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Process for decomposing gypsum through spraying and fluidizing

A spouted fluidized bed, gypsum technology, applied in the chemical industry, inorganic chemistry, sulfur compounds, etc., can solve the problems of inability to carry out industrial production, difficult operation, low device operation rate, etc., and achieve easier control and enhancement of material decomposition. Heat and mass transfer effect, the effect of large material contact area

Active Publication Date: 2014-05-28
SICHUAN HONGDA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1. Phosphogypsum is a by-product of sulfuric acid extraction of phosphoric acid. For every ton of ammonium phosphate produced, about 2.5 tons of phosphogypsum are produced. With the rapid development of my country's ammonium phosphate industry, the amount of by-product phosphogypsum is increasing, and the stacking of phosphogypsum It not only occupies a large amount of land resources, but also pollutes the atmosphere, surface groundwater and soil due to wind erosion and rain erosion, and the construction cost of phosphogypsum storage yard is also quite expensive
[0004] 2. The salt slag produced by the salt industry has been abandoned for a long time and piled up like mountains, or discharged into rivers during flood periods, causing a certain degree of environmental pollution and social hazards of land occupation
[0006] 4. A large amount of anhydrite is often discarded in gypsum mining
However, the traditional sulfuric acid co-production cement process from phosphogypsum has the following problems: coke is used as a reducing agent to decompose gypsum, and the raw material price is high, which in turn leads to high product cost; clinker is fired in the hollow kiln kiln, which is backward in the cement production process. Calcination technology, high energy consumption and low desulfurization rate; decomposition and calcination in a hollow kiln is difficult to complete in one step, serious ball and ring formation, low device operation rate, and low unit capacity
The above method is only an experimental method, because it is not a continuous reaction process, and cannot be directly industrialized. If this method is to realize industrial production, it is necessary to solve the heat balance of the first step reaction system and the inert protection of the reaction gas sulfur in the first step economically. question
Therefore, this method cannot be carried out industrialized production

Method used

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  • Process for decomposing gypsum through spraying and fluidizing
  • Process for decomposing gypsum through spraying and fluidizing
  • Process for decomposing gypsum through spraying and fluidizing

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Raw material 1: Phosphogypsum powder hemihydrate. Table 1 shows its chemical composition.

[0043] Raw material 2: sulfur (purity 99.8wt%)

[0044] Table 1 Chemical composition of phosphogypsum powder hemihydrate

[0045]

[0046] Fuel: natural gas. Table 2 shows its chemical composition.

[0047] Table 2 Chemical composition of natural gas

[0048] components

[0049] The solid sulfur is indirectly heat-exchanged with saturated water vapor in the sulfur melting tank 11 to obtain liquid sulfur at 150°C; The waste heat tail gas is subjected to indirect heat exchange, so that the liquid sulfur is gasified into sulfur vapor at 550°C, which is sent to the hot blast stove 2, and the waste heat tail gas enters the secondary cyclone preheater 8; the gypsum raw meal powder with an average particle size of 50 μm in the silo 5 is mixed with The volume ratio of the flue gas under standard conditions is 1:6000. The feeder 6 is fed into the primary cyclone preheate...

Embodiment 2

[0051] Raw material 1: desulfurized gypsum powder. Table 1 shows its chemical composition.

[0052] Raw material 2: sulfur (purity 99.8wt%)

[0053] Table 3 Chemical composition of desulfurized gypsum powder

[0054]

[0055] Fuel: Anthracite. Table 4 is its industrial analysis.

[0056] Table 4 Analysis of anthracite industry

[0057] components

[0058] The solid sulfur is indirectly heat-exchanged with saturated water vapor in the sulfur melting tank 11 to obtain liquid sulfur at 130°C; The waste heat tail gas is subjected to indirect heat exchange, so that the liquid sulfur is gasified into sulfur vapor at 450°C, which is sent to the hot blast stove 2, and the waste heat tail gas enters the secondary cyclone preheater 8; the gypsum raw meal powder with an average particle size of 120 μm in the silo 5 is mixed with The volume ratio of the flue gas under standard conditions is 1:4000. The feeder 6 is fed into the first-stage cyclone preheater 7, and the tem...

Embodiment 3

[0060] Raw material 1: salt gypsum powder. Table 5 is its chemical composition.

[0061] Raw material 2: sulfur (purity 99.8wt%)

[0062] Table 5 Chemical composition of salt gypsum powder

[0063]

[0064] Fuel: bituminous coal. Table 6 is its industrial analysis.

[0065] Table 6 Bituminous coal industry analysis

[0066] components

[0067] The solid sulfur is indirectly heat-exchanged with saturated water vapor in the sulfur melting tank 11 to obtain liquid sulfur at 130°C; The waste heat tail gas is subjected to indirect heat exchange, so that the liquid sulfur is gasified into sulfur vapor at 550°C, which is sent to the hot blast stove 2, and the waste heat tail gas enters the secondary cyclone preheater 8; the gypsum raw meal powder with an average particle size of 200 μm in the silo 5 is mixed with The volume ratio of the flue gas under standard conditions is 1:7000, fed into the first-stage cyclone preheater 7 through the feeder 6, and the temperatur...

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Abstract

The invention relates to the technical field of fluidized decomposition and calcination of gypsum, and particularly discloses a process for producing sulfuric acid by spraying, fluidizing, decomposing and calcining gypsum efficiently. The process comprises the following steps: gasifying brimstone; preheating raw gypsum; spraying, fluidizing and decomposing gypsum to prepare calcium sulfide and sulfur dioxide; preparing sulfur dioxide by calcining and decomposing the prepared calcium sulfide and heated gypsum; preparing sulfuric acid by treating the tail gas. Through the adoption of spraying and fluidizing technology, out-kiln decomposition of gypsum during acid making is realized; the calcium sulfide can be prepared efficiently with low cost; then the calcium sulfide and the preheated gypsum are calcined together for decomposition to prepare the sulfur dioxide. Therefore, the process is absolutely an excellent process for industrialized continuous production, is high in economic benefits and energy utilization ratio.

Description

technical field [0001] The invention belongs to the technical field of acid production from gypsum, and in particular relates to a fluidized out-of-kiln decomposition process of gypsum powder. The method of the invention can also simultaneously prepare sulfuric acid. Background technique [0002] With the rapid development of my country's economy, a large amount of industrial solid waste gypsum urgently needs to be digested and processed: [0003] 1. Phosphogypsum is a by-product of sulfuric acid extraction of phosphoric acid. For every ton of ammonium phosphate produced, about 2.5 tons of phosphogypsum are produced. With the rapid development of my country's ammonium phosphate industry, the amount of by-product phosphogypsum is increasing, and the stacking of phosphogypsum It not only occupies a large amount of land resources, but also pollutes the atmosphere, surface groundwater and soil due to wind erosion and rain erosion, and the construction cost of the phosphogypsum st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/77
CPCY02P20/10
Inventor 黄涛杨守明罗万林张勇韩道俊黄彦龙胡伟钟显刚王新刚杨校铃
Owner SICHUAN HONGDA
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