阅读说明：本技术 一种文石型碳酸钙晶须的制备方法 (Preparation method of aragonite type calcium carbonate whisker ) 是由 丁文金 陈秋菊 孙红娟 彭同江 于 2019-04-04 设计创作，主要内容包括：本发明涉及一种用富含氯化钙的溶液为原料制备文石型碳酸钙晶须的方法,包括如下步骤：1)取一定量富含氯化钙的溶液,通过氨水或盐酸调节溶液的pH值至中性；2)将步骤1)获得的溶液与氨水进行配料,并置于带搅拌的反应容器中反应,在反应的同时以一定速率通入CO<Sub>2</Sub>气体,在反应过程中控制溶液中钙离子的浓度、反应温度、搅拌速度和氨水量；待反应完成后将溶液进行抽滤,获得固体反应产物和滤液；3)将步骤2)得到的固体产物洗涤、烘干,即得文石型碳酸钙晶须材料。该碳酸钙晶须材料无毒、安全,同时具有白度高、补强性能好等特性,可应用于橡胶、塑料、化工等行业。(The invention relates to a method for preparing aragonite calcium carbonate whisker by taking solution rich in calcium chloride as a raw material, which comprises the following steps: 1) taking a certain amount of solution rich in calcium chloride, and adjusting the pH value of the solution to be neutral by ammonia water or hydrochloric acid; 2) mixing the solution obtained in the step 1) with ammonia water, placing the mixture into a reaction container with stirring for reaction, and introducing CO at a certain speed while reacting 2 Gas, controlling the concentration of calcium ions in the solution, the reaction temperature, the stirring speed and the ammonia water amount in the reaction process; after the reaction is finished, carrying out suction filtration on the solution to obtain a solid reaction product and filtrate; 3) washing and drying the solid product obtained in the step 2) to obtain the aragonite type calcium carbonate whisker material. The calcium carbonate whisker material is non-toxic and safe, has the characteristics of high whiteness, good reinforcing performance and the like, and can be applied to rubber,Plastics, chemical industry and other industries.)

1. A method for preparing aragonite calcium carbonate whiskers comprises the following steps:

1) taking 200mL of solution rich in calcium chloride, and adjusting the pH value of the solution to 7 by ammonia water or hydrochloric acid to obtain a neutral calcium chloride solution;

2) mixing the calcium chloride solution obtained in the step 1) with ammonia water, placing the mixture in a reaction container with stirring, and introducing CO simultaneously₂Stirring the gas at normal pressure and low temperature for reaction for 30-180 min to obtain a reaction product;

3) and (3) carrying out suction filtration, washing and drying on the reaction product obtained in the step 2) to obtain aragonite type calcium carbonate whisker solid powder.

2. The method of claim 1, wherein:

the solution rich in calcium chloride in the step 1) is mainly waste liquid rich in calcium chloride, mineral hydrochloric acid leachate rich in calcium ions or solid waste hydrochloric acid leachate rich in calcium ions obtained in the alkali making industry.

3. The method of claim 1, wherein:

the concentration of calcium ions in the calcium chloride solution in the step 1) is 3-20 g/L, and the concentration of the calcium ions in the calcium chloride solution is adjusted by adding industrial water or calcium chloride powder.

4. The method of claim 1, wherein:

the addition amount of the ammonia water in the step 2) is 5-20 mL/100 mL; CO 2₂The gas flow rate is 30-200 mL/min; the stirring speed is 100-600 r/min; the reaction temperature is 80-180 ℃.

5. The production method according to claims 1 to 4, characterized in that:

the preparation process of the aragonite calcium carbonate whisker does not add any crystal form control agent, has wide raw material sources, and is finished at low temperature and normal pressure; the aragonite calcium carbonate whisker material has a content of more than 99%, a diameter of 0.5-1 μm, a length of 6-30 μm, and a whiteness of more than 95%.

Technical Field

The invention relates to a preparation method of aragonite calcium carbonate whiskers, in particular to a method for preparing aragonite calcium carbonate whiskers by taking a solution rich in calcium chloride as a raw material without adding a crystal form control agent, and belongs to the field of inorganic functional materials and chemical materials.

Background

The calcium carbonate whisker is a novel inorganic filler following nano calcium carbonate, is non-toxic and odorless, is a white fluffy solid (needle-shaped single crystal under a microscope), and has the following properties and characteristics as a new-generation filling material: (1) the composite material has high mechanical strength and has the functions of vibration reduction, skid resistance, noise reduction, wave absorption and the like in the using process; (2) the friction coefficient is high, and the wear resistance and the heat resistance are high; (3) the heat fading and heat recovery performance is good; (4) the use amount of high-value materials such as aramid fiber, steel fiber, red copper, potassium titanate and the like in the composite material can be reduced, so that the cost of the composite material is greatly reduced; (5) the raw materials are rich in source and low in price.

The current methods for preparing calcium carbonate whiskers mainly comprise: (1) a carbonation method: the natural limestone is mainly used as a raw material, the whole preparation process needs high-temperature calcination and addition of a crystal form control agent, and the energy consumption and the cost are high. (2) Double decomposition method: soluble calcium salt and carbonate are mainly used as raw materials, other additional reagents are needed in the preparation process, the aging time is long, the preparation process conditions are not easy to control, and the requirements on the raw materials are high. (3) And (3) urea hydrolysis method: the urea and soluble calcium salt react, a crystal form control agent is not required to be added in the reaction process, but the reaction is required at high temperature and high pressure, so that the energy consumption is high, and the production risk is high. (4) Calcium bicarbonate heating hydrolysis: firstly, calcium bicarbonate solution is prepared, and then calcium carbonate crystal whisker is prepared by controlling the conditions of the heating temperature, the heating rate, the stirring strength and the like of the solution. The method has the advantages of complex process, difficult operation and low production efficiency. (5) A hypergravity reaction crystallization method: the method has the advantages of few control factors of the reaction process, easy repetition, adjustable product granularity and the like, but the method needs to be carried out in a specific hypergravity reaction device, has extremely high requirements on equipment and has larger energy consumption.

The invention patent with the patent number of CN104386728A discloses a method for preparing homogeneous-phase nano aragonite calcium carbonate by acid hydrolysis of limestone, which comprises the steps of firstly carrying out acid hydrolysis on limestone by hydrochloric acid, removing impurities by using auxiliary agents such as ammonia water, NaClO and the like, and then carbonizing to obtain a product. The whole process takes natural limestone as a raw material, a high-purity product can be obtained only by removing impurities, the whole preparation process is relatively complicated, the economic cost of the auxiliary agent is relatively high, and large-scale industrial production of the process is not facilitated.

The invention patent with the patent number of CN104480529A discloses a method for preparing calcium carbonate whiskers by using industrial by-product gypsum as a raw material, wherein the preparation process comprises the steps of adding a sodium carbonate solution into a solid-liquid mixture of phosphogypsum and water, and stirring and reacting for a period of time at 70-80 ℃ to obtain a solid finished product; the method takes the phosphogypsum as a raw material, the process is simple, but the obtained solid finished product contains a large amount of quartz and other impurity components, the whiteness is lower, the application of the calcium carbonate crystal whisker is seriously restricted, and the practical application value is lower.

The invention patent with the patent number of CN102212869A discloses a preparation method of calcium carbonate crystal whisker, the preparation process of the calcium carbonate crystal whisker mainly takes sodium carbonate and sodium chloride as raw materials, carbon dioxide gas and sodium hydroxide as auxiliary agents, and the calcium carbonate crystal whisker product is obtained after the reaction is carried out for a period of time at low temperature and is aged for 2 to 3 hours; the method takes analytical pure chemical reagents as raw materials, the cost is high, carbon dioxide needs to be introduced and sodium hydroxide needs to be added in the preparation process, further aging is needed after the reaction is finished, the whole preparation process is complex, and the economic cost is high.

Chinese patent No. CN104310451A discloses a method for preparing aragonite type white mud calcium carbonate, which comprises adding sucrose with different mass concentrations into a mixed solution of urea and calcium chloride at a certain temperature, and reacting for a period of time to obtain calcium carbonate whisker products. The process takes urea and calcium chloride as raw materials and sucrose as a crystal form control agent, and the whole process has higher economic cost.

The research on the preparation of calcium carbonate crystal whisker from desulfurized gypsum and the mechanism thereof in the academic thesis discloses that calcium carbonate crystal whisker with the diameter of 0.5-2 mu m and the length-diameter ratio of 10-20 is prepared by using pickle liquor of carbonized products of desulfurized gypsum as raw materials and by a double-injection charging method, and the method uses ammonium bicarbonate as raw materials and has higher cost of auxiliary agent; in addition, the dropping speed of the reaction raw materials is strictly controlled by a peristaltic pump in the preparation process, the volume per minute cannot exceed 2 mL, the process conditions are harsh, and the industrial production is not facilitated.

In conclusion, the existing preparation process of the calcium carbonate whisker has the problems of high raw material cost, complex preparation process, need of adding a crystal form control agent and the like, so the invention provides a novel method for preparing the aragonite calcium carbonate whisker with high whiteness at low temperature and normal pressure by taking a solution rich in calcium chloride as a raw material without adding the crystal form control agent aiming at the defects of the preparation method of the calcium carbonate whisker.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a preparation method of aragonite calcium carbonate whiskers, which takes a solution rich in calcium chloride as a raw material, does not need to add a crystal form control agent, is low in temperature and normal in pressure, is easy to realize industrially, and has good applicability.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing aragonite calcium carbonate whiskers comprises the following steps:

1) taking 200mL of solution rich in calcium chloride, and adjusting the pH value of the solution to 7 by ammonia water or hydrochloric acid to obtain a neutral calcium chloride solution;

2) mixing the calcium chloride solution obtained in the step 1) with ammonia water, placing the mixture in a reaction container with stirring, and introducing CO simultaneously₂Stirring the gas at normal pressure and low temperature for reaction for 30-180 min to obtain a reaction product;

3) and (3) carrying out suction filtration, washing and drying on the reaction product obtained in the step 2) to obtain aragonite type calcium carbonate whisker solid powder.

The solution rich in calcium chloride in the step 1) is mainly waste liquid rich in calcium chloride, mineral hydrochloric acid leachate rich in calcium ions or solid waste hydrochloric acid leachate rich in calcium ions obtained in the alkali making industry. The concentration of calcium ions in the calcium chloride solution in the step 1) is 3-20 g/L, and the concentration of the calcium ions in the calcium chloride solution is adjusted by adding industrial water or calcium chloride powder.

The addition amount of the ammonia water in the step 2) is 5-20 mL/100 mL; CO 2₂The flow rate of the gas is 30-200 mL/min; the stirring speed is 100-600 r/min; the reaction temperature is 80-180 ℃.

5. The method of claim 1, wherein:

the crystal form of the calcium carbonate whisker material produced by the method is aragonite, the content of the calcium carbonate whisker is more than 90 percent, the diameter of the whisker is 0.5-1 mu m, the length is 6-30 mu m, and the whiteness is more than 95.

The calcium carbonate crystal whisker prepared by the method has the following beneficial effects: 1) the raw materials used in the invention are solutions rich in calcium chloride, are easy to obtain and low in price, and are mostly waste water or waste residue treatment products; 2) the whole preparation process is simple in flow, easy to operate and easy for large-scale production; the method is carried out at low temperature and normal pressure, so that the equipment investment is saved and the safety is high; 3) no crystal form control agent is needed to be added, and the preparation cost is low; 4) the method realizes high-value utilization of the calcareous solid waste and partial calcareous waste liquid; 6) the purity of the produced aragonite calcium carbonate crystal whisker can reach more than 99 percent, the whiteness is more than 95, the diameter is 0.5 to 1 mu m, and the length is 6 to 30 mu m.

Drawings

Figure 1 is an XRD pattern of aragonite-type calcium carbonate whiskers prepared in example 1.

Figure 2 is an SEM image of aragonite-type calcium carbonate whiskers prepared in example 1.

Detailed Description

The invention relates to a preparation method of aragonite calcium carbonate whiskers, which comprises the following steps.

1) And (3) taking 200mL of the solution rich in calcium chloride, and adjusting the pH value of the solution to 7 by ammonia water or hydrochloric acid to obtain a neutral calcium chloride solution.

Wherein the solution rich in calcium chloride in the step 1) is mainly waste liquid rich in calcium chloride, mineral hydrochloric acid leachate rich in calcium ions or solid waste hydrochloric acid leachate rich in calcium ions obtained in the alkali making industry; the concentration of calcium ions in the calcium chloride solution is 3-20 g/L, and the concentration of the calcium ions in the calcium chloride solution is adjusted by adding industrial water or calcium chloride powder.

2) Mixing the calcium chloride solution obtained in the step 1) with ammonia water, placing the mixture in a reaction container with stirring, and introducing CO simultaneously₂Stirring the gas at normal pressure and low temperature for reaction for 30-180 min to obtain a reaction product.

Wherein the addition amount of the ammonia water in the step 2) is 5-20 mL/100 mL; CO 2₂Gas (es)The flow rate of (A) is 30-200 mL/min; the stirring speed is 100-600 r/min; the reaction temperature is 80-180 ℃.

3) And (3) carrying out suction filtration, washing and drying on the reaction product obtained in the step 2) to obtain aragonite type calcium carbonate whisker solid powder.

The crystal form of the produced calcium carbonate whisker material is aragonite, the content of the calcium carbonate whisker is more than 99 percent, the diameter of the whisker is 0.5-1 mu m, the length is 6-30 mu m, and the whiteness is more than 95.

The technical solution of the present invention is further described in detail by the following specific examples in conjunction with the accompanying drawings.

Example 1:

the calcium chloride solution in the embodiment is a hydrochloric acid leachate of phosphogypsum, and the main chemical components of the phosphogypsum are as follows by weight percent: SO (SO)₃40%，CaO30%，SiO₂5%, and the other 25%; adjusting the concentration of calcium ions in the solution to be 4.2 g/L by adding analytically pure calcium chloride, and adjusting the pH value of the solution to be neutral by adding ammonia water; CO 2₂The industrial grade gas with the purity of 99 percent comprises the following specific technical processes:

1) placing 300 mL of the calcium ion solution in a beaker, adding 45 mL of ammonia water into the solution, placing the beaker in a reaction container with stirring, and introducing CO while reacting₂Gas, CO₂The flow rate of the reaction is 63 mL/min, the stirring speed is 118 r/min, the reaction is stirred at 94 ℃ for 66 min, and after the reaction is finished, a solid reaction product is obtained by suction filtration;

2) washing and drying the solid reaction product to obtain a calcium carbonate crystal whisker sample;

3) the content of aragonite in the calcium carbonate whisker sample obtained is 99.7 percent, the diameter of the whisker is 0.8 to 1 mu m, the length is 8 to 15 mu m, and the whiteness is 97.3.

Example 2

The calcium chloride solution in the embodiment is waste liquid generated in the alkali production industry, the concentration of calcium ions in the solution is adjusted to be 10.7 g/L by adding analytically pure calcium chloride, and the pH value of the solution is adjusted to be neutral by adding ammonia water; CO 2₂The industrial grade gas with the purity of 99 percent comprises the following specific technical processes:

1) taking the calcium ion200mL of the sub-solution was placed in a beaker, 36 mL of ammonia water was added to the solution, the beaker was placed in a reaction vessel with stirring, and CO was introduced while reacting₂Gas, CO₂The flow rate of the reaction is 132 mL/min, the stirring speed is 372 r/min, the reaction is stirred at 158 ℃ for 133 min, and after the reaction is finished, a solid reaction product is obtained by suction filtration;

2) washing and drying the solid reaction product to obtain a calcium carbonate crystal whisker sample;

3) the content of aragonite in the calcium carbonate whisker sample obtained is 99.9 percent, the diameter of the whisker is 0.7 to 1 mu m, the length is 7 to 20 mu m, and the whiteness is 96.2.