CN102557386A

CN102557386A - Sludge disposal method for circulating water of coal gas station of alumina plant

Info

Publication number: CN102557386A
Application number: CN2010105791260A
Authority: CN
Inventors: 龙智春
Original assignee: CHINA ALUMINUM INTERNATIONAL TECHNOLOGY DEVELOPMENT Co Ltd
Current assignee: CHINA ALUMINUM INTERNATIONAL TECHNOLOGY DEVELOPMENT Co Ltd
Priority date: 2010-12-09
Filing date: 2010-12-09
Publication date: 2012-07-11

Abstract

The invention discloses a sludge disposal method for the circulating water of a coal gas station of an alumina plant. The method comprises the following steps that: a coagulant and a coagulant aid are added into the washing dedusting cooling water of the coal gas station of the alumina plant in a water return ditch (1); the water enters a horizontal flow sedimentation tank (2) through the water return ditch (1); after coagulating sedimentation, the supernate enters a water outlet channel (3) for recycling; the sludge produced by the coagulating sedimentation of the horizontal flow sedimentation tank (2) is conveyed by a submersible sewage pump (4) to a triple-wash hydraulic mixing tank (6) of a red mud settling separation and washing section of the alumina plant through a sludge pipe (5), and enters a red mud disposal system; and finally, the sludge and the red mud are finally conveyed together to a red mud storage yard for storage. The coagulating sedimentation time of the horizontal flow sedimentation tank (2) is not less than 3 hours. As a sludge disposal system is not arranged for the circulating water of the coal gas station, environmental pollution is reduced, the land occupation and investment are saved, the operation cost and energy consumption are reduced, and relatively high environmental and economic benefits are obtained.

Description

Alumina producer gas station Sludge in Circulating Water method of disposal

Technical field

The present invention relates to the method for disposal of a kind of alumina producer gas station Sludge in Circulating Water, belong to alumina producer gas station circulating water treatment technology field.

Background technology

Aluminium hydroxide roasting operation in the process for making alumina adopt gas suspending calcining furnace that Aluminium hydroxide roasting is become qualified alumina product, and the required fuel of stoving oven is producer gas.Aluminum oxide unit product producer gas consumption is 550～750 Nm ³/ t-Al ₂O ₃, and the required gas washing quantity of circulating water of unit producer gas is 0.02～0.05m ³/ Nm ³The alumina producer gas station generally adopts the technical process of hard coal single hop stove cooled coal gas, and three grades of purification systems are adopted in gas purification, and the first step is 1 two vertical tube of every gas furnace configuration, and second and third grade is the washing tower and the wet cottrell of centralized arrangement.Alumina producer gas station recirculated water is mainly supplied with the scrubbing dust collection cooling water of equipment such as two vertical tubes, washing tower, wet cottrell of gas cleaning system; The gas purification circulating washing water is except that containing solid impurity (suspended substance); Also have a spot of volatile phenol, ammonia nitrogen, prussiate, sulfide, COD, BOD etc.; Therefore, need recycle after handling gas washing dedusting cooling water.Horizontal sedimentation tank one-level processing technological flow is adopted in the gas station circulating water treatment mostly; The main processing object is a suspended substance; Clearance is about 50%～80%; Sludge treatment then adopt grab crane with mud grab carry out the nature mummification to sludge drying bed after, be transported to automobile again and the outer stockyard that is transported to stores.The suspended substance that contains fines in the gas washing dedusting water coolant; Mud proportion behind coagulating sedimentation is little; High and the difficult dehydration of water ratio; Adopt grab bucket that mud and water are grabbed to the sludge drying bed that artificial filtering layer is set together, moisture is difficult for from thick sludge blanket, separating natural mummification poor effect.

Sludge treatment usually adopts following two kinds of methods: the one, mud is carried out after gravity concentrates at concentration basin; Get into sludge drying bed and carry out the nature mummification; Be transported to automobile and outer with artificial or machinery from drying bed again and be transported to the stockyard storage; Shortcomings such as this method exists floor space big, and sanitary condition is poor, and level of automation is low; The 2nd, mud is concentrated the back carry out mechanical dehydration with dewatering machine such as belt filter press, chamber-type press filter, centrifuge etc.; Filter cake after the dehydration is transported to the stockyard outward with automobile and stores; This method exists the mechanical means investment bigger, safeguards and the more high shortcoming of working cost.More than two kinds of methods all need automobile as transportation means, and the ultimate disposal mode is the stockyard and stores.

In the alumina producer production technique, the waste residue that bauxite produces after operations such as stripping, separation (red mud) after operations such as sedimentation, separation and washing, or is directly stored up to red mud dump with pump delivery, or stores up with delivering to red mud dump again after the filter filtration.Produce 1 ton of aluminum oxide and need about 600 Nm of producer gas ³, need the about 18m of gas washing recirculated water ³, by suspension content 1000mg/L, sludge quantity is about 0.018 ton, produces about 1.2 tons of red muds simultaneously, i.e. and the sludge quantity of gas station recirculated water generation has only 1.5% of red mud amount.According to factors such as the character of gas station Sludge in Circulating Water, flows through technical economical analysis; Mud is disposed after red mud mixes; Can not exert an influence to process for making alumina and red mud treatment system, therefore, the present invention proposes the new method of disposal of a kind of alumina producer gas station Sludge in Circulating Water; The mud that is about to gas station recirculated water generation mixes with red mud with the three wash water power tempering tanks of pump delivery to red-mud settlement separation and washing room; Behind washing and filtering, finally deliver to red mud dump and store up, the environmental pollution of having avoided carrying out sludge treatment separately and produced, take up an area of big, technical barriers such as investment is many, maintenance management inconvenience at gas station recirculated water.

Summary of the invention

The technical problem that the present invention will solve is: a kind of alumina producer gas station Sludge in Circulating Water method of disposal is provided, and the occupation of land that exists in the prior art is big, investment is many to overcome, maintenance management bothers or the like deficiency.

The present invention is achieved in that alumina producer gas station scrubbing dust collection cooling water dosing coagulant and coagulant aids in backwater ditch 1; Get into horizontal sedimentation tank 2 through backwater ditch 1; Supernatant behind coagulating sedimentation gets into out water channel 3 and recycles; The mud that produces through horizontal sedimentation tank 2 coagulating sedimentation is transported to three wash water power tempering tanks 6 of the settlement separate and washing room of red mud for alumina plant through sludge pipe 5 with proof submersible sand discharging pump 4; Get into the red mud disposal system, finally be transported to red mud dump and store up with red mud.

The coagulating sedimentation time at horizontal sedimentation tank 2 is no less than 3 hours.。

The invention has the beneficial effects as follows: can solve the environmental pollution carrying out sludge treatment separately and produced at gas station recirculated water, take up an area of big, technical barriers such as investment is many, maintenance management inconvenience.

Description of drawings:

Fig. 1 is a schematic flow sheet of the present invention.

Embodiment:

Embodiments of the invention: at first, alumina producer gas station scrubbing dust collection cooling water and in backwater ditch 1 dosing coagulant and coagulant aids, get into horizontal sedimentation tank 2 through backwater ditch 1.

The horizontal flow velocity of horizontal sedimentation tank 2 is not more than 5mm/s, and the ST is no less than 3 hours, and long-width ratio is not less than 4, and length-depth ratio is not less than 8.

Secondly, the supernatant behind coagulating sedimentation gets into out water channel 3 and recycles.

Then, the mud that horizontal sedimentation tank 2 deposition is produced is transported to three wash water power tempering tanks 6 of the settlement separate and washing room of red mud for alumina plant through sludge pipe 5 with proof submersible sand discharging pump 4.Residual sea water pump can adopt dry type to install, and promptly is contained in outside the horizontal sedimentation tank; Also can adopt wet type to install, be about to pump and directly be contained in the horizontal sedimentation tank.The flow of residual sea water pump confirms according to the design sludge quantity, and to add the upper edge journey definite with local head loss's sum with the elevation difference on waterpower tempering tank groove top at the bottom of by the horizontal sedimentation tank pond for lift.

The outlet of residual sea water pump 4 connects sludge pipe 5, and the caliber of sludge pipe 5 calculates definite according to design discharge and flow velocity.

At last, mud is mixed with red mud at the waterpower tempering tank, behind washing and filtering, finally deliver to red mud dump and store up.

Claims

1. alumina producer gas station Sludge in Circulating Water method of disposal; It is characterized in that: alumina producer gas station scrubbing dust collection cooling water is dosing coagulant and coagulant aids in backwater ditch (1); Get into horizontal sedimentation tank (2) through backwater ditch (1); Supernatant behind coagulating sedimentation gets into out water channel (3) and recycles; The mud that produces through horizontal sedimentation tank (2) coagulating sedimentation is transported to three wash water power tempering tanks (6) of the settlement separate and washing room of red mud for alumina plant with proof submersible sand discharging pump (4) through sludge pipe (5), and entering red mud disposal system finally is transported to red mud dump with red mud and stores up.

2. alumina producer according to claim 1 gas station Sludge in Circulating Water method of disposal, it is characterized in that: the coagulating sedimentation time at horizontal sedimentation tank (2) is no less than 3 hours.