阅读说明：本技术 一种碳酸钙晶须的制备方法 (Preparation method of calcium carbonate whisker ) 是由 李雪 郑强 邓晓阳 于 2021-07-09 设计创作，主要内容包括：本发明公开了一种碳酸钙晶须的制备方法,涉及一种无机产品制备方法,该方法先将原料方解石矿或方解石尾矿或石灰石工业废料煅烧分解为氧化钙,再将氧化钙和氯化镁加入到去离子水中并在一定温度下进行消化,过滤得到滤饼打浆通入过量的CO-(2)中进行碳酸化反应制得重镁水,最后将消化转化过滤后的滤液均匀滴加到碳酸化反应过滤后的滤液中,并在一定温度和搅拌速率下进行反应,直至无沉淀产生反应结束,得到碳酸钙晶须。这种方法解决了传统碳酸化法制备碳酸钙晶须长度小、长径比低、纯度不高、母液无法多次回收利用、原料来源受限、生产成本高等问题,本发明不仅可以制得更高纯度、更大长径比的碳酸钙晶须,也可以使母液以及CO-(2)气体循环利用,节约成本,易于实现工业化生产。(The invention discloses a preparation method of calcium carbonate whiskers, and relates to a preparation method of an inorganic product 2 And finally, uniformly dropwise adding the filtrate obtained after digestion, conversion and filtration into the filtrate obtained after carbonation and filtration, and reacting at a certain temperature and stirring rate until no precipitate is generated and the reaction is finished to obtain the calcium carbonate whisker. The method solves the problems of small length, low length-diameter ratio, low purity, incapability of recycling mother liquor for multiple times, limited raw material sources, high production cost and the like of the traditional carbonation method for preparing the calcium carbonate crystal whiskerCan not only prepare calcium carbonate crystal whisker with higher purity and larger length-diameter ratio, but also make mother liquor and CO 2 The gas is recycled, the cost is saved, and the industrial production is easy to realize.)

1. A preparation method of calcium carbonate whiskers is characterized by comprising the following preparation processes:

the method comprises the following steps: grinding calcite ore or calcite tailings or industrial limestone waste residues, calcining at high temperature to decompose the ground calcite ore or calcite tailings or industrial limestone waste residues into calcium oxide, and recovering carbon dioxide gas;

step two: adding the calcium oxide and the magnesium chloride into deionized water at the temperature of 25-60 ℃ according to the mass ratio of 1: 1-1: 5, sufficiently digesting for 1-5 hours, and filtering to obtain a filter cake and a filtrate;

step three: pulping the filter cake obtained in the second filtering step to excess CO₂In (recovered CO as described in step one)₂Available gas), fully reacting, filtering and removing impurities;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three until no precipitate is generated, and stopping the reaction, and carrying out suction filtration, washing and drying on the obtained precipitate to obtain the calcium carbonate whiskers.

2. The method for preparing calcium carbonate whiskers according to claim 1, wherein the method comprises the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 60 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 800 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step (II) into the filtrate obtained in the step (III) at the speed of 5 ml/min, stirring at the speed of 100r/min, heating at the temperature of 50 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whiskers.

3. The method for preparing calcium carbonate whiskers according to claim 1, wherein the method comprises the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 90 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 60 min;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three at the speed of 5 ml/min, stirring at the speed of 150r/min, heating at the temperature of 40 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker.

4. The method for preparing calcium carbonate whiskers according to claim 1, wherein the method comprises the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 1000 deg.C for 60 min to decompose calcium oxide, and collecting CO₂A gas;

step two: weighing 11.2g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing into the beaten filter cake of the second step at the speed of 200mL/min (CO collected in the first step)₂Can be repeatedly used), reacting for 150 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three at the speed of 7 ml/min, stirring at the speed of 150r/min, heating at the temperature of 45 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker.

5. The method for preparing calcium carbonate whiskers as recited in claims 1-3, characterized in that: in the first step, the raw materials are ground and sieved, and particles with 200 meshes account for more than 85%.

6. The method for preparing calcium carbonate whiskers as recited in claims 1-3, characterized in that: and in the second step, the mass ratio of the mixture of the magnesium chloride and the calcium oxide to the deionized water is 1: 1-1: 30.

7. The method for preparing calcium carbonate whiskers as recited in claims 1-3, characterized in that: CO in the third step₂The aeration rate is 100-500 mL/min, the aeration time is 30-240 min, and the reaction temperature is 25-60 ℃.

8. The method for preparing calcium carbonate whiskers as recited in claims 1-3, characterized in that: the titration rate of the filtrate in the step four is 3-15 mL/min, and the stirring rate is 100-200 r/min.

Technical Field

The invention relates to a preparation method of inorganic chemical products, in particular to a preparation method of calcium carbonate whiskers.

Background

Calcium carbonate whiskers are a novel inorganic material which has been studied more frequently in recent years. The crystal form is single crystal, the structure is complete, and the defects in the crystal are few, so the high-modulus high-strength heat-resistant heat-insulating material has excellent performances such as high modulus, high strength, good heat resistance and heat insulation. The calcium carbonate whisker has wide raw material source and lower cost, and has wide application prospect in the fields of automobile, plastic, electric appliance parts, high-finish structural part manufacturing and the like.

At present, the preparation method of calcium carbonate whisker mainly comprises a double decomposition method, a urea hydrolysis method, a sol-gel method and Ca (HCO)₃)₂Thermal decomposition, electrochemical, hypergravity reaction crystallization, carbonation, and the like. These processes have their own advantages and disadvantages, but the most promising for industrial application is the carbonation process. The carbonation method is a mature method researched at present, and mainly uses calcite ore as a raw material, obtains calcium oxide after high-temperature calcination, and then prepares Ca (OH) after digestion₂Suspending liquid, adding proper crystal form control agent, and finally introducing CO₂And (5) preparing the calcium carbonate whiskers by gas. However, the carbonation method also has certain problems, which makes it impossible to apply the carbonation method in large-scale industrial production.

Patent CN1552959A discloses a preparation process of calcium carbonate whiskers, which comprises the steps of taking quick lime as a raw material, adding a crystal form control agent magnesium chloride solution after a digestion reaction, and finally introducing CO₂Carbonizing to obtain calcium carbonate crystal whisker. The method is a traditional carbonation method for preparing calcium carbonate whiskers, is simple to operate and low in cost, but the purity of the calcium carbonate whiskers prepared by the method disclosed by the patent is not high (the content of calcium carbonate is 92.8%).

Patent CN104790024A discloses a preparation method of an aragonite type calcium carbonate whisker with a high length-diameter ratio, which takes quicklime as a raw material and magnesium chloride solution as a crystal form control agent, and then the raw material is added into a carbonization reactor to react to prepare the aragonite type calcium carbonate whisker.

Patent CN112723403A discloses a preparation method of calcium carbonate whiskers, which takes calcium oxide as raw material and CO respectively₂And potassium hydroxide reaction product andone or two of strontium chloride, sodium phosphate and sodium citrate are used as crystal form control agents, lime kiln gas is introduced for carbonation reaction to prepare the calcium carbonate whisker, the invention only refers to the specific surface area of the product, and the important physicochemical properties such as length-diameter ratio, whiteness and purity of the whisker product are not described.

Patent CN111926386A discloses a preparation method of calcium carbonate whiskers, which takes high-purity nano calcium oxide as a raw material and silk fibroin and Arabic gum as crystal form control agents, and the calcium carbonate whiskers are prepared by carbonization reaction in a hypergravity carbonization reactor. Although the method can prepare the high-activity calcium carbonate whiskers, the process adopts a supergravity carbonization reactor and has high carbonization temperature (80-90 ℃), the cost is increased, and in addition, the raw material is high-purity nano calcium oxide, and no description is provided for whether the method is applicable to bulk raw material calcium carbonate ores and calcium carbonate tailings, so the method has relatively limited practicability.

The patent CN110904505A discloses a preparation method of calcium carbonate whiskers, which takes industrial active lime as a raw material and bischofite as a crystal form control agent, and CO is introduced at the temperature of 85-95 DEG C₂And carrying out carbonization reaction to obtain the calcium carbonate crystal whisker. The length of the prepared calcium carbonate crystal whisker is 38-48 mu m, the length-diameter ratio is 30-36, the temperature is required to be raised to 85-95 ℃ in the carbonation process, the energy consumption is increased, and the length-diameter ratio of the product crystal whisker is lower.

In summary, the main problems of the current carbonation method for preparing calcium carbonate whiskers are as follows: the purity of the calcium carbonate crystal whisker is not high; the length and the length-diameter ratio of the calcium carbonate crystal whisker are lower; the carbonization process needs heating, so that the energy consumption is increased, and the production cost is higher; the raw materials mostly adopt chemically pure or high-purity calcium oxide, and the use research on industrial calcite tailing waste residues is less, so that the raw materials are more limited; the mother liquor is not recycled, so that resource waste and environmental pollution are caused; too much crystal form control agent is introduced to cause great difficulty in subsequent wastewater treatment and the like.

Disclosure of Invention

The invention aims to provide a preparation method of calcium carbonate whiskers, wherein the heavy magnesium water prepared by the invention plays an inducing role in the nucleation and growth processes of the calcium carbonate whiskers, is more beneficial to the growth of the calcium carbonate whiskers and generates the calcium carbonate whiskers with higher purity; the production process is simple, the energy consumption is low, and the industrial production is easy to realize.

The purpose of the invention is realized by the following technical scheme:

a preparation method of calcium carbonate whiskers comprises the following preparation processes:

the method comprises the following steps: grinding calcite ore or calcite tailings or industrial limestone waste residues, calcining at high temperature to decompose the ground calcite ore or calcite tailings or industrial limestone waste residues into calcium oxide, and recovering carbon dioxide gas;

step two: adding the calcium oxide and the magnesium chloride into deionized water at the temperature of 25-60 ℃ according to the mass ratio of 1: 1-1: 5, sufficiently digesting for 1-5 hours, and filtering to obtain a filter cake and a filtrate;

step three: pulping the filter cake obtained in the second filtering step to excess CO₂In (recovered CO as described in step one)₂Available gas), fully reacting, filtering and removing impurities;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three until no precipitate is generated, and stopping the reaction, and carrying out suction filtration, washing and drying on the obtained precipitate to obtain the calcium carbonate whiskers.

The preparation method of the calcium carbonate whisker further provides the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 60 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 800 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step (II) into the filtrate obtained in the step (III) at the speed of 5 ml/min, stirring at the speed of 100r/min, heating at the temperature of 50 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whiskers.

The preparation method of the calcium carbonate whisker further provides the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 90 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 60 min;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three at the speed of 5 ml/min, stirring at the speed of 150r/min, heating at the temperature of 40 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker.

The preparation method of the calcium carbonate whisker further provides the following preparation processes:

the method comprises the following steps: calcining calcite ore with average particle size of 75 um at 1000 deg.C for 60 min to decompose calcium oxide, and collecting CO₂A gas;

step two: weighing 11.2g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing into the beaten filter cake of the second step at the speed of 200mL/min (CO collected in the first step)₂Can be repeatedly used), reacting for 150 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step two into the filtrate obtained in the step three at the speed of 7 ml/min, stirring at the speed of 150r/min, heating at the temperature of 45 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker.

According to the preparation method of the calcium carbonate whisker, after raw materials are ground and sieved in the first step of the method, particles with a particle size of-200 meshes account for more than 85%.

In the preparation method of the calcium carbonate whisker, the mass ratio of the mixture of the magnesium chloride and the calcium oxide to the deionized water in the second step is 1: 1-1: 30.

The preparation method of the calcium carbonate whisker comprises the step three, wherein CO is used as a raw material₂The aeration rate is 100-500 mL/min, the aeration time is 30-240 min, and the reaction temperature is 25-60 ℃.

In the preparation method of the calcium carbonate whisker, the titration rate of the filtrate in the step four is 3-15 mL/min, and the stirring rate is 100-200 r/min.

The invention has the advantages and effects that:

1. in the invention, a crystal form control agent magnesium chloride is added in the process of calcium oxide digestion, so that the magnesium chloride and calcium oxide are fully digested and converted;

specifically, the reaction equation includes:

CaCO₃=CaO+CO₂

CaO+H₂O+MgCl₂=Mg(OH)₂+CaCl₂

Mg(OH)₂+2CO₂=Mg(HCO₃)₂

Mg(HCO₃)₂+ CaCl₂= CaCO₃+MgCl₂+ CO₂+H₂O。

2. the heavy magnesium water prepared by the method plays an inducing role in the nucleation and growth processes of the calcium carbonate whiskers, is more beneficial to the growth of the calcium carbonate whiskers, and generates the calcium carbonate whiskers with higher purity.

3. The crystal whisker prepared by the method has higher purity, larger length-diameter ratio and higher whiteness.

4. The invention has simple production process and lower energy consumption, and is easy to realize industrial production.

5. The raw material source of the invention is wide, and the invention can use chemically pure calcium oxide, and can also use lime, calcium carbonate tailings, industrial waste residue and the like.

6. The gas generated in the calcining process and the mother liquor in the reaction process can be recycled, thereby providing possibility for further industrialization.

Drawings

FIG. 1 is an SEM image of calcium carbonate whiskers of example 1 of the present invention;

FIG. 2 is an SEM image of calcium carbonate whiskers of example 2 of the present invention;

FIG. 3 is an SEM image of calcium carbonate whiskers of example 3 of the present invention;

figure 4 is a calcium carbonate whisker XRD pattern of the embodiment 3 of the present invention.

Detailed Description

The present invention will be described in detail with reference to the embodiments shown in the drawings.

Example 1

The method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 60 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 800 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step (II) into the filtrate obtained in the step (III) at the speed of 5 ml/min, stirring at the speed of 100r/min, heating at the temperature of 50 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker, wherein the SEM image of the prepared calcium carbonate whisker is shown in figure 1. The content of the obtained calcium carbonate whiskers is about 98%, the average length-diameter ratio is 40, and the whiteness is 97.

Example 2

The method comprises the following steps: calcining calcite ore with average particle size of 75 um at 900 deg.C for 90 min to decompose and generate calcium oxide, and collecting CO₂A gas;

step two: weighing 5.6g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 60 min;

step three: introducing CO₂Introducing the mixture into the pulped filter cake in the second step at the speed of 150mL/min (CO collected in the first step)₂Recyclable), reacting for 120 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step (II) into the filtrate obtained in the step (III) at the speed of 5 ml/min, stirring at the speed of 150r/min, heating at the temperature of 40 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker, wherein the SEM image of the prepared calcium carbonate whisker is shown in figure 2. The content of the obtained calcium carbonate whiskers is about 98.8%, the average length-diameter ratio is 42, and the whiteness is 98.

Embodiment 3

The method comprises the following steps: calcining calcite ore with average particle size of 75 um at 1000 deg.C for 60 min to decompose calcium oxide, and collecting CO₂A gas;

step two: weighing 11.2g of calcium oxide and 40.6g of magnesium chloride, adding 1000 mL of deionized water for dissolving, stirring uniformly at the speed of 200 r/min, and filtering after 1 h;

step three: introducing CO₂Introducing into the beaten filter cake of the second step at the speed of 200mL/min (CO collected in the first step)₂Can be repeatedly used), reacting for 150 min, and filtering;

step four: and (3) uniformly dropwise adding the filtrate obtained in the step (II) into the filtrate obtained in the step (III) at the speed of 7 ml/min, stirring at the speed of 150r/min, heating at the temperature of 45 ℃ until no precipitate is generated, filtering, washing for 3 times, and drying the filter cake at the temperature of 80 ℃ to obtain the calcium carbonate whisker, wherein the SEM image and XRD image of the prepared calcium carbonate whisker are respectively shown in fig. 3 and fig. 4. The content of the obtained calcium carbonate whiskers is about 96.5%, the average length-diameter ratio is 38, and the whiteness is 96.