阅读说明：本技术 用高钠镁比硫酸钠工业废水制备碱式碳酸镁的方法 (Method for preparing basic magnesium carbonate by using high sodium-magnesium ratio sodium sulfate industrial wastewater ) 是由 刘志启 闫东强 赵鹏程 周自圆 李娜 胡丽娟 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种用高钠镁比硫酸钠工业废水制备碱式碳酸镁的方法,属于碱式碳酸镁制备方法领域。该方法是利用高钠镁比硫酸钠工业废水与碳酸钠溶液进行沉淀反应,待反应结束后进行过滤、洗涤,过滤滤渣在温度为80-110℃干燥5-10h即可得到形貌为花瓣状的碱式碳酸镁。本发明解决了高钠镁比的工业废水的绿色资源化利用,具有净化除镁回收高纯度硫酸钠同时制备使用价值高的碱式碳酸镁的特点,该工艺流程简单,生产成本低,无需任何有机添加剂,只要碳酸钠参与沉淀就可以制备形貌规整的花球状碱式碳酸镁。(The invention discloses a method for preparing basic magnesium carbonate from high-sodium-magnesium-ratio sodium sulfate industrial wastewater, belonging to the field of basic magnesium carbonate preparation methods. The method comprises the steps of carrying out precipitation reaction on high-sodium-magnesium-ratio sodium sulfate industrial wastewater and a sodium carbonate solution, filtering and washing after the reaction is finished, and drying filter residues for 5-10 hours at the temperature of 80-110 ℃ to obtain the petal-shaped basic magnesium carbonate. The method solves the problem of green resource utilization of industrial wastewater with high sodium-magnesium ratio, has the characteristics of purifying, removing magnesium, recovering high-purity sodium sulfate and preparing basic magnesium carbonate with high use value, has simple process flow and low production cost, does not need any organic additive, and can prepare the flower-ball-shaped basic magnesium carbonate with regular appearance as long as sodium carbonate participates in precipitation.)

1. The method for preparing basic magnesium carbonate by using the industrial wastewater of sodium sulfate with high sodium-magnesium ratio is characterized by comprising the following steps:

step 1, putting a certain amount of industrial wastewater with high sodium-magnesium ratio sodium sulfate into a reactor, continuously stirring at a constant temperature of 25-100 ℃, and adding 0.5-3.5mol/L sodium carbonate solution into the industrial wastewater with high sodium-magnesium ratio sodium sulfate for precipitation reaction; ending the reaction after the reaction is carried out for 30-120 min;

and 2, filtering the reaction solution after the reaction is finished, obtaining filtrate for measuring the magnesium content after filtering, wherein the filtrate is high-purity saturated sodium sulfate solution, and drying filter residues for 2-5 hours at the temperature of 90-105 ℃ after washing the filter residues for multiple times to obtain the basic magnesium carbonate.

2. The method for preparing basic magnesium carbonate by using the industrial wastewater with the high sodium-magnesium ratio and the sodium sulfate as claimed in claim 1, wherein in the industrial wastewater with the high sodium-magnesium ratio and the sodium-magnesium ratio, in the step 1, the content of magnesium sulfate is 0.1-0.2mol/L, and the sodium-magnesium ratio is 20-40.

3. The method for preparing basic magnesium carbonate by using industrial wastewater of sodium sulfate with high sodium-magnesium ratio as claimed in claim 1, wherein the concentration of the sodium carbonate solution in the step 1 is 0.5-3.5 mol/L.

4. The method for preparing basic magnesium carbonate by using industrial wastewater with high sodium-magnesium ratio sodium sulfate as claimed in claim 1, wherein in step 1, the ratio of the mass of the substance added into the sodium carbonate solution to the mass of the magnesium is n (Mg)²⁺)：n(CO₃ ^2-)=1:1.8-1:3.0。

5. The method for preparing basic magnesium carbonate by using industrial wastewater with sodium sulfate and magnesium sulfate with high sodium-magnesium ratio as claimed in claim 1, wherein the stirring speed in step 1 is 200-600 r/min.

6. The method for preparing basic magnesium carbonate by using industrial wastewater with high sodium-magnesium ratio sodium sulfate as claimed in claim 1, wherein the filtrate obtained in step 2 is a saturated solution of high-purity sodium sulfate.

7. The method for preparing basic magnesium carbonate by using industrial wastewater of sodium sulfate with high sodium-magnesium ratio as claimed in claim 6, wherein the drying temperature in step 2 is 80-110 ℃, and the drying time is 5-10 h.

8. The method for preparing basic magnesium carbonate by using industrial wastewater containing sodium sulfate and magnesium sulfate with high sodium-magnesium ratio as claimed in claim 1, wherein the basic magnesium carbonate obtained after drying is petal-shaped.

Technical Field

The invention relates to the field of a preparation method of basic magnesium carbonate, in particular to a method for preparing basic magnesium carbonate by using industrial wastewater of sodium sulfate with a high sodium-magnesium ratio.

Background

With the improvement of environmental protection standards in recent years in China, the green resource utilization of industrial waste liquid is greatly developed. The industrial wastewater with high sodium-magnesium ratio is mainly derived from drainage generated in the production processes of enterprises such as printing and dyeing, refining, pharmacy, salt manufacturing and the like, and has the characteristics of high content of sodium sulfate and low content of magnesium sulfate. If the direct evaporation crystallization is not processed, the purity of the sodium sulfate is too low, and the magnesium resource cannot be comprehensively utilized, so that the resource is seriously wasted. If the waste water is directly discharged, the waste water can cause serious pollution to soil and water quality.

The basic magnesium carbonate as an inorganic material has the characteristics of no toxicity, no smell, no corrosion, white, loose, high decomposition temperature and the like. Has very important application in the fields of flame retardance, environmental protection, medical use, food, rubber products and the like. The basic magnesium carbonate can be used as a chemical raw material to prepare a new product, and is an important inorganic product in the field of chemical engineering. Its usage can be roughly summarized into the following three aspects: an additive used for food and a modifier for various chemical products; is applied to the preparation of medicines and used as an auxiliary medicine for clinical treatment; it can also be used as fireproof heat-insulating material and magnesium series chemical product. The basic magnesium carbonate is assembled by flaky microcrystals and can form shapes of balls, roses, tubes and the like.

Song Xingfu et al (CN IO 1830489A) discloses reacting magnesium chloride solution with sodium carbonate solution at a certain ratio to obtain a rod-like magnesium carbonate trihydrate precursor, dissolving the rod-like magnesium carbonate trihydrate precursor in hot water, aging for a certain time while maintaining the temperature, filtering, and drying to obtain rose petal-shaped basic magnesium carbonate.

The danbo et al patent (CN 109437262B) is a micro-nano basic magnesium carbonate flame retardant obtained by uniformly mixing a sodium carbonate solution and a magnesium chloride solution at a high speed and then aging the mixture in an oven for a certain time.

Disclosure of Invention

The invention aims to provide a method for preparing basic magnesium carbonate by using high-sodium-magnesium-ratio sodium sulfate industrial wastewater, which aims to solve the problem of green resource utilization of the high-sodium-magnesium-ratio sodium sulfate industrial wastewater in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the method for preparing basic magnesium carbonate by using the industrial wastewater of sodium sulfate with high sodium-magnesium ratio comprises the following steps:

step 1, putting a certain amount of industrial wastewater with high sodium-magnesium ratio sodium sulfate into a reactor, continuously stirring at a constant temperature of 25-100 ℃, and adding 0.5-3.5mol/L sodium carbonate solution into the industrial wastewater with high sodium-magnesium ratio sodium sulfate for precipitation reaction; and finishing the reaction after the reaction is carried out for 30-120 min.

And 2, filtering the reaction solution after the reaction is finished, obtaining filtrate for measuring the magnesium content after filtering, wherein the filtrate is high-purity saturated sodium sulfate solution, and drying filter residues for 2-5 hours at the temperature of 90-105 ℃ after washing the filter residues for multiple times to obtain the basic magnesium carbonate.

Further, in the sodium sulfate industrial wastewater with high sodium magnesium ratio in the step 1, the content of magnesium sulfate is 0.1-0.2mol/L, and the sodium magnesium ratio is 20-40.

Further, the temperature of step 1 is 25-100 ℃.

Further, the concentration of the sodium carbonate solution in the step 1 is 0.5-3.5 mol/L.

Further, the ratio of the amount of the substance added to the sodium carbonate solution to the amount of the substance of magnesium in step 1 is n (Mg)²⁺)：n(CO₃ ^2-)=1:1.8-1:3.0。

Further, the stirring speed in the step 1 is 200-600 r/min.

Further, the filtrate obtained in step 2 is a saturated sodium sulfate solution with high purity.

And further, drying the filter residue in the step 2 at the temperature of 80-110 ℃ for 5-10 h.

Further, drying to obtain the basic magnesium carbonate with petal-shaped appearance.

In the invention, sodium carbonate in a sodium carbonate solution is used as a precipitator, and magnesium ions in the industrial wastewater with high sodium-magnesium ratio sodium sulfate react with carbonate ions and water through a precipitation reaction between the industrial wastewater with high sodium-magnesium ratio sodium sulfate and strong base (sodium carbonate) to generate basic magnesium carbonate precipitate, wherein the chemical reaction formula is as follows:

5MgSO₄+6Na₂CO₃+6H₂O=Mg₅(OH)₂(CO₃)₄·4H₂O↓+2NaHCO₃+5Na₂SO₄

compared with the prior art, the invention has the advantages that: the method utilizes the high sodium-magnesium ratio sodium sulfate industrial wastewater to purify and remove magnesium so as to obtain the high-purity saturated sodium sulfate solution and simultaneously prepare the basic magnesium carbonate. In the invention, only sodium carbonate is needed to be added in the preparation of basic magnesium carbonate, other reagents are not needed to be added, and the basic magnesium carbonate is not needed to be cured in a high-temperature environment; the basic magnesium carbonate prepared by the invention can be precipitated by adding sodium carbonate solution into industrial wastewater with high sodium-magnesium ratio to obtain petal-shaped basic magnesium carbonate without preparing a precursor, and has the advantages of simple process, cheap and easily-obtained raw materials and accordance with the aim of green chemistry advocated by China.

Drawings

FIG. 1 shows the ratio of the amount of sodium carbonate-added substance to the amount of magnesium-containing substance as n (Mg)²⁺)：n() Graph of magnesium content in filtrate at 1:1.8-1: 3.0.

FIG. 2 is an X-ray diffraction pattern of the product of example 1 of the present invention.

FIG. 3 is a scanning electron micrograph of a product according to example 1 of the present invention.

FIG. 4 is an X-ray diffraction pattern of the product of example 2 of the present invention.

FIG. 5 is a scanning electron micrograph of a product of example 2 of the present invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Example 1

The method for preparing basic magnesium carbonate by using the industrial wastewater of sodium sulfate with high sodium-magnesium ratio comprises the following steps:

step 1, measuring 150ml of high-sodium-magnesium-ratio sodium sulfate industrial wastewater with magnesium ion concentration of 0.1mol/L and sodium ion concentration of 3mol/L in a beaker, slowly dripping 30ml of 0.5mol/L sodium carbonate solution into the industrial wastewater at a constant temperature of 60 ℃ and a stirring speed of 300r/min for precipitation reaction for 1 h.

And 2, filtering the reaction solution after the reaction is finished, measuring the magnesium content of the filtrate, and washing the filter residue with water for multiple times. Drying the washed filter residue for 6h in an environment with the temperature of 85 ℃ to obtain the petal-shaped basic magnesium carbonate.

Example 2

Step 1, measuring 150ml of high-sodium-magnesium-ratio sodium sulfate industrial wastewater with magnesium ion concentration of 0.1mol/L and sodium ion concentration of 3mol/L in a beaker, slowly dripping 45ml of 0.5mol/L sodium carbonate solution into the industrial waste liquid for precipitation reaction for 1h at a constant temperature of 60 ℃ and a stirring speed of 300 r/min.

And 2, filtering the reaction solution after the reaction is finished, measuring the magnesium content of the filtrate, and washing the filter residue with water for multiple times. Drying the washed filter residue for 6h in an environment with the temperature of 85 ℃ to obtain the petal-shaped basic magnesium carbonate.

In FIG. 1, it can be seen from the analysis of inductively coupled plasma spectrometer that when the added precipitant is gradually increased, the magnesium content in the original solution is gradually decreased, when n (Mg)²⁺)：n() When the ratio is 1:0.9-1:2.1, the magnesium content in the solution is 0-10ppm, which shows that the magnesium in the industrial waste liquid with high sodium-magnesium ratio can be removed by the process.

The X-ray diffraction pattern analysis in fig. 2 and 4 shows that the samples prepared in examples 1 and 2 are consistent with the standard card of basic magnesium carbonate, indicating that the product obtained by the above method is consistent with the product of the present application.

The scanning electron micrographs at 3 kXmagnification in FIGS. 3 and 5 show that the products of examples 1 and 2 are in the shape of regular spheroids, indicating that the morphology of the products obtained by the above-described process is consistent with that of the application.

The embodiments of the present invention are described only for the preferred embodiments of the present invention, and not for the limitation of the concept and scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the design concept of the present invention shall fall into the protection scope of the present invention, and the technical content of the present invention which is claimed is fully set forth in the claims.