AU2016266463A1 - Method for comprehensive recovery of smelting wastewater containing magnesium - Google Patents
Method for comprehensive recovery of smelting wastewater containing magnesium Download PDFInfo
- Publication number
- AU2016266463A1 AU2016266463A1 AU2016266463A AU2016266463A AU2016266463A1 AU 2016266463 A1 AU2016266463 A1 AU 2016266463A1 AU 2016266463 A AU2016266463 A AU 2016266463A AU 2016266463 A AU2016266463 A AU 2016266463A AU 2016266463 A1 AU2016266463 A1 AU 2016266463A1
- Authority
- AU
- Australia
- Prior art keywords
- calcium
- magnesium
- containing magnesium
- bicarbonate solution
- wastewater
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 239000002351 wastewater Substances 0.000 title claims abstract description 177
- 238000003723 Smelting Methods 0.000 title claims abstract description 72
- 239000011777 magnesium Substances 0.000 title claims abstract description 49
- FYYHWMGAXLPEAU-UHFFFAOYSA-N magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 title claims abstract description 47
- 229910052749 magnesium Inorganic materials 0.000 title claims abstract description 46
- 238000011084 recovery Methods 0.000 title claims abstract description 18
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L Calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 265
- 229910000022 magnesium bicarbonate Inorganic materials 0.000 claims abstract description 148
- QWDJLDTYWNBUKE-UHFFFAOYSA-L Magnesium bicarbonate Chemical compound [Mg+2].OC([O-])=O.OC([O-])=O QWDJLDTYWNBUKE-UHFFFAOYSA-L 0.000 claims abstract description 147
- 239000002370 magnesium bicarbonate Substances 0.000 claims abstract description 147
- 235000014824 magnesium bicarbonate Nutrition 0.000 claims abstract description 147
- 239000002002 slurry Substances 0.000 claims abstract description 140
- 238000000034 method Methods 0.000 claims abstract description 115
- 238000000926 separation method Methods 0.000 claims abstract description 108
- VTHJTEIRLNZDEV-UHFFFAOYSA-L Magnesium hydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims abstract description 86
- 239000007788 liquid Substances 0.000 claims abstract description 86
- 239000000347 magnesium hydroxide Substances 0.000 claims abstract description 86
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims abstract description 86
- CSNNHWWHGAXBCP-UHFFFAOYSA-L mgso4 Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims abstract description 78
- CURLTUGMZLYLDI-UHFFFAOYSA-N carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 70
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 70
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 68
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims abstract description 64
- 239000007787 solid Substances 0.000 claims abstract description 62
- 238000003763 carbonization Methods 0.000 claims abstract description 58
- 229910001424 calcium ion Inorganic materials 0.000 claims abstract description 57
- 238000001556 precipitation Methods 0.000 claims abstract description 57
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 56
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000002893 slag Substances 0.000 claims abstract description 51
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 45
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims abstract description 39
- 235000019341 magnesium sulphate Nutrition 0.000 claims abstract description 39
- 239000011575 calcium Substances 0.000 claims abstract description 38
- 239000000126 substance Substances 0.000 claims abstract description 38
- 229960005069 Calcium Drugs 0.000 claims abstract description 35
- OYPRJOBELJOOCE-UHFFFAOYSA-N calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 35
- 229910000019 calcium carbonate Inorganic materials 0.000 claims abstract description 32
- 230000005591 charge neutralization Effects 0.000 claims abstract description 32
- 230000001264 neutralization Effects 0.000 claims abstract description 32
- 229960003563 Calcium Carbonate Drugs 0.000 claims abstract description 30
- 239000002253 acid Substances 0.000 claims abstract description 10
- 235000011132 calcium sulphate Nutrition 0.000 claims description 127
- 238000000605 extraction Methods 0.000 claims description 82
- 239000007789 gas Substances 0.000 claims description 61
- 239000000706 filtrate Substances 0.000 claims description 42
- 239000012535 impurity Substances 0.000 claims description 41
- 239000000203 mixture Substances 0.000 claims description 34
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 33
- 230000001131 transforming Effects 0.000 claims description 33
- 238000007127 saponification reaction Methods 0.000 claims description 30
- 239000000395 magnesium oxide Substances 0.000 claims description 27
- 230000002378 acidificating Effects 0.000 claims description 26
- 230000001180 sulfating Effects 0.000 claims description 24
- 230000032683 aging Effects 0.000 claims description 16
- UGFAIRIUMAVXCW-UHFFFAOYSA-N carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 14
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate dianion Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 13
- 239000003546 flue gas Substances 0.000 claims description 12
- 230000020477 pH reduction Effects 0.000 claims description 12
- 239000001175 calcium sulphate Substances 0.000 claims description 8
- 238000001354 calcination Methods 0.000 claims description 4
- 238000002386 leaching Methods 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-L oxalate Chemical compound [O-]C(=O)C([O-])=O MUBZPKHOEPUJKR-UHFFFAOYSA-L 0.000 claims description 3
- 239000000047 product Substances 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 238000005670 sulfation reaction Methods 0.000 claims description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims 1
- 229910001425 magnesium ion Inorganic materials 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 238000000746 purification Methods 0.000 abstract description 6
- 238000003860 storage Methods 0.000 abstract description 6
- 125000004122 cyclic group Chemical group 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 184
- 229910052761 rare earth metal Inorganic materials 0.000 description 95
- 150000002910 rare earth metals Chemical class 0.000 description 84
- 235000012254 magnesium hydroxide Nutrition 0.000 description 74
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium monoxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 66
- 239000012141 concentrate Substances 0.000 description 45
- 239000000292 calcium oxide Substances 0.000 description 33
- 235000012255 calcium oxide Nutrition 0.000 description 33
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 32
- AXCZMVOFGPJBDE-UHFFFAOYSA-L Calcium hydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 25
- 239000000920 calcium hydroxide Substances 0.000 description 25
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 25
- 235000011116 calcium hydroxide Nutrition 0.000 description 25
- 238000006243 chemical reaction Methods 0.000 description 23
- -1 bastnaesite Chemical compound 0.000 description 18
- 238000004064 recycling Methods 0.000 description 14
- 239000002244 precipitate Substances 0.000 description 10
- 239000010459 dolomite Substances 0.000 description 9
- 229910000514 dolomite Inorganic materials 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 9
- 239000004568 cement Substances 0.000 description 8
- IKNAJTLCCWPIQD-UHFFFAOYSA-K cerium(3+);lanthanum(3+);neodymium(3+);oxygen(2-);phosphate Chemical compound [O-2].[La+3].[Ce+3].[Nd+3].[O-]P([O-])([O-])=O IKNAJTLCCWPIQD-UHFFFAOYSA-K 0.000 description 7
- 229910052590 monazite Inorganic materials 0.000 description 7
- UXBZSSBXGPYSIL-UHFFFAOYSA-N phosphoric acid;yttrium(3+) Chemical compound [Y+3].OP(O)(O)=O UXBZSSBXGPYSIL-UHFFFAOYSA-N 0.000 description 7
- 229910000164 yttrium(III) phosphate Inorganic materials 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 230000003472 neutralizing Effects 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 6
- 239000011780 sodium chloride Substances 0.000 description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 5
- 239000003513 alkali Substances 0.000 description 5
- 229910052925 anhydrite Inorganic materials 0.000 description 5
- FBEDQOZZWWECAJ-UHFFFAOYSA-M calcium;magnesium;hydroxide Chemical compound [OH-].[Mg+2].[Ca+2] FBEDQOZZWWECAJ-UHFFFAOYSA-M 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 239000008346 aqueous phase Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- JLVVSXFLKOJNIY-UHFFFAOYSA-N magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 4
- 238000010000 carbonizing Methods 0.000 description 3
- 238000010924 continuous production Methods 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 239000011776 magnesium carbonate Substances 0.000 description 3
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000011218 segmentation Effects 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N HCl Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- ZLNQQNXFFQJAID-UHFFFAOYSA-L Magnesium carbonate Chemical group [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 2
- 235000015450 Tilia cordata Nutrition 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- CVTZKFWZDBJAHE-UHFFFAOYSA-N [N].N Chemical compound [N].N CVTZKFWZDBJAHE-UHFFFAOYSA-N 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000001095 magnesium carbonate Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006011 modification reaction Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- NKWPZUCBCARRDP-UHFFFAOYSA-L Calcium bicarbonate Chemical compound [Ca+2].OC([O-])=O.OC([O-])=O NKWPZUCBCARRDP-UHFFFAOYSA-L 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L Calcium fluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 210000004940 Nucleus Anatomy 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N Sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 229910000020 calcium bicarbonate Inorganic materials 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000001351 cycling Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000011268 mixed slurry Substances 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001376 precipitating Effects 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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
Abstract
A method for comprehensive recovery of smelting wastewater containing magnesium comprises: adjusting a pH value of acid smelting wastewater containing magnesium sulfate by using an alkaline substance, so as to obtain slurry containing magnesium hydroxide and calcium sulfate, the alkaline substance being an alkaline substance containing calcium; and introducing carbon dioxide gas into the slurry to perform carbonization, and then performing solid-liquid separation to obtain solid slag and magnesium bicarbonate solution. By means of key procedures such as neutralization, precipitation, carbonization and purification, calcium ions are converted into calcium sulfate and a small amount of calcium carbonate that is to be precipitated and recycled for use, and the content of calcium sulfate in the recycled water is reduced, thereby effectively solving the problem of scaling of pipelines, conveying pumps and storage tanks; magnesium ions in the smelting wastewater containing magnesium are converted into a magnesium bicarbonate solution that can be returned for smelting separation, and accordingly, the cyclic utilization of materials in the production process is implemented, and zero emission of wastewater is achieved.
Description
Technical field
The present invention relates to the field of smelting separation, and in particular to a method for comprehensive recovery of smelting wastewater containing magnesium.
Background art
In the production process of wet smelting separation, a large amount of wastewater has been produced. For example, Baotou mixed rare earth ore mainly uses sulfuric acid calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation separation process, and the wastewater produced in this process is mainly acidic wastewater produced during extraction and transformation of rare earth solution of sulfuric acid. The main components in the wastewater are sulfuric acid, hydrochloric acid, Mg ion, Ca ion, Al ion, F ion and heavy metal ions (such as Pb, Cd and As), and the like.
In the wastewater treatment process of the wet smelter, in order to neutralize a large number of acidic wastewater, the neutralization treatment in the traditional chemical neutralization method is conducted by adding lime or carbide slag and the like, resulting in a large number of precipitates such as calcium sulfate, calcium fluoride, magnesium hydroxide, etc.. After being clarified, the wastewater is discharged up to standard. Although the treatment process mainly consumes lime, carbide slag and other neutralizer, but the precipitation amount is large, the precipitates are complex and the operating environment is bad, the most important is that the recycling of the treated wastewater is limited. So in the wastewater treated by this process, the contents of calcium, magnesium and sulfate are saturated. In recycling, it will form calcium sulfate scale in the pipelines, conveying pumps and storage tanks and other devices with the change of temperature, and thus have a greater impact on the continuous production. In addition, the wastewater treated by this process has a very high salt content, and direct discharge will lead to an increase in the salinity of the river, causing serious pollution to the soil, surface water and groundwater, leading to further deterioration of the ecological environment. With the implementation of the new environmental law, it will be the ultimate goal to solve the problem of high salt wastewater and make the wastewater near zero discharge.
In the research and application of the recycle treatment of smelting wastewater, the current research is more of the use of membrane separation method, evaporation crystallization method, steam stripping method and broken point chlorination method and the like. The membrane separation method is the use of selective separation to separate ions, molecules or particles in water; the treatment effect is better, but it is easy to cause membrane contamination. The evaporation crystallization method is that the salt-containing wastewater is concentrated by evaporation to reach the supersaturated state, so that the salts in the wastewater form nuclei, and then gradually generate crystalline solid and then achieve separation. This method is suitable for the treatment of high salt wastewater. The steam tripping is that makes the wastewater and water steam in direct contact to diffuse the volatile substances in the wastewater to the gas phase in a certain proportion, so as to achieve the purpose to separate pollutants from the wastewater, mainly being used for the handling of volatile pollutants. The break point chlorination method is that a certain amount of chlorine gas or sodium hypochlorite is added to the wastewater, so that ammonia nitrogen is oxidized to N2, so as to achieve the purpose of removing ammonia nitrogen. These methods have the disadvantages of high operating costs and large investment costs, so the application in the industry has been limited.
Therefore, in terms of the comprehensive utilization of smelting wastewater, there is still a need to improve the existing technique to provide a treatment process for wastewater which is inexpensive, environmentally friendly and the wastewater after being treated can be recycled.
Summary of the present invention
The main object of the present invention is to provide a method for comprehensive recovery of smelting wastewater containing magnesium, so as to provide a treatment process for wastewater which is inexpensive, environmentally friendly and the treated wastewater can be recycled.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for comprehensive recovery of smelting wastewater containing magnesium, the method comprising the steps of: step SI, adjusting the pH of the smelting wastewater containing magnesium to 10.0 to 12.5 with a basic substance as a neutralizing agent to obtain a slurry containing magnesium hydroxide and calcium sulfate; wherein the smelting wastewater containing magnesium is the wastewater containing magnesium sulfate; the basic substance being a basic substance containing calcium; and step S2, introducing carbon dioxide gas into the slurry containing magnesium hydroxide and calcium sulfate to perform carbonization, and performing solid-liquid separation to the carbonized slurry to obtain a solid slag and a magnesium bicarbonate solution.
Further, the smelting wastewater containing magnesium is wastewater containing magnesium sulfate produced by sulfation calcination, water leaching, magnesium oxide neutralization and impurity removal and extraction-transformation process during smelting to separation.
Further, when the smelting wastewater containing magnesium is acidic wastewater containing magnesium sulfate, the step SI comprises the steps of: step Sil, adjusting the pH of the smelting wastewater containing magnesium to 4.0 to 10.0 with the basic substance containing calcium 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 the basic substance containing calcium to obtain the slurry containing magnesium hydroxide and calcium sulfate.
Further, the step S11 further comprises the step of adding a calcium sulfate seed crystal to the smelting wastewater containing magnesium; and/or the step of subjecting the slurry containing magnesium hydroxide and calcium sulfate to an aging treatment.
Further, in the step of subjecting the slurry containing magnesium hydroxide and calcium sulfate to an aging treatment, the aging time is 0.5 h to 6 h.
Further, the step S2 comprises the steps of: introducing carbon dioxide gas into the slurry containing magnesium hydroxide and calcium sulfate to perform carbonization and controlling the pH of the slurry in the range of 6.5 to 8.0 during the carbonization to obtain a carbonized slurry; and performing solid-liquid separation to the carbonized slurry to obtain the solid slag and the magnesium bicarbonate solution.
Further, the calcium ion concentration in the magnesium bicarbonate solution is 0.01 g/L to 0.7 g/L, preferably 0.01 g/L to 0.4 g/L.
Further, the solid slag is subjected to purifying treatment to produce io calcium sulphate or is returned to neutralize the acidic wastewater produced by smelting separation to produce calcium sulphate.
Further, the carbon dioxide gas is produced from a process exhaust gas comprising one or more of boiler flue gas, calcined kiln gas of oxalate precipitation and carbonate precipitation and the gas produced by saponification extraction of the magnesium bicarbonate solution.
Further, in the step S2, the magnesium bicarbonate solution is used in a wet smelting procedure, wherein the smelting procedure is one or more of ore sulfating calcining-water leaching-neutralization and impurity removal procedure, acid leaching-neutralization and impurity removal procedure, solution extraction and transformation or precipitation transformation procedure, solution extraction-separation procedure and solution precipitation procedure.
The technical solution of the present invention adjusts the pH to 10.0 to 12.5 by adding a basic substance to the smelting wastewater containing magnesium. A large amount of Ca2+ is converted into calcium sulfate precipitate while the Mg in the wastewater is converted into magnesium hydroxide, and after carbonization treatment, magnesium hydroxide is converted into soluble magnesium bicarbonate, and a small amount of calcium ions is further removed in the form of calcium carbonate precipitate to achieve a relatively thorough separation of calcium ion and magnesium ion, so that the calcium ion concentration in the aqueous solution of magnesium bicarbonate being recycled is low, effectively solving the problem of scaling of pipelines, conveying pumps, storage tanks and the like when water is recycled.
Brief description of the drawings
The drawings of the description, which constitute a part of this application, are intended to provide a further understanding of the present invention, and illustrative embodiments of the present invention and its description are intended to explain the present invention and do not constitute an undue limitation to the present invention. In the drawings:
Figure 1 shows a schematic flow diagram of a method for comprehensive recovery of smelting wastewater containing magnesium according to a preferred embodiment of the present invention.
Embodiments
It should be noted that embodiments and the features in embodiments in the application may be combined with each other without conflict. Hereinafter, the present invention will be described in detail with reference to embodiments.
As mentioned in the background art section, the treatment method of the smelting wastewater containing magnesium in the prior art is either too high for the cost of treatment or the treated wastewater is limited in recycling for the high salt content. In order to improve the above-described situation in the prior art, in a typical embodiment of the invention, as shown in Fig. 1, there is provided a method for comprehensive recovery and recycling of smelting wastewater containing magnesium, which comprises: adjusting the pH of the smelting wastewater containing magnesium to 10.0 to 12.5 with a basic substance as a neutralizing agent to obtain a slurry containing magnesium hydroxide and calcium sulfate; wherein the smelting wastewater containing magnesium is the wastewater containing magnesium sulfate; the basic substance being a basic substance containing calcium; and step S2, introducing carbon dioxide gas into the slurry containing magnesium hydroxide and calcium sulfate to perform carbonization, and performing solid-liquid separation to the carbonized slurry to obtain a solid slag and a magnesium bicarbonate solution.
For the smelting wastewater containing magnesium, the above method comprises adjusting the pH of the smelting wastewater to 10.0 to
12.5 by adding a basic substance containing calcium (including the basic substance containing calcium and magnesium) as the neutralizing agent to the smelting wastewater. In this process, the added calcium-containing basic substance in the smelting wastewater is removed by generating calcium sulfate precipitation in the role of H and SO4', while the Mg in the wastewater is converted into magnesium hydroxide. The carbon dioxide gas is then introduced into the slurry containing magnesium hydroxide and calcium sulfate to conduct carbonization treatment to convert the magnesium hydroxide in the wastewater into soluble
2_|_ magnesium bicarbonate while the remaining small amount of free Ca in the wastewater is converted into calcium carbonate and further separating with magnesium ions, and thus make the separation of calcium ion in recycled magnesium bicarbonate solution is more thorough, significantly reducing the content of CaSO4 in recycled water, so as to effectively solve the problem of scaling of pipelines, conveying pumps, storage tanks and the like, while the resulting magnesium bicarbonate solution is used for the smelting separation process, not only achieve recycling the production wastewater, but also achieve zero discharge of wastewater.
The wastewater containing magnesium sulphate treated in the above method includes, but is not limited to, wastewater containing magnesium sulfate produced by subjecting monazite, xenotime, bastnaesite, nickel cobalt ore and other ores to sulphate calcining, water leaching, magnesium oxide neutralization and impurity removal and extraction-transformation process during smelting separation. Wastewater containing magnesium sulfate produced during the separation of any ore can be recycled by the above-mentioned method of the present invention.
In the step SI described above, there are various ways to adjust the pH of the wastewater to 10.0 to 12.5 by adding the basic substance as the neutralizing agent, and the specific adjustment mode can be appropriately adjusted according to the actual production demand. In a preferred embodiment of the present invention, when the smelting wastewater containing magnesium is acidic wastewater containing magnesium sulfate, the above step S1 comprises the steps of: step Sil, adjusting the pH of the smelting wastewater containing magnesium to 4.0 to 10.0 with the basic substance containing calcium to obtain a solid-liquid mixture; step S12, filtering the solid-liquid mixture to obtain a filtrate; step S13, adjusting the pH of the filtrate to 10.0 to 12.5 with the basic substance containing calcium to obtain the slurry containing magnesium hydroxide and calcium sulfate.
In the preferred embodiment described above, the purpose of adjusting the pH of the smelting wastewater containing magnesium to 4.0 to 10.0 with a basic substance containing calcium to obtain the solid-liquid mixture is mainly to neutralize the H+ in the smelting wastewater while reducing the content of calcium sulfate in cycle water, so as to minimize the problem of pipe fouling arising in recycling the io recovered water. Thus, all basic substances containing calcium capable of providing a basic environment and readily converting calcium therein into calcium sulfate to be removed are suitable for use in the present invention. It is preferable to use calcium hydroxide, and the source of calcium hydroxide is not limited to the solid powder of calcium hydroxide, but also the basic calcium hydroxide obtained by reacting calcium oxide obtained by calcining calcium oxide or calcium carbonate with water. From the point of considering the treatment cost of the smelting wastewater and the recycling of raw materials, the basic substance containing calcium is preferably the basic substance containing calcium hydroxide prepared by using raw material of limestone (or dolomite) which is rich in natural and inexpensive.
Likewise, the basic substance containing calcium and magnesium refers to a mixture containing calcium hydroxide and magnesium hydroxide at the same time, which may be a mixture containing calcium hydroxide and magnesium hydroxide obtained by reacting a calcined product of an ore containing calcium and magnesium or an industrial waste containing calcium and magnesium with water, or a mixture containing calcium hydroxide and magnesium hydroxide obtained by digestion of light-burned dolomite.
In the preferred embodiment described above, adjusting the pH of the smelting wastewater to 4.0 to 10.0 with the basic substance containing calcium can both neutralize the large amount of H+ in the smelting wastewater and the separate calcium from the wastewater in form of calcium sulfate. After adjusting the pH of the smelting wastewater to 4.0 to 10.0 with the basic substance containing calcium to the solid-liquid mixture, filter the solid-liquid mixture, and remove the precipitated io calcium sulfate to obtain a filtrate, followed by adjusting the pH of the filtrate to 10.0 to 12.5 with the basic substance containing calcium and magnesium or the basic substance containing calcium. By controlling the addition amount of the neutralizing agent of basic substance containing calcium and the pH value, the calcium and magnesium ions in the wastewater are precipitated step by step, and the pH value of the filtrate after removing calcium sulfate is controlled in the range of 10.0 to 12.5 to make the Mg in the smelting wastewater convert into magnesium hydroxide under the basic condition containing calcium and/or magnesium to obtain a slurry containing magnesium hydroxide and calcium sulfate precipitate. The specific reactions occurred are as follows:
2H+(liquid)+SO42'( liquid)+Ca(OH)2(solid)^CaSO4(solid)+H2O(liquid) Mg2+( liquid)+SO42'( liquid)+Ca(OH)2(solid)~* Mg(OH)2(solid)+CaSO4(solid)
In the preferred embodiment described above, adjusting the pH of the smelting wastewater containing magnesium to 4.0 to 10.0 with a basic substance containing calcium has been able to achieve the purpose of precipitating calcium sulphate. In order to make precipitation easier occur or precipitate be more thoroughly, in another preferred embodiment of the present invention, the step SI further comprises the step of adding a calcium sulfate seed crystal to the smelting wastewater containing magnesium; and/or the step of subjecting the slurry containing magnesium hydroxide and calcium sulfate to an aging treatment. Adding the calcium sulphate seed crystal is facilitated to form the precipitation of calcium sulfate more easily and makes the precipitation reaction relatively thoroughly. And the aging treatment can also make the precipitation relatively thoroughly. The specific time of the aging may be appropriately adjusted according to the amount of the treated smelting wastewater. In a preferred embodiment of the present invention, the time of the aging treatment is less than or equal to 6 h. The aging time less than or equal to 6 h has been able to make calcium sulfate precipitate enough thoroughly, conducive to reuse the treated water, if the aging time is continued to be extended, it will lead to delay the overall process operation and not conducive to conduct the overall process of the process.
The wastewater which is recycled by the present invention is the wastewater containing magnesium sulfate. The wastewater mainly contains Mg2+, H+ and SO4 2', and may also include one or more of Na+,
Cf and NO3. The wastewater system is complex with a wide range of impurity ions. When the basic substance containing calcium is adopted to treat the wastewater, calcium ions may present in the form of calcium sulfate precipitation in the system of sulfate ions, forming a solid mixture with magnesium hydroxide and entering into the carbonization step. In the carbonation process, if there is a large amount of calcium ions in the system, it will induce bicarbonate to produce calcium carbonate crystal, reducing the production rate of magnesium bicarbonate, and leading to the decomposition of magnesium carbonate into magnesium carbonate solid to dissolve out. A large number of scaling has great impact on the continuous production.
Therefore, the present invention produces a low activity and stable crystalline calcium sulfate precipitate with a reasonable control of the pH value during the alkali conversion process, which reduces the calcium ion concentration in the alkali converted water phase, and the low activity calcium sulfate is not easy to resolve into calcium ions to reduce the carbonization rate. In the preferred embodiment described above, by segmentation control of pH value, the segmentation alkali conversion of calcium ions and magnesium ions is achieved, and then the purpose of removing the partial calcium is first achieved by solid-liquid separation, so that the calcium ion concentration in the aqueous phase at the beginning of the carbonization is reduced. And by further adding seed crystal and/or aging treatment, the calcium ions are precipitated more thoroughly in the segmentation alkali conversion precipitation, so that the calcium ion concentration in the aqueous phase at the beginning of the carbonization is lower and the carbonation is better.
In the above carbonization step, the purpose of carbonization is to convert the magnesium hydroxide in the slurry into soluble magnesium bicarbonate while further removing the remaining calcium ions in the slurry by the formation of calcium carbonate. The amount of carbon dioxide introduced in the step of carbonization can therefore be appropriately adjusted according to the amount of wastewater to be treated. In a preferred embodiment of the present invention, the step S2 described above comprises introducing carbon dioxide gas into the slurry to perform carbonization and controlling the pH of the slurry in the range of 6.5 to 8.0 during the carbonization to obtain a carbonized slurry; and performing solid-liquid separation to the carbonized slurry to obtain the solid slag and the magnesium bicarbonate solution.
The wastewater treated by the above-mentioned neutralization and precipitation is a mixed slurry containing Mg(OH)2 and CaSO4, and contains a small amount of free Ca , OH' and SO4 ' due to the micro-solubility of CaSO4. Carbon dioxide gas is used to convert the solid Mg(OH)2 into Mg(HCO3)2 solution. The free Ca in the aqueous phase is converted into CaCO3 precipitation due to the presence of a large amount of HCO3', which promotes the solidification transformation of io calcium, achieving the purpose of further removal of calcium in aqueous phase. The specific reaction of the carbonation process is as follows:
Mg(OH)2(solid)+2CO2(gas)-^Mg(HCO3)2(liquid)
Ca2++2HCO3”-*CaCO3(solid)+H2O(liquid)+CO2(gas)
The following side reaction may occur during this carbonation reaction:
Mg(OH)2(solid)+CO2(solid)+H2O—MgCO3 · 3H2O(solid)
In the preferred embodiment described above, the amount of carbon dioxide introduced is controlled by controlling the pH of the slurry in the range of 6.5 to 8.0, and the calcium ions in the slurry can be precipitated and removed as much as possible in the form of calcium carbonate to achieve separation of calcium and magnesium, so that the calcium ion concentration in magnesium bicarbonate solution is minimized. The calcium ion concentration in the magnesium bicarbonate solution obtained by solid-liquid separation is 0.01 g/L to 0.7 g/L, preferably 0.01 g/L to 0.4 g/L by using the carbonization step of the above embodiment.
The lower the calcium ion concentration in the magnesium bicarbonate solution is, the more difficult to cause pipe fouling when reused as recycled water, achieving the recycling of the smelting wastewater.
In the preferred embodiment described above, the time of carbonization may be appropriately adjusted depending on the amount of calcium ions in the slurry containing magnesium hydroxide. In still another preferred embodiment of the present invention, it is preferable that the time of carbonization in the carbonization step is 10 min to 120 min, more preferably 20 min to 60 min. The time of carbonization treatment is controlled in the range of 10 min to 120 min, which can not only achieve removing the remaining calcium ions in the slurry containing magnesium hydroxide, but also make the time of the whole treatment process of wastewater be not too long, which will also affect the cycle running period and reduce the treatment effectiveness. If the time of carbonization is too long, it is possible not only to convert calcium ions precipitated as calcium carbonate into calcium bicarbonate due to excessive carbon dioxide and difficult to remove, but also easily lead to longer processing cycle, affecting the treatment efficiency of smelting wastewater. And if the carbonization time is shorter than 10 min, it is very likely that the precipitate of calcium ions is not thorough enough, so that the calcium ion concentration in the treated cycling water is high, which is not conducive to the recycling of treated water. And the time of carbonization is controlled within 20min ~ 60min, so that the calcium ion concentration in the treated magnesium bicarbonate solution is lower, and the treatment time is relatively shorter, which is beneficial to the efficient recycling of the wastewater in enterprise.
The above-mentioned method provided by the present invention embodies the reasonable utilization of energy from various aspects, and the above-mentioned step S2 is no exception. In another preferred embodiment of the present invention, as shown in Fig. 1, the solid slag obtained in the above step S2 is purified to obtain calcium sulfate, and the specific purification treatment includes a sulfuric acidification method as shown in Fig. 1. In practical applications, the specific ways of purification may be selected according to the specific production conditions and equipments. The purified calcium sulphate can be sold as a product in order to maximize its value. In another specific embodiment, the solid slag is returned to neutralize the wastewater produced by smelting separation.
In the above step of carbonizing by introducing in carbon dioxide gas (as shown in Fig. 1), the source of the carbon dioxide gas introduced in may be one or more gases of boiler flue gas, calcined kiln gas of oxalate precipitation and carbonate precipitation and the gas produced by saponification extraction of the magnesium bicarbonate solution. As shown in Fig. 1, the present invention preferably obtains a carbon dioxide-containing gas by applying compression, purification or other treatment steps to the gas produced in the above processes as raw materials, not only to achieve the purpose of carbonizing the solution containing magnesium hydroxide using carbon dioxide to get a magnesium bicarbonate solution, but also to use the process gas reasonably, which is low-carbon and discharge reduction, in line with environmental requirements.
In the above step S2, the magnesium bicarbonate solution obtained by the treatment of smelting wastewater containing magnesium can be reused as cycle water (as shown in Fig. 1). Thus, all the procedures using water or the procedures using weakly alkaline solution in the separation and smelting processes of ores can be carried out by using the magnesium bicarbonate solution provided by the above-described method of the present invention. That is, the magnesium bicarbonate solution obtained by the above-mentioned method can be used in one or more of ore sulfating calcining-water leaching-neutralization and impurity removal procedure, acid leaching-neutralization and impurity removal procedure, solution extraction-transformation or precipitation-transformation io procedure, solution extraction-separation procedure and/or solution precipitation procedure. For example, it can be used in sulfating calcining-water leaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, transformation and extraction procedure of Baotou ore rare earth, acid leaching-neutralization and impurity removal procedure of Sichuan bastnaesite and ionized rare earth ore and extraction separation procedure of rare earth and precipitation procedure of rare earth solution, to achieve recycling.
The beneficial effects of the present invention will be further described below in connection with specific examples.
EXAMPLE 1
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide (wherein the calcium hydroxide was obtained by reacting quicklime and water) to the wastewater to bring the pH of the wastewater to 10.0 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
io The solid slag was purified by sulfuric acidification to obtain calcium sulfate.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.7 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 2
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding a mixture containing calcium hydroxide and magnesium hydroxide (obtained by reacting light burned dolomite and water) to the wastewater to bring the pH of the wastewater to 11.0 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate.
io The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.62 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 3
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide (wherein the calcium hydroxide was obtained by reacting quicklime and water) to the wastewater to bring the pH of the wastewater to 11.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate with a alkalinity of 0.24mol/L.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to carbonize for 60 min and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution with magnesium bicarbonate concentration of 3.15g/L (calculated in MgO). The carbonization rate was 65.7%.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in io the magnesium bicarbonate solution was 0.56 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 4
The wastewater containing magnesium sulfate produced by 15 subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding a mixture containing calcium hydroxide and magnesium hydroxide (obtained by reacting light burned dolomite and water) to the wastewater to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate with a alkalinity of 0.37mol/L.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution with magnesium bicarbonate concentration of 5.55g/L (calculated in MgO). The carbonization rate was 65.7%.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.45 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation io procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 5
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide (wherein the calcium hydroxide was obtained by reacting quicklime and water) to the wastewater to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.4 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution, extraction separation, and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 6
The wastewater containing magnesium sulfate produced by io subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide (wherein the calcium hydroxide was obtained by reacting quicklime and water) to the wastewater to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to carbonize for 120 min and the pH of the slurry after carbonization was controlled to 6.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.58 g/L, and the magnesium bicarbonate solution was returned to use for leaching, neutralization and impurity removal, extraction and transformation procedure of rare earth solution and extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 7
The wastewater containing magnesium sulfate produced by extraction separation of nickel cobalt solution of sulfuric acid was taken io as the treatment object. A reaction was carried out by adding calcium hydroxide (wherein the calcium hydroxide was obtained by reacting quicklime and water) to the wastewater to bring the pH of the wastewater to 12.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to carbonize for 40 min and the pH of the slurry after carbonization was controlled to 8.0. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.38 g/L, and the magnesium bicarbonate solution was returned to extraction separation procedure of the nickel cobalt solution of sulfuric acid.
EXAMPLE 8
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide to the wastewater to bring the pH of the wastewater to 12.5 to obtain a slurry to containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.0. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.49 g/L, and the magnesium bicarbonate solution was returned to use for precipitation transformation procedure of rare earth solution, extraction separation procedure of rare earth solution and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
COMPARATIVE EXAMPLE 1
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide to the wastewater to bring the pH of the wastewater to 9.5 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 1.0 g/L, and the magnesium bicarbonate solution was returned to use for extraction and transformation procedure of rare earth solution, extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
COMPARATIVE EXAMPLE 2
The wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding calcium hydroxide to the wastewater to bring the pH of the wastewater to 13.0 to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.3. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium io bicarbonate solution.
The solid slag was purified by sulfuric acidification to obtain calcium sulfate which can be used for the preparation of cement.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 1.1 g/L, and the magnesium bicarbonate solution was returned to use for extraction and transformation procedure of rare earth solution, extraction separation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 9
The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding quicklime to the wastewater and the pH of the wastewater was adjusted to 5.0 to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate;
and the pH value of the filtrate was adjusted to 12.5 by adding quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
to The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.3 g/L, and the magnesium bicarbonate solution was returned to use for acid bleaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, extraction separation procedure of rare earth solution and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 10
The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 5.0 with digested quicklime to obtain a solid-liquid mixture. After 6 h of aging, the solid-liquid mixture was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.5 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.22 g/L, and the magnesium io bicarbonate solution was returned to use for acid bleaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 11
The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 5.0 with digested quicklime to obtain a solid-liquid mixture. After 2 h of aging, the solid-liquid mixture was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 7.5 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.24 g/L, and the magnesium bicarbonate solution was returned to use for acid bleaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, and precipitation procedure of rare earth solution of Baotou rare earth ore io concentrate.
EXAMPLE 12
The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 5.0 with digested quicklime to obtain a solid-liquid mixture. After 0.5 h of aging, the solid-liquid mixture was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.5 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.27 g/L, and the magnesium bicarbonate solution was returned to use for acid bleaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 13 io The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding quicklime to the wastewater and calcium sulphate seed crystal was added during reaction, adjusting the pH to 5.0 to obtain a solid-liquid mixture. The solid-liquid mixture was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.5 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by treating the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate and the pH of the slurry after carbonization was controlled to 7.5. The carbonized slurry was subjected to solid-liquid separation to obtain a solid slag and a magnesium bicarbonate solution.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.25 g/L, and the magnesium bicarbonate solution was returned to use for acid bleaching-neutralization and impurity removal procedure of Baotou rare earth ore concentrate, and precipitation procedure of rare earth solution of Baotou rare earth ore concentrate.
EXAMPLE 14
The acidic wastewater containing magnesium sulfate produced by subjecting the monazite ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 4.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.5 with digested light-burned dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.3 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag of calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in 5 the magnesium bicarbonate solution was 0.33 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution and precipitation procedure of rare earth solution of monazite ore concentrate.
The solid slag was returned to use for the neutralization of acidic io wastewater in the smelting separation of rare earth ore.
EXAMPLE 15
The acidic wastewater containing magnesium sulfate produced by subjecting the monazite ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 6.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.5 with digested light-burned dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.3 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.3 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation procedure of rare earth solution and precipitation procedure of rare earth io solution of monazite ore concentrate.
EXAMPLE 16
The acidic wastewater containing magnesium sulfate produced by subjecting the rare earth solution of sulfuric acid to extraction separation was taken as the treatment object. The pH of the wastewater was adjusted to 9.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.5 with digested light-burned dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate with a alkalinity of 0.67mol/L.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.3 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution with magnesium bicarbonate concentration of 12.2g/L (calculated in MgO). The carbonization rate was 91.5%.
The carbonized slurry was subjected to solid-liquid separation to 5 obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.18 g/L, and the magnesium bicarbonate solution was returned to use for extraction separation io procedure of the rare earth solution of sulfuric acid and precipitation procedure of rare earth solution.
EXAMPLE 17
The acidic wastewater containing magnesium sulfate produced by subjecting the rare earth solution of sulfuric acid to extraction and transformation and extraction separation was taken as the treatment object. The pH of the wastewater was adjusted to 10.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.5 with digested light-burned dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.3 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.08 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of smelting separation of the rare earth solution of sulfuric acid.
io EXAMPLE 18
The acidic wastewater containing magnesium sulfate produced by subjecting the rare earth solution of sulfuric acid to extraction separation was taken as the treatment object. The pH of the wastewater was adjusted to 4.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 10.0 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.5 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in 5 the magnesium bicarbonate solution was 0.65 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of smelting separation of the rare earth solution of sulfuric acid.
EXAMPLE 19
The acidic wastewater containing magnesium sulfate produced by io subjecting the rare earth solution of sulfuric acid to extraction separation process was taken as the treatment object. The pH of the wastewater was adjusted to 4.0 with digested quicklime to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.0 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.5 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.58 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of smelting separation of the rare earth solution of sulfuric acid.
EXAMPLE 20
The acidic wastewater containing magnesium sulfate produced by subjecting the nickel cobalt solution of sulfuric acid to extraction separation process was taken as the treatment object. The pH of the wastewater was adjusted to 4.0 with digested quicklime to obtain a io solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.0 with digested quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by 15 comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 7.5 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.4 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of extraction separation of the nickel cobalt solution of sulfuric acid.
EXAMPLE 21
The acidic wastewater containing magnesium sulfate produced by 5 subjecting the mixed ore concentrate of monazite and xenotime to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal procedure-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 10.0 with digested quicklime to obtain a solid-liquid mixture which was io subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.5 with digested light-burned quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 6.5 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in 25 the magnesium bicarbonate solution was 0.5 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of rare earth smelting separation of the mixed ore concentrate of monazite and xenotime.
EXAMPLE 22
The acidic wastewater containing magnesium sulfate produced by 5 subjecting the mixed ore concentrate of xenotime to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal procedure-extraction and transformation process was taken as the treatment object. The pH of the wastewater was adjusted to 3.5 with digested quicklime to obtain a solid-liquid mixture which was subjected io to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 11.5 with digested light-burned quicklime to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 8.0 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in 25 the magnesium bicarbonate solution was 0.36 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of rare earth separation of the mixed ore concentrate of xenotime.
COMPARATIVE EXAMPLE 3
The acidic wastewater containing magnesium sulfate produced by subjecting the mixed ore concentrate of xenotime to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal procedure-extraction and transformation process was taken as the treatment object. A reaction was carried out by adding quicklime to the wastewater and the pH was adjusted to 11.0 to obtain large amount of solid-liquid mixture(wherein most of magnesium forms precipitate) which was subjected to solid-liquid separation to obtain a filtrate. The pH of the filtrate was adjusted to 12.5 with digested light-burned dolomite to obtain a slurry containing magnesium hydroxide and calcium sulfate.
Carbon dioxide (wherein the carbon dioxide was obtained by comprehensive recovery of boiler flue gas, calcined kiln gas of rare earth oxalate and carbonate and the gas produced by saponification extraction of the magnesium bicarbonate solution) was introduced into the slurry containing magnesium hydroxide and calcium sulfate to take carbonization and the pH was controlled to 8.0 to obtain carbonized slurry containing calcium sulfate and calcium carbonate precipitation, and magnesium bicarbonate solution with magnesium bicarbonate concentration of 0.54g/L.
The carbonized slurry was subjected to solid-liquid separation to obtain a magnesium bicarbonate solution and a solid slag containing calcium sulfate and calcium carbonate precipitation.
The result of the test showed that the calcium ion concentration in the magnesium bicarbonate solution was 0.14 g/L, and the magnesium bicarbonate solution was returned to use for the process recycle of rare earth separation of the mixed ore concentrate of xenotime.
COMPARATIVE EXAMPLE 4
The acidic wastewater containing magnesium sulfate produced by subjecting the Baotou rare earth ore concentrate to sulfating calcining-water leaching-magnesium oxide neutralization and impurity removal procedure-extraction and transformation process was taken as to the treatment object. A reaction was carried out by adding quicklime to the wastewater containing magnesium and the pH was adjusted to 6.0-9.0 to obtain a solid-liquid mixture which was subjected to solid-liquid separation to obtain a filtrate and a waste slag. The calcium ion concentration in the filtrate was 1.1 g/L. When the filtrate was recycled, the scaling of calcium sulfate and the like was easy to occur in pipelines, delivery pumps or storage tanks with the change of the temperature, which seriously affected the recycling of the wastewater and had a great impact on the continuous production.
From the above description, it can be seen that the above-mentioned examples of the present invention achieves the following technical effects:
(1) by the two key steps of neutralizing precipitation and carbonization purification, the Mg2+ in the non-saponified acidic wastewater of the sulfuric acid system is converted into magnesium bicarbonate solution; the Ca in the wastewater is converted into calcium sulfate and a small amount of calcium carbonate, achieving more thorough separation of calcium ions and magnesium ions, significantly reducing the content of CaSO4 in recycled water, so as to effectively solve the problem of scaling of pipelines, conveying pumps, storage tanks and the like.
(2) the magnesium bicarbonate solution prepared by carbonizing may be used for water bleaching, neutralization and impurity removal, saponification, extraction separation and other procedures, so as to realize closed-loop utilization of wastewater and achieve near-zero discharge, saving a lot of water resource.
io (3) the by-product of calcium sulfate in whole process has stable property, no effect on the environment; and can be further purified to achieve commercial gypsum specification.
It can be said that the present invention can obtain a magnesium bicarbonate solution by carrying out precipitation transformation and carbonization purification steps to smelting wastewater containing magnesium and then the solution is returned to smelting separation procedure of the rare earth, which can not only achieve comprehensive recycling of the wastewater during smelting process of the rare earth, but also achieve zero discharge of production wastewater. The resource utilization of entire technology route is high, and its economic and social benefits are very obvious.
The acidic wastewater containing magnesium and calcium discharged from the rare earth enterprise is recycled comprehensively with the alkali conversion carbonation method of the present invention, which can not only reduce the sewage charge but also can return the treated pure magnesium bicarbonate solution to use for neutralization and impurity removal of the rare earth solution, extraction separation of rare earth by saponification of organic phase, precipitation preparation of rare earth carbonate and other procedures, achieving wastewater recycling and zero discharge of production sewage.
The examples described above are only preferred examples of the present invention and is not intended to limit the present invention, and various changes and modifications may be made by one skilled in the art. Any modifications, equivalent substitutions, improvements and the like within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
- Claims1. A method for comprehensive recovery of smelting wastewater containing magnesium, characterized in that the method comprises the steps of:step SI, adjusting the pH of the smelting wastewater containing magnesium to 10.0 to 12.5 with a basic substance to obtain a slurry containing magnesium hydroxide and calcium sulfate; wherein the smelting wastewater containing magnesium is the wastewater containing magnesium sulfate; the basic substance being a basic substance containing calcium; and step S2, introducing carbon dioxide gas into the slurry containing magnesium hydroxide and calcium sulfate to perform carbonization, and performing solid-liquid separation to the carbonized carbon slurry to obtain a solid slag and a magnesium bicarbonate solution.
- 2. The method according to claim 1, characterized in that the smelting wastewater containing magnesium is wastewater containing magnesium sulfate produced by sulfation calcination, water leaching, magnesium oxide neutralization and impurity removal and extraction-transformation process during smelting and separation.
- 3. The method according to claim 1 or 2, characterized in that when the smelting wastewater containing magnesium is acidic wastewater containing magnesium sulfate, the step SI comprises the steps of:step Sil, adjusting the pH of the smelting wastewater containing magnesium to 4.0 to 10.0 with the basic substance containing calcium to obtain a solid-liquid mixture;step SI2, 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 the basic substance containing calcium to obtain the slurry containing magnesium hydroxide and calcium sulfate.
- 4. The method according to claim 1, characterized in that the step SI further comprises the step of adding a calcium sulfate seed crystal to the smelting wastewater containing magnesium; and/or the step of subjecting the slurry containing magnesium hydroxide and calcium sulfate to an aging treatment.
- 5. The method according to claim 4, characterized in that in the step of subjecting the slurry containing magnesium hydroxide and calcium sulfate to an aging treatment, the aging time is 0.5 h to 6 h.
- 6. The method according to claim 1, characterized in that the step S2 comprises the steps of:introducing carbon dioxide gas into the slurry containing magnesium hydroxide and calcium sulfate to perform carbonization and controlling the pH of the slurry in the range of 6.5 to 8.0 during the carbonization to obtain a carbonized slurry; and performing solid-liquid separation to the carbonized slurry to obtain the solid slag and the magnesium bicarbonate solution.
- 7. The method according to claim 1 or 6, characterized in that the calcium ion concentration in the magnesium bicarbonate solution is 0.01 g/L to 0.7 g/L, preferably 0.01 g/L to 0.4 g/L.
- 8. The method according to claim 1 or 6, characterized in that the solid slag is subjected to acidizing treatment to produce calcium sulphate or is returned to neutralize the acidic wastewater produced by the smelting and separation to produce calcium sulphate.
- 9. The method according to claim 1, characterized in that the carbon dioxide gas is produced from a process exhaust gas comprising one or more of boiler flue gas, calcined kiln gas of oxalate precipitation and carbonate precipitation and the gas produced by saponification extraction of magnesium bicarbonate solution.
- 10. The method according to claim 1, characterized in that in the step S2, the magnesium bicarbonate solution is used in a wet smelting procedure, wherein the smelting procedure is one or more of ore sulfating calcining-water leaching-neutralization and impurity removal procedure, acid leaching-neutralization and impurity removal procedure, solution extraction-transformation or precipitation transformation procedure, solution extraction separation procedure and solution precipitation procedure.1/1Figures smelting wastewater containing magnesium + basic substance _J_ adjusting the pH slurry containing magnesium hydroxide and calcium sulfateCO: gas smelting separation magnesium bicarbonate solution solid slag ίacidification treatment icalcium carbonate productFigure 1
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510276595.8A CN106277417A (en) | 2015-05-26 | 2015-05-26 | The method that smelting waste water comprehensive containing magnesium reclaims |
| CN201510276595.8 | 2015-05-26 | ||
| PCT/CN2016/082987 WO2016188387A1 (en) | 2015-05-26 | 2016-05-23 | Method for comprehensive recovery of smelting wastewater containing magnesium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2016266463A1 true AU2016266463A1 (en) | 2018-01-25 |
| AU2016266463B2 AU2016266463B2 (en) | 2019-07-18 |
Family
ID=57392558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2016266463A Active AU2016266463B2 (en) | 2015-05-26 | 2016-05-23 | Method for comprehensive recovery of smelting wastewater containing magnesium |
Country Status (4)
| Country | Link |
|---|---|
| KR (1) | KR102093004B1 (en) |
| CN (1) | CN106277417A (en) |
| AU (1) | AU2016266463B2 (en) |
| WO (1) | WO2016188387A1 (en) |
Families Citing this family (10)
| 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 |
| CN108677038A (en) * | 2018-05-29 | 2018-10-19 | 吴远怀 | A kind of ion type rareearth ore smelting separation magnesium salts utilization of wastewater resource method |
| CN109574055B (en) * | 2018-12-02 | 2021-03-26 | 河北科技大学 | Method for producing light calcium carbonate and magnesium sulfate heptahydrate from salt slurry |
| KR102163822B1 (en) * | 2018-12-18 | 2020-10-12 | 주식회사 포스코 | Method for recovering highly reactive magnesium oxide from waste water in nickel extraction process |
| CN111440946B (en) * | 2019-01-17 | 2021-12-14 | 有研稀土新材料股份有限公司 | Rare earth extraction method for realizing recycling of magnesium bicarbonate |
| CN109761327A (en) * | 2019-03-13 | 2019-05-17 | 联化科技(盐城)有限公司 | Processing method without aluminum ions waste water |
| CN109761326A (en) * | 2019-03-13 | 2019-05-17 | 联化科技(盐城)有限公司 | Processing method without aluminum ions waste water |
| CN111285526A (en) * | 2020-03-10 | 2020-06-16 | 广西赛可昱新材料科技有限公司 | Method for treating magnesium-containing wastewater from nickel smelting |
| CN113200764B (en) * | 2021-05-25 | 2022-08-16 | 陕西省建筑科学研究院有限公司 | Homogeneous carbonization preparation method of magnesium slag cementing material for silicothermic process magnesium smelting |
| CN114538486A (en) * | 2022-02-22 | 2022-05-27 | 西安交通大学 | Magnesium recovery method and system based on chlor-alkali salt mud |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2556706B2 (en) * | 1987-07-14 | 1996-11-20 | 丸尾カルシウム株式会社 | Method for producing calcium carbonate for papermaking |
| DE19847940C2 (en) * | 1998-10-09 | 2001-04-12 | Ver Energiewerke Ag | Process for the treatment of magnesium sulphate-containing water |
| CN101104522A (en) * | 2007-06-05 | 2008-01-16 | 昆明贵金属研究所 | Method for preparing active magnesium chloride by using magnesium sulfate waste liquid |
| CN101519219A (en) * | 2008-02-26 | 2009-09-02 | 中国恩菲工程技术有限公司 | Manufacturing process for light magnesium carbonate |
| CN101760637B (en) * | 2008-12-24 | 2012-02-01 | 中国恩菲工程技术有限公司 | Leaching technology of magnesium-containing ore |
| CN101760641B (en) * | 2008-12-24 | 2011-08-10 | 中国恩菲工程技术有限公司 | Technology for recovering magnesium from magnesium sulfate solution |
-
2015
- 2015-05-26 CN CN201510276595.8A patent/CN106277417A/en active Pending
-
2016
- 2016-05-23 KR KR1020177034166A patent/KR102093004B1/en active IP Right Grant
- 2016-05-23 AU AU2016266463A patent/AU2016266463B2/en active Active
- 2016-05-23 WO PCT/CN2016/082987 patent/WO2016188387A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| CN106277417A (en) | 2017-01-04 |
| WO2016188387A1 (en) | 2016-12-01 |
| KR20170138561A (en) | 2017-12-15 |
| KR102093004B1 (en) | 2020-05-27 |
| AU2016266463B2 (en) | 2019-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2016266463B2 (en) | Method for comprehensive recovery of smelting wastewater containing magnesium | |
| AU2016203453B2 (en) | Hydrometallurgy and separation method of rare earth ores | |
| CN105776150A (en) | Method for cooperative activation of fly ash and decomposition of gypsum for recovery of sulfur resource | |
| WO2009024014A1 (en) | Method for removing ammonia from coking waste water | |
| CN105060545A (en) | System and method for softening treatment of desulfurization wastewater of coal-fired power plant | |
| CN106830244B (en) | Method for separating and recovering fluorine and acid from fluorine-containing acidic wastewater | |
| CN109095578B (en) | Method for recovering calcium and magnesium in power plant desulfurization wastewater by oxalic acid precipitation method | |
| WO2013143335A1 (en) | Method for extracting aluminium oxide in fly ash by alkaline process | |
| Fang et al. | Chloride ion removal from the wet flue gas desulfurization and denitrification wastewater using Friedel’s salt precipitation method | |
| CN102923743A (en) | Technical method for comprehensively extracting aluminum and lithium from coal ash through acid process | |
| CN101745309A (en) | Flue gas desulfurization (FGD) and comprehensive utilization method for flyash pudding blast furnace slag | |
| CN106517621B (en) | Recycling process of ammonium chloride-containing wastewater | |
| CN105502765A (en) | System and method for treating desulfurization waste water and recycling resources | |
| CN109988902B (en) | Method for dealkalizing iron-reinforced red mud and separating and recovering iron | |
| CN110002415B (en) | Method for recovering phosphate radicals and sulfate radicals from iron phosphate production wastewater | |
| CN111470526A (en) | Method for producing hydrochloric acid-liquid caustic soda-composite material by using industrial waste miscellaneous salt | |
| CN102328947B (en) | Method for recovering strontium slag | |
| CN101480565B (en) | Method for recycling product of magnesium used refractory material after flue gas desulfurization | |
| CN101760638B (en) | Method for recovering magnesium from magnesium sulfate solution | |
| CN109574055A (en) | A kind of method of salt slurry production precipitated calcium carbonate and epsom salt | |
| CN105347592B (en) | A kind of recycling and zero discharge treatment process of desulfurization wastewater | |
| CN110272144B (en) | Treatment method of iron phosphate production wastewater | |
| CN110563007B (en) | Method for converting sodium sulfate into sodium bicarbonate by using calcium oxide and carbon dioxide | |
| CN102795701A (en) | Method for treating acidic waste water from titanium dioxide preparation by sulfuric acid method | |
| CN102671523A (en) | Method for fixing light calcium carbonate as CO2 byproduct by using humate and desulfurization gypsum |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| DA3 | Amendments made section 104 |
Free format text: THE NATURE OF THE AMENDMENT IS: AMEND THE NAME OF THE INVENTOR TO READ FENG, ZONGYU; HUANG, XIAOWEI; WANG, MENG; XU, YANG; SUN, XU; XIA, CHAO; PENG, XINLIN; WANG, LIANGSHI AND ZHAO, NA |
|
| FGA | Letters patent sealed or granted (standard patent) |