CN1053045A - The method of removing magnesium from sodium chloride solution - Google Patents
The method of removing magnesium from sodium chloride solution Download PDFInfo
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- CN1053045A CN1053045A CN 89105833 CN89105833A CN1053045A CN 1053045 A CN1053045 A CN 1053045A CN 89105833 CN89105833 CN 89105833 CN 89105833 A CN89105833 A CN 89105833A CN 1053045 A CN1053045 A CN 1053045A
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Abstract
A kind of method of removing magnesium from sodium chloride solution is applicable to the treating process of thick sodium chloride brine and bittern, and produces Mg (OH) with alkaline precipitation from seawater or magnesium chloride bittern
2Production process.It is characterized in that, in independent heavy magnesium process, at salty mud concentration 20-40g/l, 15-65 ℃ of salty mud temperature, medium stirring intensity, the pH value is in the 9.2-11.2 scope, determine and stable its working pH value of control, thereby slow down interionic speed of response, suppress new nucleus generation and promote coarsening rate, make the mud settling velocity reach 3-8.1m/h, filter factor is brought up to 500-2980 * 10
-7Cm/s has solved mud and has been difficult to isolating difficulty, clear liquid magnesium content<1ppm.
Description
The present invention relates to a kind of method of from the sodium chloride solution that contains magnesium ion, removing magnesium ion, be applicable to the treating process of sodium chloride brine and bittern with alkaline precipitation, and the production process of from seawater or magnesium chloride bittern, producing magnesium hydroxide.
The magnesium ion that is contained in the sodium chloride solution is generally all used and is added a kind of alkali precipitation agent (for example Ca(OH)
2Or NaOH solution etc.), make it to generate the very little Mg(OH of solubility product)
2The precipitation and remove.But the main drawback of this method is because the magnesium ion in the liquid phase and the cross reaction speed of hydroxide ion are exceedingly fast, to cause the Mg(OH that generates)
2Crystallization trickle, mud is colloidal state, the liquid-solid separation of the NaCl solution mud after the demagging is difficulty very, the high fluctuation of suspension content is big in the refined brine, cause thus making the technico-economical comparison decline that alkali (soda ash or caustic soda) is produced, consuming increases, and cost raises, saltiness height in the slag, contaminate environment; Cause treating process equipment big simultaneously, investment is high.
In existing improvement project, usually adopt and return subsider mud, add means such as flocculation agent, with the strainability that improves mud (as " chlorine industry " 1987 the 9th phases, the 4-7 page or leaf " improves brine quality with the salt slurry of handling " and " chlorine industry " 1989 the 8th phases, 9-10 page or leaf " preparation of settling agent and interpolation " is introduced), but effect is undesirable.And the method that U.S. Pat 4336232 is introduced is strict with adding NaCO earlier
3, add the sequential control addition of NaOH, Na again
2CO
3The excessive 0.6g/l that is no less than, the excessive 0.1g/l that is no less than of NaOH, heavy magnesium process has mechanical stirring and generates easy filtering floss with sedimentary calcium slag is common in advance, but needs special strainer to filter.
Deficiency at aforesaid method the objective of the invention is, and proposes a kind ofly can suppress Mg(OH)
2Nucleus formation speed, promotion Mg(OH)
2The method of crystal growth speed uses increasing substantially the salty mud settling velocity, makes it to be easy to filtration washing, makes suspension content reduction in the refined brine simultaneously, and the NaCl loss reduces and can prevent the pollution of the environment.
The objective of the invention is to realize by following measure: being provided with an independent heavy magnesium process, in heavy magnesium process, with the medium tenacity stirred slurry, is 15-65 ℃ in the salty mud temperature, Mg(OH in the mud)
2Concentration is the scope of 20-40g/l, and the working pH value by selecting with the oppositely corresponding mode of mud temperature, concentration of hydraulic mixture, and is controlled its fluctuation<0.2pH value in the scope of 9.2-11.2.
The working pH value is relevant with mud content (crystal seed amount) with temperature.In general, the salty mud temperature is low, mud content is low, and then mud working pH value is tending towards raising; Vice versa.When the salty mud temperature be 15 ℃, when concentration is 20g/l, the pH value is 11.2; The salty mud temperature is 65 ℃, when concentration is 40g/l, the pH value is 9.2.Determine the working pH value like this, the interionic cross reaction speed that slowed down can be controlled the generation of new nucleus simultaneously effectively under the effect of high concentration slurry, impel nuclei growth.The angle of the metallization processes that conforms to the principle of simplicity and minimizing energy consumption considers that temperature can be selected in low scope, preferably at 20-30 ℃.
Mg(OH in the crystal seed mud)
2Particle diameter preferably is controlled at below 5 μ, to improve crystal seed activity.
For crude brine, crystal seed mud and alkali precipitation agent are mixed rapidly, crude brine and alkali precipitation agent should be added simultaneously continuously, and the in addition stirring of medium tenacity.
Enter the salt solution that contains magnesium ion of heavy magnesium process, its pH value should be greater than 9.2, in order to avoid the magnesium ion in the solution is precipitated out outside the characteristic condition of the present invention's regulation in advance in a large number.NaCl concentration is not limit in the salt solution, and magnesium ion concentration should be less than 17g/l, and magnesium calcium when other impurity is not limit; Certainly, for well, can reduce the consumption of alkali when the calcium in the bittern, Mg content are low.
Accompanying drawing 1 is for precipitating the process flow sheet of magnesium ion from sodium chloride solution with the alkali precipitation agent;
Accompanying drawing 2 is for precipitating the process flow sheet of magnesium ion from sodium chloride solution with the soda ash soda processes.
Further specify below in conjunction with accompanying drawing.
As shown in Figure 1, near saturated salt solution or bittern and return mud and the alkali precipitation agent is added in the heavy magnesium groove with medium stirring intensity continuously, the mud temperature can be selected in 15-65 ℃ of scope in the heavy magnesium groove, concentration of hydraulic mixture is 20-40g/l, and it is given according to the throughput balance by under meter that brinish adds speed.When NaOH was used in the alkali precipitation agent, the scope of working pH value was 9.2-10.6; When using Ca(OH)
2The time, the scope of working pH value is 10-11.2.When the working pH value less than 9.8 the time, should add Ca(OH)
2Or NaOH is transferred to, and OH concentration is about 0.1g/l in the liquid phase.Carrying out in time, the mud that overflows from heavy magnesium groove flows to a hydraulic mixer earlier, the polyacrylamide (PAM), sodium polyacrylate (TXY) or the carboxymethyl cellulose (CMC) that add the concentration prepare in advance simultaneously and be thousandth to ten thousand/five in hydraulic mixer, addition be 100,000 of salty mud gross weight/to 1,000,000/.Mud after mixing enters the settlement separate body refuse of subsider, and the concentration of hydraulic mixture of subsider underflow is 95-150g/l, and classified machine classification, Mg(OH in the overflow of grading machine)
2Particle diameter less than 5 μ accounts for 95%, turns back to heavy magnesium groove as crystal seed, and the grading machine underflow enters filter and filters and wash.Subsider overflow and filter filtrate are merged into the demagging refined brine, and wherein magnesium ion content is less than 1ppm.The purification ammonium usual method of calcium ion is added NaCO in the salt solution
3Or NH
4CO
3Remove.
As shown in Figure 2, when adopting crude salt also to produce refined brine, should in a carbonating groove, feed CO with recovered brine, washing lotion and the former salt of new water dissolution
2Gas (or flue gas) carries out carbonating to above-mentioned solution and handles, and makes NaOH be converted into Na
2CO
3, the Na of Sheng Chenging wherein
2CO
3Amount should be enough to guarantee that the calcium ion in the crude brine all generates CaCO
3, and excessive at least 0.4-0.6g/l.The pH value of control carbonating solution is 9.2 to be advisable.Carbonating is finished liquid and is produced crude brine again in new water is added to the dissolved salt bucket, deliming simultaneously.Rough salt solution is added in the heavy magnesium groove with medium stirring intensity continuously, and returning mud content from the classifier overflow mouth of subsider underflow simultaneously is that the mud of 95-150g/l advances to sink the magnesium groove, and keeps Mg(OH in the heavy magnesium groove)
2Concentration is 20-40g/l.Contain NaOH15-25%(weight) the interpolation speed of solution by working pH value decision in the given heavy magnesium groove, by the dosage of automatic adjusting control NaOH solution.Processing temperature can be selected in the 15-65 ℃ of scope and carry out in the heavy magnesium groove, but preferably carries out under 20-30 ℃, so not only can reduce the steam consumption and can also simplify technological process.Heavy magnesium groove volume stops in groove by total mud amount and was designed to suitable in 20-40 minute.Carry out mud can flow into the subsider top continuously from heavy magnesium groove overflow port hydraulic mixer with process, enter subsider again.The subsider underflow is through hydroclone classification, and the overflow of hydrocyclone turns back to heavy magnesium groove, and underflow then advances filter and filters and wash.The filter residue water ratio is about about 50%, can fully utilize or store up.Washing lotion then turns back to the carbonating groove.Subsider overflow and filter filtrate are merged into refined brine, magnesium<1ppm in the liquid phase, calcium<4ppm.
The present invention and prior art relatively have following advantage:
1. salty mud has good sedimentation strainability, and its settling velocity is 3-8.1m/h, and filter factor is 500-2980 * 10
-7Cm/s, thus the throughput of sedimentation filter plant improved significantly.
2. salt refining process operation is continuous, stable, and it is few to cross alkali number, and suspension content is low, and calcium is less than 4ppm in the refined brine, and magnesium is less than 1ppm.
3. technical process and equipment are simple, can combine closely with existing brine rectification process, and production process can automatically-controlled continuous.
4. two alkali consumptions are few, and chlor-alkali plant can outsourcing soda, does not consume or consume less hydrochloric acid; NaCl loss is little, and body refuse can fully utilize or store up, and eliminates or has alleviated environmental pollution, and social benefit and overall economic efficiency are good.
Embodiment:
1. with 10 liters of crude brines, its chemical constitution (g/l) is: NaCl 312, Ca
2+0.69, Mg
2+0.79, SO
2-
42.20 the pH value is 7.2 in the time of 20 ℃.The chemical constitution of the milk of lime that agent is used as alkali precipitation (g/l) is: CaO136.80, MgO0.76, Fe
2O
30.02, Al
2O
30.22, SiO
20.54 the pH value is 12.45 in the time of 20 ℃.The mud of using as crystal seed is to contain Mg(OH)
2Be that master, concentration of hydraulic mixture are 98g/l.Crude brine, milk of lime and the mud of using as crystal seed are added in the heavy magnesium groove of φ a 200 * 120mm continuously, and keeping the mud temperature is 20 ℃ ± 0.5 ℃, and concentration of hydraulic mixture is 30 ± 2g/l, and the interpolation speed of alkali is 11.2 ± 0.2 given by the working pH value.The heavy magnesium activity duration amounts to 144 minutes.After heavy magnesium operation is finished, mud being moved on in the settlement barrel of a 200 * 600mm, is millesimal PAM solution 15ml toward the previously prepared concentration of the interior interpolation of settlement barrel, leaves standstill 20 minutes after stirring up and down, and recording settling velocity is 4.2m/h.Take out 9.8 liters of supernatant liquors with siphonage, remaining 5.78 liters of compression zone mud are 0.06MPa in vacuum tightness, and filtration area is 630cm
2Strainer of the false end in filter, obtain 4.53 liters of filtrates in 151 seconds of filtration time, filter factor is 1429 * 10
-7Cm/s.Supernatant liquor and filtrate are merged into demagging salt solution, and its chemical constitution (g/l) is: NaCl311.80, Ca
2+1.52, Mg
2+0.0008, SO
2-
42.19.With 3 liters of 50 ℃ of hot water filter cake is carried out not the dump washing, NaCl concentration 1.81g/l in the last washing lotion.The filter cake oven dry is weighed 565 grams altogether, and its change composition (%) is: MgO66.74, CaO0.8, Fe
2O
30.29, Al
2O
30.21, SiO
20.47, Cl
-0.23, igloss 31.08.
2. with chemical constitution (g/l) be: NaCl305, Ca
2+0.23, Mg
2+0.46, SO
2- 41.42 the pH value is 10 liters of 7.1 crude brines in the time of 20 ℃.Contain Mg(OH in the mud as crystal seed) 95g/l, NaCl304g/l wherein, concentration is that 22% NaOH and concentration are 40% Na
2CO
3Solution is as precipitation agent.In crude brine, add Na by stoichiometry slowly
2CO
312.5 gram stirred 30 minutes down at 40 ℃, was added to continuously in the heavy magnesium groove of φ a 200 * 120mm who has a medium stirring intensity with crystal seed mud and NaOH solution then, the interpolation speed of crude brine is 4 liters/minute.Temperature is 60 ± 0.5 ℃ in the groove, and the maintenance concentration of hydraulic mixture is 27-28g/l.NaOH solution then adds by given working pH value, and the working pH value is 9.2 ± 0.2.Total operation time is 146 minutes.Make 16.15 liters in mud altogether.Mud is moved on in the settlement barrel of a 200 * 600mm, adjusting the pH value with NaOH solution is 10.6, and adding previously prepared concentration then is millesimal PAM solution 18ml, leaves standstill 20 minutes after stirring up and down, and recording settling velocity is 7.2m/h.Take out 10.12 liters of supernatant liquors with siphonage, remaining 6 liters of compression zone mud are that 0.06Mpa, filtration area are 630cm in vacuum tightness
2Strainer of the false end in filter, obtain 4.8 liters of filtrates in 122 seconds of filtration time, filter factor is 1874 * 10
-7Cm/s.The merging of supernatant liquor and filtrate amount to 14.92 liters.Its chemical constitution (g/l) is: NaCl302.50, Ca
2+0.0005, Mg
2+0.00088, SO
2-
41.40, Na
2CO
30.42.Filter cake is carried out not the dump washing with 3 liters of 50 ℃ of hot water, NaCl concentration 2.10g/l in the last washing lotion.The filter cake oven dry is weighed 574.2 grams altogether, and its change composition (%) is: MgO68.10, CaO0.56, Cl
-0.23, igloss 30.89.Contain NaCl48.80g/l in the washing lotion.
3. bittern chemical constitution (g/l) is: NaCl243.82, Ca
2+0.46, Mg
2+16.52, SO
2-
41.34 the pH value is 10 liters of 7.1 crude brines in the time of 30 ℃.With milk of lime is precipitation agent, and the chemical constitution of milk of lime is with example 1.With containing Mg(OH) mud of 95g/l is crystal seed, in the heavy magnesium groove of φ 200 * 120mm that it is 2.8-3m/s that former bittern, crystal seed mud and milk of lime are added to a stirring rake linear velocity continuously, the interpolation speed of crude brine is 4 liters/minute.Keeping the interior temperature of groove is 30 ± 0.5 ℃, and concentration of hydraulic mixture is 38 ± 2g/l.The pH value is 10.8 ± 0.2.Total operation time is 128 minutes.Make 13.56 liters in mud altogether.Mud is moved on in the settlement barrel of a 200 * 600mm, adding previously prepared concentration is millesimal PAM solution 14ml, leaves standstill 20 minutes after stirring up and down, and recording settling velocity is 5.6m/h.Take out 8.1 liters of supernatant liquors with siphonage, remaining 5.5 liters of compression zone mud are 0.05Mpa in vacuum tightness, and filtration area is 630cm
2Strainer of the false end in filter, filtration time 188 seconds, 1.8 centimetres of filter cake thickness average out to obtain 4.2 liters of filtrates, filter factor is 1277 * 10
-7Cm/s.The merging of supernatant liquor and filtrate amount to 12.3 liters.Its chemical constitution (g/l) is: NaCl206.72, Mg
2+0.00092, SO
2-
41.35.Filter cake inclined with 3 liters of 50 ℃ of hot water wash, NaCl concentration is 2.20g/l in the last wash water.Filter cake oven dry back weighs 516 grams altogether, and its change composition (%) is; MgO67.20, CaO1.62, Cl
-0.38, igloss 31.02.Contain NaCl42.86g/l in the washing lotion.
Claims (9)
1, a kind of method of removing magnesium from sodium chloride solution is with containing the sodium chloride solution of magnesium ion, under the condition of medium stirring intensity, is precipitation agent with alkali, is crystal seed with the mud that returns, and makes magnesium ion be Mg (OH) 2 and separates out, and adds alkali adjusted in case of necessity; Add flocculation agent then,, remove and contain the magnesium slag, obtain containing the salt solution of magnesium ion<1ppm, the invention is characterized in again through settlement separate:
In independent heavy magnesium process, in the mud temperature is that Mg (OH) 2 concentration are the scope of 20-40g/l in 15-65 ℃, mud, the working pH value in the scope of 9.2-11.2 by adjusting with the oppositely corresponding mode of temperature, concentration, and make its be stabilized in ± scope of 0.2pH value in.
2, method according to claim 1 is characterized in that: when being the alkali precipitation agent with NaOH, the scope of working pH value is 9.2-10.6; Use Ca(OH)
2During for the alkali precipitation agent, the scope of working pH value is 10-11.2.
3, method according to claim 1 and 2 is characterized in that: described alkali is prefabricated into 15-25%(weight for heavy dose) the aqueous solution or suspension.
4, method according to claim 1 and 2 is characterized in that: described flocculation agent addition is 100,000/to 1,000,000/weight, is prefabricated into the aqueous solution that weight concentration is 0.1-0.05%.
5, method according to claim 1 and 2 is characterized in that: the pH value that reclaims the sodium-chlor salinated water is adjusted to less than 9.2.
6, method according to claim 1 and 2 is characterized in that: enter magnesium ion concentration<17g/l in the thick bittern of heavy magnesium process.
7, method according to claim 1 and 2 is characterized in that: the Mg(OH in the described crystal seed mud)
2Particle diameter less than 5 μ.
8, method according to claim 7 is characterized in that: the overflow with the subsider underflow after classified is as crystal seed mud.
9, method according to claim 1 and 2 is characterized in that: the linear velocity of agitating vane is 2-3m/s.
Priority Applications (1)
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---|---|---|---|
CN 89105833 CN1021963C (en) | 1989-12-30 | 1989-12-30 | Method for removing magnesium from sodium chloride solution |
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---|---|---|---|
CN 89105833 CN1021963C (en) | 1989-12-30 | 1989-12-30 | Method for removing magnesium from sodium chloride solution |
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CN1053045A true CN1053045A (en) | 1991-07-17 |
CN1021963C CN1021963C (en) | 1993-09-01 |
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Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1083801C (en) * | 1997-01-14 | 2002-05-01 | 中国科学院海洋研究所 | Process for preparing salt by working up seawater |
CN1331751C (en) * | 2004-03-08 | 2007-08-15 | 多氟多化工股份有限公司 | Method for refining industrial salt |
CN101925535B (en) * | 2007-12-28 | 2012-11-28 | 蒂森克虏伯伍德有限公司 | Removal of silicon from brine |
CN103232147A (en) * | 2013-05-21 | 2013-08-07 | 唐山三友化工股份有限公司 | Method for improving primary salty mud washing ability |
CN106477600A (en) * | 2016-10-09 | 2017-03-08 | 青海盐湖工业股份有限公司 | A kind of tail salt removes magnesium apparatus |
CN107324359A (en) * | 2017-08-10 | 2017-11-07 | 重庆合川盐化工业有限公司 | Alkali amine industrial salt production technology |
CN107344724A (en) * | 2016-05-04 | 2017-11-14 | 广州市睿石天琪能源技术有限公司 | A kind of method that simple and efficient reduces content of magnesium in salt lake bittern |
CN113264541A (en) * | 2021-05-20 | 2021-08-17 | 山东海化集团有限公司 | Magnesium removal method and device for crude brine |
CN114560478A (en) * | 2022-02-22 | 2022-05-31 | 西安交通大学 | Raw salt refining method and system |
-
1989
- 1989-12-30 CN CN 89105833 patent/CN1021963C/en not_active Expired - Fee Related
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1083801C (en) * | 1997-01-14 | 2002-05-01 | 中国科学院海洋研究所 | Process for preparing salt by working up seawater |
CN1331751C (en) * | 2004-03-08 | 2007-08-15 | 多氟多化工股份有限公司 | Method for refining industrial salt |
CN101925535B (en) * | 2007-12-28 | 2012-11-28 | 蒂森克虏伯伍德有限公司 | Removal of silicon from brine |
CN103232147A (en) * | 2013-05-21 | 2013-08-07 | 唐山三友化工股份有限公司 | Method for improving primary salty mud washing ability |
CN107344724A (en) * | 2016-05-04 | 2017-11-14 | 广州市睿石天琪能源技术有限公司 | A kind of method that simple and efficient reduces content of magnesium in salt lake bittern |
CN107344724B (en) * | 2016-05-04 | 2020-06-16 | 广州市睿石天琪能源技术有限公司 | Simple and efficient method for reducing magnesium content in salt lake brine |
CN106477600A (en) * | 2016-10-09 | 2017-03-08 | 青海盐湖工业股份有限公司 | A kind of tail salt removes magnesium apparatus |
CN106477600B (en) * | 2016-10-09 | 2018-01-05 | 青海盐湖工业股份有限公司 | A kind of tail salt removes magnesium apparatus |
CN107324359A (en) * | 2017-08-10 | 2017-11-07 | 重庆合川盐化工业有限公司 | Alkali amine industrial salt production technology |
CN107324359B (en) * | 2017-08-10 | 2019-03-01 | 重庆合川盐化工业有限公司 | Alkali amine industrial salt production technology |
CN113264541A (en) * | 2021-05-20 | 2021-08-17 | 山东海化集团有限公司 | Magnesium removal method and device for crude brine |
CN114560478A (en) * | 2022-02-22 | 2022-05-31 | 西安交通大学 | Raw salt refining method and system |
Also Published As
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