Application of anionic polyacrylamide  in mineral processing

 

Polyacrylamide product introduction: polyacrylamide (PAM) is a water-soluble polymer, insoluble in most organic solvents, has good flocculation, can reduce the friction resistance between the liquid, according to the ionic characteristics can be divided into non-ionic, anion, cation and amphoteric type four types. (Note: Polyacrylamide is different from acrylamide)

PAM polyacrylamide is made of acrylamide (AM) monomer by free radical polymerization of water-soluble linear polymer, has good flocculation, can reduce the friction resistance between the liquid, according to the ionic characteristics can be divided into non ion, anion, cation and amphoteric type four types. Polyacrylamide (PAM) is insoluble in most organic solvents, such as methanol, ethanol, acetone, ether, aliphatic hydrocarbons and aromatic hydrocarbons, with the exception of a few organic solvents, such as acetic acid, acrylic acid, chloroacetic acid, ethylene glycol, glycerin, molten urea and formamide. However, these organic solvents have limited solubility and often need to be heated, otherwise there is little application value.

 

At a suitable low concentration, the polyacrylamide solution can be regarded as a network structure, which is formed by mechanical entanglement and hydrogen bond between chains. At higher concentrations, PAM solutions are gelatinous because they contain many chain-by-chain contact points. PAM aqueous solution has good compatibility with many organic compounds that are mutually soluble with water, and has good compatibility with electrolytes. It is not sensitive to such substances as amine chloride, calcium sulfate, copper sulfate, potassium hydroxide, sodium carbonate, sodium borate, sodium nitrate, sodium phosphate, sodium sulfate, zinc chloride, boric acid and phosphoric acid.

 

Polyacrylamide mesh:

Mesh refers to the particle size or fineness of the material, mesh is the number of squares per unit area. The general definition refers to the number of meshes in an area of 1 inch *1 inch, that is, the number of meshes of the screen. Such as 600 mesh is 600 square mesh per square inch, polyacrylamide mesh 20 ~80 mesh, that is, between 0.85mm~0.2mm, this is the mesh size of granular polyacrylamide, powder polyacrylamide mesh size can be controlled in about 100 mesh, the larger the polyacrylamide is more easily dissolved, The size of polyacrylamide mesh alone is unable to measure the quality of the product!

 

Polyacrylamide is white powder or small particles, density of 1.32g/cm3(23 degrees), glass temperature of 188 degrees, softening temperature of nearly 210 degrees, the general method of drying contains a small amount of water, dry and will soon absorb water from the environment, with freeze-drying separation of homopolymer is white soft amorphous solid, But when precipitated from the solution and drying is vitreous partially transparent solid, completely dry PAM PAM is brittle solid white, dry goods polyacrylamide is usually under the condition of moderate dry, average moisture content is 5% ~ 15%, casting preparation of polymer film on the glass, are transparent, hard, brittle solid.

Industrial application of polyacrylamide

1, used in papermaking industry, one is to improve the retention rate of filler, pigment, etc. To reduce the loss of raw materials and environmental pollution; Two is to improve the strength of the paper (including dry strength and wet strength), in addition, the use of PAM can also improve the tear resistance and porosity of the paper, to improve the visual and printing performance, but also used in food and tea wrapping paper.

 

2, used in the petroleum industry, oil recovery, drilling mud, waste mud treatment, prevent water channelling, reduce friction, improve oil recovery, three oil recovery has been widely used.

 

3, used for textile sizing agent, slurry stable performance, less falling pulp, fabric breakage rate is low, clean cloth.

 

4, PAM is also widely used in thickening, stable colloid, drag reduction, bonding, film forming, biomedical materials and so on.

 

5, other industries, food industry, used for sugar cane sugar, sugar beet sugar production sugar juice clarification and syrup phosphorus float extraction. Enzyme preparation fermented liquid flocculation clarifying industry, also used in feed protein recovery, stable quality, good performance, recovery of protein powder to chickens and raising the survival rate of weight gain, no adverse effects of egg production, synthetic resin coating, civil water plugging grouting materials, building materials industry, improve the quality of cement, construction adhesive, caulking repair and plugging agent, soil improvement, electroplating industry, printing and dyeing, etc.

 

Polyacrylamide for air flotation:

First of all, understand which industries are commonly used to the air flotation industry, air flotation is mainly the use of gas to oxidize sewage, air flotation is mostly for the depth treatment of secondary biological treatment, the current common industry is for the supplementary treatment of oily sewage after oil separation. Air flotation can be used to concentrate activated sludge effectively. Removal of suspended impurities in sewage. Anionic polyacrylamide used in air flotation has better effect, especially partial reflux dissolved gas flotation, which has the advantages of full reflux and dissolved gas flotation. Compared with distributed air flotation, it has the characteristics of large amount of sewage treatment and high treatment effect. Compared with the electrolysis float method, it has the advantages of saving electric energy and lower operating cost, and is suitable for the requirements of energy saving, environmental protection, consumption reduction and efficiency increase of modern enterprises.

 

Polyacrylamide features:

1, flocculation. PAM can electrically neutralize suspended substances and flocculate them

 

2, adhesion. Can through the physical chemical action and so on to play the role of adhesion

 

3, thickening agent. Thickening in both neutral and acidic conditions, PAM readily hydrolyzes if the PH is above 10.

 

Polyacrylamide precautions:

Cationic polyacrylamide use precautions:

 

1, the size of flocs: flocs too small will affect the speed of drainage, flocs too large so that flocs bind more water and reduce the mud biscuit degree. By choosing the molecular weight of polyacrylamide can adjust the size of the floc.

 

2, sludge characteristics: a point to understand the source of sludge, characteristics and composition, proportion. According to different properties, sludge can be divided into organic and inorganic sludge. Cationic polyacrylamide is used for the disposal of organic sludge, relative anionic polyacrylamide flocculant for inorganic sludge, strong alkaline anionic polyacrylamide, and strong acid should not be used anionic polyacrylamide, high solid content of sludge usually polyacrylamide dosage is also large.

 

3, flocs strength: flocs should be stable and not broken under shear action. Improving the molecular weight of polyacrylamide or choosing suitable molecular structure can improve the stability of the flocculation.

 

4, polyacrylamide ionic degree: for dehydrated sludge, can use different ionic degree of flocculant after doing the first test selection, choose the best suitable polyacrylamide, so that can get the best flocculant effect, and can make the dosage is less, save money.

 

5, the dissolution of polyacrylamide: good solution to give full play to flocculation. Sometimes the need to accelerate the dissolution rate, then you can think of improving the concentration of polyacrylamide solution.

 

Polyacrylamide use characteristics:

1, flocculation: PAM can make suspended material through electric neutralization, bridge adsorption, flocculation.

 

2, adhesion: through mechanical, physical, chemical action, play the role of adhesion.

 

3, resistance reduction: PAM can effectively reduce fluid friction resistance, adding trace PAM in water can reduce resistance by 50-80%.

 

4, thickening: PAM in neutral and acid conditions have thickening effect, when the PH value of PAM is more than 10 easy hydrolysis. Thickening will be more pronounced with a semi-reticular structure.