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WO-2026091405-A1 - PHOSPHOGYPSUM RECYCLING SYSTEM

WO2026091405A1WO 2026091405 A1WO2026091405 A1WO 2026091405A1WO-2026091405-A1

Abstract

Provided in the present invention is a phosphogypsum recycling system, comprising an acid washing tank, a clarification tower and a reaction furnace, wherein the acid washing tank is provided with a raw material feeding port and a washing liquid discharging port; the clarification tower is provided with a washing liquid feeding port, an acid washing slurry discharging port and an acid washing clarified liquid discharging port; the reaction furnace is provided with a crude product feeding port, a fuel feeding port, an acid gas discharging port and a product discharging port; and the washing liquid discharging port is connected to the washing liquid feeding port via a washing liquid pipeline, and the acid washing slurry discharging port is connected to the crude product feeding port. In the present invention, a large amount of calcium oxide having a wide application range is generated while waste residues are cleaned and treated. Moreover, it is ensured that tail gas meets the environmental protection standard and reaches the discharge standard, and by-products of sulfuric acid and steam are produced. This not only treats the waste residues of phosphogypsum, but also generates a certain economic value.

Inventors

  • LI, JIAN
  • WANG, DAN
  • HUANG, RUI

Assignees

  • 科洋环境工程（上海）有限公司

Dates

Publication Date
20260507
Application Date
20250401
Priority Date
20241104

Claims (10)

  1. A phosphogypsum recycling system, characterized in that it includes an acid washing tank (V-101), a clarification tower (T-101), and a reaction furnace (R-101); The pickling tank (V-101) is equipped with a raw material inlet and a washing liquid outlet; the clarification tower (T-101) is equipped with a washing liquid inlet, a pickling slurry outlet and a pickling clear liquid outlet; the reactor (R-101) is equipped with a crude product inlet, a fuel inlet, an acid gas outlet and a product outlet. The washing liquid outlet and the washing liquid inlet are connected through a washing liquid pipeline, and the pickling slurry outlet is connected to the crude product inlet. The pickling solution outlet is also connected to the pickling solution treatment unit, which includes a pickling solution collection tank (V-102). The pickling solution collection tank (V-102) is provided with a solution inlet, a treatment agent inlet, and a treatment slurry outlet; the solution outlet is connected to the solution inlet. The pickling solution treatment unit further includes a slurry filter (F-102), which includes a slurry inlet, a reflux filtrate outlet, and a filter cake outlet. The slurry inlet and the slurry outlet are connected via a slurry pipeline. A slurry pump (P-103) is installed on the slurry pipeline. The pickling tank (V-101) is also provided with a filtrate return port, and the filtrate return outlet is connected to the filtrate return port through a filtrate return pipeline.
  2. The phosphogypsum recycling system as described in claim 1 is characterized in that the pickling tank (V-101) is equipped with a stirring device; the washing liquid pipeline is equipped with a washing liquid pump (P-101); the raw material inlet includes a phosphogypsum inlet and a dilute acid inlet; and the height of the pickling slurry outlet is lower than the height of the pickling clear liquid outlet.
  3. The phosphogypsum recycling system according to at least one of claims 1 and 2 is characterized in that a reflux filtrate pump (P-104) is provided on the reflux filtrate pipeline; and the slurry treatment filter (F-102) is a plate and frame filter.
  4. The phosphogypsum recycling system according to at least one of claims 2 and 3 is characterized in that an acid washing slurry treatment unit is further provided between the acid washing slurry outlet and the crude product inlet, the acid washing slurry treatment unit including an acid washing slurry filter (F-101) and a dryer (D-101); the acid washing slurry filter (F-101) is provided with an acid washing slurry inlet, an acid washing filtrate outlet and an acid washing filter cake outlet; the dryer (D-101) is provided with an acid washing filter cake inlet, a crude product outlet and a tail gas outlet; the acid washing slurry inlet is connected to the acid washing slurry outlet, the acid washing filter cake outlet is connected to the acid washing filter cake inlet, and the crude product outlet is connected to the crude product inlet.
  5. The phosphogypsum recycling system as described in claim 4 is characterized in that the pickling slurry treatment unit further includes a dryer dust collector (X-101), the dryer dust collector (X-101) is provided with an exhaust gas inlet, a second exhaust gas outlet and a second coarse product outlet, the exhaust gas inlet is connected to the exhaust gas outlet and the second coarse product outlet is connected to the coarse product inlet; The second exhaust outlet can be connected to the air inlet of the drying blower (C-101); the pickling slurry treatment unit also includes a conveyor, the crude product outlet is connected to the feed end of the conveyor, and the discharge end of the conveyor is connected to the crude product inlet.
  6. The phosphogypsum recycling system as described in claim 5 is characterized in that: the dryer (D-101) is a drum dryer; the drum of the drum dryer is an inclined and rotatable drum; the drum of the drum dryer is equipped with forward lifting plates; the conveyor includes a belt conveyor (L-101) and a bucket elevator (L-102) connected in sequence; a crusher (X-102) is also provided between the discharge end of the conveyor and the feed inlet of the coarse product; the crusher (X-102) is a vibrating crusher; and the pickling slurry filter (F-101) is a plate and frame filter.
  7. The phosphogypsum recycling system according to at least one of claims 5 and 6 is characterized in that an acid pickling slurry treatment unit may be provided between the pickling slurry outlet and the crude product inlet, the acid pickling slurry treatment unit comprising an acid pickling slurry filter (F-101), a dryer (D-101), a dryer dust collector (X-101), a belt conveyor (L-101), a bucket elevator (L-102), and a crusher (X-102); The pickling slurry filter (F-101) is equipped with a pickling slurry inlet, a pickling filtrate outlet, and a pickling filter cake outlet; the dryer (D-101) is equipped with a pickling filter cake inlet, a coarse product outlet, and a tail gas outlet; the dryer dust collector (X-101) is equipped with a tail gas inlet, a second tail gas outlet, and a second coarse product outlet. The pickling slurry inlet is connected to the pickling slurry outlet. The pickling filtrate outlet is connected to the clear liquid inlet via a clear liquid pipe. A clear liquid pump (P-102) is installed on the clear liquid pipe. The pickling filter cake outlet is connected to the pickling filter cake inlet. The coarse product outlet and the second coarse product outlet are connected to the inlet end of the belt conveyor (L-101). The outlet end of the belt conveyor (L-101) is connected to the inlet end of the bucket elevator (L-102). The outlet end of the bucket elevator (L-102) is connected to the inlet end of the crusher (X-102). The outlet end of the crusher (X-102) is connected to the coarse product inlet. The exhaust gas inlet is connected to the exhaust gas outlet. The second exhaust gas outlet is connected to the inlet of the drying induced draft fan (D-101).
  8. The phosphogypsum recycling system according to at least one of claims 1-7 is characterized in that the acid gas outlet and the product outlet can also be connected to a product processing unit, the product processing unit including an acid gas dust collector (X-103) and a silo (V-103), the acid gas dust collector (X-103) is provided with an acid gas inlet, a second acid gas outlet and a second product outlet, the acid gas inlet is connected to the acid gas outlet, the second product outlet and the product outlet are connected to the inlet of the silo (V-103); the outlet of the silo (V-103) is also connected to the inlet of a product crusher (X-104).
  9. The phosphogypsum recycling system according to at least one of claims 1-8 is characterized in that the reactor (R-101) is a cross-shaped reactor; there are two fuel inlets, located on both sides of the reactor (R-101); the acid gas outlet is located at the top of the reactor (R-101); and the product outlet is located at the bottom of the reactor (R-101).
  10. The phosphogypsum recycling system according to at least one of claims 1-9 is characterized in that the furnace lining of the reactor (R-101) is made of refractory bricks.

Description

A phosphogypsum recycling system This application claims priority to Chinese patent application 2024226753707, filed on November 4, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field This invention relates to a phosphogypsum recycling system. Background Technology Phosphogypsum is an industrial waste produced during the production of phosphate fertilizers. Its main component is calcium sulfate dihydrate ( CaSO₄ · 2H₂O ). The wet process production of 1 ton of phosphoric acid ( calculated as P₂O₅ ) generates approximately 5 tons of phosphogypsum. Currently, the world's annual phosphogypsum emissions are approximately 200 million tons, while China's annual emissions exceed 20 million tons, with stockpiles exceeding 300 million tons. The utilization rate is only 30%. Besides occupying a large amount of land, phosphogypsum stockpiles also cause environmental problems such as dust, groundwater, and soil pollution. With the continuous expansion of the wet-process phosphoric acid processing industry both domestically and internationally, the comprehensive utilization of phosphogypsum has become a common issue for the sustainable development of the industry. The main ways to comprehensively utilize phosphogypsum in my country are to replace natural gypsum in the production of cement retarders, the preparation of building materials, the production of soil conditioners, and the co-production of acid and cement. While these methods are currently used industrially, they are insufficient to solve the comprehensive utilization of phosphogypsum. For example, although effective in producing cement retarders, their application is limited by the scale of cement production and the number of manufacturers using phosphogypsum to replace natural gypsum. The use of phosphogypsum in building materials is also limited due to the high impurity content affecting material performance. Phosphogypsum can be used to produce soil conditioners for saline-alkali land and soil structure improvement, but its widespread adoption still has a long way to go. The co-production of acid and cement from phosphogypsum is still in its early stages, requiring highly precise instruments and equipment for raw material preparation. The operation and control of rotary kilns are challenging due to the narrow decomposition range of gypsum and numerous side reactions. Therefore, the process of co-producing acid and cement from phosphogypsum still requires innovation and improvement in both technology and operation. Summary of the Invention The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a phosphogypsum recycling system. The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a phosphogypsum recycling system, which includes an acid washing tank, a clarification tower and a reaction furnace; The pickling tank is provided with a raw material inlet and a washing liquid outlet; the clarification tower is provided with a washing liquid inlet, a pickling slurry outlet and a pickling clear liquid outlet; the reactor is provided with a crude product inlet, a fuel inlet, an acid gas outlet and a product outlet. The washing liquid outlet and the washing liquid inlet are connected through a washing liquid pipeline, and the pickling slurry outlet is connected to the crude product inlet. The pickling solution outlet is also connected to the pickling solution treatment unit, which includes a pickling solution collection tank. The pickling solution collection tank is provided with a solution inlet, a treatment agent inlet, and a treatment slurry outlet. The solution outlet is connected to the solution inlet. The pickling solution treatment unit further includes a slurry filter, which includes a slurry inlet, a reflux filtrate outlet, and a filter cake outlet; the slurry inlet and the slurry outlet are connected by a slurry pipeline. In this invention, the main component of phosphogypsum is dihydrate gypsum ( CaSO₄ · 2H₂O ). Besides the main component calcium sulfate, it also contains small amounts of phosphoric acid, silicon, fluorine, magnesium, iron, aluminum, and organic impurities. The presence of these impurities significantly hinders the reuse of phosphogypsum. These impurities must be removed before the calcination stage (dissolving in dilute acid) to reduce their impact on subsequent products such as CaO and acid gas. Since F⁻ cannot be released from the solution, CaO is added to the liquid to allow F⁻ to exist in the solution as CaF₂ for collection and storage. In this invention, the pickling tank may be equipped with a stirring device. In this invention, a washing liquid pump may be installed on the washing liquid pipeline. In this invention, the raw material inlet may include a phosphogypsum inlet and a dilute acid inlet. In this invention, a s