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Reductive decomposition method of phosphogypsum by microwave process

A technology of phosphogypsum and microwave method, which is applied in the field of microwave chemistry, can solve the problems of limiting the utilization value of decomposition tailings and poor gypsum decomposition effect, and achieve the effects of reducing drying time, improving drying efficiency, and improving economic benefits

Active Publication Date: 2017-03-08
KUNMING METALLURGY INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention relies on high concentrations of SO produced by sulfur reactions 2 Sulfuric acid production, gypsum decomposition effect is not good, thus limiting the utilization value of decomposition tailings

Method used

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  • Reductive decomposition method of phosphogypsum by microwave process
  • Reductive decomposition method of phosphogypsum by microwave process
  • Reductive decomposition method of phosphogypsum by microwave process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] A microwave reaction device with an effective volume of 50 L was designed for the reduction and decomposition of phosphogypsum. The material is placed in the reaction chamber 1, and an appropriate amount of air is blown in by the air pump 7 to maintain the weak reducing atmosphere of the reaction system. The gas after the reaction is discharged from the reactor through the gas outlet 2 through the flue gas pipe 5; the powder of the phosphogypsum material is relatively fine, and the reduction During the decomposition process, the stirring paddle 6 is used to mix the materials intermittently to complete a sufficient reaction, and after the reaction is completed, the roasted slag is taken out for subsequent processing.

[0039] Mix phosphogypsum and coke in proportion according to the mass ratio of 1:0.06, and add wave-absorbing auxiliary materials and mineralizers. The wave-absorbing auxiliary materials account for 5% of the total mass of the mixture, including iron oxide,...

Embodiment 2

[0041] Using the same microwave reaction device as in Example 1, the proportion of reduced coal, the drying process and the process flow are also exactly the same as in Example 1. The microwave-absorbing auxiliary materials account for 4% of the total mass of the mixture, including iron oxide, activated alumina, and ferrite, which are 45%, 45%, and 10% of the active materials, respectively. The amount of mineralizer added is 4% of the total weight of the mixture. The mineralizers include fluorite, cryolite and magnesium oxide, accounting for 40%, 40% and 20% of the composite mineralizer respectively. Phosphogypsum was dried for 20 min at a microwave output frequency of 915 MHz to remove moisture; after sieving with a 200-mesh sieve, 20 kg of dried phosphogypsum mixture was sent to the reaction chamber of the decomposition device, and the microwave output frequency was 2450 MHz, 1000 ℃ reduction decomposition for 45 min, take out the roasted slag, its XRD pattern is shown in ...

Embodiment 3

[0043] Using the same microwave reaction device as in Example 1, the proportion of reduced coal, the drying process and the process flow are also exactly the same as in Example 1. The microwave-absorbing auxiliary materials account for 6% of the total mass of the mixed materials, including iron oxide, activated alumina, and activated silica, which are 45%, 45%, and 10% of the active materials, respectively. The addition amount of the mineralizer is 3% of the total weight of the mixture, and the mineralizer includes fluorite and cryolite, accounting for 50% and 50% of the composite mineralizer respectively. Phosphogypsum was dried for 18 minutes under the microwave output frequency of 2450MHz to remove moisture; after sieving with a 180-mesh sieve, 20 kg of dried phosphogypsum mixture was sent to the reaction chamber of the decomposition device, and the microwave output frequency was 2450MHz. MHz, 950°C reduction decomposition for 60 min, the roasted slag was taken out, its XRD...

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Abstract

The invention discloses a reductive decomposition method of phosphogypsum by a microwave process. The method comprises the following steps: A. pretreatment; B. proportioning; and C. phosphogypsum decomposition. The microwave drying technique is adopted to effectively lower the energy consumption, shorten the drying time and enhance the drying efficiency. The wave-absorbing auxiliary material is added to enhance the wave-absorbing property of the raw material, and thus, microwave direct heating and silicon carbide or graphite reactor assisted heating are adopted to ensure the heating efficiency, thereby effectively solving the problem of poor raw material wave-absorbing property in the wave heating process. Compared with the traditional technique in which the phosphogypsum decomposition temperature is up to 1250-1300 DEG C, the phosphogypsum decomposition temperature in the microwave technique is lowered to 950-1000 DEG C (by about 300 DEG C). The microwave heating mode obviously lowers the energy consumption in the phosphogypsum decomposition process, and enhances the economic benefits of the phosphogypsum recycling technique.

Description

technical field [0001] The invention belongs to the technical field of microwave chemistry, and relates to a method for reducing and decomposing phosphogypsum by microwave method with simple structure and convenient use. Background technique [0002] Phosphogypsum is a by-product of the wet-process phosphoric acid production process. It is a typical bulk solid waste, and its stacking volume has exceeded 300 million tons. The increasing production and discharge of phosphogypsum has seriously affected the sustainable development of the environment, and its comprehensive treatment and disposal has become an important problem to be solved urgently in the phosphorus chemical industry. However, due to the complex chemical composition and stable properties of phosphogypsum, there are problems in varying degrees in its resource utilization technology. Although a large number of experimental studies have been carried out at home and abroad, the industrial application of phosphogypsu...

Claims

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Application Information

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IPC IPC(8): C01B17/50C01F11/08C01B17/44C01B33/24C01B32/70
CPCC01B17/44C01B17/506C01B33/24C01F11/08C01P2002/72
Inventor 王少龙谢容生金自钦彭秋燕谢天鉴谢菱芳任帅鹏赵晖
Owner KUNMING METALLURGY INST
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