CN205087969U - Titanium white powder plain boiled water recycling system - Google Patents

Abstract

The utility model discloses a titanium white powder plain boiled water recycling system, this scheme uses the plain boiled water that produces as raw materials water in the sulfate process titanium dioxide powder production technology, at first filter through a membrane system and get rid of solid particle, then filter through the secondary membrane system and get rid of ferrous sulfate, titanyl sulfate and partial sulphuric acid, and water purification that the secondary membrane filtration produced can direct retrieval and utilization be washed to two. The titanium unit of this scheme dialogue aquatic have the high rate of holding back, therefore can improve the titanium white rate of recovery, this scheme can also reduce the quantity of the fresh water of washing in addition, reduces the emission of waste water. This scheme configuration is nimble, can be used in plain boiled water filter sediment workshop section after, also substituted plain boiled water filter sediment workshop section. This scheme is applicable to sulfate process titanium dioxide powder trade, can improve the titanium white rate of recovery, reduces the fresh water quantity of washing, reduces wastewater discharge.

Description

A titanium dioxide white water reuse system

technical field

The utility model relates to a sulfuric acid method titanium dioxide process, in particular to a titanium dioxide white water reuse process.

Background technique

The sulfuric acid titanium dioxide process has a large demand for water. At present, the second washing water is directly applied to the first washing. The first washing water (white water) is filtered or precipitated and then discharged to the water treatment workshop. The amount of white water is 20-30 tons. / ton of titanium dioxide.

Because the white water also contains a lot of metatitanic acid particles that pass through the filter, in order to recover this part of titanium, the white water needs to be filtered or precipitated before being discharged to the water treatment workshop. Commonly used filters include core filter, CN filter, tubular filter and hollow fiber membrane filter, and the sedimentation tank is generally a high-density inclined plate/tube sedimentation tank. Various forms of filters and sedimentation tanks play an important role, but they also have their own defects, such as frequent replacement of core filter elements, loss of metatitanic acid in the early stage of CN filter cake formation and backwashing, tubular filtration The energy consumption of the machine is high, the flux of the hollow fiber membrane is small, the solid resistance is poor, the backwash is not easy, and the precision of the sedimentation tank is low.

The conventional treatment method for white water after filtration or precipitation is to add lime to neutralize the precipitation. Although the treatment process is not complicated, the treatment process is long and the treatment cost is high. In order to save energy and protect the environment, many enterprises have adopted the reclaimed water recycling process with the membrane process as the core. The water quality of the membrane process is good, but the discharge of concentrated brine is the main problem they face. The "Notice of the State Council on Printing and Distributing the Action Plan for Water Pollution Prevention and Control" (referred to as "Water Ten Measures") issued by the State Council of China has strict requirements on the salt content indicators and the total amount of salt in the effluent, so the treatment of concentrated brine will be a big deal. investment.

From the perspective of energy saving and environmental protection, white water reuse is an obvious way, and membrane treatment process is the main way of white water reuse. There are three core issues in the membrane process:

The first is the choice of the pre-filter of the membrane, because metatitanic acid mostly exists in the form of submicron particles in white water, which is easy to adhere to the surface of the separation membrane, block the separation membrane, and is not easy to clean, which will greatly affect the separation efficiency of the separation membrane and service life.

The second is the discharge of concentrated brine. The discharge of concentrated brine is inevitable, but the discharge can be more or less.

The third is the water quality of the clear liquid treated by the membrane. If the clear liquid is to be reused, it must be ensured that the acidity of the clear liquid is within a certain range, too high or too low acidity will affect the quality of titanium dioxide; in addition, it must be ensured that the concentration of ferrous ions in the clear liquid is low enough to ensure that the washed material Can pass.

Utility model content

In view of the problems existing in the white water reuse technology in the existing sulfuric acid titanium dioxide process, the purpose of the utility model is to provide a white water reuse system that can improve the recovery rate of titanium dioxide, reduce the amount of fresh water for washing, and reduce the discharge of waste water.

In order to achieve the above object, the utility model adopts the following technical solutions:

A titanium dioxide white water reuse system, the system mainly includes:

A primary membrane system, which removes solid particles in white water to form clear liquid;

A secondary membrane system, the secondary membrane system removes iron ions, titanium ions and sulfuric acid in the clear liquid formed by the primary membrane system to form purified water.

Preferably, the raw material inlet of the primary membrane system is connected to the white water produced in the sulfuric acid titanium dioxide production process, the concentrated liquid outlet is connected to the first washing tank in the sulfuric acid titanium dioxide production process, and the clear liquid outlet is connected to the secondary Import of membrane system.

Preferably, the primary membrane filtration adopts a tubular microfiltration membrane, the precision of the microfiltration membrane is 50-500 nanometers, and the transmembrane pressure difference is 0.05-0.8 MPa.

Preferably, the concentrated liquid outlet of the secondary membrane system is connected to the wastewater treatment plant, and the purified water outlet is connected to the secondary washing system in the sulfuric acid titanium dioxide production process.

Preferably, the sulfuric acid concentration in the purified water produced by the secondary membrane filtration is 0.05-6%, the ferrous ion concentration is 0-2ppm, and the overall recovery rate is 75-95%.

Preferably, the secondary membrane system includes the cooperation of the nanofiltration membrane and the reverse osmosis membrane, the concentrated liquid produced by the nanofiltration membrane and the reverse osmosis membrane is combined and sent to the wastewater treatment workshop, and the clear liquid produced by the nanofiltration membrane and the reverse osmosis membrane is combined Afterwards, it is reused in the secondary washing system in the sulfuric acid method titanium dioxide production process.

Preferably, the nanofiltration membrane intercepts ferrous ions and titanyl sulfate in waste acid, allowing sulfuric acid to pass through, and its rejection rate to ferrous ions is 85-99.8%, and the rejection rate to titanyl sulfate is 80-99.8%. 99.8%, the sulfuric acid resistance concentration is 0-30%, and the operating pressure is 1.5-6.5MPa.

Preferably, the reverse osmosis membrane retains ferrous ions, titanyl sulfate and sulfuric acid in waste acid, and its rejection rate to ferrous ions is 98-99.8%, and the retention rate to titanyl sulfate is 80-99.8%, The rejection rate of sulfuric acid is 85-99.8%, the sulfuric acid resistance concentration is 0-15%, and the operating pressure is 3.5-6.5MPa.

The scheme provided by the utility model has a very high interception rate for titanium elements in white water, which can improve the recovery rate of titanium dioxide; in addition, this scheme can also reduce the consumption of fresh water for washing and reduce the discharge of waste water; moreover, this scheme is flexible in configuration, It can be used after the white water filtration and precipitation section, and can also replace the white water filtration and precipitation section.

Therefore, this scheme is suitable for the sulfuric acid process titanium dioxide industry, which can improve the recovery rate of titanium dioxide, reduce the amount of fresh water for washing, and reduce waste water discharge.

Description of drawings

The utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is the schematic diagram of titanium dioxide white water reuse system in the utility model;

Fig. 2 is the application schematic diagram of titanium dioxide white water reuse system in the utility model;

Fig. 3 is the process flow diagram of titanium dioxide white water reuse in the utility model.

detailed description

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, the utility model will be further elaborated below in conjunction with specific illustrations.

The titanium dioxide white water reuse scheme provided by the utility model cooperates with the sulfuric acid method titanium dioxide production scheme, and the white water produced in the sulfuric acid method titanium dioxide production process is used as raw material water. Firstly, the raw material water is subjected to a membrane filtration to remove solid particles in the raw material water. Form the supernatant (the produced concentrated solution is returned to the first cleaning tank in the sulfuric acid titanium dioxide production process); then the clear solution is subjected to secondary membrane filtration to remove iron ions, titanium ions and sulfuric acid to form clean water (the produced concentrated The liquid is sent to the wastewater treatment workshop for wastewater treatment), and the purified water is directly reused for the second washing in the sulfuric acid titanium dioxide production process.

Accordingly, the utility model realizes the reuse of titanium dioxide white water through a titanium dioxide white water reuse system.

Referring to FIG. 1 , the titanium dioxide white water reuse system mainly includes two parts: a primary membrane system 100 and a secondary membrane system 200 . The titanium dioxide white water reuse system thus constituted cooperates with the sulfuric acid method titanium dioxide production system to realize the reuse of titanium dioxide white water.

The primary membrane system 100 is used to remove solid particles in white water produced in the sulfuric acid titanium dioxide production process to form a corresponding clear liquid.

The primary membrane system 100 is mainly composed of tubular microfiltration membranes, and has a raw material inlet, a concentrated liquid outlet, and a clear liquid outlet. In the first washing and loading tank in the titanium dioxide production process of the French method, the clear liquid outlet is used to connect to the inlet of the secondary membrane system 200 .

The precision of the microfiltration membrane used in the tubular microfiltration membrane in the primary membrane system 100 is 50-500 nanometers, and the transmembrane pressure difference is 0.05-0.8MPa. Therefore, the raw material water entering from the raw material import (i.e. produced in the production process of sulfuric acid titanium dioxide) white water) to filter, remove solid particles (such as metatitanic acid particles) in the white water as raw material water, form the corresponding clear liquid, and pass to the inlet of the secondary membrane system 200 through the clear liquid outlet; The liquid is passed through the concentrated liquid outlet to the first washing tank in the sulfuric acid titanium dioxide production process.

The secondary membrane system 200 is used to remove iron ions, titanium ions and sulfuric acid in the clear liquid formed by the primary membrane system 100 to form clean water that can be used for secondary washing in the sulfuric acid titanium dioxide production process.

The secondary membrane system 200 is mainly composed of a multi-stage nanofiltration membrane and a multi-stage reverse osmosis membrane, and has a clear liquid inlet, a purified water outlet, and a concentrated liquid outlet, wherein the clear liquid inlet is connected to the clear liquid of the primary membrane system 100. The liquid outlet, the concentrated liquid outlet is connected to the wastewater treatment workshop, and the purified water outlet is connected to the secondary washing and filtering equipment in the sulfuric acid titanium dioxide production process. In the secondary membrane system 200 thus constituted, the concentrated liquid produced by the nanofiltration membrane and the reverse osmosis membrane is combined and sent to the wastewater treatment plant, and the purified water produced by the nanofiltration membrane and the reverse osmosis membrane is combined and reused to the secondary washing system.

Among them, the nanofiltration membrane in the secondary membrane system 200 is used to intercept ferrous ions and titanyl sulfate in waste acid, allowing sulfuric acid to pass through. The rejection rate of the nanofiltration membrane to ferrous ions is 85-99.8%. The interception rate of titanyl sulfate is 80-99.8%, the sulfuric acid resistance concentration is 0-30%, and the operating pressure is 1.5-6.5MPa. In actual use, secondary or tertiary nanofiltration membranes can be used.

The reverse osmosis membrane in the secondary membrane system 200 is used as the interception of ferrous ions, titanyl sulfate and sulfuric acid in the waste acid. The rate is 80-99.8%, the rejection rate of sulfuric acid is 85-99.8%, the sulfuric acid resistance concentration is 0-15%, and the operating pressure is 3.5-6.5MPa. In actual use, secondary or tertiary reverse osmosis membranes can be used.

The concentration of sulfuric acid in the purified water produced by the secondary membrane system 200 thus constituted is 0.05-6%, and the concentration of ferrous ions is 0-2ppm. The secondary membrane system 200 is capable of achieving an overall recovery of 75-95%.

Referring to Fig. 2, when the titanium dioxide white water recycling system formed based on the above scheme is in specific application, the inlet of the primary membrane system 100 is connected to the white water of the primary washing filter device 400 in the sulfuric acid process titanium dioxide production system through the corresponding filtration/sedimentation equipment 300 Outlet, the clear liquid outlet is connected to the clear liquid inlet of the secondary membrane system 200, and the concentrated liquid outlet is connected to a washing and loading tank.

In addition, the primary membrane system 100 can replace the filtration/sedimentation device 300 and be directly connected to the primary filtration device 400 as needed.

The clean water outlet of the secondary membrane system 200 is connected to the clear liquid inlet of the secondary washing filter equipment 500 in the sulfuric acid titanium dioxide production system, and the concentrated liquid outlet is connected to the wastewater treatment equipment 600 in the wastewater treatment workshop.

Thus, the process of reusing the titanium dioxide white water produced in the sulfuric acid titanium dioxide production process is as follows (see Figure 3):

First, the white water produced by the first washing filter equipment 400 enters the filtration/precipitation equipment 300, and the filtered or precipitated white water enters the primary membrane system 100, and the primary membrane system 100 completely intercepts the metatitanic acid particles in the white water, and the produced metatitanic acid The acid granule dope returns to a washing and loading tank and enters a washing and filtering device 400 again. In this way, the metatitanic acid particles in the white water are completely trapped in the system and will not enter the wastewater treatment system for loss.

The clear liquid produced by the first washing filter device 400 enters the secondary membrane system 200, the secondary membrane system 200 is partly a nanofiltration membrane and partly a reverse osmosis membrane, wherein the nanofiltration membrane can withstand sulfuric acid with a mass concentration of 30%, and allows sulfuric acid to permeate However, it can intercept ferrous ions and titanyl sulfate. The reverse osmosis membrane can withstand sulfuric acid with a mass concentration of 15%, and can intercept sulfuric acid, ferrous ions and titanyl sulfate.

In this way, the acidity of the supernatant after combining the water produced by the nanofiltration membrane and the reverse osmosis membrane is maintained in an appropriate range. And higher than the water.

In this way, the ferrous ion concentration of the supernatant after the combination of nanofiltration membrane water and reverse osmosis membrane water production is lower than 2ppm, which fully meets the washing water requirements of the secondary washing water. The concentrated liquid produced by the nanofiltration membrane and the reverse osmosis membrane is sent to the waste water treatment equipment 600 for waste water treatment, and the concentrated water amount does not exceed 10% of the white water amount, which is far lower than the white water amount directly sent to the waste water treatment.

The scheme is further illustrated by a specific example as follows:

In this example, the quality of the filtered white water is 2300 mg/L of ferrous ion concentration, 1500 mg/L of titanyl sulfate, and 3% of sulfuric acid. The white water is firstly treated by the tubular microfiltration membrane of the primary membrane system. The microfiltration membrane has a precision of 500 nanometers and a transmembrane pressure difference of 0.2MPa.

After being treated by the primary membrane system, the concentrated solution containing metatitanic acid is returned to the first washing tank, and the clear solution is sent to the secondary membrane system.

In the secondary membrane system, the operating pressure of nanofiltration membrane is 2MPa, and the operating pressure of reverse osmosis is 3.5MPa. The titanyl content is 2.4 mg/L, and the sulfuric acid content is 0.5%.

The clear liquid thus formed is sent to the secondary washing section for use as secondary washing water. The amount of dope produced by the secondary membrane system is 8.5% of the water inflow of membrane system 1.

The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (6)

1. a titanium dioxide white water recycling system, is characterized in that, described system mainly comprises:

A membranous system, a described membranous system removes the solid particulate in plain boiled water, forms clear liquid;

Secondary membranous system, iron ion, titanium ion and sulfuric acid that described secondary membranous system is removed in the clear liquid of a membranous system formation form water purification;

A described membrane filtration adopts tube type filter membrance, and its microfiltration membrane precision is 50-500 nanometer, and transmembrane pressure is 0.05-0.8MPa;

Described secondary membranous system comprises nanofiltration membrane and reverse osmosis membrane has coordinated, send effluent treatment plant after the dope that nanofiltration membrane and reverse osmosis membrane produce merges, after the clear liquid that nanofiltration membrane and reverse osmosis membrane produce merges, reuse washes system to two in sulfuric acid method titanium pigment production technique.

2. a kind of titanium dioxide white water recycling system according to claim 1, it is characterized in that, the material inlet of a described membranous system is communicated with the plain boiled water produced in sulfuric acid method titanium pigment production technique, dope outlet is connected to one in sulfuric acid method titanium pigment production technique and washes in film trap, and purified liquor outlet is connected to the import of secondary membranous system.

3. a kind of titanium dioxide white water recycling system according to claim 1, is characterized in that, the outlet of the dope of described secondary membranous system is connected to effluent treatment plant, and what pure water inlet was connected in sulfuric acid method titanium pigment production technique two washes system.

4. a kind of titanium dioxide white water recycling system according to claim 1, is characterized in that, in the water purification that described secondary membrane filtration produces, sulfuric acid concentration is 0.05-6%, and ferrous ion concentration is 0-2ppm, and the overall rate of recovery is 75-95%.

5. a kind of titanium dioxide white water recycling system according to claim 1, it is characterized in that, described nanofiltration membrane retains ferrous ion in spent acid and titanyl sulfate, allow sulfuric acid through, it is 85-99.8% to the rejection of ferrous ion, be 80-99.8% to the rejection of titanyl sulfate, resistance to sulfuric acid concentration is 0-30%, and working pressure is 1.5-6.5MPa.

6. a kind of titanium dioxide white water recycling system according to claim 1, it is characterized in that, described reverse osmosis membrane retains ferrous ion, titanyl sulfate and sulfuric acid in spent acid, it is 98-99.8% to the rejection of ferrous ion, be 80-99.8% to the rejection of titanyl sulfate, be 85-99.8% to the rejection of sulfuric acid, resistance to sulfuric acid concentration is 0-15%, and working pressure is 3.5-6.5MPa.