阅读说明：本技术 一种纸面石膏板生产用磷石膏的预处理方法 (Pretreatment method of phosphogypsum for producing gypsum plasterboard ) 是由 朱路遥 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种纸面石膏板生产用磷石膏的预处理方法,处理步骤包括如下：水洗处理：首先将磷石膏进行温水洗涤,将磷石膏放置在化浆池中进行漂洗,然后使用工具对磷石膏进行搅拌,使其可以分散开来,接着静置沉淀,然后采用抽水机将表面的水抽掉。本发明通过在对磷石膏中和时,采用石灰结合低浓度硫酸的方式,来达到将磷石膏改性的效果,只需要首先加入石灰进行初次反应,然后继续加入低浓度的硫酸,这样二者相互结合的方式即可实现对磷石膏中和改性的效果,从而可以较好的去除磷石膏中含有的可溶磷和氟等有害物质,并且在后续中采用筛分的方式,来将磷石膏中的磷、氟、绿色物等杂质剔除掉,此种预处理方法操作简单便捷,实用性较强。(The invention discloses a pretreatment method of phosphogypsum for producing a gypsum plaster board, which comprises the following treatment steps: and (3) water washing treatment: firstly, washing phosphogypsum with warm water, putting the phosphogypsum into a pulping tank for rinsing, then stirring the phosphogypsum by using a tool to disperse the phosphogypsum, then standing for precipitation, and then pumping water on the surface by using a water pump. According to the invention, when the phosphogypsum is neutralized, the effect of modifying the phosphogypsum is achieved by combining lime with low-concentration sulfuric acid, only the lime is added for primary reaction, and then the low-concentration sulfuric acid is continuously added, so that the effect of neutralizing and modifying the phosphogypsum can be realized by combining the lime and the low-concentration sulfuric acid, therefore, harmful substances such as soluble phosphorus, fluorine and the like contained in the phosphogypsum can be better removed, and impurities such as phosphorus, fluorine, green substances and the like in the phosphogypsum are removed by adopting a screening mode in the follow-up process.)

1. The pretreatment method of the phosphogypsum for producing the gypsum plasterboard is characterized by comprising the following treatment steps of:

s1, water washing treatment: firstly, washing phosphogypsum with warm water, putting the phosphogypsum into a pulping tank for rinsing, then stirring the phosphogypsum by using a tool to disperse the phosphogypsum, then standing and precipitating, then pumping water on the surface by using a water pump, and repeating the steps to finish 3-4 times of washing work, so that the phosphogypsum is neutral;

s2, neutralization: because the soluble P2O5 in the phosphogypsum has stronger use influence, lime and low-concentration sulfuric acid are needed to be adopted to convert residual phosphoric acid in the phosphogypsum into inert substances, the lime, the low-concentration sulfuric acid and the soluble P2O5 and F-react to generate the inert substances, the harm of soluble phosphorus and fluorine can be removed, the inert substances are uniformly stirred, and then the aging treatment is carried out;

s3, screening treatment: because impurities such as phosphorus, fluorine, greenness and the like are not uniformly distributed in the phosphogypsum, the impurity contents of the phosphogypsum with different granularities have the principle of great difference, so that the mixed impurities are removed;

s4, flotation: mixing water and phosphogypsum which are twice of the total amount of the phosphogypsum together, stirring, scraping oily suspended matters on the surface of the phosphogypsum by using a tool, stirring again, scraping the oily suspended matters on the surface of the phosphogypsum by using the tool, and repeating the steps until the oily suspended matters can not be stirred;

s5, grinding: putting phosphogypsum into a ball mill, adding free water, controlling the specific surface area to be 3500-4000 cm < 2 > 2g, and continuously performing ball milling;

s6, calcining: the phosphogypsum is placed in an electric heating oven for firing, and then the firing temperature is set to be 150 ℃, so that the characteristic that the phosphogypsum is decomposed into gas or partially converted into inert and stable indissolvable phosphate compounds at a high temperature can be utilized, harmful substances are decomposed or converted into inert substances at the high temperature, a small amount of phosphorus is converted into gas at the high temperature and is discharged, inorganic phosphorus is combined with calcium at the high temperature to form inert calcium pyrophosphate, and the harm of impurities such as phosphorus, inorganic phosphorus and the like to the performance of gypsum is removed.

2. The method for pretreating phosphogypsum for producing a gypsum plaster board according to claim 1, wherein in step S1, the phosphogypsum is washed by warm water, rinsed in a pulping tank, and stirred by a tool for 8min to disperse, then left to stand for precipitation and kept for 15min, and then the water on the surface is pumped out by a water pump, and the above steps are repeated for 3-4 times to complete the washing operation, so that the phosphogypsum is neutral.

3. The method for pre-treating phosphogypsum for producing gypsum plasterboards according to claim 1, wherein in step S2, due to the strong use effect of the soluble P2O5 in phosphogypsum, lime and low-concentration sulfuric acid are used to convert the residual phosphoric acid in phosphogypsum into inert substances, and the lime, the low-concentration sulfuric acid and the soluble P2O5 and F-react to generate inert substances, so as to remove the harm of soluble phosphorus and fluorine, only the lime is added into phosphogypsum with free water content of about 15% and is uniformly stirred for 20min, then the low-concentration sulfuric acid is added while the concentration of the sulfuric acid is kept between 10-30%, and then the aging treatment is carried out for 2.3 h.

4. The method for pretreating phosphogypsum for producing a gypsum plasterboard according to claim 1, wherein in step S3, because impurities such as phosphorus, fluorine, green matters and the like are not uniformly distributed in the phosphogypsum, the content of the impurities of the phosphogypsum with different particle sizes has a principle of large difference, a sieving machine with a corresponding mesh number is selected according to the actual treatment condition, and the phosphogypsum is sieved for three times, so that the mixed impurities are removed.

5. The method for pretreating phosphogypsum for producing a gypsum plasterboard according to claim 1, wherein in step S4, water and phosphogypsum are mixed together according to twice the total amount of the phosphogypsum, then stirring is carried out for 3min, then a tool is used for scraping off oily suspended matters on the surface of the phosphogypsum, then stirring is carried out again for 4min, then a tool is used for scraping off the oily suspended matters on the surface of the phosphogypsum, and the steps are repeated, wherein the stirring time is increased by 1min each time until the oily suspended matters can not be stirred out.

6. The pretreatment method of phosphogypsum for producing paper-faced gypsum boards according to claim 1, characterized in that in step S5, phosphogypsum is put into a ball mill, then free water is added, the proportion of the free water is kept less than 1%, meanwhile, the specific surface area is required to be controlled to be 3500-4000 cm2g, then ball milling is continuously carried out, and the processing time is kept to be 13-16 min.

7. The method for pretreating phosphogypsum for producing a paper-faced gypsum board according to claim 1 is characterized in that in step S6, the phosphogypsum is placed in an electric heating oven to be fired, and meanwhile, the thickness of the material is required to be ensured to be between 3cm and 5cm, the heating rate is 2-3 ℃/min, then the calcining temperature is set to be 150 ℃, and the constant temperature is kept for 2.1 hours, so that the characteristics of decomposing into gas or partially converting into inert and stable insoluble phosphate compounds at a high temperature state are utilized, harmful substances are decomposed or converted into inert substances at the high temperature, a small amount of phosphorus is converted into gas at the high temperature to be discharged, and inorganic phosphorus is combined with calcium to form inert calcium pyrophosphate at the high temperature state, so that the damage of impurities such as phosphorus and inorganic phosphorus to the performance of gypsum is eliminated.

Technical Field

The invention relates to the technical field of phosphogypsum, in particular to a pretreatment method of phosphogypsum for producing a gypsum plasterboard.

Background

The phosphogypsum mainly comprises gray black and gray white, the particle diameter is generally 5-50 mu m, the content of crystal water is 20-25%, the composition of the phosphogypsum is complex, besides calcium sulfate, incompletely decomposed phosphorite, residual phosphoric acid, fluoride, acid insoluble substances, organic matters and the like are also contained, and the existence of fluorine and the organic matters has the greatest influence on the resource utilization of the phosphogypsum. The random discharge and accumulation of the phosphogypsum seriously damage the ecological environment, not only pollutes underground water resources, but also causes the waste of land resources.

When the phosphogypsum on the market is applied to specific product processing, only some harmful substances in the phosphogypsum can be simply pretreated, soluble phosphorus and fluorine in the phosphogypsum cannot be removed in the treatment process, the harmfulness of the soluble phosphorus and the fluorine is high, certain limitation exists in the application process, impurities such as phosphorus, fluorine, green substances and the like with different degrees are mixed in the phosphogypsum, and if the impurities are not removed in the use process, the subsequent processing and use are influenced.

Disclosure of Invention

The invention provides a method for pretreating phosphogypsum for producing a gypsum plaster board, aiming at the defects in the background technology.

The invention adopts the following technical scheme to solve the phenomenon, and the treatment method of the phosphogypsum for producing the gypsum plasterboard comprises the following steps:

s1, water washing treatment: firstly, washing phosphogypsum with warm water, putting the phosphogypsum into a pulping tank for rinsing, then stirring the phosphogypsum by using a tool to disperse the phosphogypsum, then standing and precipitating, then pumping water on the surface by using a water pump, and repeating the steps to finish 3-4 times of washing work, so that the phosphogypsum is neutral;

s2, neutralization: because the soluble P2O5 in the phosphogypsum has stronger use influence, lime and low-concentration sulfuric acid are needed to be adopted to convert residual phosphoric acid in the phosphogypsum into inert substances, the lime, the low-concentration sulfuric acid and the soluble P2O5 and F-react to generate the inert substances, the harm of soluble phosphorus and fluorine can be removed, the inert substances are uniformly stirred, and then the aging treatment is carried out;

s3, screening treatment: because impurities such as phosphorus, fluorine, greenness and the like are not uniformly distributed in the phosphogypsum, the impurity contents of the phosphogypsum with different granularities have the principle of great difference, so that the mixed impurities are removed;

s4, flotation: mixing water and phosphogypsum which are twice of the total amount of the phosphogypsum together, stirring, scraping oily suspended matters on the surface of the phosphogypsum by using a tool, stirring again, scraping the oily suspended matters on the surface of the phosphogypsum by using the tool, and repeating the steps until the oily suspended matters can not be stirred;

s5, grinding: putting phosphogypsum into a ball mill, adding free water, controlling the specific surface area to be 3500-4000 cm < 2 > 2g, and continuously performing ball milling;

s6, calcining: the phosphogypsum is placed in an electric heating oven for firing, and then the firing temperature is set to be 150 ℃, so that the characteristic that the phosphogypsum is decomposed into gas or partially converted into inert and stable indissolvable phosphate compounds at a high temperature can be utilized, harmful substances are decomposed or converted into inert substances at the high temperature, a small amount of phosphorus is converted into gas at the high temperature and is discharged, inorganic phosphorus is combined with calcium at the high temperature to form inert calcium pyrophosphate, and the harm of impurities such as phosphorus, inorganic phosphorus and the like to the performance of gypsum is removed.

As a further preferable mode of the present invention, in step S1, firstly, warm water washing is performed on phosphogypsum, the phosphogypsum is placed in a slurrying pool for rinsing, and meanwhile, the water retention amount is three times of the total amount of the phosphogypsum, then, the phosphogypsum is stirred by using a tool, the stirring time lasts for 8min, so that the phosphogypsum can be dispersed, then, the phosphogypsum is kept standing for precipitation and 15min, then, a water pump is adopted to pump off the surface water, and the above steps are repeated to complete 3-4 times of washing work, so that the phosphogypsum is neutral.

As a further preferred mode of the present invention, in step S2, due to the strong use effect of the soluble P2O5 in phosphogypsum, lime and low-concentration sulfuric acid are used to convert the residual phosphoric acid in phosphogypsum into inert substances, and the lime, the low-concentration sulfuric acid and the soluble P2O5, F-react to generate inert substances, so as to remove the hazards of soluble phosphorus and fluorine, only the lime is added into phosphogypsum with free water content of about 15%, and is stirred uniformly, and the stirring time lasts for 20min, then the low-concentration sulfuric acid is added, and the sulfuric acid concentration is kept between 10-30%, and then the aging treatment is carried out, and the aging time is 2.3 h.

As a further preferred embodiment of the present invention, in step S3, since the impurities such as phosphorus, fluorine, greenness, etc. are not uniformly distributed in the phosphogypsum, the screening machines with corresponding mesh numbers are selected according to the actual treatment condition on the principle that the impurity contents of the phosphogypsum with different particle sizes are greatly different, so as to remove the mixed impurities.

As a further preferable mode of the present invention, in step S4, water and phosphogypsum in an amount twice the total amount of the phosphogypsum are mixed together, then stirring is performed for 3min, then a tool is used to scrape off oily suspended matters on the surface of the phosphogypsum, then stirring is performed again for 4min, then a tool is used to scrape off oily suspended matters on the surface of the phosphogypsum, the above steps are repeated, and the stirring time is increased by 1min each time until no oily suspended matters are stirred out.

As a further preferable mode of the invention, in step S5, the phosphogypsum is put into a ball mill, then the free water is added, the proportion of the free water is kept less than 1%, meanwhile, the specific surface area of the phosphogypsum is required to be controlled to be 3500-4000 cm2g, then the ball milling processing is continuously carried out, and the processing time is kept within 13-16 min.

As a further preferable mode of the present invention, in step S6, the phosphogypsum is placed in an electric heating oven for firing, and the thickness of the material is ensured to be between 3cm and 5cm, the temperature rise rate is 2-3 ℃/min, then the firing temperature is 150 ℃, and the constant temperature time is kept for 2.1h, so that the characteristics of decomposing into gas or partially converting into inert and stable insoluble phosphate compounds at high temperature can be utilized, harmful substances are decomposed or converted into inert substances at high temperature, a small amount of phosphorus is converted into gas at high temperature and discharged, and inorganic phosphorus is combined with calcium at high temperature to become inert calcium pyrophosphate, so as to remove the harm of impurities such as phosphorus and inorganic phosphorus to the performance of gypsum.

According to the invention, when the phosphogypsum is neutralized, the effect of modifying the phosphogypsum is achieved by combining lime with low-concentration sulfuric acid, only the lime is added for primary reaction, and then the low-concentration sulfuric acid is continuously added, so that the effect of neutralizing and modifying the phosphogypsum can be realized by combining the lime and the low-concentration sulfuric acid, and harmful substances such as soluble phosphorus, fluorine and the like contained in the phosphogypsum can be better removed.

Drawings

FIG. 1 is a flow chart of the pretreatment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: a pretreatment method of phosphogypsum for producing a paper-surface gypsum board comprises the following steps:

s1, firstly washing the phosphogypsum with warm water, placing the phosphogypsum in a pulping tank for rinsing, then stirring the phosphogypsum by using a tool to disperse the phosphogypsum, then standing and precipitating, then pumping water on the surface by using a water pump, and repeating the steps to finish 3-4 times of washing work, so that the phosphogypsum is neutral;

s2, because the soluble P2O5 in the phosphogypsum has strong use influence, lime and low-concentration sulfuric acid are needed to be adopted to convert residual phosphoric acid in the phosphogypsum into inert substances, the lime, the low-concentration sulfuric acid, the soluble P2O5 and F-react to generate the inert substances, the harm of soluble phosphorus and fluorine can be removed, the inert substances are uniformly stirred, and then aging treatment is carried out;

s3, because impurities such as phosphorus, fluorine, green substances and the like are not uniformly distributed in the phosphogypsum, the impurity contents of the phosphogypsum with different granularities have the principle of great difference, so that mixed impurities are removed;

s4, mixing water and phosphogypsum which are twice of the total amount of the phosphogypsum together, stirring, scraping oily suspended matters on the surface of the phosphogypsum by using a tool, stirring again, scraping the oily suspended matters on the surface of the phosphogypsum by using the tool, and repeating the steps until the oily suspended matters can not be generated by stirring;

s5, putting the phosphogypsum into a ball mill, adding free water, controlling the specific surface area to be 3500-4000 cm & lt 2 & gt 2g, and continuously performing ball milling;

s6, placing the phosphogypsum in an electric heating oven for firing, setting the firing temperature at 150 ℃, and then utilizing the characteristic that the phosphogypsum is decomposed into gas or partially converted into inert and stable indissolvable phosphate compounds at high temperature, so that harmful substances are decomposed or converted into inert substances at high temperature, a small amount of phosphorus is converted into gas at high temperature and discharged, and inorganic phosphorus is combined with calcium at high temperature to form inert calcium pyrophosphate, thereby removing the harm of impurities such as phosphorus, inorganic phosphorus and the like to the performance of gypsum.

In step S1, firstly, warm water washing is carried out on the phosphogypsum, the phosphogypsum is placed in a pulping tank for rinsing, meanwhile, the water retention amount is three times of the total amount of the phosphogypsum, then, a tool is used for stirring the phosphogypsum for 8min so that the phosphogypsum can be dispersed, then, standing and precipitating are carried out, the standing time is 15min, then, a water pump is used for pumping off the surface water, and the steps are repeated to finish 3-4 times of washing work, so that the phosphogypsum is neutral.

In the step S2, as the soluble P2O5 in the phosphogypsum has strong use influence, lime and low-concentration sulfuric acid are needed to be adopted to convert residual phosphoric acid in the phosphogypsum into inert substances, the lime, the low-concentration sulfuric acid and the soluble P2O5 and F-react to generate the inert substances, the harm of soluble phosphorus and fluorine can be removed, only the lime is needed to be added into the phosphogypsum with free water content of about 15%, the phosphogypsum is stirred uniformly, the stirring time lasts for 20min, then the low-concentration sulfuric acid is added, the sulfuric acid concentration is kept between 10% and 30%, and then aging treatment is carried out, and the aging time is 2.3 h.

In step S3, because the impurities such as phosphorus, fluorine, green substances, etc. are not uniformly distributed in the phosphogypsum, the phosphogypsum with different granularities has the principle of large difference in impurity content, and the screening device with the corresponding mesh number is selected according to the actual treatment condition to screen the phosphogypsum for three times, so as to remove the mixed impurities.

In the step S4, water and phosphogypsum which are twice of the total amount of the phosphogypsum are mixed together, then stirring is carried out for 3min, then an oily suspended substance on the surface of the phosphogypsum is scraped by a tool, then stirring is carried out again for 4min, then the oily suspended substance on the surface of the phosphogypsum is scraped by the tool, the steps are repeated, and the stirring time is increased by 1min each time until the oily suspended substance can not be stirred.

In the step S5, the phosphogypsum is put into a ball mill, then the free water is added, the proportion of the free water is kept to be less than 1%, meanwhile, the specific surface area of the phosphogypsum is required to be controlled to be 3500-4000 cm < 2 > 2g, then the ball milling processing is continuously carried out, and the processing time is kept to be 13-16 min.

In step S6, the phosphogypsum is placed in an electric heating oven to be fired, meanwhile, the thickness of the material is required to be ensured to be between 3cm and 5cm, the heating rate is 2-3 ℃/min, then the calcining temperature is set to be 150 ℃, and the constant temperature is kept for 2.1h, so that the characteristic that the phosphogypsum is decomposed into gas or partially converted into inert and stable indissolvable phosphate compounds at a high temperature can be utilized, harmful substances are decomposed or converted into inert substances at the high temperature, a small amount of phosphorus is converted into gas at the high temperature to be discharged, and inorganic phosphorus is combined with calcium at the high temperature to form inert calcium pyrophosphate, so that the damage of impurities such as phosphorus, inorganic phosphorus and the like to the performance of the gypsum is eliminated.

In conclusion, the invention achieves the effect of modifying the phosphogypsum by combining lime with low-concentration sulfuric acid during the neutralization of the phosphogypsum, only the lime is added for the primary reaction, then the low-concentration sulfuric acid is continuously added, and the effect of neutralizing and modifying the phosphogypsum can be realized by combining the lime and the low-concentration sulfuric acid, so that the harmful substances such as soluble phosphorus, fluorine and the like contained in the phosphogypsum can be better removed, and the impurities such as phosphorus, fluorine, green substances and the like in the phosphogypsum are removed by adopting a screening mode in the follow-up process, so that the purity of the phosphogypsum in the follow-up use process can be greatly improved, and the pollution and the harmful conditions are avoided.

While there have been shown and described what are at present considered the fundamental principles and essential features of the invention and its advantages, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.