CN101423203B

CN101423203B - Water-saving and emission-reducing wet method phosphoric acid manufacture process

Info

Publication number: CN101423203B
Application number: CN2008100689875A
Authority: CN
Inventors: 喻爱民; 李龙; 程绪鑫
Original assignee: Guizhou Kailin Group Co Ltd
Priority date: 2008-11-13
Filing date: 2008-11-13
Publication date: 2011-12-07
Anticipated expiration: 2028-11-13
Also published as: CN101423203A

Abstract

The invention discloses a wet-process phosphoric acid production process used for saving water and reducing exhaust, relating to a process which produces the wet-process phosphoric acid by a dehydrate method. The process comprises the steps as follows: qualified pulp is concentrated and filtrated; part of the filtrated mineral powder is conveyed to a metering auger by a belt conveyor and subsequently added into a mixed trough; the other part of the filtrated mineral powder is stored in a mineral powder bin; the mineral powder which enters the mixed trough is reacted with return phosphoric acid of the wet-process phosphoric acid and washed water under stirring and sent to a wet-process phosphoric acid extraction reaction trough by a pump; the dilute phosphoric acid is prepared according to the traditional method; the water separated by a filter is sent to a wet grinder, and is measured and mixed with phosphate ore, and then the mixture is grinded in a grinding machine and repeatedly used. The production process has the advantages that (1) a great amount of supplemented water of ore grinding part is saved, the drained water quantity is greatly reduced; (2) the pulp storage equipment is not needed completely, the energy resource consumption and burdensome labor consumption are reduced; and (3) the production capacity of the phosphoric acid is about 16-30 percent, furthermore, compared with the original process, the change of the investment of the process is little.

Description

A kind of wet method phosphoric acid manufacture process of water-saving and emission-reducing

Technical field

The present invention is relevant with phosphoric acid, and is particularly, relevant with the technology that adopts dihydrate process production phosphoric acid by wet process.

Technical background

Wet-process Phosphoric Acid Production is the most ripe, technology is to adopt phosphorus ore and sulfuric acid through producing the technology of dilute phosphoric acid behind reaction, extraction and the filtering separation dihydrate gypsum the most widely, and uniserial industrial scale has reached 1000t/a100%P ₂O ₅The sewage that production process of phosphoric acid produces is the main sewage discharge source of phosphatic fertilizer company, its sewage discharge accounts for 50%～80% of phosphatic fertilizer company total amount, the large-scale phosphatic fertilizer company that particularly adopts ore pulp to produce, because ore pulp is brought a large amount of water into, its blowdown flow rate more is difficult to control.Improvement at wet method phosphoric acid manufacture process, some relevant patent applications have appearred, for example No. 92108530.3 " flushing cinder water closed circulation process for continuously thickening gold in the phosphoric acid by wet process filter ", No. 96115617.1 " utilizing phosphoric acid extraction, secondary decomposing phosphate rock novel process ", 97115189.X number " a kind of novel process of phosphoric acid by wet process ", No. 01138286.4 " a kind of process for preparing wet phosphoric acid by dihydrate method " etc.Though these inventions have some effects, and isorrheic problem in the unresolved technology.

The ore pulp that existing wet milling obtains moisture 30%～50%.After ore pulp was brought a large amount of water into the Wet-process Phosphoric Acid Production system, just must reduce the phosphorus-containing wastewater that certainly leads in the technology was back to the amount of production system, and was difficult to control, particularly was difficult to realize the balance of process water.Thus can be to producing following influence: the one, the phosphoric acid washing water consumption reduces, wash insufficient, the water-soluble residual phosphorus increase of phosphogypsum; The 2nd, dilute phosphoric acid concentration reduces, and throughput descends, and the Phosphoric Acid Concentration steam consumption increases; The 3rd, the system water imbalance, quantity of wastewater effluent strengthens, and increases environmental protection risk and cost of sewage disposal.

Summary of the invention

Purpose of the present invention just is to provide a kind of wet method phosphoric acid manufacture process of water-saving and emission-reducing, to overcome the defective of prior art, saves the consumption of water and reduces quantity discharged, improves the throughput of phosphoric acid.

The contriver studies at the water balance problem that troubles Wet-process Phosphoric Acid Production for a long time, under the prerequisite of advantages such as acting on that the wet grinding mill flow process is simple, equipment is few, ground phosphate rock need not be dry, save the energy, eliminate dust pollution, fall end grinding machine noise, reduce the phosphorus loss, maintenance load is few to ore grinding after system process redesign, reduce the water content in the breeze to greatest extent, be beneficial to the production of phosphoric acid by wet process, solve the water balance problem that troubles Wet-process Phosphoric Acid Production from the source.The wet method phosphoric acid manufacture process of the water-saving and emission-reducing that the contriver provided is before the phosphorus ore slurry enters extraction tank, and ore pulp is carried out following pre-treatment:

The ore pulp that phosphorus ore and water form after wet wheeling machine grinds, separate through cyclone separator, underproof coarse particles is discharged from the swirler bottom and is reentered the grinding machine grinding, the qualified ore pulp for moisture 50% that discharge at the swirler top enters Hhigh-efficient thickener and carries out densely, is pumped to filter then to filter; Breeze after the filtration, a part is transported to the breeze hopper through belt, is delivered to metering screw through disk feeder, and the metering back adds tempering tank; Another part breeze is then delivered to the breeze warehousing and is deposited, and when grinding system is shut down, to rotary conveyor, delivers to tempering tank with the driving grasping operation then; Enter the breeze of tempering tank and under the stirring action of tempering tank agitator, react, be sent by pumping to phosphoric acid by wet process extractive reaction groove, extract, produce dilute phosphoric acid according to traditional method from rephosphorization acid, the washing water of phosphoric acid by wet process; The water that filter is separated is pumped to wet wheeling machine after collecting, be mixed into grinding machine with phosphorus ore after metering and grind, and reuses.

Above-mentioned filter is ceramic filter or turntable type filter or band filter, can be provided with one according to throughput, or many is arranged in parallel; Can independently move, also many operations simultaneously.

Used breeze granularity is-200 orders～60 orders in the said process; Breeze after the filtration is moisture less than 10%; Entering the tempering tank material is 60%～75% through the slip solid content that reaction forms.

The wet method phosphoric acid manufacture process advantage of water-saving and emission-reducing provided by the invention is: 1. because the water separated returns the grinding that grinding machine participates in phosphorus ore again, so the water yield that ore grinding partly replenishes saves in a large number, and the water yield of discharging also reduces significantly; 2. do not need the ore pulp bunkerage fully, can reduce required consumption was stored and stirred to ore pulp a large amount of energy and the unexpected onerous toil consumption such as causing the necessary clear groove of breeze precipitation that has a power failure greatly; 3. combine with Wet-process Phosphoric Acid Production, can improve phosphoric acid production ability about 16%～30%; And compare with former technology, investment changes little.

Description of drawings

Accompanying drawing 1 is a system process block diagram behind the ore grinding of wet method phosphoric acid manufacture process of water-saving and emission-reducing of the present invention, and Fig. 2 is a process flow sheet.Among the figure, 1 is thickener, and 2 is the ore pulp transferpump, 3 is the ore pulp header tank, and 4 is ceramic filter, and 5,6 is rotary conveyor, 7 is tempering tank, 8 is the slip transferpump, and 9 is the ore pulp overflow groove, and 10 are overflow ore pulp pump, 11 is the water accumulator tank, 12 for reclaiming water pump, and 13 is thickener water accumulator tank, and 14 are thickener recovery water pump.

Embodiment

Embodiment 1 as the ore grinding of the wet method phosphoric acid manufacture process of accompanying drawing after system process, the ore pulp that phosphorus ore and water form after wet wheeling machine grinds, separate through cyclone separator, underproof coarse particles is discharged from the swirler bottom and is reentered the grinding machine grinding, the qualified ore pulp for moisture 50% that discharge at the swirler top enters Hhigh-efficient thickener 1 and carries out dense, deliver to the header tank 3 of filter 4 then with ore pulp transferpump 2, be lowered into filter 4 and filter; Breeze after the filtration, a part to the breeze hopper, is delivered to metering screw through disk feeder through rotary conveyor 5,6, and the metering back adds tempering tank 7; Another part breeze is then delivered to the breeze bunker and is stored, and when grinding system is shut down, to rotary conveyor 6, delivers to tempering tank 7 with the driving grasping operation then; Enter the breeze of tempering tank 7 and under the stirring action of tempering tank 7 agitators, react, deliver to phosphoric acid by wet process extractive reaction groove, extract, produce dilute phosphoric acid according to traditional method by slip transferpump 8 from rephosphorization acid, the washing water of phosphoric acid by wet process; The water that filter 4 is separated enters ore pulp overflow groove 9 after collecting, deliver to wet wheeling machine with overflow ore pulp pump 10, is mixed into grinding machine with phosphorus ore after metering and grinds, and reuses.

After the enforcement, compare, mainly contain the effect of following aspect: 1. water saving: implement the back and economize on water about more than 80% than existing technology with existing manufacturing technique; 2. improve gypsum washing rate, reduce the residual phosphorus of phosphogypsum, the washing rate can improve 0.5%～1%, and the corresponding residual phosphorus of phosphogypsum can descend 0.5%, and phosphorous recovery improves greatly; 3. dilute phosphoric acid concentration can be stablized and is increased to 17%～28%, saves steam more than 50%; 4. reduce quantity of wastewater effluent 80%, save the sewage disposal expense greatly; 5. operation is simple more, reliable; 6. can store a large amount of ground phosphate rock and not need consumes energy; 7. improve throughput 16%～30%; 8. improve the phosphogypsum crystal effect, be the thick gypsum crystal of growing, improving intensity filter provides soft terms to play promoter action.

Claims

1. the wet method phosphoric acid manufacture process of a water-saving and emission-reducing, it is characterized in that this technology is before the phosphorus ore slurry enters extraction tank, ore pulp is carried out following pre-treatment: the ore pulp that phosphorus ore and water form after wet wheeling machine grinds, separate through cyclone separator, underproof coarse particles is discharged from the swirler bottom and is reentered the grinding machine grinding, the qualified ore pulp for moisture 50% that discharge at the swirler top enters Hhigh-efficient thickener and carries out densely, pumps into filter then to filter; Breeze after the filtration, a part is transported to the breeze hopper through belt, is delivered to metering screw through disk feeder, and the metering back adds tempering tank; Another part breeze is then delivered to the breeze warehousing and is deposited, and when grinding system is shut down, to rotary conveyor, delivers to tempering tank with the driving grasping operation then; Enter the breeze of tempering tank and under the stirring action of tempering tank agitator, react,, extract, produce dilute phosphoric acid according to traditional method by pumping into phosphoric acid by wet process extractive reaction groove from rephosphorization acid, the washing water of phosphoric acid by wet process; The water that filter is separated is after collecting, and pump is mixed into grinding machine with phosphorus ore after metering and grinds to wet wheeling machine, reuses.

2. according to the described production technique of claim 1, it is characterized in that described filter is ceramic filter or turntable type filter or band filter; One or more is set is arranged in parallel; Independent operating or many operations simultaneously.

3. according to the described production technique of claim 1, it is characterized in that used breeze granularity is-200 orders～60 orders; Breeze after the filtration is moisture less than 10%; The material that enters tempering tank is 60%～75% through the slip solid content that reaction forms.