Method for producing sodium tripolyphosphate by using crude sodium pyrophosphate

A technology of sodium tripolyphosphate and crude sodium pyrophosphate is applied in the refining process field of crude sodium pyrophosphate to achieve the effects of increasing solid content, improving refining process and realizing secondary waste resource recovery
CN106335889BActive Publication Date: 2018-09-25YIBIN TIANYUAN GRP CO LTD +1

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
YIBIN TIANYUAN GRP CO LTD
Publication Date
2018-09-25

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Abstract

The invention relates to a utilization method of crude sodium pyrophosphate and specifically discloses a method for producing sodium tripolyphosphate by the utilization of crude sodium pyrophosphate. The method of the invention comprises the following steps: (1) washing crude sodium pyrophosphate; (2) filter-pressing washed slag; (3) dissolving filter cake, adding an impurity remover into the solution to remove metal ion; (4) press-filtering the deimpurity solution; (5) adding a decolorising agent to remove pigment, acidifying by adding phosphoric acid, accelerating dissolution, and finally adjusting pH value by adding alkali lye; (6) cooling for crystallization, and carrying out solid-liquid separation to obtain sodium pyrophosphate crystal; and (7) using the sodium pyrophosphate crystal as a production raw material for production of sodium tripolyphosphate. The invention has the following advantages: 1) recovery of waste resources is realized; 2) implementation is simple, and production efficiency is high; 3) purity of the sodium pyrophosphate crystal is high; and 4) production cost of sodium tripolyphosphate is reduced.
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Description

technical field

[0001] The invention relates to a refining process of crude sodium pyrophosphate, in particular to a method for utilizing crude sodium pyrophosphate. Background technique

[0002] At present, most of the preparation methods of sodium tripolyphosphate are to make sodium tripolyphosphate directly with neutralizing solution, wherein the neutralizing solution is prepared by phosphoric acid and liquid caustic soda, and it is added to the neutralizing solution preparation tank in proportion or by metering during production. Phosphoric acid and caustic soda, and then follow-up process to make sodium tripolyphosphate. This process is a mature traditional process that has been used for many years. However, with the changes in the market, the prices of caustic soda and phosphoric acid have continued to rise in recent years, resulting in rising costs of sodium tripolyphosphate. The profit margin is getting smaller and smaller, and it is on the verge of loss.

[0003] C...

Claims

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