阅读说明：本技术 一种聚合氯化铝溶液的纯化脱色工艺 (Purification and decoloration process of polyaluminium chloride solution ) 是由 李逢旺 杨长建 张小蓉 于 2021-09-14 设计创作，主要内容包括：本发明提供一种聚合氯化铝溶液的纯化脱色工艺,包括如下步骤：(1)调节聚合氯化铝溶液的pH至3.5～4.5,加入铝屑,加热升温,磁力搅拌处理,恒温静置,过滤,取滤液Ⅰ；(2)调节滤液Ⅰ的pH至7.0～7.5,加入改性沸石与硅胶的复合材料,于45～55℃恒温条件下,持续搅拌处理,过滤,得到滤液Ⅱ；(3)将滤液Ⅱ加热至60～65℃,调节滤液Ⅱ的pH至4.5～5.0,经大孔树脂吸附纯化,得到无色透明的聚合氯化铝溶液,本发明的聚合氯化铝溶液的纯化脱色工艺,可制备获得高纯度的聚合氯化铝溶液,既有效降低了聚合氯化铝溶液色度,又提高聚合氯化铝溶液的多核铝含量,碱化度稳定,使之更有效用于造纸施胶剂中。(The invention provides a purification and decoloration process of polyaluminium chloride solution, which comprises the following steps: (1) adjusting the pH value of the polyaluminium chloride solution to 3.5-4.5, adding aluminum scraps, heating, performing magnetic stirring treatment, standing at constant temperature, and filtering to obtain a filtrate I; (2) adjusting the pH value of the filtrate I to 7.0-7.5, adding a composite material of modified zeolite and silica gel, continuously stirring at a constant temperature of 45-55 ℃, and filtering to obtain a filtrate II; (3) and heating the filtrate II to 60-65 ℃, adjusting the pH value of the filtrate II to 4.5-5.0, and performing adsorption and purification by macroporous resin to obtain a colorless and transparent polyaluminum chloride solution.)

1. A purification and decoloration process of polyaluminium chloride solution is characterized in that: the method comprises the following steps:

(1) primary decoloring: adjusting the pH value of the polyaluminium chloride solution to 3.5-4.5, adding aluminum scraps, heating to 60-80 ℃, performing magnetic stirring treatment for 5-8 min, standing at constant temperature for 15-20 min, and filtering to obtain a filtrate I;

(2) and (3) secondary decolorization: adjusting the pH value of the filtrate I to 7.0-7.5, adding a composite material of modified zeolite and silica gel, continuously stirring at a constant temperature of 45-55 ℃ for 20-25 min at a speed of 90-100 r/min, and filtering to obtain a filtrate II;

(3) refining and purifying: and heating the filtrate II to 60-65 ℃, adjusting the pH of the filtrate II to 4.5-5.0, and adsorbing and purifying by using macroporous resin to obtain a colorless and transparent polyaluminum chloride solution.

2. The process of claim 1, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the composite material of the modified zeolite and the silica gel is prepared by mixing particle modified zeolite, the silica gel and water according to a mass ratio of (5-8) to (1-3) to (10-20), heating to 150-170 ℃, ball-milling for 3-5 h, adding 0.2-0.3 times of 1-2 mol/L hydrochloric acid solution, keeping at 60-70 ℃ for 25-30 min, naturally cooling, drying and dehydrating.

3. The process of claim 2, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the particle modified zeolite is prepared by grinding zeolite to 200-300 mesh, adding 1.5-2 times of sodium chloride solution with mass concentration of 4-6 mol/L, mixing and soaking for 5-7 h, washing with distilled water, and drying.

4. The process of claim 1, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the material-liquid ratio of the composite material of the modified zeolite and the silica gel to the filtrate I is (3-5) to (100-120) g/ml.

5. The process of claim 1, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the feed-liquid ratio of the aluminum scraps to the polyaluminium chloride solution is 1: (80-100) g/ml, and the magnetic stirring speed is 500-600 r/min.

6. The process of claim 1, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the macroporous resin is a series resin column formed by connecting a 7120H resin column and a D402 resin column in series.

7. The process of claim 6, wherein the purification and decolorization of the polyaluminum chloride solution comprises: the diameter-height ratio of the series resin columns is 0.5:1, and the flow rate is 1-2 times of the resin volume/hour.

8. The process of claim 1, wherein the purification and decolorization of the polyaluminum chloride solution comprises: and (3) adsorbing and eluting by using macroporous resin, eluting at 60 ℃ by using a hydrochloric acid solution with the mass concentration of 6-8% as an eluent at the flow rate of 1-2 times the volume of the resin per hour, recovering the macroporous resin, and recycling.

Technical Field

The invention relates to the technical field of papermaking materials, in particular to a purification and decoloration process of a polyaluminium chloride solution.

Background

Polymeric chlorineAluminium oxide, Poly Aluminium (PAC), is between AlCl₃And Al (OH)₃A water-soluble inorganic high molecular polymer with a chemical general formula of [ Al₂(OH)nCl6-n]m, has the advantages of high flocculation precipitation rate, wide applicable pH range, strong adsorption capacity and the like, is widely used in the water purification treatment process, and in the field of papermaking, white polyaluminum chloride can be used for replacing aluminum sulfate as a papermaking sizing agent to realize sizing under neutral conditions, and CaCO can be adopted₃As the filler, the sizing agent has the advantages of good sizing effect, low sizing dosage, high folding strength and tensile strength of paper and the like.

At present, for the preparation process of polyaluminium chloride, coal gangue, waste aluminium ash, bauxite, aluminium scraps, byproduct hydrochloric acid and the like are generally adopted to produce the polyaluminium chloride, and the polyaluminium chloride is generally prepared into yellow, tawny and other polyaluminium chloride finished products, which are difficult to meet the requirements of a papermaking sizing agent on the colorlessness, high purity and no iron of the polyaluminium chloride, so that the method is an important way for supplying white polyaluminium chloride for the decoloration and purification process of the polyaluminium chloride. However, the existing decolorizing and purifying process for the polyaluminium chloride has poor effect of removing metallic iron ions and the like, the removal of the iron ions is insufficient, the performance of the polyaluminium chloride is easily influenced by different decolorizing treatment processes, the alkalization degree of the decolorized polyaluminium chloride is different, the content of polynuclear aluminum is reduced, the sizing effect is unstable, and the whiteness, folding resistance, tensile strength and the like of paper are influenced. Therefore, a new purification and decoloration process of polyaluminium chloride solution is found, which not only can effectively maintain the performance of the polyaluminium chloride, but also can effectively and fully remove nonferrous metal ions, so that the polyaluminium chloride can be better applied to a papermaking sizing agent, and the market demand of white polyaluminium chloride on the papermaking sizing agent is met.

Disclosure of Invention

In view of the above, the invention provides a purification and decoloration process of a polyaluminum chloride solution, which is used for preparing a high-purity polyaluminum chloride solution, so that the chroma of the polyaluminum chloride solution is effectively reduced, the polynuclear aluminum content of the polyaluminum chloride solution is effectively increased, the alkalization degree is stable, and the polyaluminum chloride solution is more effectively used in a papermaking sizing agent.

The technical scheme of the invention is realized as follows:

the invention provides a purification and decoloration process of polyaluminium chloride solution, which comprises the following steps:

(1) primary decoloring: adjusting the pH value of the polyaluminium chloride solution to 3.5-4.5, adding aluminum scraps, heating to 60-80 ℃, performing magnetic stirring treatment for 5-8 min, standing at constant temperature for 15-20 min, and filtering to obtain a filtrate I;

(2) and (3) secondary decolorization: adjusting the pH value of the filtrate I to 7.0-7.5, adding a composite material of modified zeolite and silica gel, continuously stirring at a constant temperature of 45-55 ℃ for 20-25 min at a speed of 90-100 r/min, and filtering to obtain a filtrate II;

(3) refining and purifying: and heating the filtrate II to 60-65 ℃, adjusting the pH of the filtrate II to 4.5-5.0, and adsorbing and purifying by using macroporous resin to obtain a colorless and transparent polyaluminum chloride solution. Wherein, hydrochloric acid or sodium hydroxide is adopted as a pH regulator.

Further, the composite material of the modified zeolite and the silica gel is prepared by mixing the particulate modified zeolite, the silica gel and water according to the mass ratio of (5-8) to (1-3) to (10-20), heating to 150-170 ℃, ball-milling for 3-5 h, adding 0.2-0.3 times of 1-2 mol/L hydrochloric acid solution, keeping at 60-70 ℃ for 25-30 min, naturally cooling, drying and dehydrating.

Further, the particle modified zeolite is obtained by grinding zeolite to pass through a 200-300-mesh sieve, adding 1.5-2 times of sodium chloride solution with the mass concentration of 4-6 mol/L, mixing, soaking for 5-7 hours, washing with distilled water, and drying.

Further, the material-liquid ratio of the composite material of the modified zeolite and the silica gel to the filtrate I is (3-5): 100-120) g/ml.

Further, the feed-liquid ratio of the aluminum chips to the polyaluminum chloride solution is 1: (80-100) g/ml, and the magnetic stirring speed is 500-600 r/min.

Further, the macroporous resin is a series resin column formed by connecting a 7120H resin column and a D402 resin column in series.

Further, the diameter-height ratio of the series resin columns is 0.5:1, and the flow rate is 1-2 times of the resin volume/hour.

Further explaining, in the step (3), macroporous resin adsorption elution treatment is further included, hydrochloric acid solution with the mass concentration of 6-8% is used as an eluent to elute at the temperature of 60 ℃, the flow rate is 1-2 times of the volume of the resin per hour, and the macroporous resin is recovered and reused.

Compared with the prior art, the invention has the beneficial effects that: (1) the invention provides a purification and decoloration process of a polyaluminium chloride solution, which adopts a composite material of aluminum scraps, modified zeolite and silica gel to carry out twice decoloration treatment under different pH values of the polyaluminium chloride solution, accelerates the removal speed of metals and organic matters, enables copper, iron, manganese, mercury ions and the like to be removed more fully and stably, effectively reduces the chromaticity of the polyaluminium chloride solution, effectively improves the multinuclear aluminum content of the polyaluminium chloride solution, stabilizes the alkalization degree, simultaneously reduces the pH value of the decolored polyaluminium chloride solution, and combines macroporous resin adsorption purification treatment to obtain the high-purity polyaluminium chloride solution.

(2) The invention adopts effective combination of twice decolorization and macroporous resin adsorption, can greatly shorten the decolorization time, improve the purification and decolorization efficiency of the polyaluminium chloride solution, and can realize good recovery and full utilization of the adsorption resin.

Detailed Description

In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.

The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

The materials, reagents and the like used in the examples of the present invention can be obtained commercially without specific description.

Example 1

The method for purifying and decoloring the polyaluminium chloride solution comprises the following steps:

step 1: primary decoloring: adjusting the pH value of the polyaluminium chloride solution to 3.5, and mixing the materials according to a material-liquid ratio of 1: adding aluminum scraps into 90g/ml, heating to 60 ℃, performing magnetic stirring treatment at 500r/min for 5min, standing at constant temperature for 15min, and filtering to obtain filtrate I;

step 2: and (3) secondary decolorization: adjusting the pH value of the filtrate I to 7.0, adding a composite material of modified zeolite and silica gel according to the material-liquid ratio of 3:100g/ml, continuously stirring at the constant temperature of 45 ℃ for 20min at 90r/min, and filtering to obtain a filtrate II;

and step 3: refining and purifying: and heating the filtrate II to 60 ℃, adjusting the pH value of the filtrate II to 4.5, and adsorbing and purifying by 7120H macroporous resin with the diameter-height ratio of 0.5:1 at the flow rate of 1 time of the volume of the resin per hour to obtain a colorless and transparent polyaluminum chloride solution.

Example 2

The method for purifying and decoloring the polyaluminium chloride solution comprises the following steps:

step 1: primary decoloring: adjusting the pH value of the polyaluminium chloride solution to 4.5, and mixing the polyaluminium chloride solution and the polyaluminium chloride solution according to a feed-liquid ratio of 1: adding aluminum scraps into 90g/ml, heating to 80 ℃, performing magnetic stirring treatment at 600r/min for 8min, standing at constant temperature for 20min, and filtering to obtain filtrate I;

step 2: and (3) secondary decolorization: adjusting the pH value of the filtrate I to 7.5, adding a composite material of modified zeolite and silica gel according to the material-liquid ratio of 5:120g/ml, continuously stirring at 100r/min for 25min at the constant temperature of 55 ℃, and filtering to obtain a filtrate II;

and step 3: refining and purifying: and heating the filtrate II to 65 ℃, adjusting the pH value of the filtrate II to 5.0, and adsorbing and purifying by using D402 resin with the diameter-height ratio of 0.5:1 at the flow rate of 2 times the volume of the resin per hour to obtain a colorless and transparent polyaluminum chloride solution.

The modified zeolite and silica gel composite material adopted in the above examples 1 and 2 is prepared by mixing the fine particle modified zeolite, silica gel and water according to the mass ratio of 5:1:10, heating to 150 ℃, ball-milling for 5h, adding 2mol/L hydrochloric acid solution with 0.2 times volume, keeping at 60 ℃ for 30min, naturally cooling, drying and dehydrating.

The particle modified zeolite is prepared by crushing and grinding zeolite to 200 meshes, adding 2 times of sodium chloride solution with mass concentration of 4mol/L, mixing and soaking for 5 hours, washing with distilled water, and drying.

Example 3

(1) Preparing a composite material of modified zeolite and silica gel:

crushing and grinding zeolite to be sieved by a 300-mesh sieve, adding 1.5 times of sodium chloride solution with the mass concentration of 6mol/L by volume, mixing and soaking for 7 hours, washing with distilled water, and drying to obtain the particle modified zeolite:

the composite material of the modified zeolite and the silica gel is prepared by mixing the particle modified zeolite, the silica gel and water according to the mass ratio of 8:3:20, heating to 170 ℃, ball-milling for 3h, adding 1mol/L hydrochloric acid solution with the volume being 0.3 times that of the mixture, keeping the mixture at the temperature of 70 ℃ for 25min, naturally cooling, drying and dehydrating the mixture.

(2) And (3) decoloring and purifying:

the method for purifying and decoloring the polyaluminium chloride solution comprises the following steps:

primary decoloring: adjusting the pH value of the polyaluminium chloride solution to 4.0, and mixing the polyaluminium chloride solution and the polyaluminium chloride solution according to a feed-liquid ratio of 1: adding aluminum scraps into 90g/ml, heating to 70 ℃, performing magnetic stirring treatment at 550r/min for 7min, standing at constant temperature for 18min, and filtering to obtain filtrate I;

and (3) secondary decolorization: adjusting the pH value of the filtrate I to 7.3, adding a composite material of modified zeolite and silica gel according to the material-liquid ratio of 4:110g/ml, continuously stirring at the constant temperature of 50 ℃ for 22min at 95r/min, and filtering to obtain a filtrate II;

refining and purifying: heating the filtrate II to 63 ℃, adjusting the pH value of the filtrate II to 4.8, and performing adsorption purification by adopting a series resin column formed by connecting a 7120H resin column and a D402 resin column in series, wherein the diameter-height ratio of the resin column is 0.5:1, and the flow rate is 1.5 times of the resin volume/hour, so as to obtain a colorless and transparent polyaluminum chloride solution; and (3) eluting at 60 ℃ by taking a hydrochloric acid solution with the mass concentration of 6% as an eluent at the flow rate of 1.5 times of the volume of the resin per hour, and recovering and recycling the macroporous resin.

Example 4

The purification and decolorization process was carried out according to the same polyaluminum chloride solution of example 3, except that: the composite material of the modified zeolite and the silica gel is prepared by mixing the modified zeolite, the silica gel and water according to the mass ratio of 8:3:20, heating to 170 ℃, ball-milling for 3h, adding a 0.3-time volume of 1mol/L hydrochloric acid solution, keeping at 70 ℃ for 25min, naturally cooling, drying and dehydrating.

The modified zeolite is prepared by directly adding 1.5-time volume of sodium chloride solution with mass concentration of 6mol/L into zeolite with a particle size of 80 meshes, mixing and soaking for 7 hours, washing with distilled water, and drying.

Comparative example 1

A process for the purification and decolorization of a polyaluminum chloride solution according to example 3, with the difference that: adjusting the pH value of the polyaluminium chloride solution to 4.0, and mixing the polyaluminium chloride solution and the polyaluminium chloride solution according to a feed-liquid ratio of 1: adding aluminum scraps into 90g/ml, standing at 70 ℃ for 60min, filtering, and directly refining and purifying the filtrate to obtain the purified polyaluminum chloride solution.

Comparative example 2

A process for the purification and decolorization of a polyaluminum chloride solution according to example 3, with the difference that: and adjusting the pH values of the polyaluminum chloride solutions in the primary decolorization and the secondary decolorization to 7.0, and refining and purifying the obtained filtrate II to obtain a purified polyaluminum chloride solution.

Comparative example 3

A process for the purification and decolorization of a polyaluminum chloride solution according to example 3, with the difference that: in the secondary decoloring step, the filtrate I is added into a composite material of modified zeolite and silica gel, and the mixture is continuously stirred at the normal temperature of 28 ℃ to obtain a filtrate II.

Comparative example 4

A process for the purification and decolorization of a polyaluminum chloride solution according to example 3, with the difference that: in the refining and purification, the pH value of the filtrate II is adjusted to 6.0, and the purified polyaluminium chloride solution is obtained by adsorption and purification through a series resin column formed by connecting a 7120H resin column and a D402 resin column in series.

A commercially available polyaluminum chloride solution having a chroma of 500 ℃ was subjected to decolorization purification by the method for decolorizing and purifying a polyaluminum chloride solution according to the above examples and comparative examples, and the polyaluminum chloride was measuredThe method comprises determining and analyzing chromaticity, metal content, aluminum distribution and basicity before and after decolorizing and purifying the solution by visual colorimetry of platinum and cobalt to determine chromaticity of polyaluminum chloride solution, ICP-AES to determine metal content, and aluminum precipitant²⁷Al-NMR analysis determines the distribution of aluminum in the polyaluminum chloride, and the salinity of the polyaluminum chloride is determined according to GB/T15892-2009 standard, and the results are shown in the following table:

as can be seen from the above table, the decolorization and purification method for polyaluminum chloride solutions of examples 1 to 4 of the present invention significantly reduces the chromaticity, iron, copper, and manganese contents, and multinuclear aluminum Al₁₃The content and the basicity are increased; the method for decoloring and purifying the polyaluminium chloride solution can effectively maintain the performance of the polyaluminium chloride, effectively and fully remove non-ferrous metal ions, is better applied to a papermaking sizing agent, is beneficial to improving the sizing effect of paper and ensures the requirements of whiteness, folding resistance and tensile strength of the paper. And with different particle sizes of the modified zeolite, the composite material of the modified zeolite and the silica gel has different decolorizing effects on the polyaluminium chloride solution. As can be seen from the comparison between the example 3 and the comparative examples 1 to 4, the comparative example 1 is directly refined and purified without secondary decolorization, the contents of iron, copper and manganese are sufficiently removed, and the effect of elution and recycling of the resin column in the refining process is easily influenced. In the two decolorization processes in the comparative example 2, when the pH values of the polyaluminum chloride solutions are all 7.0, the decolorization effect is also obviously reduced, and the polynuclear aluminum Al₁₃The content is obviously reduced; comparative example 3 adjustment of temperature for lowering Secondary decoloring Process, polynuclear aluminum Al thereof₁₃The content and basicity are reduced, and comparative example 4, the pH value of the polyaluminium chloride solution is adjusted up, and the polyaluminium chloride solution isThe decoloring effect of (b) is decreased.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.