WO2022088379A1 - 一种膜法处理钛白酸性废水副产高品质钛石膏的方法和装置 - Google Patents

一种膜法处理钛白酸性废水副产高品质钛石膏的方法和装置 Download PDF

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WO2022088379A1
WO2022088379A1 PCT/CN2020/133543 CN2020133543W WO2022088379A1 WO 2022088379 A1 WO2022088379 A1 WO 2022088379A1 CN 2020133543 W CN2020133543 W CN 2020133543W WO 2022088379 A1 WO2022088379 A1 WO 2022088379A1
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membrane
gypsum
filter
acid
wastewater
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PCT/CN2020/133543
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English (en)
French (fr)
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周添明
丁邦超
王肖虎
白祖国
彭文博
肖维溢
范克银
党建兵
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江苏久吾高科技股份有限公司
南京同畅新材料研究院有限公司
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Publication of WO2022088379A1 publication Critical patent/WO2022088379A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C01F11/468—Purification of calcium sulfates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B11/00—Calcium sulfate cements
    • C04B11/02—Methods and apparatus for dehydrating gypsum
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/38—Treatment of water, waste water, or sewage by centrifugal separation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • C02F1/4695—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis electrodeionisation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32

Definitions

  • the invention relates to a device and method for treating high-quality titanium gypsum by-product of titanium dioxide acid waste water by a membrane method, and belongs to the field of source treatment and resource utilization of titanium gypsum.
  • titanium dioxide by sulfuric acid method my country is a big producer of titanium dioxide by sulfuric acid method, producing about 3 million tons of titanium dioxide every year, of which titanium dioxide by sulfuric acid method accounts for more than 90% of the total output.
  • the annual emission of titanium gypsum is about 15 million tons.
  • titanium gypsum used as a cement additive most of the titanium gypsum is disposed of by storage or landfill.
  • the comprehensive utilization rate is almost zero.
  • the landfill volume is nearly 100 million tons. In addition to occupying a lot of land resources, it also has to pay a high cost for the construction of the yard. If it is not handled properly, it will cause triple pollution of water, air and soil.
  • Titanium gypsum is an industrial sludge produced by adding quicklime (or calcium carbide slag, white mud) to the acid wastewater of titanium dioxide enterprises by sulfuric acid method and neutralizing it. Its main component is CaSO 4 . 2H 2 O, usually with a grade of 70-80%, is acidic or neutral.
  • the titanium gypsum produced by the existing neutralization process has small crystals and high iron content, resulting in a reddish-brown color, high moisture content of 40-50%, and high post-treatment costs.
  • the gypsum crystals produced during the neutralization process are small, so the strength after calcination into beta hemihydrate gypsum is extremely low or even no strength, and it can hardly be used in the field of construction.
  • titanium gypsum In order to improve the comprehensive utilization rate of titanium gypsum, my country has done a lot of research on iron removal technology, such as wet iron removal process (organic extraction iron removal method, reduction bleaching method, acid leaching iron removal method, adsorption flotation method and liquid phase reduction method. - magnetic separation method, etc.) and dry iron removal process (high temperature reduction-magnetic separation and chlorination method, etc.), the titanium gypsum treated by these iron removal methods has high cost and high operation requirements, which is not conducive to industrialization.
  • wet iron removal process organic extraction iron removal method, reduction bleaching method, acid leaching iron removal method, adsorption flotation method and liquid phase reduction method. - magnetic separation method, etc.
  • dry iron removal process high temperature reduction-magnetic separation and chlorination method, etc.
  • titanium gypsum treatment methods cannot be To meet the green development requirements of titanium dioxide enterprises, it is urgent to develop a titanium gypsum treatment technology with simple process, low cost and high product added value.
  • the present invention is to provide a titanium gypsum treatment technology with simple process, low cost and high product added value. Through the combination of membrane purification of titanium dioxide acid waste water and gypsum crystallization technology, it can produce high purity, large particle size, low moisture content and whiteness. High titanium plaster.
  • a method for treating titanium dioxide acid waste water by-product high-quality titanium gypsum by membrane method comprising the following steps:
  • the first step is to filter the acidic wastewater produced in the process of producing titanium dioxide by the sulfuric acid method with an organic membrane to remove Fe2+ ions;
  • a neutralizing agent is added to the wastewater obtained in the second step, and a precipitation reaction is carried out with the sulfate ions in the wastewater to generate calcium sulfate, and crystallization is carried out;
  • the crystal obtained in the second step is subjected to solid-liquid separation to obtain titanium gypsum.
  • step 1 a step of pre-treatment and/or pre-filtration of acidic wastewater is required; in one embodiment, pre-filtration is used to remove metatitanic acid and suspended solids.
  • pretreatment refers to one or a combination of steps of homogenization, precipitation, pH adjustment, and sulfate ion concentration adjustment;
  • the adjusting the sulfate ion concentration refers to adjusting to 3-5 wt%.
  • the pre-filtration employs one of a microfiltration membrane, an ultrafiltration membrane, a sand filter, or a bag filter.
  • the filtration is performed using a ceramic ultrafiltration membrane.
  • the filtration method of the ultrafiltration membrane includes: S1, soaking the ceramic ultrafiltration membrane in saturated lime water, taking it out and drying it naturally, and then filtering the sodium carbonate solution, so that the membrane pores of the ceramic ultrafiltration membrane are Calcium carbonate is generated in the middle, and the filtration is stopped; S2, the waste water is filtered by an ultrafiltration membrane, so that a filter cake is formed on the surface of the ultrafiltration membrane, and the filtration is stopped; S3, the dilute acid solution is filtered by an ultrafiltration membrane, so that the calcium carbonate is dissolved, Stop the filtration; S4, continue to filter the waste water by using an ultrafiltration membrane.
  • the average pore size range of the ceramic ultrafiltration membrane is 20-50 nm
  • the concentration of the sodium carbonate solution is 10-15 wt %
  • the dilute acid solution is 1-5 wt % hydrochloric acid solution.
  • the pressure of the filtration process is controlled at 0.02-0.05 bar.
  • the organic membrane adopts a nanofiltration membrane.
  • the nanofiltration membrane has a rejection rate of 90%-98% for Fe 2+ and 15%-30% for sulfuric acid.
  • the neutralizing agent can be one or more of limestone ore (powder), quicklime, calcium carbide slag, white mud, salt mud, slaked lime, and alkali slag; the neutralizing agent is added in the form of slurry , the solid content of the slurry is 5%-35%.
  • adjusting the pH of the clear liquid refers to adjusting the pH to 5-9, and the clear liquid after adjusting the pH is sent to the membrane for concentration Integrated system for purification.
  • any one or more of RO membranes or EDI devices are used in the integrated membrane concentration system.
  • the solid-liquid separation adopts a cyclone separator, a filter separator or a centrifugal separator.
  • the solid after the solid-liquid separation, the solid also needs to be dehydrated; the dehydration adopts plate and frame filter press.
  • a device for treating high-quality titanium gypsum by-product of titanium dioxide acid wastewater by membrane method comprising:
  • the organic membrane system is used for nanofiltration to remove Fe 2+ from the acidic wastewater produced in the production of titanium dioxide by the sulfuric acid method;
  • the gypsum crystallizer is connected to the permeation side of the organic membrane system, and is used for precipitation and crystallization of the filtrate obtained by the organic membrane system;
  • the neutralizer slurry tank is connected to the gypsum crystallizer and used for adding neutralization to the gypsum crystallizer. precipitation reaction;
  • the solid-liquid separator connected to the gypsum crystallizer, is used for solid-liquid separation of calcium sulfate precipitation in the crystallization process.
  • a pre-filter which is connected to the water outlet of the acid waste water conditioning tank and used for pre-filtering the produced water of the acid waste water conditioning tank, and the pre-filter is connected with the organic membrane system.
  • It also includes: an acid waste water conditioning tank, which is used for homogenizing and precipitation treatment of the acid waste water; and the acid waste water conditioning tank is connected with the permeate side of the pre-filter.
  • the pre-filter is one of an inorganic membrane filter, a sand filter, or a bag filter.
  • the inorganic membrane is a microfiltration membrane or an ultrafiltration membrane.
  • the inorganic membrane includes a casing and heads at both ends, a tubular or multi-channel inorganic membrane is installed inside the casing, and the head is provided with a liquid inlet and a liquid outlet, respectively,
  • the channel of the inorganic membrane near one end of the liquid inlet is provided with a conical feed port, and one end of the smaller section faces the inorganic membrane, and a thread groove is arranged inside the conical feed port, and the thread groove is used for The fluid entering the inorganic membrane is swirled.
  • the pre-filter is a tubular or multi-channel inorganic membrane.
  • it also includes: a pre-filtered concentrate recovery tank, connected to the concentration side of the pre-filter, and used for collecting the concentrate obtained by the pre-filter.
  • the organic membrane system is a nanofiltration membrane.
  • it further includes: an organic membrane dope recovery tank, connected to the concentration side of the organic membrane system, for collecting the dope of the organic membrane system.
  • it also includes: a gypsum dehydrator, connected to the solid-liquid separator, for dehydrating the calcium sulfate precipitate obtained by separation.
  • it further includes: a regulating sedimentation tank, connected to the filtrate side of the solid-liquid separator, and used to adjust the pH of the filtrate obtained in the solid-liquid separator.
  • it further includes: a neutral water storage tank, connected to the adjustment sedimentation tank, for adjusting the pH of the wastewater in the adjustment sedimentation tank.
  • it further includes: a membrane concentration system, connected to the neutral water storage tank, for concentrating and filtering the neutral wastewater obtained in the neutral water storage tank.
  • the membrane concentration system is an RO membrane or an RO membrane or an EDI device.
  • it also includes: a concentrated water recovery tank, connected to the concentrated liquid side of the membrane concentration system, for collecting the concentrated solution obtained in the membrane concentration system.
  • it further includes: a reuse water storage tank, connected to the filtrate side of the membrane concentration system, and used for collecting the filtrate obtained in the membrane concentration system.
  • the invention is mainly based on the concept of "source treatment" of titanium gypsum, utilizes the effect of the organic membrane system on the high interception rate of Fe 2+ in the acid wastewater of titanium dioxide first-washing, improves the purity and whiteness of titanium gypsum, and increases the particle size of titanium gypsum. Reduce the moisture content of titanium gypsum; use the membrane concentration integrated system for neutral water reuse.
  • the grade of titanium gypsum produced by this technology is 90%-98%, and the whiteness can reach 80%-95%. Medical, cement and other industries.
  • this technology not only solves the problem of storage and landfill of titanium gypsum from the source, but also expands the product field for enterprises and realizes a win-win situation of social and economic benefits.
  • the whole technical process is simple, the cost is low, and the added value of the product is high, which meets the green development requirements of titanium dioxide enterprises.
  • Fig. 1 is the process flow diagram of the present invention
  • Fig. 2 is the equipment diagram of the present invention
  • Fig. 3 is ultrafiltration membrane operating flux curve
  • Example 4 is a SEM photograph of the titanium gypsum prepared in Example 1.
  • FIG. 5 is a SEM photograph of the titanium gypsum prepared in Comparative Example 1.
  • FIG. 6 is a SEM photograph of the titanium gypsum prepared in Comparative Example 1.
  • FIG. 7 shows the structure of an inorganic membrane filter.
  • Acid wastewater conditioning tank 2-1. Pre-filter, 2-1a. Shell, 2-1b. Head, 2-1c. Liquid inlet, 2-1d. Liquid outlet, 2-1e .Inorganic membrane, 2-1f. Conical inlet, 2-1g. Threaded groove, 2-1h. Permeate outlet, 2-2.
  • Pre-filtration concentrate recovery tank 2-3.
  • Organic membrane system 2- 4.
  • Organic membrane concentrate recovery tank 3.
  • Neutralizer slurry mixing tank 4-1. Gypsum crystallizer, 4-2. Solid-liquid separator, 4-3. Gypsum dehydrator, 4-4. Adjustment sedimentation tank , 5.
  • Neutral water reservoir 6-1. Membrane concentration system, 6-2. Concentrated water recovery pool, 6-3. Reuse reservoir.
  • the wastewater to be treated in the present invention is mainly acidic wastewater produced in the process of producing titanium dioxide by the sulfuric acid method.
  • the wastewater is acidic and also contains more metatitanic acid, Fe 2+ , Fe 3+ , titanium dioxide and the like.
  • the processing method of the present invention comprises the following steps:
  • (1) Allocation of acid waste water The acid waste water is put into the acid waste water conditioning tank for homogenization, precipitation, and the sulfuric acid concentration of the acid waste water is adjusted to 3%-5%;
  • the wastewater also contains a certain amount of titanium dioxide, which can be preliminarily separated by precipitation treatment;
  • Acidic wastewater purification The homogenized acidic wastewater is transported to the pre-filter for impurity removal to remove metatitanic acid and suspended solids in the acid wastewater, and the filtered impurities are transported to the pre-filtered concentrate recovery tank for metatitanic acid removal
  • the filtered acid wastewater is transported to the organic membrane system to remove Fe 2+ in the acid wastewater, the Fe 2+ content in the purified acid wastewater is controlled at 10-600ppm, and the organic membrane concentrate is transported to the organic membrane concentrate recycling pool for recycling;
  • the metatitanic acid in the acidic wastewater can be separated through a pre-filter.
  • the pre-filter used here mainly plays the role of solid-liquid separation, and inorganic ultrafiltration membranes, hollow fiber membranes, organic ultrafiltration membranes, and organic ultrafiltration membranes can be selected. Any one or several of filter membrane, sand filter, bag filter or self-cleaning filter, the retention rate of metatitanic acid and suspended solids is 100%.
  • metatitanic acid filter cake is formed on the surface to form a filter cake layer.
  • the filter cake layer is easily eliminated under the action of cross-flow (for example, the cross-flow filtration mode of 1-6 m/s is used for inorganic ultrafiltration membrane), and the filter cake thickness is kept at a low level, which has a negative impact on flux attenuation.
  • the ceramic ultrafiltration membrane is first pre-treated, and the ceramic membrane is immersed in a lime solution, so that Ca(OH) 2 is infiltrated inside the channel of the membrane pores, and after drying, Ca(OH) 2 is formed in the membrane pores, and then by slowly filtering the sodium carbonate solution under a small pressure, calcium carbonate can be generated in the membrane pores, and the membrane pores are artificially blocked;
  • filter cake pollution can be generated directly on the surface of the membrane.
  • the metatitanic acid filter cake layer is directly formed on the membrane surface.
  • a stable filter cake layer is formed, Then slowly filter with a dilute acid solution, so that the calcium carbonate in the membrane pores can be dissolved, and the filter cake layer can be retained;
  • the membrane layer has a higher filtration flux and is easily cleaned by cross-flow or backflushing.
  • the inorganic membrane filter is composed of a shell 2-1a and a head 2-1b at both ends, and a tubular or multi-channel inorganic membrane 2-1e is installed inside the shell 2-1a, and the head
  • the liquid inlet 2-1c and the liquid outlet 2-1d are respectively set on 2-1b.
  • the flow rate at the liquid inlet 2-1c is relatively large, and the filter cake layer is easily blown off, making the filter cake layer thin at the front of the liquid inlet.
  • a tapered feed port 2-1f is set at one end of the inorganic film 2-1e close to the liquid inlet 2-1c, and the smaller cross-section end faces the inorganic film 2-1e.
  • the inside of the feed port 2-1f is provided with a thread groove 2-1g.
  • Its function is to make the feed form a swirling flow, so that the particles in the feed liquid are concentrated in the middle of the channel when entering, so as to avoid the particles at the entrance to the membrane.
  • the friction of the surface reduces the occurrence of wear and prolongs the life of the inorganic membrane tube.
  • the suspended solids and colloids in the wastewater are eliminated, and the Fe 2+ in the acidic wastewater can be separated by a nanofiltration membrane, which has a retention rate of 90% for Fe 2+ -98%, the retention rate of sulfuric acid is 15%-30%;
  • the nanofiltration membrane can be used in one or more stages to ensure the Fe 2+ content in the acidic solution;
  • the nanofiltration membrane concentrate can be used for acid hydrolysis of raw ore and production of flocculant. , any one of the production of green alum and the production of iron pigments;
  • Root ions carry out precipitation reaction to generate calcium sulfate
  • the neutralizing agent used here can be one or more of limestone ore (powder), quicklime, calcium carbide slag, white mud, salt mud, slaked lime, and soda slag, and the neutralizing agent passes through
  • the neutralizer is prepared in a slurry tank to prepare a slurry with a solid content of 5%-35%; the slurry concentration in the gypsum crystallizer is controlled by a solid-liquid separator.
  • the steps are: adjusting the pH value of the feed liquid in the settling tank by neutralizing agent, and controlling the pH value to be 7-9; the material liquid in the adjusting settling tank realizes solid-liquid separation by natural sedimentation; adjusting The supernatant of the sedimentation tank is transported to the neutral water storage tank for recycling; the sediment in the sedimentation tank is adjusted and transported to the gypsum crystallizer to continue crystallization; -70°C, stirring speed 80-400r/min, pH value 5-8, crystallization time 1-10 hours;
  • step (2) the gypsum slurry that has been crystallized in step (2) is transported to a gypsum dehydrator, and the clear liquid in the dehydration process is transported to a regulating sedimentation tank, and the moisture content of the dehydrated titanium gypsum is 5%-20%;
  • the adjusted neutral water in step (3) is transported to the membrane concentration integrated system for purification, the membrane filtration concentrate is transported to the concentrate recovery tank, and the membrane filtration clear liquid is transported to the return Using a reservoir, the recovery rate can reach 50%-80%, and the conductivity of the produced water is less than or equal to 20 ⁇ s/cm; the scale inhibitor needs to be added before the neutral water enters the membrane concentration system; the added amount of the scale inhibitor is 10ppm; In the treatment of steps (1)-(4), most of the suspended solids, colloids, sulfate ions, and iron ions in the wastewater have been removed, and the remaining small amount of ions can be separated through the membrane concentration treatment step in this step, and the return is obtained. Use water.
  • Membrane concentration integrated system is any one or several of RO membrane or EDI;
  • the liquid outlet of the acid waste water conditioning tank 1 is connected with the liquid inlet of the organic membrane purification device 2, the clear liquid outlet of the organic membrane purification device 2 is connected with the liquid inlet of the gypsum crystallization dehydration device 4, and the neutralizer slurry preparation tank 3
  • the slurry outlet It is connected with the neutralizer feed port of the gypsum crystallization dehydration device 4, the clear liquid outlet of the gypsum crystallization dehydration device 4 is connected with the liquid inlet of the neutral water reservoir 5, and the liquid outlet of the neutral water reservoir 5 is respectively connected with the neutral water reservoir 5.
  • the liquid inlet of the natural water reuse membrane integrated device 6 is connected with the liquid inlet of the neutralizer slurry preparation tank 3;
  • the organic membrane purification device 2 includes a pre-filter 2-1, a pre-filtration concentrated solution recovery tank 2-2, an organic membrane system 2-3, an organic membrane concentrated solution recovery tank 2-4, and an acidic wastewater conditioning system.
  • the liquid outlet of the pool 1 is connected with the liquid inlet of the pre-filter 2-1; the concentrated liquid outlet of the pre-filter 2-1 is connected with the liquid inlet of the pre-filtered concentrated liquid recovery tank 2-2; the pre-filter
  • the clear liquid outlet of 2-1 is connected with the liquid inlet of the organic membrane system 2-3;
  • the concentrated liquid outlet of the organic membrane system 2-3 is connected with the liquid inlet of the organic membrane concentrated liquid recovery tank 2-4;
  • the organic membrane The supernatant liquid outlet of the system 2-3 is connected with the liquid inlet of the gypsum crystal dehydration device 4 .
  • the pre-filter 2-1 is a hollow fiber membrane
  • the organic membrane system 2-3 is an organic nanofiltration membrane.
  • Pre-filter 2-1 can also choose one of inorganic ultrafiltration membrane, organic ultrafiltration membrane, sand filter, bag filter or self-cleaning filter; organic membrane system 2-3 can also choose organic ultrafiltration membrane.
  • the gypsum crystallizing dehydration device 4 includes a gypsum crystallizer 4-1, a solid-liquid separator 4-2, a gypsum dehydrator 4-3 and a regulating sedimentation tank 4-4.
  • the clear liquid outlet of the organic membrane system 2-3 is connected with the liquid inlet of the gypsum crystallizer 4-1; the slurry outlet of the neutralizer slurry preparation tank 3 is connected with the neutralizer feed port of the gypsum crystallizer 4-1;
  • the slurry outlet of the crystallizer 4-1 is connected with the liquid inlet of the solid-liquid separator 4-2; the clear liquid outlet of the solid-liquid separator 4-2 is connected with the liquid inlet of the regulating sedimentation tank 4-4; the solid-liquid separator 4 -2
  • the concentrated liquid outlet is respectively connected with the 4-1 return port of the gypsum crystallizer and the 4-3 feed port of the gypsum dehydrator; ; Adjust the clear liquid outlet of the sedimentation tank 4-4 to connect with the liquid inlet of the neutral water reservoir 5; adjust the slurry outlet of the sedimentation tank 4-4 to connect with the return port of the gypsum crystallizer 4-1.
  • the solid-liquid separator 4-2 is a cyclone separator, and the gypsum dehydrator 4-3 is a plate and frame filter press dehydrator.
  • the solid-liquid separator 4-2 can also choose a solid-liquid separation filter or a gravity settling tank, and the gypsum dehydrator 4-3 can also choose a vacuum belt dehydrator, a belt filter press dehydrator or a centrifugal dehydrator.
  • the neutral water reuse membrane integrated device 6 includes a membrane concentration integrated system 6-1, a concentrated water recovery tank 6-2 and a reuse storage tank 6-3.
  • the liquid outlet of neutral water reservoir 5 is connected with the liquid inlet of the membrane concentration integrated system 6-1; the concentrated liquid outlet of the membrane concentrated integrated system 6-1 is connected with the liquid inlet of the concentrated water recovery tank 6-2;
  • the clear liquid outlet of the integrated system 6-1 is connected with the liquid inlet of the reuse reservoir 6-3.
  • Membrane concentration integrated system 6-1 is RO membrane.
  • the Membrane Concentration Integrated System 6-1 can also use EDI.
  • the gypsum crystallizer is any one of a stirring tank (kettle) or a stirring tank with a variable frequency stirring paddle; the gypsum crystallizer is equipped with heating and heat preservation functions; the gypsum crystallizer is equipped with a pH monitoring function.
  • the method comprises the following steps: (1) preparing acid waste water; (2) purifying acid waste water; (3) neutralizing and crystallizing acid waste water; ( 4) Dehydration of titanium gypsum; (5) Neutral water regulation discharge; wherein,
  • (1) Allocation of acidic wastewater Take the sulfuric acid method titanium dioxide factory as an example, the acidic wastewater generated in a leaf washing filter is pumped to the acidic wastewater conditioning tank 1, and the acidic wastewater is uniformized in the acidic wastewater conditioning tank 1. quality, precipitation, adjust the concentration of sulfuric acid in acid wastewater to 3.5%, Fe 2+ content ⁇ 6000ppm, flow rate 300L/h;
  • the organic membrane purification device 2 includes a pre-filter 2-1, a pre-filtration concentrated solution recovery tank 2-2, an organic membrane system 2-3, and an organic membrane concentrated solution recovery tank 2-4.
  • the adjusted acidic wastewater is pumped to the pre-filter 2-1.
  • the pre-filter 2-1 uses a multi-channel ceramic membrane with an average pore size of 50nm to filter and remove the metatitanic acid at a flow rate of 3m/s on the membrane surface.
  • the concentrated solution with high metatitanic acid content is obtained by filtration and concentration by the pre-filter and pumped to the pre-filtered concentrated solution recovery tank 2-2 for the recovery of meta-titanic acid, and the clear solution filtered by the pre-filter is pumped to the organic membrane System 2-3 is purified (using polyamide nanofiltration membrane), in which the flow rate of concentrate is 15L/h, and the flow rate of clear liquid is 285L/h; the clear liquid purified by the organic membrane system is pumped to gypsum crystallization 4-1 for In the crystallization reaction, the organic membrane concentrated solution concentrated by the organic membrane system is pumped to the organic membrane concentrated solution recovery tank 2-4 for acid hydrolysis of titanium ore .
  • the content is 10-600ppm, the content of sulfuric acid is 3%, the water output of the organic membrane dope is 28.5L/h, the content of Fe 2+ is ⁇ 54600ppm, and the content of sulfuric acid is 8%;
  • the purified acidic wastewater is pumped to the gypsum crystallizer 4-1, and the prepared neutralizer slurry is added to the gypsum crystallizer 4-1 at the same time. It is a limestone powder solution with a solid content of 20%.
  • the temperature of the gypsum crystallizer is controlled at 50 ° C, the stirring speed is 300 r/min, and the pH value is 5-8.
  • the solid-liquid separator 4-2 is used to control the slurry concentration in the gypsum crystallizer. 20%, fully stirring and crystallizing for 2 hours; the clear liquid separated by the solid-liquid separator is transported to the regulating sedimentation tank 4-4.
  • Neutral water regulation and discharge according to the pH value of the feed liquid in the regulation settling tank 4-4, add a neutralizing agent to the regulation settling tank, adjust the feed liquid in the settling tank to adjust the pH value to 8-9, and settle the slurry Pump to the gypsum crystallizer 4-1 to continue the crystallization reaction, the supernatant liquid is transported to the neutral water storage tank 5, and the 65L/h neutral water is transported to the neutralizer slurry preparation tank 3 to be used as neutralizer slurry preparation water, 252L/h of neutral water is discharged up to the standard, the conductivity of neutral water is 12000 ⁇ s/cm, and the total water production is 317L/h;
  • the produced titanium gypsum is in the form of board granules, as shown in Figure 3, the particle size distribution is 70-110 ⁇ m, the gypsum grade is 90%, the whiteness is 90%, and the gypsum moisture content is 8%.
  • Example 1 The difference from Example 1 is that the filtration process of metatitanic acid by ultrafiltration membrane is improved.
  • the method comprises the following steps: (1) preparing acid waste water; (2) purifying acid waste water; (3) neutralizing and crystallizing acid waste water; ( 4) Dehydration of titanium gypsum; (5) Neutral water regulation discharge; wherein,
  • (1) Allocation of acidic wastewater Take the sulfuric acid method titanium dioxide factory as an example, the acidic wastewater generated in a leaf washing filter is pumped to the acidic wastewater conditioning tank 1, and the acidic wastewater is uniformized in the acidic wastewater conditioning tank 1. quality, precipitation, adjust the concentration of sulfuric acid in acid wastewater to 3.5%, Fe 2+ content ⁇ 6000ppm, flow rate 300L/h;
  • the organic membrane purification device 2 includes a pre-filter 2-1, a pre-filtration concentrated solution recovery tank 2-2, an organic membrane system 2-3, and an organic membrane concentrated solution recovery tank 2-4.
  • the pre-filter 2-1 uses a multi-channel ceramic membrane with an average pore size of 50nm. It is immersed in saturated lime solution so that Ca(OH)2 is completely immersed in the membrane pores. The sodium carbonate solution is subjected to micro-positive pressure filtration to maintain a trace flux condition, so that calcium carbonate is generated in the membrane pores; this step is repeated 3 times.
  • the adjusted acidic wastewater is pumped to the pre-filter 2-1, filtered under the condition of the membrane surface flow rate of 3 m/s, a metatitanic acid filter cake layer is formed on the surface of the multi-channel ceramic membrane, and the filtration is stopped immediately;
  • the flux change curve in the above-mentioned filtration process is shown in FIG. 3 .
  • the flux decay of the ultrafiltration membrane in Example 3 is slower and the flux is higher, indicating that the pretreatment method for the membrane is adopted, and calcium carbonate can be used first. Occupying the membrane pores, and then dissolving and removing the calcium carbonate in the membrane pores after the filter cake is formed on the surface, can effectively avoid the clogging of the membrane pores and help to improve the flux.
  • the concentrated solution with high metatitanic acid content obtained by pre-filter filtration and concentration is pumped to the pre-filtered concentrated solution recovery tank 2-2 for meta-titanic acid recovery, and the clear solution filtered by the pre-filter is pumped to the organic membrane system 2-3 Purify (using polyamide nanofiltration membrane), wherein the flow rate of the concentrate is 15L/h, and the flow rate of the clear liquid is 285L/h; the clear liquid purified by the organic membrane system is pumped to the gypsum crystal 4-1 for crystallization Reaction, the organic membrane concentrated solution concentrated by the organic membrane system is pumped to the organic membrane concentrated solution recovery tank 2-4 for acid hydrolysis of titanium ore, wherein the organic membrane clear liquid water yield is 256.5L /h, Fe 10-600ppm, sulfuric acid content 3%, organic membrane dope water output is 28.5L/h, Fe 2+ content ⁇ 54600ppm, sulfuric acid content 8%;
  • the purified acidic wastewater is pumped to the gypsum crystallizer 4-1, and the prepared neutralizer slurry is added to the gypsum crystallizer 4-1 at the same time.
  • It is a calcium hydroxide solution with a solid content of 20%.
  • the temperature of the gypsum crystallizer is controlled at 50°C, the stirring speed is 300r/min, and the pH value is 5-8.
  • the solid-liquid separator 4-2 is used to control the slurry concentration and solid content in the gypsum crystallizer. is 20%, fully stirring and crystallizing for 2 hours; the clear liquid separated by the solid-liquid separator is transported to the regulating sedimentation tank 4-4.
  • the produced titanium gypsum is in the form of board particles, as shown in Figure 4, the particle size distribution is 40-80 ⁇ m, and the particle size distribution is very uniform, the gypsum grade is 94%, the whiteness is 92%, and the gypsum moisture content is 11%.
  • Example 2 The difference from Example 1 is that the acidic wastewater does not use an organic membrane to filter and remove Fe 2+ .
  • (1) Allocation of acidic wastewater Take the sulfuric acid method titanium dioxide factory as an example, the acidic wastewater generated in a leaf washing filter is pumped to the acidic wastewater conditioning tank 1, and the acidic wastewater is uniformized in the acidic wastewater conditioning tank 1. quality, precipitation, adjust the concentration of sulfuric acid in acid wastewater to 3.5%, Fe 2+ content ⁇ 6000ppm, flow rate 300L/h;
  • the adjusted acidic wastewater is pumped to the pre-filter 2-1.
  • the pre-filter 2-1 uses a multi-channel ceramic membrane with an average pore size of 50 nm at a flow rate of 3 m/s on the membrane surface.
  • Metatitanic acid is removed by filtration under the pre-filter, and the concentrated solution with high meta-titanic acid content is obtained by pre-filter filtration and pumped to the pre-filter concentrated solution recovery tank 2-2 for the recovery of meta-titanic acid.
  • the clear liquid is pumped to gypsum crystal 4-1 for crystallization reaction, the pre-filter water production is 285L/h, the Fe 2+ content is ⁇ 6000ppm, and the sulfuric acid content is 3.5%;
  • the purified acidic wastewater is pumped to the gypsum crystallizer 4-1, and the prepared neutralizer slurry is added to the gypsum crystallizer 4-1 at the same time.
  • It is a calcium hydroxide solution with a solid content of 20%.
  • the temperature of the gypsum crystallizer is controlled at 50°C, the stirring speed is 300r/min, and the pH value is 5-8.
  • the solid-liquid separator 4-2 is used to control the slurry concentration and solid content in the gypsum crystallizer. is 20%, fully stirring and crystallizing for 2 hours; the clear liquid separated by the solid-liquid separator is transported to the regulating sedimentation tank 4-4.
  • the produced titanium gypsum is in needle-like shape, as shown in Figure 5 and Figure 6, with a particle size distribution of 5-20 ⁇ m, mostly small-sized crystalline particles, gypsum grade of 87%, whiteness 28%, and gypsum moisture content. 43%. It can be seen that the titanium gypsum obtained directly by the neutralization and crystallization of acid wastewater without organic nanofiltration membrane has small particle size and low purity.

Abstract

一种膜法处理钛白酸性废水副产高品质钛石膏的方法，第1步，对硫酸法生产钛白粉过程中产生的酸性废水采用有机膜过滤，去除Fe 2+离子；第2步，对第2步得到的废水中加入中和剂，与废水中的硫酸根离子进行沉淀反应生成硫酸钙，并进行结晶；第3步，对第2步得到的结晶进行固液分离，得到钛石膏。还公开了一种膜法处理钛白酸性废水副产高品质钛石膏的装置，包括依次连通的有机膜系统（2-3）、石膏结晶器（4-1）和固液分离器（4-2），中和剂配浆池（3）连接于石膏结晶器（4-1），用于向石膏结晶器（4-1）中加入中和剂进行沉淀反应。

Description

一种膜法处理钛白酸性废水副产高品质钛石膏的方法和装置 技术领域
本发明涉及一种膜法处理钛白酸性废水副产高品质钛石膏的装置和方法，属于钛石膏源头治理及资源化利用领域。
背景技术
我国是硫酸法钛白粉生产大国，每年生产钛白粉约300万吨左右，其中硫酸法钛白占总产量90％以上。据统计钛石膏的年排放量约1500万吨左右，除了少量的钛石膏用于水泥添加剂，绝大部分钛石膏采用堆存或填埋方式进行处理，综合利用率近乎为零，历年累计堆存填埋量近亿吨，除了占用大量土地资源、还要付出高额的堆场环建费用，如果处理不好则会造成水、大气和土壤三重污染。
钛石膏是硫酸法钛白企业酸性废水中加入生石灰(或电石渣、白泥)中和后产生的工业污泥，其主要成分为CaSO 4﹒2H 2O，通常品位在70～80％，呈酸性或中性。现有中和工艺产出的钛石膏晶体细小，铁含量高，导致其颜色呈红褐色，含水率高达40-50％，后处理成本高。由于钛白酸性废水中铁含量较高，导致中和过程中产生的石膏晶体细小，因此煅烧成β半水石膏后强度极低，甚至无强度，几乎无法应用于建筑领域。
我国为了提高钛石膏综合利用率，在除铁工艺方面做了大量研究，如湿法除铁工艺(有机物萃取除铁法、还原漂白法、酸浸除铁法、吸附浮选法和液相还原-磁分离法等)和干法除铁工艺(高温还原-磁分离和氯化法等)，这些除铁方法处理的钛石膏成本大，操作要求高，不利于工业化推广。
综上所述，钛石膏资源化再利用问题已成为硫酸法钛白粉企业发展的瓶颈，现有钛石膏处理方法因工艺过程复杂、能耗高、设备投资大、产品附加值低等原因，不能满足钛白企业的绿色发展要求，因此急需开发一种工艺简单，成本低廉，产品附加值高的钛石膏处理技术。
发明内容
本发明在于提供一种工艺简单，成本低廉，产品附加值高的钛石膏处理技术，通过膜净化钛白酸性废水和石膏结晶技术的结合，生产出纯度高、粒度大、含水率低和白度高的钛石膏。
一种膜法处理钛白酸性废水副产高品质钛石膏的方法，包括以下步骤：
第1步，对硫酸法生产钛白粉过程中产生的酸性废水采用有机膜过滤，去除Fe2+离子；
第2步，对第2步得到的废水中加入中和剂，与废水中的硫酸根离子进行沉淀反应生成硫酸钙，并进行结晶；
第3步，对第2步得到的结晶进行固液分离，得到钛石膏。
在一个实施方式中，在第1步之后，需要对酸性废水进行预处理和/或预过滤的步骤；在一个实施方式中，预过滤是用于去除偏钛酸和悬浮物。
在一个实施方式中，预处理是指均质、沉淀、调节pH、调节硫酸根离子浓度中的一步或几步的组合；
在一个实施方式中，所述的调节硫酸根离子浓度是指调节至3-5wt％。
在一个实施方式中，预过滤采用微滤膜、超滤膜、砂滤器或者袋式过滤器中的一种。
在一个实施方式中，采用陶瓷超滤膜进行过滤。
在一个实施方式中，超滤膜的过滤方法包括：S1，将陶瓷超滤膜浸泡于饱和石灰水中，取出后自然晾干，再对碳酸钠溶液进行过滤，使在陶瓷超滤膜的膜孔中生成碳酸钙，停止过滤；S2，采用超滤膜对废水进行过滤，使超滤膜的表面形成滤饼，停止过滤；S3，采用超滤膜对稀酸溶液进行过滤，使碳酸钙溶解，停止过滤；S4，采用超滤膜继续对废水进行过滤。
在一个实施方式中，陶瓷超滤膜的平均孔径范围是20-50nm，所述的碳酸钠溶液的浓度10-15wt％，稀酸溶液是1-5wt％的盐酸溶液。
在一个实施方式中，所述的S1和S3步骤中，过滤过程的压力控制在0.02-0.05bar。
在一个实施方式中，所述的第1步中，有机膜采用的是纳滤膜。
在一个实施方式中，纳滤膜对Fe 2+的截留率90％-98％，对硫酸的截留率15％-30％。
在一个实施方式中，中和剂可以是石灰石矿(粉)、生石灰、电石渣、白泥、盐泥、消石灰、碱渣的一种或几种；中和剂加入时是以浆料方式加入，浆料固含量为5％-35％。
在一个实施方式中，还需要对第3步中得到的清液调节pH；在一个实施方式中，清液调节pH是指调节至5-9，并且在调节pH之后的清液送入膜浓缩集成系统进行纯化。
在一个实施方式中，膜浓缩集成系统中采用RO膜或EDI设备任意一种或几种。
在一个实施方式中，第3步中，固液分离采用旋流分离器或者过滤分离器或者离心分离器。
在一个实施方式中，固液分离后，还需要对固体进行脱水；脱水采用的是板框压滤。
一种膜法处理钛白酸性废水副产高品质钛石膏的装置，包括：
有机膜系统，用于对硫酸法生产钛白粉过程中产生的酸性废水进行纳滤去除Fe 2+处理；
石膏结晶器，连接于有机膜系统的渗透侧，用于对有机膜系统得到的滤液进行沉淀、结晶处理；中和剂配浆池连接于石膏结晶器，用于向石膏结晶器中加入中和剂进行沉淀反应；
固液分离器，连接于石膏结晶器，用于对结晶过程的硫酸钙沉淀进行固液分离。
还包括：预过滤器，连接于酸性废水调节池的出水口，用于对酸性废水调节池产水进行预过滤处理，并且预过滤器与有机膜系统连接。
还包括：酸性废水调节池，用于对酸性废水进行均质、沉淀处理；并且酸性废水调节池与预过滤器的渗透侧连接。
在一个实施方式中，预过滤器是无机膜过滤器、砂滤器或者袋式过滤器中的一种。
在一个实施方式中，所述的无机膜是微滤膜或者超滤膜。
在一个实施方式中，所述的无机膜包括壳体以及两端的封头，在壳体的内部安装有管式或者多通道式的无机膜，封头上分别设进液口以及出液口，所述的无机膜的靠近进液口一端的通道处设锥形进料口，其较小截面一端朝向无机膜，在锥形进料口的内部设有螺纹槽，所述的螺纹槽用于将进入无机膜的流体产生旋流。
在一个实施方式中，预过滤器是管式或者多通道式的无机膜。
在一个实施方式中，还包括：预过滤浓液回收池，连接于预过滤器的浓缩侧，用于对预过滤器得到的浓液进行收集。
在一个实施方式中，所述的有机膜系统是纳滤膜。
在一个实施方式中，还包括：有机膜浓液回收池，连接于有机膜系统的浓缩侧，用于收集有机膜系统的浓液。
在一个实施方式中，还包括：石膏脱水机，连接于固液分离器，用于对分离得到的硫酸钙沉淀进行脱水。
在一个实施方式中，还包括：调节沉降池，连接于固液分离器的滤液侧，用于对固液分离器中得到的滤液进行pH调节。
在一个实施方式中，还包括：中性水蓄水池，连接于调节沉降池，用于对调节沉降池中的废水的pH进行调节。
在一个实施方式中，还包括：膜浓缩系统，连接于中性水蓄水池，用于对中性水蓄水池中得到的中性废水进行浓缩过滤。
在一个实施方式中，所述的膜浓缩系统是RO膜或者RO膜或EDI设备。
在一个实施方式中，还包括：浓水回收池，连接于膜浓缩系统的浓液侧，用于对膜浓缩 系统中得到的浓缩液进行收集。
在一个实施方式中，还包括：回用蓄水池，连接于膜浓缩系统的滤液侧，用于对膜浓缩系统中得到的滤液进行收集。
上述的装置在用于生产钛石膏中的应用。
有益效果
本发明主要依据钛石膏的“源头治理”理念，利用有机膜系统对钛白一洗酸性废水中Fe 2+的高截留率的作用，提高钛石膏的纯度和白度，增大钛石膏粒度，降低钛石膏含水率；利用膜浓缩集成系统进行中性水回用。该技术生成钛石膏品位90％-98％,、白度可达80％-95％，煅烧后的β半水石膏的强度为2h抗折3.0MPa-3.8MPa，可广泛应用于建材、模具、医用、水泥等多个行业领域。该技术与目前钛白酸性废水和钛石膏处理技术相比，不仅从源头上解决了钛石膏的堆存填埋的问题，还为企业拓宽的产品领域，实现社会和经济效益双赢态势。整个技术工艺简单，成本低廉，产品附加值高，满足了钛白企业的绿色发展要求。
附图说明
图1是本发明的工艺流程图；
图2是本发明的设备图；
图3是超滤膜运行通量曲线；
图4是实施例1中制备得到的钛石膏SEM照片。
图5是对照例1中制备得到的钛石膏SEM照片。
图6是对照例1中制备得到的钛石膏SEM照片。
图7是无机膜过滤器的结构。
其中，1.酸性废水调节池，2-1.预过滤器，2-1a.壳体，2-1b.封头，2-1c.进液口，2-1d.出液口，2-1e.无机膜，2-1f.锥形进料口，2-1g.螺纹槽，2-1h.渗透液出口，2-2.预过滤浓液回收池，2-3.有机膜系统，2-4.有机膜浓液回收池，3.中和剂配浆池，4-1.石膏结晶器，4-2.固液分离器，4-3.石膏脱水机，4-4.调节沉降池，5.中性水蓄水池，6-1.膜浓缩系统，6-2.浓水回收池，6-3.回用蓄水池。
具体实施方式
本发明中所要处理的废水主要是硫酸法生产钛白粉过程中产生的酸性废水，废水呈酸性， 同时还含有较多的偏钛酸、Fe 2+、Fe 3+、钛白粉等。
本发明的处理方法，包括以下几步：
(1)酸性废水调配：酸性废水放入酸性废水调节池内进行均质，沉淀，调节酸性废水硫酸浓度3％-5％；本步骤的目的，可以使酸性废水的水质更为稳定，同时由于酸性废水中还含有一定量的钛白粉，通过沉淀处理可以将钛白粉初步分离；
(2)酸性废水净化：均质后的酸性废水输送至预过滤器进行除杂，去除酸性废水中的偏钛酸和悬浮物，滤除的杂质输送至预过滤浓液回收池进行偏钛酸的回收，经过滤后的酸性废水输送至有机膜系统，去除酸性废水中的Fe 2+，净化后的酸性废水中含Fe 2+控制在10-600ppm，有机膜浓液输送至有机膜浓液回收池进行回收；
本步骤中，可以实现通过预过滤器将酸性废水中的偏钛酸的分离，这里所用的预过滤器主要是起到了固液分离的作用，可以选用无机超滤膜、中空纤维膜、有机超滤膜、砂滤器、袋式过滤器或自清洗过滤器中的任意一种或几种，对偏钛酸和悬浮物的截留率100％。
由于偏钛酸的粒径较小，直接采用无机超滤膜进行过滤时，特别是在过滤初期会导致过多的偏钛酸首先进入到膜孔中，形成膜孔堵塞，进而再在膜的表面形成偏钛酸滤饼，形成滤饼层。而滤饼层在错流的作用下(例如采用无机超滤膜是采用1-6m/s的错流过滤模式)，是很容易消除并且保持在较低的滤饼厚度，其对通量衰减造成的影响有限；而对于膜孔堵塞来说，其不容易通过错流的作用消除，而且通过反冲洗的方式也不容易去除，会导致较为严重的膜通量衰减以及较低的通量恢复率。因此，本发明中在对偏钛酸进行过滤时，首先对陶瓷超滤膜进行前处理，将陶瓷膜浸泡于石灰溶液中，使Ca(OH) 2浸润于膜孔的通道内部，干燥之后，在膜孔中形成Ca(OH) 2，然后通过在较小的压力下缓慢过滤碳酸钠溶液，使在膜孔中可以生成碳酸钙，将膜孔形成一部分的人为堵塞；在这之后，对酸性废水进行过滤时，可以直接在膜的表面生成滤饼污染，由于碳酸钙占据了偏钛酸的位置，使得偏钛酸滤饼层直接在膜表面生成，当形成了稳定的滤饼层之后，再用稀酸溶液缓慢地过滤，可以使膜孔中的碳酸钙被溶解，而保留滤饼层；这样的操作之后，可以生成具有滤饼层且不含有膜孔堵塞的偏钛酸结构，使得膜层的过滤通量更高，并且容易被错流或反冲清洗。
另外，在对生成的偏钛酸采用管式或者多通道式无机膜进行过滤时，在通道内部中所积聚的滤饼的厚度存在着在料液进口和出口位置厚度不均一的现象，如图7所示，无机膜过滤器是由壳体2-1a以及两端的封头2-1b组成，在壳体2-1a的内部安装有管式或者多通道式的无机膜2-1e，封头2-1b上分别设进液口2-1c以及2出液口2-1d，进液口2-1c处的流速较大，易将滤饼层吹脱，使得在进液前端滤饼层薄，而在过滤过程中随着渗透液排出，在出液口2-1d 处的流速减慢，使得滤饼增厚；靠近进口处由于滤饼厚度较小，易使膜层受到料液中的粒子的刮擦，磨损严重；因此，无机膜2-1e的靠近进液口2-1c一端处设锥形进料口2-1f，其较小截面一端朝向无机膜2-1e，在锥形进料口2-1f的内部设有螺纹槽2-1g，其的作用是使进料形成旋流，使料液中的颗粒进入时集中于通道的中间位置，避免了入口处的粒子对膜面的摩擦，减小了磨损的发生，延长了无机膜管的寿命。
在去除废水中的偏钛酸后，消除了废水中的悬浮物以及胶体，可以通过纳滤膜对酸性废水中的Fe 2+进行分离，所述纳滤膜对Fe 2+的截留率90％-98％，对硫酸的截留率15％-30％；所述纳滤膜可用一级或多级保证酸性溶液中的Fe 2+含量；纳滤膜浓液可用于原矿酸解、生产絮凝剂、生产绿矾和生产铁颜料的任意一种；
(3)酸性废水中和结晶：净化后的酸性废水输送至石膏结晶器，同时向石膏结晶器中加入配制好的中和剂浆料，加入中和剂的目的是可以与酸性废水中的硫酸根离子进行沉淀反应生成硫酸钙；这里所使用的中和剂可以是石灰石矿(粉)、生石灰、电石渣、白泥、盐泥、消石灰、碱渣的一种或几种，中和剂通过中和剂配浆池调配至固含量为5％-35％的浆液；通过固液分离器控制石膏结晶器内浆料浓度。
由于在上述的中和沉淀的步骤中，废水中仍然有少量的硫酸根未被沉淀分离，进一步地通过加入中和剂进行深度沉淀，使硫酸根以及Fe 2+离子被沉淀，通过加入石灰可以生成硫酸钙沉淀；步骤是：调节沉降池中料液通过中和剂进行pH值调节，控制pH值为7-9；所述所述调节沉降池中料液通过自然沉降实现固液分离；调节沉降池上清液输送至中性水蓄水池回收再利用；调节沉降池中的沉淀物输送至石膏结晶器继续结晶；控制石膏结晶器的料液浓度固含量10％-40％，温度30℃-70℃，搅拌速度80-400r/min，pH值5-8，结晶时间1-10小时；
(4)钛石膏脱水：步骤(2)中经结晶完成的石膏浆液输送至石膏脱水机，脱水过程中的清液输送至调节沉降池，脱水后的钛石膏含水率为5％-20％；
(5)中性水膜法回用：步骤(3)中经调节后的中性水输送至膜浓缩集成系统进行纯化，膜过滤浓液输送至浓液回收池，膜过滤清液输送至回用蓄水池，回收率可达到50％-80％，产水电导率≤20μs/cm；中性水进膜浓缩系统前需添加阻垢剂；所述阻垢剂的添加量为10ppm；通过步骤(1)-(4)处理，废水中大部分的悬浮物、胶体、硫酸根离子、铁离子都已经被去除，剩余的少量离子通过本步骤中的膜浓缩处理步骤可以得到分离，得到回用水。膜浓缩集成系统为RO膜或EDI任意一种或几种；
基于以上的方法，本发明提供的装置如图1所示：
包括酸性废水调节池1，有机膜净化装置2，中和剂配浆池3，石膏结晶脱水装置4，中 性水蓄水池5，中性水回用膜集成装置6；
酸性废水调节池1的出液口与有机膜净化装置2进液口相连接，有机膜净化装置2清液出口与石膏结晶脱水装置4进液口相连接，中和剂配浆池3浆液出口与石膏结晶脱水装置4中和剂进料口相连接，石膏结晶脱水装置4清液出口与中性水蓄水池5进液口相连接，中性水蓄水池5出液口分别与中性水回用膜集成装置6进液口和中和剂配浆池3进液口相连接；
在一具体实施方式中，有机膜净化装置2包括预过滤器2-1，预过滤浓液回收池2-2，有机膜系统2-3，有机膜浓液回收池2-4，酸性废水调节池1的出液口与预过滤器2-1的进液口相连接；预过滤器2-1的浓液出口与预过滤浓液回收池2-2的进液口相连接；预过滤器2-1的清液出口与有机膜系统2-3的进液口相连接；有机膜系统2-3的浓液出口与有机膜浓液回收池2-4的进液口相连接；有机膜系统2-3的清液出口与石膏结晶脱水装置4的进液口相连接。
在一个实施方式中，预过滤器2-1为中空纤维膜，有机膜系统2-3为有机纳滤膜。预过滤器2-1还可以选用无机超滤膜、有机超滤膜、砂滤器、袋式过滤器或自清洗过滤器中的一种；有机膜系统2-3还可以选用有机超滤膜。
在一具体实施方式中，石膏结晶脱水装置4包括石膏结晶器4-1、固液分离器4-2、石膏脱水机4-3和调节沉降池4-4。有机膜系统2-3的清液出口与石膏结晶器4-1进液口相连接；中和剂配浆池3浆料出口与石膏结晶器4-1中和剂进料口相连接；石膏结晶器4-1浆料出口与固液分离器4-2进液口相连接；固液分离器4-2清液出口与调节沉降池4-4进液口相连接；固液分离器4-2浓液出口分别与石膏结晶器4-1回料口和石膏脱水机4-3进料口相连接；石膏脱水机4-3清液出口与调节沉降池4-4进液口相连接；调节沉降池4-4清液出口与中性水蓄水池5进液口相连接；调节沉降池4-4浆液出口与石膏结晶器4-1回料口相连接。
固液分离器4-2为旋流分离器，石膏脱水机4-3为板框压滤脱水机。固液分离器4-2还可以选用固液分离过滤器或重力沉降罐，石膏脱水机4-3还可以选用真空带式脱水机，带式压滤脱水机或离心脱水机。
在一具体实施方式中，中性水回用膜集成装置6包括膜浓缩集成系统6-1、浓水回收池6-2和回用蓄水池6-3。中性水蓄水池5出液口与膜浓缩集成系统6-1进液口相连接；膜浓缩集成系统6-1浓液出口与浓水回收池6-2进液口相连接；膜浓缩集成系统6-1清液出口与回用蓄水池6-3进液口相连接。膜浓缩集成系统6-1为RO膜。膜浓缩集成系统6-1还可以用EDI。
在一具体实施方式中，石膏结晶器为带变频搅拌桨的搅拌罐(釜)或搅拌池任意一种； 所述的石膏结晶器配有加热和保温功能；所述的石膏结晶器配有pH监测功能。
实施例1
利用上述的装置完成一种有机膜与中和剂生产高品质钛石膏的方法，其包括如下步骤：(1)酸性废水调配；(2)酸性废水净化；(3)酸性废水中和结晶；(4)钛石膏脱水；(5)中性水调节排放；其中，
(1)酸性废水调配：以硫酸法钛白粉厂为例，来自一洗叶滤机中产生的酸性废水，由输送泵送至酸性废水调节池1，酸性废水在酸性废水调节池1内进行均质，沉淀，调节酸性废水硫酸浓度3.5％，Fe 2+含量≥6000ppm，流量300L/h；
(2)酸性废水净化：有机膜净化装置2包括预过滤器2-1，预过滤浓液回收池2-2，有机膜系统2-3，有机膜浓液回收池2-4。调节好的酸性废水泵送至预过滤器2-1，预过滤器2-1中采用的是平均孔径是50nm的多通道陶瓷膜在3m/s的膜面流速条件下进行过滤去除偏钛酸，经预过滤器过滤浓缩得到偏钛酸含量高的浓液泵送至预过滤浓液回收池2-2，用于偏钛酸回收，经预过滤器过滤后的清液泵送至有机膜系统2-3进行净化(采用聚酰胺纳滤膜)，其中浓液流量为15L/h，清液流量为285L/h；经有机膜系统净化后的清液泵送至石膏结晶4-1进行结晶反应，经有机膜系统浓缩后的有机膜浓液泵送至有机膜浓液回收池2-4，用于钛矿酸解，其中有机膜清液产水量为256.5L/h，Fe 2+含量10-600ppm，硫酸含量3％，有机膜浓液产水量为28.5L/h，Fe 2+含量≥54600ppm，硫酸含量8％；
(3)酸性废水中和结晶：净化后的酸性废水泵送至石膏结晶器4-1，同时向石膏结晶器4-1中加入配制好的中和剂浆料，所述中和剂浆料为固含量20％的石灰石粉溶液，控制石膏结晶器温度50℃，搅拌速度300r/min，pH值5-8，同时通过固液分离器4-2控制石膏结晶器内浆料浓度固含量为20％，充分搅拌结晶2小时；固液分离器分离的清液输送至调节沉降池4-4。
(4)钛石膏脱水：经结晶完成的石膏浆液通过固液分离器4-2浓缩至固含量35％后输送至石膏脱水机4-3，脱水过程中的清液输送至调节沉降池4-4，脱水后的钛石膏产量16.3kg/h，钛石膏含水率为8％；
(5)中性水调节排放：根据调节沉降池4-4中料液的pH值情况，向调节沉降池中添加中和剂，调节沉降池中料液调节至pH值8-9，沉降浆液泵送至石膏结晶器4-1继续结晶反应，上清液输送至中性水蓄水池5，65L/h中性水输送至中和剂配浆池3用作中和剂配浆水，252L/h中性水达标排放，中性水电导率12000μs/cm，总产水量317L/h；
所生产的钛石膏呈板粒状，如图3所示，粒度分布70-110μm，石膏品位90％、白度90％，石膏含水率为8％。
实施例2
与实施例1的区别是：对超滤膜对偏钛酸的过滤过程进行了改进。
利用上述的装置完成一种有机膜与中和剂生产高品质钛石膏的方法，其包括如下步骤：(1)酸性废水调配；(2)酸性废水净化；(3)酸性废水中和结晶；(4)钛石膏脱水；(5)中性水调节排放；其中，
(1)酸性废水调配：以硫酸法钛白粉厂为例，来自一洗叶滤机中产生的酸性废水，由输送泵送至酸性废水调节池1，酸性废水在酸性废水调节池1内进行均质，沉淀，调节酸性废水硫酸浓度3.5％，Fe 2+含量≥6000ppm，流量300L/h；
(2)酸性废水净化：有机膜净化装置2包括预过滤器2-1，预过滤浓液回收池2-2，有机膜系统2-3，有机膜浓液回收池2-4。
预过滤器2-1中采用的是平均孔径是50nm的多通道陶瓷膜，将其浸泡于饱和石灰溶液中，使Ca(OH)2完全浸入膜孔中，取出后自然晾干，然后采用饱和碳酸钠溶液进行微正压过滤，保持微量的通量条件，使在膜孔中生成碳酸钙；本步骤重复3次。
然后将调节好的酸性废水泵送至预过滤器2-1，在3m/s的膜面流速条件下进行过滤，在多通道陶瓷膜的表面生成偏钛酸滤饼层，随即停止过滤；再采用稀盐酸在微正压的条件下进行过滤，使稀盐酸进入膜孔中将碳酸钙溶解并带出，然后继续采用酸性废水进行过滤；
上述的过滤过程中的通量变化曲线如图3所示。从图中可以看出，相对于实施例1来说，实施例3中的超滤膜的通量衰减更为缓慢，通量较高，说明采用了对膜的预处理方法可以先用碳酸钙占据膜孔中，再在表面生成滤饼之后再溶解去除膜孔中的碳酸钙，可以有效地避免膜孔堵塞污染，有助于提高通量。
经预过滤器过滤浓缩得到偏钛酸含量高的浓液泵送至预过滤浓液回收池2-2，用于偏钛酸回收，经预过滤器过滤后的清液泵送至有机膜系统2-3进行净化(采用聚酰胺纳滤膜)，其中浓液流量为15L/h，清液流量为285L/h；经有机膜系统净化后的清液泵送至石膏结晶4-1进行结晶反应，经有机膜系统浓缩后的有机膜浓液泵送至有机膜浓液回收池2-4，用于钛矿酸解，其中有机膜清液产水量为256.5L/h，Fe 2+含量10-600ppm，硫酸含量3％，有机膜浓液产水量为28.5L/h，Fe 2+含量≥54600ppm，硫酸含量8％；
(3)酸性废水中和结晶：净化后的酸性废水泵送至石膏结晶器4-1，同时向石膏结晶器 4-1中加入配制好的中和剂浆料，所述中和剂浆料为固含量20％的氢氧化钙溶液，控制石膏结晶器温度50℃，搅拌速度300r/min，pH值5-8，同时通过固液分离器4-2控制石膏结晶器内浆料浓度固含量为20％，充分搅拌结晶2小时；固液分离器分离的清液输送至调节沉降池4-4。
(4)钛石膏脱水：经结晶完成的石膏浆液通过固液分离器4-2浓缩至固含量35％后输送至石膏脱水机4-3，脱水过程中的清液输送至调节沉降池4-4，脱水后的钛石膏产量16.3kg/h，钛石膏含水率为11％；
(5)中性水调节排放：根据调节沉降池4-4中料液的pH值情况，向调节沉降池中添加中和剂，调节沉降池中料液调节至pH值8-9，沉降浆液泵送至石膏结晶器4-1继续结晶反应，上清液输送至中性水蓄水池5，36L/h中性水输送至中和剂配浆池3用作中和剂配浆水，252L/h中性水达标排放，中性水电导率12000μs/cm，总产水量288L/h；
所生产的钛石膏呈板粒状，如图4所示，粒度分布40-80μm，并且粒径颗粒分布非常均匀，石膏品位94％、白度92％，石膏含水率为11％。
对照例1
与实施例1的区别在于：酸性废水未采用有机膜对Fe 2+进行过滤去除。
(1)酸性废水调配：以硫酸法钛白粉厂为例，来自一洗叶滤机中产生的酸性废水，由输送泵送至酸性废水调节池1，酸性废水在酸性废水调节池1内进行均质，沉淀，调节酸性废水硫酸浓度3.5％，Fe 2+含量≥6000ppm，流量300L/h；
(2)酸性废水净化：调节好的酸性废水泵送至预过滤器2-1，预过滤器2-1中采用的是平均孔径是50nm的多通道陶瓷膜在3m/s的膜面流速条件下进行过滤去除偏钛酸，经预过滤器过滤浓缩得到偏钛酸含量高的浓液泵送至预过滤浓液回收池2-2，用于偏钛酸回收，经预过滤器过滤后的清液泵送至石膏结晶4-1进行结晶反应，预过滤器产水量为285L/h，Fe 2+含量≥6000ppm，硫酸含量3.5％；
(3)酸性废水中和结晶：净化后的酸性废水泵送至石膏结晶器4-1，同时向石膏结晶器4-1中加入配制好的中和剂浆料，所述中和剂浆料为固含量20％的氢氧化钙溶液，控制石膏结晶器温度50℃，搅拌速度300r/min，pH值5-8，同时通过固液分离器4-2控制石膏结晶器内浆料浓度固含量为20％，充分搅拌结晶2小时；固液分离器分离的清液输送至调节沉降池4-4。
(4)钛石膏脱水：经结晶完成的石膏浆液通过固液分离器4-2浓缩至固含量35％后输 送至石膏脱水机4-3，脱水过程中的清液输送至调节沉降池4-4，脱水后的钛石膏产量35kg/h，钛石膏含水率为43％；
(5)中性水调节排放：根据调节沉降池4-4中料液的pH值情况，向调节沉降池中添加中和剂，调节沉降池中料液调节至pH值8-9，沉降浆液泵送至石膏结晶器4-1继续结晶反应，上清液输送至中性水蓄水池5，29L/h中性水输送至中和剂配浆池3用作中和剂配浆水，266L/h中性水达标排放，中性水电导率12000μs/cm，总产水量295L/h；
所生产的钛石膏呈针片状，如图5和图6所示，粒度分布5-20μm，较多的是小粒径的结晶颗粒，石膏品位87％、白度28％，石膏含水率为43％。可以看出，直接采用未经过有机纳滤膜处理酸性废水进行中和结晶得到的钛石膏粒径小、纯度低。

Claims (10)

  1. 一种膜法处理钛白酸性废水副产高品质钛石膏的方法，其特征在于，包括以下步骤：
    第1步，对硫酸法生产钛白粉过程中产生的酸性废水采用有机膜过滤，去除Fe 2+离子；
    第2步，对第2步得到的废水中加入中和剂，与废水中的硫酸根离子进行沉淀反应生成硫酸钙，并进行结晶；
    第3步，对第2步得到的结晶进行固液分离，得到钛石膏。
  2. 根据权利要求1所述的膜法处理钛白酸性废水副产高品质钛石膏的方法，其特征在于，在一个实施方式中，在第1步之后，需要对酸性废水进行预处理和/或预过滤的步骤；在一个实施方式中，预过滤是用于去除偏钛酸和悬浮物；在一个实施方式中，预处理是指均质、沉淀、调节pH、调节硫酸根离子浓度中的一步或几步的组合；
    在一个实施方式中，所述的调节硫酸根离子浓度是指调节至3-5wt％；
    在一个实施方式中，预过滤采用微滤膜、超滤膜、砂滤器或者袋式过滤器中的一种。
  3. 根据权利要求1所述的膜法处理钛白酸性废水副产高品质钛石膏的方法，其特征在于，在一个实施方式中，预过滤采用陶瓷超滤膜进行过滤；
    在一个实施方式中，超滤膜的过滤方法包括：S1，将陶瓷超滤膜浸泡于饱和石灰水中，取出后自然晾干，再对碳酸钠溶液进行过滤，使在陶瓷超滤膜的膜孔中生成碳酸钙，停止过滤；S2，采用超滤膜对废水进行过滤，使超滤膜的表面形成滤饼，停止过滤；S3，采用超滤膜对稀酸溶液进行过滤，使碳酸钙溶解，停止过滤；S4，采用超滤膜继续对废水进行过滤；
    在一个实施方式中，陶瓷超滤膜的平均孔径范围是20-50nm，所述的碳酸钠溶液的浓度10-15wt％，稀酸溶液是1-5wt％的盐酸溶液；
    在一个实施方式中，所述的S1和S3步骤中，过滤过程的压力控制在0.02-0.05bar。
  4. 根据权利要求1所述的膜法处理钛白酸性废水副产高品质钛石膏的方法，其特征在于，在一个实施方式中，所述的第1步中，有机膜采用的是纳滤膜；
    在一个实施方式中，纳滤膜对Fe 2+的截留率90％-98％，对硫酸的截留率15％-30％；
    在一个实施方式中，中和剂可以是石灰石矿(粉)、生石灰、电石渣、白泥、盐泥、消石灰、碱渣的一种或几种；中和剂加入时是以浆料方式加入，浆料固含量为5％-35％；
    在一个实施方式中，还需要对第3步中得到的清液调节pH；在一个实施方式中，清液调节pH是指调节至5-9，并且在调节pH之后的清液送入膜浓缩集成系统进行纯化。
  5. 根据权利要求1所述的膜法处理钛白酸性废水副产高品质钛石膏的方法，其特征在于，在一个实施方式中，膜浓缩集成系统中采用RO膜或EDI设备任意一种或几种；
    在一个实施方式中，第3步中，固液分离采用旋流分离器或者过滤分离器或者离心分离器；
    在一个实施方式中，固液分离后，还需要对固体进行脱水；脱水采用的是板框压滤。
  6. 一种膜法处理钛白酸性废水副产高品质钛石膏的装置，其特征在于，包括：
    有机膜系统(2-3)，用于对硫酸法生产钛白粉过程中产生的酸性废水进行纳滤去除Fe 2+处理；
    石膏结晶器(4-1)，连接于有机膜系统(2-3)的渗透侧，用于对有机膜系统(2-3)得到的滤液进行沉淀、结晶处理；中和剂配浆池(3)连接于石膏结晶器(4-1)，用于向石膏结晶器(4-1)中加入中和剂进行沉淀反应；
    固液分离器(4-2)，连接于石膏结晶器(4-1)，用于对结晶过程的硫酸钙沉淀进行固液分离。
  7. 根据权利要求6所述的膜法处理钛白酸性废水副产高品质钛石膏的装置，其特征在于，
    还包括：预过滤器(2-1)，连接于酸性废水调节池(1)的出水口，用于对酸性废水调节池(1)产水进行预过滤处理，并且预过滤器(2-1)与有机膜系统(2-3)连接；
    还包括：酸性废水调节池(1)，用于对酸性废水进行均质、沉淀处理；并且酸性废水调节池(1)与预过滤器(2-1)的渗透侧连接；
    在一个实施方式中，预过滤器(2-1)是无机膜过滤器、砂滤器或者袋式过滤器中的一种；
    在一个实施方式中，预过滤器是管式或者多通道式的无机膜；
    在一个实施方式中，所述的无机膜包括壳体(2-1a)以及两端的封头(2-1b)，在壳体(2-1a)的内部安装有管式或者多通道式的无机膜(2-1e)，封头(2-1b)上分别设进液口(2-1c)以及出液口(2-1d)，所述的无机膜(2-1e)的靠近进液口(2-1c)一端的通道处设锥形进料口(2-1f)，其较小截面一端朝向无机膜(2-1e)，在锥形进料口(2-1f)的内部设有螺纹槽(2-1g)，所述的螺纹槽(2-1g)用于将进入无机膜(2-1e)的流体产生旋流；
    在一个实施方式中，所述的无机膜(2-1e)是微滤膜或者超滤膜；
    在一个实施方式中，还包括：预过滤浓液回收池(2-2)，连接于预过滤器(2-1)的浓缩侧，用于对预过滤器(2-1)得到的浓液进行收集；
    在一个实施方式中，所述的有机膜系统(2-3)是纳滤膜。
  8. 根据权利要求6所述的膜法处理钛白酸性废水副产高品质钛石膏的装置，其特征在于，在一个实施方式中，还包括：有机膜浓液回收池(2-4)，连接于有机膜系统(2-3)的浓缩侧，用于收集有机膜系统(2-3)的浓液；
    在一个实施方式中，还包括：石膏脱水机(4-3)，连接于固液分离器(4-2)，用于对分离 得到的硫酸钙沉淀进行脱水；
    在一个实施方式中，还包括：调节沉降池(4-4)，连接于固液分离器(4-2)的滤液侧，用于对固液分离器(4-2)中得到的滤液进行pH调节；
    在一个实施方式中，还包括：中性水蓄水池(5)，连接于调节沉降池(4-4)，用于对调节沉降池(4-4)中的废水的pH进行调节。
  9. 根据权利要求6所述的膜法处理钛白酸性废水副产高品质钛石膏的装置，其特征在于，在一个实施方式中，还包括：膜浓缩系统(6-1)，连接于中性水蓄水池(5)，用于对中性水蓄水池(5)中得到的中性废水进行浓缩过滤；
    在一个实施方式中，所述的膜浓缩系统(6-1)是RO膜或者RO膜或EDI设备；
    在一个实施方式中，还包括：浓水回收池(6-2)，连接于膜浓缩系统(6-1)的浓液侧，用于对膜浓缩系统(6-1)中得到的浓缩液进行收集；
    在一个实施方式中，还包括：回用蓄水池(6-3)，连接于膜浓缩系统(6-1)的滤液侧，用于对膜浓缩系统(6-1)中得到的滤液进行收集。
  10. 权利要求6所述的膜法处理钛白酸性废水副产高品质钛石膏的装置在用于生产钛石膏中的应用。
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CN116177779A (zh) * 2022-12-09 2023-05-30 四川大学 钛白废水的回收利用方法
CN116177779B (zh) * 2022-12-09 2024-04-19 四川大学 钛白废水的回收利用方法

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