A kind of method of producing chloride-free, fluoride-free sodium tripolyphosphate

Abstract

The invention discloses a method for producing sodium tripolyphosphate without chloride or fluoride. The method comprises the following steps: firstly, neutralization reaction: adding water into a neutralization pot for heating, and adding sodium carbonate for stirring until the sodium carbonate is completely dissolved; when the temperature of a solution is raised to 90 to 120 DEG C, slowly addingphosphoric acid while stirring and adjusting the K value of neutralizing slurry to 2.8+ / -0.2; then adding silicon dioxide, continuously reacting for 3.5+ / -0.5 hours until a mixed solution is viscous,and filtering to obtain a viscous slurry for later use; secondly, drying and dehydrating: feeding the viscous slurry obtained by neutralization into a drying tower for atomization and dehydration; thirdly, polymerization and generation: carrying out polymerization reaction on dried and dehydrated raw materials to obtain the sodium tripolyphosphate; fourthly, carrying out alkali wash on tail gas contained hydrogen chloride, hydrogen fluoride and silicon tetrafluoride and emptying after the substances are determined to be qualified by detecting. The production method of the sodium tripolyphosphate, provided by the invention, has the advantages that the cost of the raw materials is low, the process is simple, the industrialization is easy to realize and the raw materials are easy to obtain;the obtained sodium tripolyphosphate does not contain the chloride or the fluoride.

Description

technical field

[0001] The invention relates to a preparation method of sodium tripolyphosphate, in particular to a method for producing sodium tripolyphosphate free of chloride and fluoride. Background technique

[0002] Sodium tripolyphosphate is used as a softener, dispersant, and dyeing aid. Used as a softener for industrial water, reducing the content of calcium, magnesium, iron and other metal ions in industrial water, and reducing the hardness of water; used as a dispersant in industrial configurations such as paint, kaolin, magnesium oxide, calcium carbonate, etc., used for drilling mud dispersion agent. In addition, it can also be used as a water reducer for molds such as detergent additives, food additives, and gypsum. When used as a water softener to soften industrial water, excessive chloride and fluoride residues will limit the further application of industrial water. When used as a dispersant in industrial configurations such as paint, kaolin, magnesium oxide...

Examples

Embodiment 1

[0036] First add 5 tons of water into the neutralization pot, heat it to 80°C with steam, add 4.5 tons of industrial grade soda ash, stir to completely dissolve the soda ash, and when the temperature of the solution rises to 90°C, slowly add 85% wet-process phosphoric acid and 3.5 tons of solid sodium carbonate were reacted, and the neutralization degree K value of the neutralizing solution was adjusted to 2.6 to stop acid addition, and the amount of phosphoric acid added was measured by a metering pump. Control the specific gravity of the neutralized slurry at 1.4, add silicon dioxide, continue the reaction for 3 hours, send it to the drying tower after fine filtration, and polymerize at a reaction temperature of 380°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0037] In the above reaction, silicon dioxide is added according to 0.1% of the mass of phosphoric acid. The overall reaction ...

Embodiment 2

[0045] First add 10 tons of water into the neutralization pot, heat it to 80°C with steam, add 6 tons of industrial grade soda ash, stir to completely dissolve the soda ash, when the temperature of the solution rises to 100°C, slowly add wet-process phosphoric acid and 7 tons of The soda ash is reacted, and the neutralization degree K value of the neutralizing solution is adjusted to 2.8 to stop acid addition, and the amount of phosphoric acid added is measured by a metering pump. Control the specific gravity of the neutralized slurry at 1.5, add silicon dioxide, continue the reaction for 3.5 hours, send it into the drying tower after fine filtration, and polymerize at a reaction temperature of 400°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0046] Silica is added according to 0.3% of phosphoric acid mass.

[0047] Fluoride test method: According to GB25566-2010 national food safety stan...

Embodiment 3

[0051] First add 15 tons of water into the neutralization pot, heat to 80°C with steam, add 12 tons of industrial grade soda ash, stir to completely dissolve the soda ash, when the temperature of the solution rises to 110°C, slowly add wet-process phosphoric acid and 10 tons of The solid sodium carbonate is reacted, and the neutralization degree K value of the neutralizing solution is adjusted to 3.0 to stop acid addition, and the amount of phosphoric acid added is metered by a metering pump. Control the specific gravity of the neutralized slurry at 1.6, add silicon dioxide, continue the reaction for 4 hours, send it to the drying tower after fine filtration, and polymerize at a reaction temperature of 420°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0052] Silica is added according to 0.5% of phosphoric acid mass.

[0053] Fluoride test method: According to GB25566-2010 national food s...

technical field

[0001] The invention relates to a preparation method of sodium tripolyphosphate, in particular to a method for producing sodium tripolyphosphate free of chloride and fluoride. Background technique

[0002] Sodium tripolyphosphate is used as a softener, dispersant, and dyeing aid. Used as a softener for industrial water, reducing the content of calcium, magnesium, iron and other metal ions in industrial water, and reducing the hardness of water; used as a dispersant in industrial configurations such as paint, kaolin, magnesium oxide, calcium carbonate, etc., used for drilling mud dispersion agent. In addition, it can also be used as a water reducer for molds such as detergent additives, food additives, and gypsum. When used as a water softener to soften industrial water, excessive chloride and fluoride residues will limit the further application of industrial water. When used as a dispersant in industrial configurations such as paint, kaolin, magnesium oxide...

Examples

Embodiment 1

[0036] First add 5 tons of water into the neutralization pot, heat it to 80°C with steam, add 4.5 tons of industrial grade soda ash, stir to completely dissolve the soda ash, and when the temperature of the solution rises to 90°C, slowly add 85% wet-process phosphoric acid and 3.5 tons of solid sodium carbonate were reacted, and the neutralization degree K value of the neutralizing solution was adjusted to 2.6 to stop acid addition, and the amount of phosphoric acid added was measured by a metering pump. Control the specific gravity of the neutralized slurry at 1.4, add silicon dioxide, continue the reaction for 3 hours, send it to the drying tower after fine filtration, and polymerize at a reaction temperature of 380°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0037] In the above reaction, silicon dioxide is added according to 0.1% of the mass of phosphoric acid. The overall reaction ...

Embodiment 2

[0045] First add 10 tons of water into the neutralization pot, heat it to 80°C with steam, add 6 tons of industrial grade soda ash, stir to completely dissolve the soda ash, when the temperature of the solution rises to 100°C, slowly add wet-process phosphoric acid and 7 tons of The soda ash is reacted, and the neutralization degree K value of the neutralizing solution is adjusted to 2.8 to stop acid addition, and the amount of phosphoric acid added is measured by a metering pump. Control the specific gravity of the neutralized slurry at 1.5, add silicon dioxide, continue the reaction for 3.5 hours, send it into the drying tower after fine filtration, and polymerize at a reaction temperature of 400°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0046] Silica is added according to 0.3% of phosphoric acid mass.

[0047] Fluoride test method: According to GB25566-2010 national food safety stan...

Embodiment 3

[0051] First add 15 tons of water into the neutralization pot, heat to 80°C with steam, add 12 tons of industrial grade soda ash, stir to completely dissolve the soda ash, when the temperature of the solution rises to 110°C, slowly add wet-process phosphoric acid and 10 tons of The solid sodium carbonate is reacted, and the neutralization degree K value of the neutralizing solution is adjusted to 3.0 to stop acid addition, and the amount of phosphoric acid added is metered by a metering pump. Control the specific gravity of the neutralized slurry at 1.6, add silicon dioxide, continue the reaction for 4 hours, send it to the drying tower after fine filtration, and polymerize at a reaction temperature of 420°C to form sodium tripolyphosphate. After the tail gas passes through the alkali washing tower to collect impurity gas, it is emptied.

[0052] Silica is added according to 0.5% of phosphoric acid mass.

[0053] Fluoride test method: According to GB25566-2010 national food s...

Images