CN102795646A - Method for preparing low-surface activity and large-grain size magnesium hydroxide - Google Patents
Method for preparing low-surface activity and large-grain size magnesium hydroxide Download PDFInfo
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- CN102795646A CN102795646A CN2012102167575A CN201210216757A CN102795646A CN 102795646 A CN102795646 A CN 102795646A CN 2012102167575 A CN2012102167575 A CN 2012102167575A CN 201210216757 A CN201210216757 A CN 201210216757A CN 102795646 A CN102795646 A CN 102795646A
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- bittern
- lime
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- marinco
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Abstract
The invention provides a method for preparing low-surface activity and large-grain size magnesium hydroxide. The method comprises the following steps of: 1, adding a small amount of lime milk and a calcium chloride solution into brine, stirring to form a small quantity of Mg(OH)2 flocculent precipitates, filtering the precipitates, and removing SO4<2-> and other impurities in the brine; 2, adding calcium chloride in the brine from which the impurities are removed, so that the brine contains Ca<2+> of certain medium concentration; 3, adding the lime milk into the brine containing Ca<2+> of certain medium concentration, and after reaction is finished, precipitating magnesium hydroxide crystallite precipitates; and 4, settling the magnesium hydroxide crystallite precipitates, filtering, washing and drying.
Description
Technical field
The present invention relates to the production technique of chemical products, especially relate to the preparation method of the big particle diameter Marinco H of a kind of low surfactivity.
Background technology
Because Marinco H and brucite powder surface have positive charge, and iso-electric point is higher, therefore, uses AS that Marinco H is carried out surface modification treatment usually.Powder surface modification method commonly used comprises coating modification, surface chemical modification, precipitin reaction modification, encapsulated modification and mechanochemical modification etc.At present, the method that is mainly used in the magnesium hydrate powder surface-treated is surface chemical modification.
U.S. Pat 5461101 discloses a kind of method of, chemosynthesis flame retardant of magnesium hydroxide powder wet-process modified with StNa and sodium oleate, and the consumption of StNa is 5% of a Marinco H quality, and controlled temperature is 80 ℃.
The Japan scholar once adopted silane coupling agent and titanate coupling agent to carry out surface modification treatment to the brucite powder that is applied to cable industry and rubber industry; Obtained good modified effect; Brucite after the modification has the good flame performance, also has certain acid resistance simultaneously.
The Japan scholar develops fire retardant with lipid acid or its amine salt with the ratio modification brucite powder (granularity is 2-6 μ m) of 1.5-6.0%, and draws in the adding of the fire retardant powder after the modification olefin resin conclusion that can produce flame-retarded resin after deliberation.
Human Triple Pressed Stearic Acid such as Schofield.W C.E are handled Marinco H and are filled EVA, and its result shows: can improve elongation at break, melting index and the limiting oxygen index(LOI) of material after handling with Triple Pressed Stearic Acid, and tensile strength decreases.
The domestic present surface treatment method of using morely mainly is two kinds of wet method and dry method, and tensio-active agent mainly is StNa or sodium oleate, and consumption is the 1%-3% of massfraction.
There is bibliographical information can adopt elastomerics coating filler and method of plasma processing that Marinco H is carried out surface treatment.People such as Schreiber use argon plasma and methane plasma treatment inorganic filling material surface first, are used to fill LLDPE, though these two kinds of methods have the people to study, still are in the starting stage.
In sum, though change Mg (OH) at present
2Surface-active technology is a lot, but that the common issue with that each item technology exists is complex process, cost is higher, is unfavorable for the requirement that industrialization is produced.
Summary of the invention
The present invention is directed to the weak point that exists in the prior art; A kind of method for preparing the low big particle diameter Marinco H of surfactivity is provided, adopts the preparation of high-calcium ionic medium method to have the magnesium hydroxide crystal of ideal sheet or acicular grains, low specific surface area and greater particle size.
To achieve these goals, this aspect provides the method for a low big particle diameter Marinco H of surfactivity of preparation, comprises following sequential steps:
Step 1 adds a small amount of milk of lime and calcium chloride solution in the bittern, and stirring reaction forms a spot of Mg (OH)
2Flocks, the elimination throw out is removed the SO in the bittern
4 2-With other impurity.
Step 2 is removed in the bittern of impurity and is added calcium chloride, makes the Ca that contains certain concentration of medium in the bittern
2+
Step 3 contains the Ca of certain concentration of medium
2+Bittern in add milk of lime, separate out Marinco H crystallite throw out after reaction finishes.
Step 4 is carried out sedimentation, filtration, washing, oven dry to the Marinco H crystallite throw out that generates in the step 3.
In a preferred embodiment provided by the invention, said method also comprises step 0, and said step 0 is for to become unslaked lime with limestone calcination, and aquation is prepared into milk of lime.Further in the preferred embodiment, said limestone calcination temperature is 900-1200 ℃, calcination time 2-4 hour.Further in the preferred embodiment, the milk of lime fineness that is prepared into is 0.06-0.010mm, screen over-size≤3.0%, Ca in the milk of lime (OH)
2Concentration be 2-5wt%.
In a preferred embodiment provided by the invention, the degree Beaume of said bittern is Be25 °-30 °.
In a preferred embodiment provided by the invention, milk of lime adds in the bittern with 100-140 rev/min of stirring velocity at normal temperatures in the step 1, and the pH value of bittern is transferred to 8.0-9.0.
In a preferred embodiment provided by the invention, the Ca in the bittern behind the adding calcium chloride in the step 2
2+Concentration of medium is 2.0-3.0mol/L, Mg
2+Concentration is 0.25-0.75mol/L.
In a preferred embodiment provided by the invention, the pH value of solution is 10.0 during reaction terminating.
In a preferred embodiment provided by the invention, the feed rate that adds milk of lime in the step 3 is 6-12ml/min, 120 rev/mins of stirring velocitys.
Method provided by the invention adopts the Ca in the calcium chloride conditioned reaction liquid phase
2+Concentration of medium, thereby control Marinco H crystallization speed and grain diameter make lower specific surface area and the surfactivity of powder that makes to greatly reduce production cost, have reduced technological process and equipment, have promoted the raising of production efficiency.
Embodiment
The present invention provides a kind of method for preparing the low big particle diameter Marinco H of surfactivity, can prepare the magnesium hydroxide crystal with ideal sheet or acicular grains, low specific surface area and greater particle size through method provided by the invention.
Usually the pattern of synthetic magnesium hydroxide product is unformed fine crystals; Particle diameter is in nano level; Agglomeration is very serious; Must manage to eliminate its crystalline surface polarity as fire-retardant Marinco H, promptly require crystal to have special big crystal grain (tabular or needle-like), low specific surface area and low microcosmic internal strain.
Under the certain reaction temperature, influence the synthetic Mg (OH) of bittern lime method
2The principal element of crystal grain-growth is Mg (OH)
2Speed of separating out, from
Ca(OH)
2+MgCl
2＝Mg(OH)
2+CaCl
2
The angle of molecular balance and reaction kinetics under the normal temperature condition, influences Mg (OH)
2The principal element of speed of separating out be the concentration of reactant and product in the solution.
Because Mg (OH)
2Solubility product be far smaller than Ca (OH)
2Solubility product, therefore above-mentioned reaction equilibrium constant is very big, shows that tendency and degree that deposition transforms are very big, speed of response is exceedingly fast.If the feed rate of milk of lime is too fast, degree of supersaturation is too high, Mg (OH)
2Formation will concentrate on nucleation rate and greatly carry out at the place, a large amount of tiny nucleus are separated out fast, and these tiny nucleus can not shoot up and are tabular or acicular large size crystal grain, and make Mg (OH)
2Sedimentation strainability extreme difference.Therefore suppress Mg (OH)
2Too fastly separate out, promote Mg (OH)
2Crystalline is grown up, and becomes Marinco H synthetic key link.
The present invention's technology adopts the high-calcium ionic medium method, in aqueous salt brine, injects a certain amount of calcium salt (like calcium chloride, be the accessory substance of reaction, need not outsourcing) earlier, makes building-up reactions at high Ca
2+Carry out under the concentration of medium, impel speed of response to slow down, thereby make the Marinco H nucleus have adequate time to grow up, effectively promote crystalline to grow up.Make the magnesium hydroxide crystal of acquisition have ideal sheet or acicular grains, low specific surface area and bigger particle diameter.
Below through being that embodiment does further explain to preparation method provided by the invention so that better understand the content that this aspect is created, but the content of embodiment does not limit the protection domain of the invention.
Embodiment 1
Wingdale was formed unslaked lime in 3 hours at 1050 ℃ of temperature lower calcinations, and the unslaked lime of generation adopts aquation to prepare milk of lime, and the milk of lime fineness of formation is 0.08mm, screen over-size≤1.0%, wherein Ca (0H)
2Concentration be 3wt%.
It is in the Be28 ° of bittern that the milk of lime of preparation before a small amount of is added to degree Beaume, adds an amount of calcium chloride solution simultaneously, and the pH value of regulating bittern is to 8.0-8.5, adds SO in amount and the bittern of calcium chloride
4 2Amount quite.With 120 rev/mins of stirring velocitys, add milk of lime and calcium chloride solution at normal temperatures, whole process is carried out 30 minutes time.Stirring reaction forms a spot of Mg (0H)
2Flocks, the elimination throw out, and can effectively remove the SO in the bittern
4 2-With other impurity.
In purified brine, add calcium chloride, make and form certain C a in the bittern
2+Concentration of medium.Ca in the control bittern
2+Concentration of medium is 2.5mol/L, Mg
2+Concentration is 0.5mol/L.
(about 25 ℃) at normal temperatures, with before the milk of lime of preparation add with the feed rate of 8-10ml/min and contain certain C a
2+React in the bittern of concentration of medium, add milk of lime with 120 rev/mins of kind stirred solutions.When the pH of solution value reached 10.0, termination reaction was separated out Marinco H crystallite throw out.
The sedimentation of Marinco H crystallite throw out, filtration, washing, oven dry with reaction forms have the big particle diameter Marinco H of low surfactivity thereby form.The temperature of oven dry is 160 ℃, and the time of oven dry is 2 hours.
At certain temperature and Mg
2+Concentration (0.5mol/L) under, regulate Ca
2+Concentration of medium, effectively conditioned reaction Ca (OH)
2+ Mg
2+=Mg (OH)
2+ Ca
2Speed and process, control Marinco H crystallization speed and grain diameter, thus effectively control the specific surface area and the surfactivity of powder.Work as Ca
2+When concentration of medium reached 2.5mol/L, the magnesium hydrate precipitate composition granule particle diameter of acquisition was maximum, D
50And D
98Reach 30.1 μ m and 113.5 μ m respectively.
With MgCl
2+ Ca (OH)
2→ CaCl
2+ Mg (OH)
2The endpoint pH of reaction is controlled at below 10, guarantees that the synthetic magnesium hydrate powder that makes has higher purity.
Embodiment 2
Wingdale was formed unslaked lime in 2.5 hours at 1200 ℃ of temperature lower calcinations, and the unslaked lime of generation adopts aquation to prepare milk of lime, and the milk of lime fineness of formation is 0.07mm, screen over-size≤2.0%, wherein Ca (OH)
2Concentration be 4wt%.
It is in the Be30 ° of bittern that the milk of lime of preparation before a small amount of is added to degree Beaume, adds an amount of calcium chloride solution simultaneously, and the pH value of regulating bittern is to 8.1-8.6, adds SO in amount and the bittern of calcium chloride
4 2Amount quite.With 110 rev/mins of stirring velocitys, add milk of lime and calcium chloride solution at normal temperatures, whole process is carried out 40 minutes time.Stirring reaction forms a spot of Mg (0H)
2Flocks, the elimination throw out, and can effectively remove the SO in the bittern
4 2-With other impurity.
In purified brine, add calcium chloride, make and form certain C a in the bittern
2+Concentration of medium.Ca in the control bittern
2+Concentration of medium is 2.6mol/L, Mg
2+Concentration is 0.6mol/L.
(about 25 ℃) at normal temperatures, with before the milk of lime of preparation add with the feed rate of 10-12ml/min and contain certain C a
2+React in the bittern of concentration of medium, add milk of lime with 120 rev/mins of kind stirred solutions.When the pH of solution value reached 10.0, termination reaction was separated out Marinco H crystallite throw out.
The sedimentation of Marinco H crystallite throw out, filtration, washing, oven dry with reaction forms have the big particle diameter Marinco H of low surfactivity thereby form.The temperature of oven dry is 180 ℃, and the time of oven dry is 1.5 hours.
Embodiment 3
Wingdale was formed unslaked lime in 4 hours at 900 ℃ of temperature lower calcinations, and the unslaked lime of generation adopts aquation to prepare milk of lime, and the milk of lime fineness of formation is 0.10mm, screen over-size≤1.0%, wherein Ca (OH)
2Concentration be 5wt%.
It is in the Be25 ° of bittern that the milk of lime of preparation before a small amount of is added to degree Beaume, adds an amount of calcium chloride solution simultaneously, and the pH value of regulating bittern is to 8.4-9.0, adds SO in amount and the bittern of calcium chloride
4 2Amount quite.With 140 rev/mins of stirring velocitys, add milk of lime and calcium chloride solution at normal temperatures, whole process is carried out 25 minutes time.Stirring reaction forms a spot of Mg (OH)
2Flocks, the elimination throw out, and can effectively remove the SO in the bittern
4 2-With other impurity.
In purified brine, add calcium chloride, make and form certain C a in the bittern
2+Concentration of medium.Ca in the control bittern
2+Concentration of medium is 2.4mol/L, Mg
2+Concentration is 0.4mol/L.
(about 25 ℃) at normal temperatures, with before the milk of lime of preparation add with the feed rate of 6-9ml/min and contain certain C a
2+React in the bittern of concentration of medium, add milk of lime with 120 rev/mins of kind stirred solutions.When the pH of solution value reached 10.0, termination reaction was separated out Marinco H crystallite throw out.
The sedimentation of Marinco H crystallite throw out, filtration, washing, oven dry with reaction forms have the big particle diameter Marinco H of low surfactivity thereby form.The temperature of oven dry is 150 ℃, and the time of oven dry is 3 hours.
More than specific embodiment of the present invention is described in detail, but it is just as example, the present invention is not restricted to the specific embodiment of above description.To those skilled in the art, any equivalent modifications that the present invention is carried out with substitute also all among category of the present invention.Therefore, not breaking away from impartial conversion and the modification of being done under the spirit and scope of the present invention, all should contain within the scope of the invention.
Claims (10)
1. one kind prepares the method for hanging down the big particle diameter Marinco H of surfactivity, and its characteristic exists, and comprises following sequential steps:
Step 1 adds a small amount of milk of lime and calcium chloride solution in the bittern, and stirring reaction forms a spot of Mg (OH)
2Flocks, the elimination throw out is removed the SO in the bittern
4 2-With other impurity;
Step 2 is removed in the bittern of impurity and is added calcium chloride, makes the Ca that contains certain concentration of medium in the bittern
2+
Step 3 contains the Ca of certain concentration of medium
2+Bittern in add milk of lime, separate out Marinco H crystallite throw out after reaction finishes;
Step 4 is carried out sedimentation, filtration, washing, oven dry to the Marinco H crystallite throw out that generates in the step 3.
2. method according to claim 1 is characterized in that said method also comprises step 0, and said step 0 is for to become unslaked lime with limestone calcination, and aquation is prepared into milk of lime.
3. method according to claim 2 is characterized in that, said limestone calcination temperature is 900-1200 ℃, calcination time 2-4 hour.
4. method according to claim 2 is characterized in that, the milk of lime fineness that is prepared into is 0.06-0.010mm, screen over-size≤3.0%, Ca in the milk of lime (OH)
2Concentration be 2-5wt%.
5. method according to claim 1 is characterized in that, the degree Beaume of said bittern is Be25 °-30 °.
6. method according to claim 1 is characterized in that, milk of lime adds in the bittern with 100-140 rev/min of stirring velocity at normal temperatures in the step 1, and the pH value of bittern is transferred to 8.0-9.0.
7. method according to claim 1 is characterized in that, the Ca in the bittern behind the adding calcium chloride in the step 2
2+Concentration of medium is 2.0-3.0mol/L, Mg
2+Concentration is 0.25-0.75mol/L.
8. method according to claim 1 is characterized in that, the pH value of solution is 10.0 during reaction terminating.
9. method according to claim 1 is characterized in that, the feed rate that adds milk of lime in the step 3 is 6-12m1/min, 120 rev/mins of stirring velocitys.
10. method according to claim 1 is characterized in that, said Marinco H crystallite throw out places 150-180 ℃ to dry 1.5-4 hour down.
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|---|---|---|---|
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114436301A (en) * | 2022-02-18 | 2022-05-06 | 洛阳中超新材料股份有限公司 | Preparation method of magnesium hydroxide large single crystal |
| CN116730644A (en) * | 2023-04-23 | 2023-09-12 | 扬州大学 | Preparation method of bittern carbonization synergistic reinforcement recycled aggregate |
Citations (1)
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|---|---|---|---|---|
| CN1554587A (en) * | 2003-12-22 | 2004-12-15 | 国家海洋局天津海水淡化与综合利用研 | Process for preparing magnesium hydroxide by light burning bitter spar and concentrated sea water |
-
2012
- 2012-06-28 CN CN201210216757.5A patent/CN102795646B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1554587A (en) * | 2003-12-22 | 2004-12-15 | 国家海洋局天津海水淡化与综合利用研 | Process for preparing magnesium hydroxide by light burning bitter spar and concentrated sea water |
Non-Patent Citations (6)
| Title |
|---|
| 《河北科技大学学报》 20100831 赵华等 "高浓度氯化钙水热环境下氢氧化镁颗粒生长行为研究" 第312-316、329页 1-10 第31卷, 第4期 * |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114436301A (en) * | 2022-02-18 | 2022-05-06 | 洛阳中超新材料股份有限公司 | Preparation method of magnesium hydroxide large single crystal |
| CN114436301B (en) * | 2022-02-18 | 2024-04-05 | 洛阳中超新材料股份有限公司 | Preparation method of magnesium hydroxide large monocrystal |
| CN116730644A (en) * | 2023-04-23 | 2023-09-12 | 扬州大学 | Preparation method of bittern carbonization synergistic reinforcement recycled aggregate |
| CN116730644B (en) * | 2023-04-23 | 2023-12-29 | 扬州大学 | Preparation method of bittern carbonization synergistic reinforcement recycled aggregate |
| US12017956B1 (en) | 2023-04-23 | 2024-06-25 | Yangzhou University | Method for preparing bittern-carbonization synergistic reinforced recycled aggregate |
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