Novel method for producing cement sulfuric acid from phosphogypsum with calcium oxide as intermediate and sulfur as anti-clinkering agent

Abstract

The invention relates to a novel method for producing cement sulfuric acid from phosphogypsum with calcium oxide as an intermediate and sulfur as an anti-clinkering agent. The novel method comprises the following steps: (1) putting gypsum and solid sulfur after drying and mixing with a heater into a decomposing furnace for pyrolysis to obtain a solid product calcium oxide and a gas product containing sulfur dioxide; (2) putting the solid product calcium oxide and other raw materials required for cement production in proportion into a rotary kiln to prepare cement; (3) after indirectly drying gypsum by using the gas product containing sulfur dioxide, feeding the dried gypsum into a sulfuric acid workshop to produce sulfuric acid; and (4) after directly heating the gypsum by using tail gas in a cement calcining kiln, and directly carrying out evacuation through simple treatment. The main purpose of adding sulfur is to reduce a clinkering phenomenon in the decomposition process of gypsum,so that the decomposition rate of gypsum is increased, the waste heat of tail gas in the gypsum decomposing furnace can be further utilized sufficiently by using dry gypsum as a by-product in the process, and the heat efficiency in the process is improved.

Description

technical field

[0001] The invention belongs to the field of chemical industry, and relates to a new method for preparing cement sulfuric acid by using gypsum, specifically a new method for preparing cement sulfuric acid from phosphogypsum with calcium oxide as an intermediate and sulfur as an anti-sintering agent. Background technique

[0002] Phosphogypsum is a solid waste of the phosphate fertilizer industry. With the rapid development of high-concentration compound fertilizer industry in recent years, the phosphogypsum discharged by phosphate fertilizer chemical enterprises exceeds tens of millions of tons every year. As one of the main raw materials for engineering construction, cement is widely used. Reductive decomposition of phosphogypsum to produce sulfuric acid co-production of cement is one of the most effective ways to solve the environmental pollution of the phosphate fertilizer industry, reduce land occupation and effectively utilize resources.

[0003] Patent...

Examples

Embodiment 1

[0026] A new method for preparing cement sulfuric acid from phosphogypsum with calcium oxide as an intermediate and sulfur as an anti-sintering agent, comprising steps:

[0027] 1) The gypsum and solid sulfur after drying and mixing by the heater are put into the decomposition furnace to be heated and decomposed through the screw feeder. The heating temperature is 800°C, and the solid product calcium oxide and the gas product containing sulfur dioxide are obtained;

[0028] 2) The solid product calcium oxide and other raw materials required for cement production are put into the rotary kiln to make cement;

[0029] 3) The gaseous product containing sulfur dioxide is indirectly dried on the gypsum by an isolated heater, and then sent to the sulfuric acid workshop to produce sulfuric acid. The gypsum in the isolated heater is stirred by a screw auger.

[0030] 4) The tail gas from the cement kiln is directly heated to the gypsum, then filtered and emptied.

Embodiment 2

[0032] A new method for preparing cement sulfuric acid from phosphogypsum, comprising steps:

[0033] 1) The gypsum and solid sulfur after being dried and mixed by the heater are put into the decomposition furnace to be heated and decomposed through the screw feeder. The heating temperature is 750°C, and the solid product calcium oxide and the gas product containing sulfur dioxide are obtained;

[0034] 2) The solid product calcium oxide and other raw materials required for cement production are put into the rotary kiln to make cement;

[0035] 3) The gaseous product containing sulfur dioxide is indirectly dried on the gypsum by an isolated heater, and then sent to the sulfuric acid workshop to produce sulfuric acid. The gypsum in the isolated heater is stirred by a screw auger.

[0036] 4) The exhaust gas from the cement kiln directly heats the gypsum and then is directly emptied after simple filtration. The exhaust gas from the cement kiln directly heats the gypsum in the pr...

technical field

[0001] The invention belongs to the field of chemical industry, and relates to a new method for preparing cement sulfuric acid by using gypsum, specifically a new method for preparing cement sulfuric acid from phosphogypsum with calcium oxide as an intermediate and sulfur as an anti-sintering agent. Background technique

[0002] Phosphogypsum is a solid waste of the phosphate fertilizer industry. With the rapid development of high-concentration compound fertilizer industry in recent years, the phosphogypsum discharged by phosphate fertilizer chemical enterprises exceeds tens of millions of tons every year. As one of the main raw materials for engineering construction, cement is widely used. Reductive decomposition of phosphogypsum to produce sulfuric acid co-production of cement is one of the most effective ways to solve the environmental pollution of the phosphate fertilizer industry, reduce land occupation and effectively utilize resources.

[0003] Patent...

Examples

Embodiment 1

[0026] A new method for preparing cement sulfuric acid from phosphogypsum with calcium oxide as an intermediate and sulfur as an anti-sintering agent, comprising steps:

[0027] 1) The gypsum and solid sulfur after drying and mixing by the heater are put into the decomposition furnace to be heated and decomposed through the screw feeder. The heating temperature is 800°C, and the solid product calcium oxide and the gas product containing sulfur dioxide are obtained;

[0028] 2) The solid product calcium oxide and other raw materials required for cement production are put into the rotary kiln to make cement;

[0029] 3) The gaseous product containing sulfur dioxide is indirectly dried on the gypsum by an isolated heater, and then sent to the sulfuric acid workshop to produce sulfuric acid. The gypsum in the isolated heater is stirred by a screw auger.

[0030] 4) The tail gas from the cement kiln is directly heated to the gypsum, then filtered and emptied.

Embodiment 2

[0032] A new method for preparing cement sulfuric acid from phosphogypsum, comprising steps:

[0033] 1) The gypsum and solid sulfur after being dried and mixed by the heater are put into the decomposition furnace to be heated and decomposed through the screw feeder. The heating temperature is 750°C, and the solid product calcium oxide and the gas product containing sulfur dioxide are obtained;

[0034] 2) The solid product calcium oxide and other raw materials required for cement production are put into the rotary kiln to make cement;

[0035] 3) The gaseous product containing sulfur dioxide is indirectly dried on the gypsum by an isolated heater, and then sent to the sulfuric acid workshop to produce sulfuric acid. The gypsum in the isolated heater is stirred by a screw auger.

[0036] 4) The exhaust gas from the cement kiln directly heats the gypsum and then is directly emptied after simple filtration. The exhaust gas from the cement kiln directly heats the gypsum in the pr...