳化60min，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液，碳酸氢镁浓度为3.15g/L(以MgO计)，碳化率为65.7％。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.56g/L，返回用于包头稀土精矿的稀土溶液萃取分离工序中。
实施例4
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加入含氢氧化钙和氢氧化镁的混合物(由轻烧白云石与水反应得到)进行反应，使废水的pH值达到12.5，得到含氢氧化镁和硫酸钙的浆液，浆液碱度为0.37mol/L；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液，碳酸氢镁浓度为5.55g/L(以MgO计)，碳化率为75.5％。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.45g/L，返回用于包头稀土精矿的稀土溶液萃取分离工序中。
实施例5
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，向废水中加氢氧化钙(其中，氢氧化钙是生石灰与水反应得到)进行反应，使废水的pH值达到12.5，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.4g/L，返回用于包头稀土精矿的稀土溶液萃取转型工序、稀土溶液萃取分离、沉淀工序中。
实施例6
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，向废水中加氢氧化钙(其中，氢氧化钙是生石灰与水反应得到)进行反应，使废水的pH值达到12.5，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，碳化120min，控制碳化后浆液的pH值为6.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.58g/L，返回用于包头稀土精矿的浸出中和除杂、稀土溶液萃取转型工序、稀土溶液萃取分离工序中。
实施例7
以硫酸镍钴溶液萃取分离产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙(其中，氢氧化钙是生石灰与水反应得到)进行反应，使废水的pH值达到12.5，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，碳化40min，控制碳化后浆液的pH值为8.0。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.38g/L，返回用于硫酸镍钴溶液的萃取分离工序中。
实施例8
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙进行反应，使废水的pH值达到12.5，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.0。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为0.49g/L，返回用于包头稀土精矿的稀土溶液沉淀转型工序、稀土溶液萃取分离、溶液沉淀工序中。
对比例1
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙进行反应，使废水的pH值达到9.5，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为1.0g/L，返回用于包头稀土精矿的稀土溶液萃取转型工序、稀土溶液萃取分离工序中。
对比例2
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的废水为处理对象，向废水中加氢氧化钙进行反应，使废水的pH值达到13.0，得到含氢氧化镁和硫酸钙的浆液；
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.3。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
采用硫酸酸化法对固体渣进行纯化，得到硫酸钙，用于水泥的制备。
经检测，碳酸氢镁的溶液中钙离子浓度为1.1g/L，返回用于包头稀土精矿的稀土溶液萃取转型工序、稀土溶液萃取分离工序中。
实施例9
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，向废水中加生石灰进行反应，pH值调节至5.0，得到固液混合物，固液分离得到滤液；用生石灰将所述滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经检测，碳酸氢镁的溶液中钙离子浓度为0.3g/L，重新用于包头稀土精矿的酸浸-中和除杂工序和包头稀土精矿的稀土溶液沉淀工序中。
实施例10
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至5.0，得到固液混合物，陈化6h固液分离得到滤液；生石灰消化后将滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经检测，碳酸氢镁的溶液中钙离子浓度为0.22g/L，重新用于包头稀土精矿的酸浸-中和除杂工序和包头稀土精矿的稀土溶液沉淀工序中。
实施例11
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至5.0，得到固液混合物，陈化2h固液分离得到滤液；生石灰消化后将滤液的pH值调节为7.5，得到含氢氧化镁和硫酸钙的浆液。
向氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经检测，碳酸氢镁的溶液中钙离子浓度为0.24g/L，重新用于包头稀土精矿的酸浸-中和除杂工序和包头稀土精矿的稀土溶液沉淀工序中。
实施例12
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至5.0，得到固液混合物，陈化0.5h固液分离得到滤液；生石灰消化后将所述滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
向上述含氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经检测，碳酸氢镁的溶液中钙离子浓度为0.27g/L，重新用于包头稀土精矿的酸浸-中和除杂工序和包头稀土精矿的稀土溶液沉淀工序中。
实施例13
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，向废水中加生石灰进行反应，反应过程中加入硫酸钙晶种，pH值调节至5.0，得到固液混合物，固液分离得到滤液；生石灰消化后将所述滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
向上述含氢氧化镁和硫酸钙的浆液中通入二氧化碳(其中二氧化碳是碳酸氢镁溶液皂化萃取产生的气体处理后得到)，控制碳化后浆液的pH值为7.5。对碳化后的浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
经检测，碳酸氢镁的溶液中钙离子浓度为0.25g/L，重新用于包头稀土精矿的酸浸-中和除杂工序和包头稀土精矿的稀土溶液沉淀工序中。
实施例14
以独居石精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至4.0，得到固液混合物，固液分离得到滤液；轻烧白云石消化后将滤液的pH值调节为11.5，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.3，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将碳化浆液进行固液分离，得到碳酸氢镁溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.33g/L，此溶液返回独居石精矿的稀土溶液萃取分离工序和稀土溶液沉淀工序中。
固体渣返回用于稀土矿冶炼分离中酸性废水的中和。
实施例15
以独居石精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至6.0，得到固液混合物，固液分离得到滤液；用消化后的轻烧白云石将滤液的pH值调节为11.5，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.3，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.3g/L，此溶液返回独居石精矿的稀土溶液萃取分离工序和稀土溶液沉淀工序中。
实施例16
以硫酸稀土溶液经萃取分离产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至9.0，得到固液混合物，固液分离得到滤液；轻烧白云石消化后将滤液的pH值调节为11.5，得到含氢氧化镁和硫酸钙的浆液，浆液碱度为0.67mol/L。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.3，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液，碳酸氢镁浓度为12.2g/L(以MgO计)，碳化率为91.5％；
将上述碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.18g/L，此溶液返回硫酸稀土溶液萃取分离工序和稀土溶液沉淀工序中。
实施例17
以硫酸稀土溶液萃取转型、萃取分离产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至10.0，得到固液混合物，固液分离得到滤液；用轻烧白云石将滤液的pH值调节为11.5，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.3，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将上述碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.08g/L，此溶液返回硫酸稀土溶液的冶炼分离工艺循环中使用。
实施例18
以硫酸稀土溶液萃取分离产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至4.0，得到固液混合物，固液分离得到滤液；生石灰消化后将滤液的pH值调节为10.0，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.5，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.65g/L，此溶液返回硫酸稀土溶液的冶炼分离工艺循环中使用。
实施例19
以硫酸稀土溶液经萃取分离工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至4.0，得到固液混合物，固液分离得到滤液；生石灰消化后将滤液的pH值调节为11.0，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.5，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.58g/L，此溶液返回硫酸稀土溶液的冶炼分离工艺循环中使用。
实施例20
以硫酸镍钴溶液经萃取分离工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至4.0，得到固液混合物，固液分离得到滤液；生石灰消化后将滤液的pH值调节为12.0，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为7.5，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.4g/L，此溶液返回硫酸镍钴溶液的萃取分离工艺循环中使用。
实施例21
以独居石矿与磷钇矿的混合精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至10.0，得到固液混合物，固液分离得到滤液；轻烧白云石消化后将滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
得到含氢氧化镁和硫酸钙的浆液，向浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为6.5，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将碳化浆液进行固液分离，得到碳酸氢镁的溶液和含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.5g/L，此溶液返回独居石矿与磷钇矿的混合精矿稀土冶炼分离工艺循环中使用。
实施例22
以磷钇矿的混合精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，生石灰消化后调节废水pH值至3.5，得到少量固液混合物，固液分离得到滤液；轻烧白云石消化后将滤液的pH值调节为11.5，得到含氢氧化镁和硫酸钙的浆液。
向含氢氧化镁和硫酸钙的浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为8.0，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液；
将碳化浆液进行固液分离，得到碳酸氢镁的溶液，以及含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.36g/L，此溶液返回磷钇矿的混合精矿稀土分离工艺循环中使用。
对比例3
以磷钇矿的混合精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，向废水中加生石灰进行反应，pH值调节至11.0，得到大量固液混合物，镁大部分形成沉淀，固液分离得到滤液；轻烧白云石消化后将滤液的pH值调节为12.5，得到含氢氧化镁和硫酸钙的浆液。
向含氢氧化镁和硫酸钙的浆液中通入二氧化碳(由锅炉烟气、稀土草酸盐和碳酸盐的焙烧窑气、碳酸氢镁溶液皂化萃取产生气体综合回收得到)进行碳化处理，控制pH值为8.0，得到碳化浆液，碳化浆液中含有硫酸钙和碳酸钙沉淀，以及碳酸氢镁溶液，经检测，碳酸氢镁浓度为0.54g/L；
将碳化浆液进行固液分离，得到碳酸氢镁的溶液，以及含硫酸钙和碳酸钙沉淀的固体渣；
经检测，碳酸氢镁的溶液中钙离子浓度为0.14g/L，此溶液返回磷钇矿的混合精矿稀土分离工艺循环中使用。
对比例4
以包头稀土精矿经硫酸焙烧-水浸-氧化镁中和除杂-萃取转型工艺产生的含硫酸镁的酸性废水为处理对象，采用生石灰与含镁的废水进行反应，pH值调节至6.0～9.0，固液分离得到滤液和废渣，滤液中钙离子浓度为1.1g/L。滤液循环使用时，随着温度的变化在管道、输送泵 或储槽上容易形成硫酸钙等结垢，严重影响废水的循环利用，对连续化生产造成了较大影响。
从以上的描述中，可以看出，本发明上述的实施例实现了如下技术效果：
(1)通过中和沉淀和碳化提纯两个关键步骤，将硫酸体系非皂化酸性废水中的Mg2+转化为碳酸氢镁溶液；将废水中的Ca2+转化为硫酸钙和少量碳酸钙，实现钙镁离子较为彻底的分离，大幅度降低回用水中CaSO4含量，从而有效解决管道、输送泵、储槽等结垢问题。
(2)碳化制备的碳酸氢镁溶液，可以用于水浸、中和除杂、皂化以及萃取分离等工序，可以实现废水的闭路循环利用，达到近零排放，节省了大量水资源。
(3)整个体中副产硫酸钙，性质稳定，对环境无影响；且可通过进一步纯化研究达到市售石膏规格。
可以说，本发明对含镁的冶炼废水进行沉淀转型和碳化提纯步骤后即可制得碳酸氢镁溶液，再返回用于稀土冶炼分离工序。既实现了稀土冶炼过程中废水综合循环使用，又实现了生产污水的零排放，整个技术路线资源利用率高，其经济效益和社会效益都十分明显。
对稀土企业排出的含镁和钙酸性废水采用本发明的碱转碳化法进行综合回收利用，不但可以降低排污费用，且处理得到纯净的碳酸氢镁溶液返回应用稀土溶液中和除杂、皂化有机相萃取分离稀土、沉淀制备碳酸稀土等工序中，实现废水循环利用及生产污水的零排放。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种含镁的冶炼废水综合回收的方法，其特征在于，所述方法包括：
    步骤S1，用碱性物质将所述含镁的冶炼废水的pH调节至10.0～12.5，得到含氢氧化镁和硫酸钙的浆液；其中，所述含镁的冶炼废水为含硫酸镁的废水；所述碱性物质为含钙的碱性物质；以及
    步骤S2，向所述含氢氧化镁和硫酸钙的浆液中通入二氧化碳气体进行碳化反应，并对碳化后的所述浆液进行固液分离，得到固体渣和碳酸氢镁溶液。
  2. 根据权利要求1所述的方法，其特征在于，所述含镁的冶炼废水为冶炼分离中经硫酸化焙烧、水浸、氧化镁中和除杂以及萃取转型工艺处理后所产生的含硫酸镁的废水。
  3. 根据权利要求1或2所述的方法，其特征在于，所述含镁的冶炼废水为含硫酸镁的酸性废水时，所述步骤S1包括：
    步骤S11，用所述含钙的碱性物质将所述含镁的冶炼废水的pH值调节至4.0～10.0，得到固液混合物；
    步骤S12，对所述固液混合物进行过滤，得到滤液；以及
    步骤S13，用所述含钙的碱性物质将所述滤液的pH值调节至10.0～12.5，得到所述含氢氧化镁和硫酸钙的浆液。
  4. 根据权利要求1所述的方法，其特征在于，在所述步骤S1中，还包括向所述含镁的冶炼废水中加入硫酸钙晶种的步骤；和/或对含氢氧化镁和硫酸钙的浆液进行陈化处理的步骤。
  5. 根据权利要求4所述的方法，其特征在于，对所述含氢氧化镁和硫酸钙的浆液进行陈化处理的步骤中，所述陈化的时间为0.5h～6h。
  6. 根据权利要求1所述的方法，其特征在于，所述步骤S2包括：
    向所述含氢氧化镁和硫酸钙的浆液中通入二氧化碳气体进行碳化，并在所述碳化过程中控制所述浆液的pH值在6.5～8.0范围内，得到碳化后的浆液；以及
    对所述碳化后的浆液进行固液分离，得到所述固体渣和所述碳酸氢镁溶液。
  7. 根据权利要求1或6所述的方法，其特征在于，所述碳酸氢镁溶液中的钙离子浓度为0.01g/L-0.7g/L，优选为0.01g/L-0.4g/L。
  8. 根据权利要求1或6所述的方法，其特征在于，所述固体渣经酸化处理制备得到硫酸钙，或者返回对冶炼分离产生的酸性废水进行中和处理制备得到硫酸钙。
  9. 根据权利要求1所述的方法，其特征在于，所述二氧化碳气体由工艺废气制备得到，所述工艺废气包括锅炉烟气、草酸盐沉淀和碳酸盐沉淀的焙烧窑气以及碳酸氢镁溶液皂化萃取产生的气体中的一种或几种。
  10. 根据权利要求1所述的方法，其特征在于，在所述步骤S2中，所述碳酸氢镁溶液用于湿法冶炼工序，所述冶炼工序为矿硫酸焙烧-水浸-中和除杂工序、酸浸-中和除杂工序、溶液萃取转型或沉淀转型工序、溶液萃取分离工序和溶液沉淀工序中的一种或几种。
PCT/CN2016/082987 2015-05-26 2016-05-23 含镁的冶炼废水综合回收的方法 WO2016188387A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2016266463A AU2016266463B2 (en) 2015-05-26 2016-05-23 Method for comprehensive recovery of smelting wastewater containing magnesium
KR1020177034166A KR102093004B1 (ko) 2015-05-26 2016-05-23 마그네슘 함유 제련 폐수를 종합 회수하는 방법

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201510276595.8A CN106277417A (zh) 2015-05-26 2015-05-26 含镁的冶炼废水综合回收的方法
CN201510276595.8 2015-05-26

Publications (1)

Publication Number Publication Date
WO2016188387A1 true WO2016188387A1 (zh) 2016-12-01

Family

ID=57392558

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2016/082987 WO2016188387A1 (zh) 2015-05-26 2016-05-23 含镁的冶炼废水综合回收的方法

Country Status (4)

Country Link
KR (1) KR102093004B1 (zh)
CN (1) CN106277417A (zh)
AU (1) AU2016266463B2 (zh)
WO (1) WO2016188387A1 (zh)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110937586A (zh) * 2018-09-25 2020-03-31 杭州长凯能源科技有限公司 制备材料的循环经济工艺
US10968126B2 (en) 2017-07-07 2021-04-06 Katz Water Tech, Llc Pretreatment of produced water to facilitate improved metal extraction
CN113200764A (zh) * 2021-05-25 2021-08-03 陕西省建筑科学研究院有限公司 一种硅热法炼镁镁渣胶凝材料的匀质性碳化制备方法
CN114538486A (zh) * 2022-02-22 2022-05-27 西安交通大学 一种基于氯碱盐泥的镁回收方法及系统
CN115215339A (zh) * 2022-05-30 2022-10-21 湖北工业大学 一种由电石渣制备碳酸钙碳化晶核并进行固废固碳的方法
CN116477610A (zh) * 2023-06-09 2023-07-25 西南石油大学 一种用含镁废水制备的石墨烯纳米片及其制备方法与应用

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108677038A (zh) * 2018-05-29 2018-10-19 吴远怀 一种离子型稀土矿冶炼分离镁盐废水资源化利用方法
CN109574055B (zh) * 2018-12-02 2021-03-26 河北科技大学 一种盐泥生产轻质碳酸钙和七水硫酸镁的方法
KR102163822B1 (ko) * 2018-12-18 2020-10-12 주식회사 포스코 니켈 습식제련 공정에서 얻어지는 석출용액의 후처리 공정에서 우수한 반응성의 산화마그네슘 회수 방법
CN111440946B (zh) * 2019-01-17 2021-12-14 有研稀土新材料股份有限公司 一种实现碳酸氢镁循环利用的稀土萃取方法
CN109761327A (zh) * 2019-03-13 2019-05-17 联化科技(盐城)有限公司 不含铝离子的废水的处理方法
CN109761326A (zh) * 2019-03-13 2019-05-17 联化科技(盐城)有限公司 不含铝离子的废水的处理方法
CN111285526A (zh) * 2020-03-10 2020-06-16 广西赛可昱新材料科技有限公司 一种处理镍冶炼含镁废水的方法
CN115072812B (zh) * 2021-03-16 2023-07-11 宝山钢铁股份有限公司 硅钢氧化镁废水资源化处理方法及处理系统
CN115385366A (zh) * 2022-09-01 2022-11-25 广东邦普循环科技有限公司 一种含镁废液的处理方法
CN115818677A (zh) * 2022-12-07 2023-03-21 攀钢集团研究院有限公司 一种氢氧化镁的制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6418911A (en) * 1987-07-14 1989-01-23 Maruo Calcium Production of calcium carbonate for paper making
DE19847940A1 (de) * 1998-10-09 2000-04-20 Ver Energiewerke Ag Verfahren zur Aufbereitung von magnesiumsulfathaltigen Wässern
CN101104522A (zh) * 2007-06-05 2008-01-16 昆明贵金属研究所 一种利用硫酸镁废液制备活性氧化镁的方法
CN101519219A (zh) * 2008-02-26 2009-09-02 中国恩菲工程技术有限公司 轻质碳酸镁制备工艺
CN101760641A (zh) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 从硫酸镁溶液中回收镁的工艺
CN101760637A (zh) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 含镁矿石的浸出工艺

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6418911A (en) * 1987-07-14 1989-01-23 Maruo Calcium Production of calcium carbonate for paper making
DE19847940A1 (de) * 1998-10-09 2000-04-20 Ver Energiewerke Ag Verfahren zur Aufbereitung von magnesiumsulfathaltigen Wässern
CN101104522A (zh) * 2007-06-05 2008-01-16 昆明贵金属研究所 一种利用硫酸镁废液制备活性氧化镁的方法
CN101519219A (zh) * 2008-02-26 2009-09-02 中国恩菲工程技术有限公司 轻质碳酸镁制备工艺
CN101760641A (zh) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 从硫酸镁溶液中回收镁的工艺
CN101760637A (zh) * 2008-12-24 2010-06-30 中国恩菲工程技术有限公司 含镁矿石的浸出工艺

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10968126B2 (en) 2017-07-07 2021-04-06 Katz Water Tech, Llc Pretreatment of produced water to facilitate improved metal extraction
US11685676B2 (en) 2017-07-07 2023-06-27 Katz Water Tech, Llc Pretreatment of produced water to facilitate improved metal extraction
CN110937586A (zh) * 2018-09-25 2020-03-31 杭州长凯能源科技有限公司 制备材料的循环经济工艺
CN110937586B (zh) * 2018-09-25 2023-09-22 杭州长凯能源科技有限公司 制备材料的循环经济工艺
CN113200764A (zh) * 2021-05-25 2021-08-03 陕西省建筑科学研究院有限公司 一种硅热法炼镁镁渣胶凝材料的匀质性碳化制备方法
CN114538486A (zh) * 2022-02-22 2022-05-27 西安交通大学 一种基于氯碱盐泥的镁回收方法及系统
CN115215339A (zh) * 2022-05-30 2022-10-21 湖北工业大学 一种由电石渣制备碳酸钙碳化晶核并进行固废固碳的方法
CN115215339B (zh) * 2022-05-30 2023-10-10 湖北工业大学 一种由电石渣制备碳酸钙碳化晶核并进行固废固碳的方法
CN116477610A (zh) * 2023-06-09 2023-07-25 西南石油大学 一种用含镁废水制备的石墨烯纳米片及其制备方法与应用
CN116477610B (zh) * 2023-06-09 2023-09-12 西南石油大学 一种用含镁废水制备的石墨烯纳米片及其制备方法与应用

Also Published As

Publication number Publication date
AU2016266463B2 (en) 2019-07-18
CN106277417A (zh) 2017-01-04
KR20170138561A (ko) 2017-12-15
KR102093004B1 (ko) 2020-05-27
AU2016266463A1 (en) 2018-01-25

Similar Documents

Publication Publication Date Title
WO2016188387A1 (zh) 含镁的冶炼废水综合回收的方法
CA2659451C (en) Desalination methods and systems that include carbonate compound precipitation
CN107337292B (zh) 深度处理脱硫废水的工艺流程
JP6877459B2 (ja) 塩の回収のための方法および配置
US20230159346A1 (en) Facile, low-energy routes for the production of hydrated calcium and magnesium salts from alkaline industrial wastes
Mattila et al. Production of precipitated calcium carbonate from steel converter slag and other calcium-containing industrial wastes and residues
WO2009024014A1 (fr) Procédé pour éliminer de l'ammoniac à partir d'eau usée de cokéfaction
CN109095578B (zh) 一种草酸沉淀法回收电厂脱硫废水钙镁的方法
KR101816677B1 (ko) 해수 담수화 농축수를 이용한 이산화탄소 처리방법
CN105502765A (zh) 一种处理脱硫废水协同回收资源的系统及方法
BR112018001304B1 (pt) Processo de tratamento de efluentes - refinamento de ph para a remoção de sulfato
CN106277005B (zh) 一种从氟化钙污泥资源中回收冰晶石、碳酸钙和硫酸钠的方法
CN101480565B (zh) 一种镁质用后耐火材料用于烟气脱硫后的产物回收的方法
KR20190028937A (ko) 해수 담수화 농축수의 친환경 처리방법
KR20190028936A (ko) pH 연속 조절을 통한 해수 담수화 농축수의 친환경 처리방법
KR101860331B1 (ko) 해수 담수화 농축수 처리방법
CN102671523A (zh) 利用腐植酸盐和脱硫石膏固定co2副产轻质碳酸钙的方法
CN113461237A (zh) 一种盐类废水处理零排放系统
JP2005000840A (ja) フッ素含有排水の処理方法
KR20220101979A (ko) 건식 배연탈황설비의 폐기물을 처리하는 방법
JP2005262186A (ja) ホウ素含有排水の処理方法
CN117295848A (zh) 电化学材料生产和加工
JP2019155217A (ja) 水処理方法及び水処理装置
AU2022255317A1 (en) Electrochemical materials production and processing
JPH04164809A (ja) 水酸化マグネシウムの製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16799275

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20177034166

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2016266463

Country of ref document: AU

Date of ref document: 20160523

Kind code of ref document: A

122 Ep: pct application non-entry in european phase

Ref document number: 16799275

Country of ref document: EP

Kind code of ref document: A1