阅读说明：本技术 一种磷酸法生产活性炭中磷酸除铁的方法 (Method for removing iron from phosphoric acid in production of activated carbon by phosphoric acid method ) 是由 程振国 于 2019-11-29 设计创作，主要内容包括：本发明涉及一种磷酸法生产活性炭中磷酸除铁的方法,包括以下几个步骤：步骤1)回收洗涤工序回收下来的含有正磷酸、焦磷酸和/或偏磷酸组分的磷酸,先采用粗过滤除去其中含有的活性炭等固体杂质；步骤2)将粗过滤好的液体与浓硫酸混合,静置后通过过滤设备除去硫酸钙与硫酸镁沉淀,有效降低液体中所含有的钙、镁成分；步骤3)将过滤好的液体与一定浓度的沉铁剂溶液合成反应来最终降低磷酸中的铁离子含量。该方法减小了对设备的腐蚀,减少了循环磷酸中铁的含量,能够在化工、制药等行业得到良好的利用。(The invention relates to a method for removing iron from phosphoric acid in the production of active carbon by a phosphoric acid method, which comprises the following steps: step 1) recovering phosphoric acid containing orthophosphoric acid, pyrophosphoric acid and/or metaphosphoric acid components recovered in the washing process, and removing solid impurities such as active carbon and the like contained in the phosphoric acid by coarse filtration; step 2) mixing the roughly filtered liquid with concentrated sulfuric acid, standing, and removing calcium sulfate and magnesium sulfate precipitates through a filtering device, so that calcium and magnesium components contained in the liquid are effectively reduced; and 3) carrying out synthetic reaction on the filtered liquid and an iron precipitation agent solution with a certain concentration to finally reduce the content of iron ions in the phosphoric acid. The method reduces the corrosion to equipment, reduces the content of iron in the circulating phosphoric acid, and can be well utilized in the industries of chemical engineering, pharmacy and the like.)

1. A method for removing iron from phosphoric acid in the production of activated carbon by a phosphoric acid method is characterized by comprising the following steps:

step 1) recovering phosphoric acid containing orthophosphoric acid, pyrophosphoric acid and/or metaphosphoric acid components recovered in the washing process, and removing solid impurities such as active carbon and the like contained in the phosphoric acid by coarse filtration;

step 2) mixing the roughly filtered liquid with concentrated sulfuric acid, standing, and removing calcium sulfate and magnesium sulfate precipitates through a filtering device, so that calcium and magnesium components contained in the liquid are effectively reduced;

and 3) carrying out synthetic reaction on the filtered liquid and an iron precipitation agent solution with a certain concentration to finally reduce the content of iron ions in the phosphoric acid.

2. The method for removing iron from phosphoric acid in the production of activated carbon by the phosphoric acid method as claimed in claim 1, wherein the phosphoric acid concentration of the components containing orthophosphoric acid, pyrophosphoric acid and/or metaphosphoric acid in the step 1) is 35-45 baume degrees, and a filter barrel device is adopted for coarse filtration.

3. The method for removing iron from phosphoric acid in the production of activated carbon by the phosphoric acid method according to claim 1, wherein the use amount of concentrated sulfuric acid in the step 2) is 5% -15% of the weight of phosphoric acid, stirring is performed after adding sulfuric acid, the stirring time is 0.5-1 hour, and the operation of removing precipitate is performed after standing for more than 24 hours.

4. The method for removing iron from phosphoric acid in the production of activated carbon by the phosphoric acid method according to claim 1, wherein the precipitation removal operation is performed by acid and alkali resistant plate and frame filter press equipment.

5. The method for removing iron from phosphoric acid in the production of activated carbon by the phosphoric acid method according to claim 1, wherein the iron precipitation agent in the step 3) is one or more of sodium magnesium, EDTA and oxalic acid.

6. The method for removing iron from phosphoric acid in the production of activated carbon by the phosphoric acid method according to claim 1, wherein the concentration of the iron precipitation agent is 10% -30%, the addition amount is 1% -10% of the weight of the phosphoric acid to be treated, and the treatment time is 2-6 hours.

Technical Field

The invention relates to the technical field of activated carbon production, in particular to a method for removing iron from phosphoric acid in activated carbon production by a phosphoric acid method.

Background

The activated carbon is produced by two major methods, i.e. chemical phosphoric acid, zinc chloride, sodium hydroxide and the like, and gas activation. The zinc chloride method has the biggest defect of serious environmental pollution and is a problem which is urgently needed to be solved. Phosphoric acid is a medium strong acid, and has an activation mechanism of dehydration and oxidation properties similar to those of zinc chloride, and thus is widely used.

Phosphoric acid is reduced into pyrophosphoric acid and metaphosphoric acid in the pyrolysis process, and is changed into orthophosphoric acid again after being recycled and washed and meeting water, and the orthophosphoric acid can be recycled as zinc chloride medicine. The iron salt of the phosphoric acid method activated carbon mainly appears in two aspects: (1) the entering of the raw materials such as wood chips, phosphoric acid and the like can be controlled by strict screening and detection; (2) in the production process, the circulating phosphoric acid is usually subjected to calcium and magnesium removal by using sulfuric acid or calcium and magnesium, iron and the like removal by using ion exchange resin, but hydrochloric acid is used for activation when the ion exchange resin is inactivated, so that the circulating phosphoric acid contains sulfuric acid or hydrochloric acid components, the components corrode equipment, and the content of iron in the circulating phosphoric acid is greatly increased. But compared with the activated carbon produced by zinc chloride, the quality of the activated carbon has the defect of high iron salt, and the application of the activated carbon in the industries of chemical engineering, pharmacy and the like is limited.

Disclosure of Invention

The purpose of the invention is as follows: the invention provides a method for removing iron from phosphoric acid in the production of active carbon by a phosphoric acid method.

The technical scheme is as follows: in order to achieve the above object, the present invention is embodied in such a way that: a method for removing iron from phosphoric acid in the production of activated carbon by a phosphoric acid method comprises the following steps:

step 1) recovering phosphoric acid containing orthophosphoric acid, pyrophosphoric acid and/or metaphosphoric acid components recovered in the washing process, and removing solid impurities such as active carbon and the like contained in the phosphoric acid by coarse filtration;

step 2) mixing the roughly filtered liquid with concentrated sulfuric acid, standing, and removing calcium sulfate and magnesium sulfate precipitates through a filtering device, so that calcium and magnesium components contained in the liquid are effectively reduced;

and 3) carrying out synthetic reaction on the filtered liquid and an iron precipitation agent solution with a certain concentration to finally reduce the content of iron ions in the phosphoric acid.

The phosphoric acid concentration of the components containing orthophosphoric acid, pyrophosphoric acid and/or metaphosphoric acid in the step 1) is 35-45 Baume degrees, and a filter barrel device is adopted for coarse filtration.

The usage amount of the concentrated sulfuric acid in the step 2) is 5-15% of the weight of the phosphoric acid, stirring operation is carried out after the sulfuric acid is added, the stirring time is 0.5-1 hour, and the operation of removing the precipitate is carried out after standing for more than 24 hours.

And the precipitation removing operation adopts acid and alkali resistant plate and frame filter press equipment.

The iron precipitation agent in the step 3) is one or more of sodium magnesium sulfate, EDTA and oxalic acid.

The concentration of the iron precipitation agent is 10-30%, the adding amount is 1-10% of the weight of the phosphoric acid to be treated, and the treatment time is 2-6 hours.

The invention has the beneficial effects that: the method for removing iron from phosphoric acid in the production of the activated carbon by the phosphoric acid method reduces the corrosion to equipment, reduces the content of iron in the circulating phosphoric acid, and can be well utilized in the industries of chemical engineering, pharmacy and the like.

Detailed Description

The practice of the invention is further described below in connection with specific examples.