Method for producing phosphoric acid by utilizing middle grade phosphate ore

A technology of phosphate rock and phosphoric acid, applied in the direction of phosphoric acid, phosphorus oxyacid, etc., can solve the problems of ring formation and blockage of tail gas pipelines, achieve the effects of solving ring formation and blockage, reducing CO gas consumption, and reducing coal consumption

Inactive Publication Date: 2011-07-20
SICHUAN UNIV
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Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies of the existing rotary kiln technology, to provide a method for producing phosphoric acid with medium-grade phosphate rock, to solve the problem of P in the gas phase. 2 o 5 The problem of ring formation and blockage in the rotary kiln and tail gas pipeline caused by the generation of metaphosphoric acid with water vapor, and improve the heat utilization rate

Method used

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  • Method for producing phosphoric acid by utilizing middle grade phosphate ore
  • Method for producing phosphoric acid by utilizing middle grade phosphate ore
  • Method for producing phosphoric acid by utilizing middle grade phosphate ore

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Embodiment 1

[0023] In the present embodiment, the method for producing phosphoric acid is as follows:

[0024] (1) Preparation of pellets with a double-layer composite structure. The raw materials of the inner layer pellets include medium-grade phosphate rock powder, coal powder and silica powder, and the chemical composition (both percentages by weight) of the medium-grade phosphate rock powder is: P 2 o 5 20.6%, CaO 25.8%, SiO 2 46.9%; the chemical composition of coal dust (both percent by weight) is: fixed carbon 77.9%, ash 17.4% (wherein SiO 2 84.3%, Fe 2 o 3 8.3%, CaO 2.0%); SiO in silica powder 2 The content is 95.3% (percentage by weight). When batching, the pulverized coal is based on the P in the phosphate rock 2 o 5 Measure 1.5 times of the theoretical amount of fixed carbon required for reduction, and the silica powder is based on the SiO contained in the three raw materials of medium-grade phosphate rock powder, coal powder and silica powder. 2 / CaO=3 (molar ratio)...

Embodiment 2

[0036] (1) prepare the material ball of double-layer composite structure, raw material and its proportioning and operation are with embodiment 1;

[0037] (2) Feed the material balls into the rotary kiln continuously from the tail of the rotary kiln at a speed of 220kg / h, and continuously feed CO gas into the rotary kiln from the head of the rotary kiln, and its speed varies with the oxygen concentration in the oxygen-enriched air , the dehydrated oxygen-enriched air is preheated to 550°C and then continuously input to the rotary kiln from the head of the rotary kiln. The theoretical oxygen required for complete combustion is calculated by 10% excess. In the rotary kiln, the high-temperature gas generated by the combustion of CO gas and the balls run in reverse to exchange heat. The balls are heated to a reaction temperature of 1300°C to 1350°C in the main reaction section, and the residence time of the balls in the main reaction section is at least 40 minutes. P 2 o 5 Exha...

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Abstract

The invention discloses a method for producing phosphoric acid by utilizing middle grade phosphate ore, comprising the following steps: (1) preparing a double-layer composite structure pellet containing the middle grade phosphate ore, wherein, the water content of the pellet is less than or equal to 0.5wt%; (2) sending the pellet into a rotary kiln from the tail part of the rotary kiln; delivering the carbon monoxide (CO) coal gas, dehydration air or dehydration oxygen-enriched air into the rotary kiln from the head part of the rotary kiln; carrying out heat exchanging on the high-temperaturegas generated in burning of the CO coal gas and the pellet in reversed operation in the rotary kiln; heating the pellet to the reaction temperature of 1250-1400 DEG C; carrying out heat exchanging onthe tail gas containing P2O5 generated in reaction and the pellet entering into the rotary kiln; cooling to the temperature of 600-650 DEG C, and leading out from the tail part of the rotary kiln; and (3) dedusting the tail gas containing the P2O5 led out from the rotary kiln; and absorbing P2O5 by utilizing recycle acid to prepare the phosphoric acid.

Description

technical field [0001] The invention belongs to the field of phosphoric acid produced by kiln method, in particular to a process for producing phosphoric acid from medium-grade phosphate rock. Background technique [0002] The technical core of kiln-process phosphoric acid is to use the heat of phosphorus combustion reaction for the reduction of phosphate ore. It uses less electricity and no acid, and can directly use medium-grade phosphate ore, especially suitable for high-silicon ore that is difficult to beneficiate. As early as the 1930s, the United States began to carry out the kiln-process phosphoric acid process test with the rotary kiln as the main reaction equipment. ) completed the intermediate test (US Patent No. 4389384, 4351813, 7378070). In the mid-to-late 1980s, our country also began to carry out technical research on kiln-process phosphoric acid. The tunnel kiln process (Chinese patent ZL 89100292.8) represented by Jiang Shanxiang, Design Institute of Nanjin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/18
Inventor 梁斌李春吕莉邱礼有王黎明吴潘蒋炜
Owner SICHUAN UNIV
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