Method for waste water treatment and preparing magnetic flocculant by reclaimed flocculant

Technical Field

This invention belongs to the field of environmental resources, relates to the recovery of iron in iron-containing waste water, turbidity removing and magnetic flocculant producing process, in order to realize iron and in waste water reuse of floc.

Technical background

In recent years, because of economic development and increase of the population, my metallurgical, thermal power plant also increase rapidly, gas and the like caused by this more cleaning waste water, also of the iron ions in waste water is gradually increased, which not only pollute the environment but caused by shortage of water resources, therefore, for containing solid suspended matter, such as iron powder in the waste water has become a major problem of water treatment.

The treatment of solid suspended matter commonly used method is to use a flocculant, commonly used inorganic flocculating agent with aluminum salts and iron salt two major categories, iron salt to ferric sulfate, ferric chloride-based. Although the development of polymeric aluminum synthesized, polymerized ferric sulfate and the like has the water treatment agent, the polymer not only has the role of adsorption and stable, but also can play a stiction, bridged and flocculation volume sweeping, have reduced the cost of processing, improves the efficacy, large water content, however, after the body, simply polymeric flocculating agent settling speed is slow, but also can not achieve the purpose of recycling, waste of resources, and the outer row of secondary pollution is caused.

In the existing literature, public number CN101054222 Patent, process for producing of flocculating agent of the composite and method of harnessing alga bloom, mainly utilizes the fly ash, ultra-pure magnet powder, the reaction product of concentrated hydrochloric acid, iron and aluminum polychloride is by mixing, which can not only effectively absorb and flocculate antialgae, the cotton wool body is big and formed compact, rapid sedimentation speed, through the outer magnetic field can be rapidly algae cotton wool body out the role of the water, in the water and nitrogen, phosphor removing effect is very remarkable, and the sample can be done, fundamentally hazards posed by the outbreak of algal bloom. In ocean tide and laky eutrophication fields has popularization and application prospects. Discloses number 101186370 of the Patent for the purification of industrial waste water containing chromium composite flocculant magnetite powder, by using composite flocculant purifying industrial waste water containing chromium method, a reference for the purification of industrial waste water containing chromium composite flocculant magnetite powder, the composite flocculant and coagulant aid composite formed by the flocculating agent, the flocculating agent is cationic polyacrylamide high-molecular flocculant and polymerization of ferrous sulfate as the composite ratio is: iron/organic ratio is 0.6-1.2/1 . 8-2.8. In optimization scheme also added composite flocculant 200-800mg/L of the magnet powder, is mainly used for the removal of chromium from waste solution. Separating the papers in the literature and magnetic flocculation research is more extensive, such as guo Yufeng , such as dong Haigang , zhongnan University Journal, 2006 years 4 months, mentioned selective flocculation magnetic separation recovery of nickel PCCMPS of magnetite in; li Qiuping , JiangXi non-ferrous metal, 1996 years 1 month, from a certain ore of recovering iron pyrite in the study of cinder; yang Yongle , money permanent magnet separation of the rolling use in waste water treatment, Shanghai metal, 1999 years 1 month; wang Zuoshun the application of the test of the sewage treating steel rolling magnetism flocculation law , metallurgical power, 1994 years 5 months, zheng Xuehai , cheap yang Yan Taoeast Liu and magnetic and magnetic flocculation development and application of the separation device, the water supply and drainage, 2000 years 8 months, shen Xiaoli , by jiang Yongnianshen Jing and the high magnetic separation treatment of waste water containing heavy metals by electro-plating nickel-containing waste water application to process the intermediate test, environment science and technology, 1988 years 1 month, the magnetic field of and luo Manlu Zhu sterilization of water treatment study the effects on performance, water treatment technology, 2001 year 3 months, of DALIAN University of active carbon powder bestows on magnetism removing the organic matter in the drinking water, the water supply and drainage, 2001 year 2 months, and natural polymer modified flocculant performance and synergistic coagulation study of effectiveness of the magnetic field, environmental science, 1999 years 1 month, and a series of papers, mainly utilizes an external magnetic field to the iron of adsorption or magnetized and under the action of external magnetic field to remove the pollutant in the technical and theoretical research.

Although the method of the above-mentioned literature referred to play a certain role to improve the environment, but not to the flocculating agent and in the recovery of waste water to the iron element, not completely solve the problem of environmental pollution, from the perspective of the use of resources is a waste.

Although the method of the above-mentioned literature referred to play a certain role to improve the environment, but not to the flocculating agent and in the recovery of waste water to the iron element, not completely solve the problem of environmental pollution, from the perspective of the use of resources is a waste.

Content of the invention

The technical scheme of the present invention are as follows:

Step 1. The ferrous iron and trivalent molysite in accordance with the molar ratio of 2 the [...] 3 mixing, heating and stirring to rise to the 55 [...] , slowly adding sodium hydroxide or ammonia, the molar ratio of alkali iron with the 1 [...] the 4-1 [...] 3, curing 0.5-5 hours; then adding acid to adjust stock solution is an acidic, add 3%-10% hydrogen peroxide or blast air to all oxidation of ferrous ions to a ferric iron, containing flocculant gelatineous of the magnetic powder;

In the process according to the acid-water corrosion and scaling for determination of the characteristics, such as sulfuric acid or hydrochloric acid in the waste water of other acid dissolution siderous floc, filtering, be ferrous salt and molysite; and utilize the air partial oxidation into ferric sulfate or ferric chloride.

Step 2. The molysite and magnetic powder according to the proportion of the 30-5 [...] 1 obtained by mixing a plurality of groups of flocculating agent liquid.

Step 3. The above-mentioned plurality of groups of flocculating agent for treating iron-containing waste water, respectively, is determined according to the degree of turbidity and iron magnetic flocculant lower than the adding amount of 20 milligram/L, to stir, adding an amount of alkali for pH 8-10, rapid stirring then slowly stirring first, is provided with a surface magnetic field is then put in 0.2-1.5T of the permanent magnet, static precipitation.

Step 4. After clarification to be the supernatant fluid, the water is discharged or use of vacuum suction. Device for removing the magnetic field by using a mechanical or air swept recovery of the precipitated floc, or not mobile magnetic field device is directly proceeding to the next step.

Step 5. In the process according to the acid-water corrosion and scaling for determination of the characteristics, such as sulfuric acid or hydrochloric acid in the waste water of other acid dissolution siderous floc generating molysite, filtering, ferrous salt and molysite obtained. According to step 1 of preparation of magnetic flocculating agent.

The beneficial effect of the invention is through the use of the recovered flocculate synthetic magnetic flocculating agent, for treating iron-containing waste water can be dense floc, and the fast sedimentation cotton wool physical ability , low water content; and the turbidity of the water sample are all very high removal rate of the iron; in using permanent magnet device can be 0.2-1.5T the floc recycling, wherein the magnetic powder can be preparing magnetic flocculant, to achieve the results of the repeated use, and the loss of magnetic powder do not, in the recovery process.

Backwater the iron content can be controlled within 1.0 milligram/L, turbidity in the 5 milligram/L the following, some enterprises achieve flushing water standard production process.

By using recycled body and a magnetic powder of the flocculant is not only used for the process, used for other waste water, such as algae-containing waste water also has good effect.

Description of drawings

With photos for ferromagnesian waste water treatment process flow chart.

Specific embodiment

With a combination of the following detailed description and the specific examples of this invention.

Embodiment 1

The iron-containing waste water, the turbidity of the water is measured for 300, suspended matter 200 milligram/L, total iron content is 30 milligram/L, with the above-mentioned method homestyle ferric sulfate flocculant and homestyle magnetic powder proportional mixing, to present a large number of dense floc, and after mixing, heating the supernatant, turbidity and iron content of the finder. The results are as follows (all heating 40 milliliter water sample):

Embodiment 2

Taking the old age soil homestyle high turbidity of the sample water, the water is measured for turbidity of 69.3 milligram/L, of ferric chloride with proportional mixing of the flocculating agent and the magnetic powder, a large amount of room for the body, and after mixing, heating the supernatant, turbidity and iron content of the finder. The results are as follows (all heating 40 milliliter water sample):

Embodiment 3

Respectively for turbidity takes contains 55.33 algae-containing water sample of 150 milliliter, pH is 7.51, according to for 0.15mmol/L add magnetic concentration of the flocculating agent, stirring the rear, taking supernatant turbidity and iron content of the finder. The results are as follows: