A method for preparing battery-grade iron phosphate from heavy metal sludge

Abstract

The invention discloses a method for preparing battery-level iron phosphate from heavy metal sludge and heavy metal waste acid. The method comprises the following steps of performing seven times of filtering, two times of distilling, two times of electrolysis and one time of roasting. Compared with the conventional preparation process, the method for preparing the battery-level iron phosphate fromheavy metal sludge and heavy metal waste acid provided by the invention has no generation of sulfur dioxide; in addition, the prepared iron aluminum phosphate does not contain iron oxide and chloridion, so that the quick charging effect of an iron aluminum phosphate battery is optimized, the content of iron phosphate is higher, the new energy material can be converted from solid waste, the problem of local environmental pollution is solved, and sustainable development of the metal product industry is promoted; and meanwhile, lead zinc raw materials, ferrous chloride and sodium hypochlorite can be prepared from the heavy metal sludge, so that popularization and application can be promoted.

Description

technical field

[0001] The invention belongs to the technical field of chemical industry, and more specifically relates to a method for preparing battery-grade iron phosphate by using heavy metal sludge, heavy metal waste acid, waste acid sludge and waste phosphoric acid. Background technique

[0002] Ferric phosphate, also known as ferric phosphate or ferric orthophosphate, has a molecular formula of FePO4 and is a white, off-white monoclinic crystal powder. It is the salt of iron salt solution and sodium phosphate, and the iron in it is positive trivalent. Its main purpose is to manufacture lithium iron phosphate battery materials, catalysts and ceramics. The color of high-purity ferric phosphate dihydrate is near white or light (light) yellow-white powder. With the loss of crystal water, the color gradually turns yellow, and the pure anhydrous is yellow-white powder. When the phosphorus in ferric phosphate dihydrate exceeds the standard, the appearance is off-white or d...

Examples

Embodiment 1

[0027] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0028] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 2. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0029] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 3. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0030] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0031] S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 can...

Embodiment 2

[0046] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0047] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 2.5. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0048] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 3.5. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0049] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0050]S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 ...

Embodiment 3

[0065] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0066] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 3. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0067] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 4. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0068] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0069] S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 can...

technical field

[0001] The invention belongs to the technical field of chemical industry, and more specifically relates to a method for preparing battery-grade iron phosphate by using heavy metal sludge, heavy metal waste acid, waste acid sludge and waste phosphoric acid. Background technique

[0002] Ferric phosphate, also known as ferric phosphate or ferric orthophosphate, has a molecular formula of FePO4 and is a white, off-white monoclinic crystal powder. It is the salt of iron salt solution and sodium phosphate, and the iron in it is positive trivalent. Its main purpose is to manufacture lithium iron phosphate battery materials, catalysts and ceramics. The color of high-purity ferric phosphate dihydrate is near white or light (light) yellow-white powder. With the loss of crystal water, the color gradually turns yellow, and the pure anhydrous is yellow-white powder. When the phosphorus in ferric phosphate dihydrate exceeds the standard, the appearance is off-white or d...

Examples

Embodiment 1

[0027] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0028] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 2. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0029] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 3. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0030] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0031] S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 can...

Embodiment 2

[0046] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0047] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 2.5. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0048] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 3.5. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0049] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0050]S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 ...

Embodiment 3

[0065] A method for preparing battery-grade iron phosphate by using heavy metal sludge and heavy metal waste acid, comprising the steps of:

[0066] S1. Put the iron oxide waste into the reaction kettle, and add waste acid to adjust the pH value to 3. After stirring evenly, use a filter press to filter to obtain filter residue 1 and filtrate 1;

[0067] S2. Add the filter residue 1 in the step S1 to the reaction kettle, and add phosphoric acid and hydrochloric acid to adjust the pH value to 4. After stirring and reacting, use a filter press to filter to obtain filter residue 2 and filtrate 2;

[0068] S3, adding sodium sulfide solution to filtrate 1, stirring and reacting, and then filtering to obtain filter residue 3 and filtrate 3;

[0069] S4. Add the filter residue 2 in the step S2 to the reaction kettle, and add tap water to wash and filter to obtain the filter residue 4 and the filtrate 4. The filter residue 4 can be directly discharged harmlessly, and the filtrate 4 can...