A kind of chloride process titanium dioxide high-salt wastewater method of comprehensive utilization
Technical field
The invention belongs to comprehensive utilization of resources field, be specifically related to a kind of chloride process titanium dioxide high-salt wastewater method of comprehensive utilization.
Background technology
Titanium dioxide is a kind of white inorganic pigment, there is best opacity, best whiteness and luminance brightness and the characteristic such as nontoxic, being recognized is the white pigment that performance is best in the world at present, is widely used in the industry such as coating, plastics, papermaking, printing-ink, chemical fibre, rubber, makeup.TiCl
4be the raw material producing titanium sponge and titanium dioxide, its production technique mainly contains fluidizing chlorination method and fused salt chlorimation method.Fluidizing chlorination method utilizes the compound of titanium slag and refinery coke in fluidizing furnace and Cl
2under gas is in fluidised state, reaction generates TiCl
4.Fused salt chlorimation method is suspended in fused-salt medium titanium slag and refinery coke, and Cl
2solid/liquid/gas reactions generates TiCl
4.
Aforesaid method is adopted often to produce 1tTiCl
4, about output dust-slag collection 200kg, waste hydrochloric acid 550 ~ 650kg, lower concentration sodium hypochlorite waste water 500kg.Containing a large amount of muriate in these refuses; At present, send slag field landfill after solidifying to dust-slag collection, waste hydrochloric acid underflow and lime slurry neutralization, residue chloride containing calcium is that main high-salt wastewater recycles.At production TiCl
4process in tail gas contain a small amount of chlorine, adopt liquid caustic soda drip washing to produce a large amount of lower concentration sodium hypochlorite waste water, this waste water is low containing available chlorine, and based on sodium-chlor and sodium bicarbonate, salinity is high, does not have good utility value.
As a kind of fine inorganic chemicals pigment, there is certain defect in titanium dioxide, needs to carry out surface treatment.At present, the technique that Rutile type Titanium Dioxide inorganic coating is more ripe mainly contains sial coating, zirconium aluminium coating and single aluminium coating.Coating reagent is mainly containing sulfate ion, chlorion etc.Titanium dioxide after coating needs de-salted water to wash, and thus can produce a large amount of containing sulfate radicals and the washes of chlorion, can direct qualified discharge after the mixing of this part waste water.But a large amount of water is not recycled, and is unfavorable for enterprise clean production, energy-saving and emission-reduction.
Summary of the invention
To be solved by this invention is low cost can not make full use of the technical problem of chloride process titanium dioxide height calcium salt waste water, high sodium salt, protosulfate waste water in prior art, a kind of chloride process titanium dioxide high-salt wastewater method of comprehensive utilization is provided, the method processing costs is low, can make full use of chloride process titanium dioxide height calcium salt, high sodium salt, protosulfate waste water, and part utilizes by-product hydrochloric acid and produces the underflow waste of hypo.
The present invention solve the technical problem adopted technical scheme:
Chloride process titanium dioxide high-salt wastewater method of comprehensive utilization, comprises the following steps:
The pre-treatment of a, lower concentration sodium hypochlorite waste water
TiCl will be produced
4the lower concentration sodium hypochlorite waste water of output in advance with the discarded underflow process 15 ~ 45min producing hypo, then is reacted to pH=1 ~ 3 with by-product hydrochloric acid, is finally adjusted to pH=6 ~ 9 with 20% liquid caustic soda, produces the waste water of saliferous mass percentage 10 ~ 35%;
The preparation of b, sodium sulfate wastewater
The waste water that step a is produced and the waste water being mixed with contains sodium sulfate mass percentage 5 ~ 20%, sodium-chlor mass percentage 5 ~ 20% through concentrated titanium dioxide washes according to the mass ratio of 1:1 ~ 1:3;
Producing of c, gypsum
Gained waste water in step b is added in calcium chloride solution, fully filters after reaction, obtain gypsum product through washing and drying process; Described calcium chloride solution obtains after being the acid waste water that produces of fused salt chlorimation and fluidizing chlorination with lime slurry neutralization to pH=6 ~ 9, and wherein the mass percentage of calcium chloride is greater than 12%, and the mass percentage of sodium-chlor is less than 5%;
D, evaporative crystallization sodium-chlor
Direct for step c gained filtrate evaporative crystallization sodium-chlor is back to fused salt chlorimation supply salt.
Further, the sodium hypochlorite waste water of lower concentration described in step a is that TiCl is produced in 20% liquid caustic soda drip washing
4tail gas produce containing Na
2sO
4mass percentage is not more than 2%, NaHCO
3mass percentage is greater than 6%, NaClO mass percentage and is not more than the waste water that 2%, NaCl mass percentage is greater than 5%.
Further, the discarded underflow of hypo described in step a produces the refuse in hypo product process, wherein Na
2sO
4mass percentage be greater than 85%, Na
2sO
3mass percentage is not more than 10%, Na
2s
2o
3mass percentage is not more than 5%.
Further, in step a, the add-on of hypo underflow is NaClO:(Na
2sO
3+ 1/4Na
2s
2o
3) mol ratio=1:1.
Further, by-product hydrochloric acid described in step a is TiCl
4in production process, water wash tail gas produces, and HCl mass percentage is not less than 10%.
Further, in step a, by-product hydrochloric acid add-on is NaHCO
3: HCl mol ratio=1:1.05.
Further, the waste water in step a after liquid caustic soda process is containing Na
2sO
4mass percentage be less than 20%, NaCl mass percentage and be less than 22%.
Further, the titanium dioxide washes through concentrating in step b is the waste water that titanium dioxide first produces after inorganic agent process, wherein Na
2sO
4mass percentage is less than 2%, NaCl mass percentage is less than 1%, then after film process, Na in waste water
2sO
4mass percentage 6 ~ 10%, NaCl mass percentage 2 ~ 5%;
Further, step a waste water and the preparation mass ratio=1:2 through concentrated titanium dioxide washes in step b.
Further, in step c, in step b, the add-on of gained waste water is sodium sulfate amount of substance: calcium chloride amount of substance=1.2:1 ~ 1:1.
Further, evaporative crystallization described in steps d is multiple-effect evaporation mode.
Beneficial effect of the present invention is: the protosulfate waste water taking full advantage of chloride process titanium dioxide calcium chloride wastewater, lower concentration sodium hypochlorite waste water, titanium dioxide washing generation, part utilizes by-product hydrochloric acid, hypo to produce underflow waste, produce gypsum, sodium-chlor product, the a large amount of waste water of reuse, do not introduce new water, without discharge, with low cost, and the sodium-chlor produced is back to fused salt chlorimation, solve the problem of chloride process titanium dioxide high-salt wastewater high investment low value, economic benefit and social benefit are very remarkable, have good promotion prospect.
Embodiment
Chloride process titanium dioxide high-salt wastewater method of comprehensive utilization, comprises the following steps:
The pre-treatment of a, lower concentration sodium hypochlorite waste water
Lower concentration sodium hypochlorite waste water in advance with the discarded underflow process 15 ~ 45min producing hypo, then is reacted to pH=1 ~ 3 with by-product hydrochloric acid, is finally adjusted to pH=6 ~ 9 with 20% liquid caustic soda, produces the waste water of saliferous mass percentage 10 ~ 35%.Described lower concentration sodium hypochlorite waste water is that TiCl is produced in 20% liquid caustic soda drip washing
4tail gas produce containing Na
2sO
4mass percentage is not more than 2%, NaHCO
3mass percentage is greater than 6%, NaClO mass percentage and is not more than the waste water that 2%, NaCl mass percentage is greater than 5%; The discarded underflow of described hypo produces the refuse in hypo product process, wherein Na
2sO
4mass percentage be greater than 85%, Na
2sO
3mass percentage is not more than 10%, Na
2s
2o
3mass percentage is not more than 5%; Described by-product hydrochloric acid is TiCl
4in production process, water wash tail gas produces, and HCl mass percentage is not less than 10%;
The discarded underflow add-on of described production hypo is NaClO:(Na2SO3+1/4Na2S2O3) mol ratio=1:1.By-product hydrochloric acid add-on is: NaHCO3:HCl mol ratio=1:1.05.
This process both can utilize by-product hydrochloric acid and hypo underflow, can improve again the content of sodium sulfate and sodium-chlor.
Principal reaction equation is as follows:
NaClO+Na
2SO
3=NaCl+Na
2SO
4
4NaClO+Na
2S
2O
3+2NaHCO
3=4NaCl+2Na
2SO
4+H
2O+2CO
2↑
HCl+NaHCO
3=NaCl+CO
2↑+H
2O
HCl+NaOH=NaCl+H
2O
Waste water after liquid caustic soda process is less than 20%, NaCl mass percentage containing the mass percentage of Na2SO4 and is less than 22%.
The preparation of b, sodium sulfate wastewater
Step a is mixed with contains sodium sulfate 5 ~ 20% according to the mass ratio of 1:1 ~ 1:3, the waste water of sodium-chlor 5 ~ 20% with through concentrated titanium dioxide washes; Titanium dioxide washes through concentrating is the waste water that titanium dioxide first produces after inorganic agent process, wherein Na
2sO
4mass percentage is less than 2%, NaCl mass percentage is less than 1%, then after film process, Na in waste water
2sO
4mass percentage 6 ~ 10%, NaCl mass percentage 2 ~ 5% (in order to reduce subsequent evaporation cost, improve the percent crystallization in massecuite of calcium sulfate, adopt ripe waste water treatment process to concentrate through film processing mode to protosulfate waste water, and produce a large amount of reuse waters).
Producing of c, gypsum
Add in calcium chloride solution by gained sodium sulfate wastewater in step b, in step b, the add-on of gained waste water is sodium sulfate amount of substance: calcium chloride amount of substance=1.2:1 ~ 1:1; Filter after abundant reaction, obtain gypsum or crystal whisker products through washing and drying process; Described calcium chloride solution be the acid waste water that produces of fused salt and fluidizing chlorination and lime slurry neutralization to pH=6 ~ 9, the mass percentage of calcium chloride is greater than 12%, and the mass percentage of sodium-chlor is less than 5%;
Principal reaction equation is as follows:
CaCl
2+Na
2SO
4+2H
2O=NaCl+CaSO
4·2H
2O↓
D, evaporative crystallization sodium-chlor: direct for step c gained filtrate evaporative crystallization sodium-chlor is back to fused salt chlorimation supply salt.
Below in conjunction with embodiment, the invention will be further described, but therefore do not limit the present invention among described scope of embodiments.
Embodiment 1
The present embodiment is raw materials used:
Calcium chloride solution: calcium chloride mass percentage 20.3%; Hypo underflow: Na
2sO
4mass percentage 85.1%, Na
2sO
3mass percentage 10%, Na
2s
2o
3mass percentage 5%, derives from CITIC Jinzhou Metal Co., Ltd..Lower concentration sodium hypochlorite waste water: Na
2sO
4mass percentage 2%, NaHCO
3mass percentage 8%, NaClO mass percentage 2%, NaCl mass percentage 15%.By-product hydrochloric acid HCl mass percentage 20%.Titanium dioxide washes after concentrated: Na
2sO
4mass percentage 6%, NaCl mass percentage 4%.20% Ionic Membrane.
1, the pre-treatment of lower concentration sodium hypochlorite waste water
Get 1500 grams of lower concentration sodium hypochlorite waste water, add 196 grams of hypo underflows, after stirring 40min, add by-product hydrochloric acid 273 grams and be neutralized to pH=2.55; Finally add 20% liquid caustic soda 3.9 grams and be neutralized to pH=7, record Na
2sO
4mass percentage 12.4%, NaCl mass percentage 11.8%.
2, the preparation of sodium sulfate wastewater
Get the protosulfate waste water 1000 grams after concentrating, the lower concentration sodium hypochlorite waste water after process 500 grams, is mixed with containing Na
2sO
4mass percentage 8.1%, NaCl mass percentage 6.6%.
3, gypsum is produced
By sodium sulfate amount of substance: calcium chloride amount of substance=1.1:1, in 1500 grams of sodium sulfate wastewaters in step 2, add the calcium chloride solution 427 grams that concentration is 20.3%.The completely rear filtration washing of question response, collects filtrate, obtains terra alba filter cake 270 grams, filtrate 1658 grams, sodium chloride concentration 10.6% in filtrate.
Terra alba drying and processing in service water washing, 160 DEG C of baking ovens obtains 138 grams, product gypsum, wherein calcium sulphate content 98.6%.
4, evaporative crystallization sodium-chlor: by the direct evaporative crystallization of step 3 gained filtrate, obtain 183 grams, thick sodium-chlor, wherein sodium chloride content 97.3%.
Embodiment 2
The present embodiment is raw materials used: calcium chloride solution: calcium chloride mass percentage 13%, sodium-chlor mass percentage 4%; Hypo underflow: Na
2sO
4mass percentage 95%, Na
2sO
3mass percentage 2%, Na
2s
2o
3mass percentage 3%, derives from CITIC Jinzhou Metal Co., Ltd..Lower concentration sodium hypochlorite waste water: Na
2sO
4mass percentage 0.5%, NaHCO
3mass percentage 10%, NaClO mass percentage 0.5%, NaCl mass percentage 10.5%.By-product hydrochloric acid HCl mass percentage 10%.Protosulfate waste water after concentrated: Na
2sO
4mass percentage 10%, NaCl mass percentage 2%.20% Ionic Membrane.
1, the pre-treatment of lower concentration sodium hypochlorite waste water
Get 2000 grams of lower concentration sodium hypochlorite waste water, add 147 grams of hypo underflows, after stirring 15min, add by-product hydrochloric acid 912.5 grams and be neutralized to pH=1.39; Finally add 20% liquid caustic soda 6.9 grams and be neutralized to pH=7.6, record Na
2sO
4mass percentage 5.4%, NaCl mass percentage 12.4%.
2, the preparation of sodium sulfate wastewater
Get the lower concentration sodium hypochlorite waste water 1000 grams that in step 1, pre-treatment is good, mix with the protosulfate waste water 1000 grams after concentrated, be mixed with containing Na
2sO
4the waste water of mass percentage 10.3%, NaCl mass percentage 9.6%.
3, gypsum is produced
By sodium sulfate amount of substance: calcium chloride amount of substance=1.2:1, in 2000 grams of sodium sulfate wastewaters in step 2, add the calcium chloride solution 1032 grams that concentration is 13%.The completely rear filtration washing of question response, collects filtrate, obtains terra alba filter cake 415 grams, filtrate 2116 grams, the sodium chloride concentration 14.3% of filtrate.
Terra alba obtains 210 grams, product gypsum, wherein calcium sulphate content 97.5% through service water washing, 160 DEG C of drying and processings.
4, evaporative crystallization sodium-chlor
By the direct evaporative crystallization of step 1 gained filtrate, obtain 385 grams, thick sodium-chlor, wherein sodium chloride content 97.8%.
Embodiment 3
Calcium chloride solution: calcium chloride mass percentage 30%; Hypo underflow: Na
2sO
4mass percentage 91.5%, Na
2sO
3mass percentage 7%, Na
2s
2o
3mass percentage 1.5%, derives from CITIC Jinzhou Metal Co., Ltd..Lower concentration sodium hypochlorite waste water: Na
2sO
4mass percentage 1.5%, NaHCO
3mass percentage 7%, NaClO mass percentage 1.0%, NaCl mass percentage 15%.By-product hydrochloric acid HCl mass percentage 15%.Titanium dioxide washes after concentrated: Na
2sO
4mass percentage 8%, NaCl mass percentage 3%.20% Ionic Membrane.
1, the pre-treatment of lower concentration sodium hypochlorite waste water
Get 1500 grams of lower concentration sodium hypochlorite waste water, add 196 grams of hypo underflows, after stirring 30min, add by-product hydrochloric acid 213 grams and be neutralized to pH=2.04; Finally add 20% liquid caustic soda 2.3 grams and be neutralized to pH=6.5, record Na
2sO
4mass percentage 17.8%, NaCl mass percentage 14.9%.
2, the preparation of sodium sulfate wastewater
Get the protosulfate waste water 1200 grams after concentrating, the lower concentration sodium hypochlorite waste water after process 400 grams, is mixed with containing Na
2sO
4mass percentage 10.5%, NaCl mass percentage 6.0%.
3, gypsum is produced
By sodium sulfate amount of substance: calcium chloride amount of substance=1:1, in 1600 grams of sodium sulfate wastewaters in step 2, add the calcium chloride solution 580 grams that concentration is 30%.The completely rear filtration washing of question response, collects filtrate, obtains terra alba filter cake 539 grams, filtrate 2040 grams, sodium chloride concentration 21.6% in filtrate.
Terra alba drying and processing in service water washing, 160 DEG C of baking ovens obtains 273 grams, product gypsum, wherein calcium sulphate content 96.9%.
4, evaporative crystallization sodium-chlor
By the direct evaporative crystallization of step 3 gained filtrate, obtain 360 grams, thick sodium-chlor, wherein sodium chloride content 98.5%.
Also do not occur in prior art a kind of can the method for low cost comprehensive utilization chloride process titanium dioxide high-salt wastewater, a large amount of waste water entrusts environmental protection processed in units, and cost substantial contribution, there is certain risk, resource does not have recycle yet.Known by embodiment: the inventive method solves this problem, present method makes full use of chloride process titanium dioxide high-salt wastewater, byproduct sulfite, with low cost, not only can save the expense of process chloride process titanium dioxide high-salt wastewater, and multiple Chemicals can be produced: gypsum, sodium-chlor etc., the sodium-chlor of production and distilled water can return use, and the inventive method economic benefit is very remarkable as can be seen here.Chloride process titanium dioxide high-salt wastewater calcium chloride solution, present method is by adding lower concentration sodium hypochlorite waste water, other chemical industrial waste thing sodium sulfate, produce gypsum (purity is greater than 96%) and sodium-chlor, without discharge, pollution-free, efficiently solve the environmental problem of chloride process titanium dioxide high-salt wastewater, namely solve and perplex the low-cost technologies difficult problem that chlorination process produces titanium dioxide industry for a long time, social benefit is remarkable, has good promotional value.
These are only specific embodiments of the invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.