Method for preparing water purifying agent containing polyaluminum sulfate from aluminum ash, sulfuric acid and optional red mud

Abstract

The invention provides a method for preparing a water purifying agent containing polyaluminum sulfate from aluminum ash, sulfuric acid and optional red mud, and the method comprises the following steps: uniformly mixing the aluminum ash with sodium carbonate and / or sodium hydroxide and a calcium-containing raw material, roasting at 400-1000 DEG C in an oxidizing atmosphere, reacting a roasted product with the sulfuric acid and the optional red mud until the pH value of slurry filtrate is 3.0-4.0, Al2O3 accounts for 5-12m%, and the basicity is 40-75, filtering to obtain filtrate as the water purifying agent containing the polyaluminum sulfate, and washing filter residue to obtain solid residue for further utilization or tockpiling and landfill. Through the steps of mixing and roasting, theflammable and combustible problems of hydrogen released by metal aluminum hydrolysis or acidolysis, the ammonium nitrogen problem in purified water caused by entering of ammonium produced by acid hydrolysis of aluminum nitride into the water purifying agent, the activation problem of low-activity alumina, especially alpha-alumina, and the problems of stabilization and harmlessness of fluorine in the aluminum ash which need two or three steps to be treated in the prior art can be solved in one time. The hardness of treated water increases slightly during the use of the water purifying agent product.

Description

technical field

[0001] The invention belongs to the technical field of nonferrous metallurgy and environmental protection, and specifically relates to a method for preparing a water purifying agent containing polyaluminum sulfate from aluminum ash, sulfuric acid and optional red mud. Background technique

[0002] Aluminum ash is an important solid waste in the aluminum industry. According to different sources and metal aluminum content, it is generally divided into primary aluminum ash and secondary aluminum ash; in addition to metal aluminum, aluminum ash generally also contains sodium chloride, potassium chloride, Fluoride salts, alumina, aluminum nitride. Primary aluminum ash has a relatively high metal aluminum content, and metal aluminum is usually recovered by methods such as salt bath treatment. Secondary aluminum ash includes the residue after recycling metal aluminum from primary aluminum ash, and its metal aluminum content is lower than that of primary aluminum as...

Examples

Embodiment 1

[0046] Prepare the water purifying agent containing polyaluminum sulfate as follows:

[0047] A. Take a secondary aluminum ash M1000kg (-10 mesh, see Table 1 for chemical composition), put 550kg sodium hydroxide and 65kg calcium oxide into the ball mill, mix and ball mill for 5hrs to -80 mesh, and the powder after grinding is in the air atmosphere of a small tunnel kiln Roasting at 500°C for 3 hours to obtain a roasted product;

[0048] B. In the 5000L reaction tank, add 2700L of tap water, start stirring, add 875kg of 98m% industrial sulfuric acid, and gradually put in slightly warm roasting raw material for reaction. Appropriately reduce the feeding temperature and feeding speed of the roasted raw material, the reaction time is 1.5hr, until the pH of the slurry filtrate is 3.8, the Al 2 o 3 6.3m%, basicity 51;

[0049] C. The slurry in step B is filtered through a leaf filter, and the filtrate is a liquid water purifier containing polyaluminum sulfate; the filter residue ...

Embodiment 2

[0054] Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum sulfate, the difference is that the ground powder in step A is roasted at 700°C in the tunnel kiln to obtain the roasted product; in step B, add 1200L of tap water, and replace the remaining tap water with 1500 L of washing water collected in Step C of Example 1 for washing the filter residue with water.

[0055] The roasted product obtained in the detection step A no longer contains fluorides other than metallic aluminum, aluminum nitride and calcium fluoride.

[0056] In the reaction of step B, the concentration and quantity of added sulfuric acid, the charging amount of the roasted material, the control range of the slurry temperature, and the reaction time are all the same, and the pH of the slurry filtrate is 3.9, and the Al 2 o 3 6.8m%, basicity 54; calculation of Al in roasted raw materials 2 o 3 The stripping rate is 80%, and Al has been subtracted from the 15...

Embodiment 3

[0058] Substantially repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum sulfate, the difference is that step A sodium hydroxide 550kg is changed into 650kg of sodium carbonate, calcium oxide 65kg is changed into 120kg of heavy calcium carbonate powder with an average particle diameter of 2.3 μm, and The final powder was roasted in the tunnel kiln at 850° C. for 4 hours to obtain a roasted product; step B was added with 1200 L of tap water, and the remaining tap water was replaced with 1500 L of washing water collected by washing the filter residue in step C of Example 2.

[0059] The roasted product obtained in the detection step A no longer contains fluorides other than metallic aluminum, aluminum nitride and calcium fluoride.

[0060] In the reaction of step B, the concentration and quantity of added sulfuric acid, the charging amount of the roasted material, the control range of the slurry temperature, and the reaction time are all the...

technical field

[0001] The invention belongs to the technical field of nonferrous metallurgy and environmental protection, and specifically relates to a method for preparing a water purifying agent containing polyaluminum sulfate from aluminum ash, sulfuric acid and optional red mud. Background technique

[0002] Aluminum ash is an important solid waste in the aluminum industry. According to different sources and metal aluminum content, it is generally divided into primary aluminum ash and secondary aluminum ash; in addition to metal aluminum, aluminum ash generally also contains sodium chloride, potassium chloride, Fluoride salts, alumina, aluminum nitride. Primary aluminum ash has a relatively high metal aluminum content, and metal aluminum is usually recovered by methods such as salt bath treatment. Secondary aluminum ash includes the residue after recycling metal aluminum from primary aluminum ash, and its metal aluminum content is lower than that of primary aluminum as...

Examples

Embodiment 1

[0046] Prepare the water purifying agent containing polyaluminum sulfate as follows:

[0047] A. Take a secondary aluminum ash M1000kg (-10 mesh, see Table 1 for chemical composition), put 550kg sodium hydroxide and 65kg calcium oxide into the ball mill, mix and ball mill for 5hrs to -80 mesh, and the powder after grinding is in the air atmosphere of a small tunnel kiln Roasting at 500°C for 3 hours to obtain a roasted product;

[0048] B. In the 5000L reaction tank, add 2700L of tap water, start stirring, add 875kg of 98m% industrial sulfuric acid, and gradually put in slightly warm roasting raw material for reaction. Appropriately reduce the feeding temperature and feeding speed of the roasted raw material, the reaction time is 1.5hr, until the pH of the slurry filtrate is 3.8, the Al 2 o 3 6.3m%, basicity 51;

[0049] C. The slurry in step B is filtered through a leaf filter, and the filtrate is a liquid water purifier containing polyaluminum sulfate; the filter residue ...

Embodiment 2

[0054] Basically repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum sulfate, the difference is that the ground powder in step A is roasted at 700°C in the tunnel kiln to obtain the roasted product; in step B, add 1200L of tap water, and replace the remaining tap water with 1500 L of washing water collected in Step C of Example 1 for washing the filter residue with water.

[0055] The roasted product obtained in the detection step A no longer contains fluorides other than metallic aluminum, aluminum nitride and calcium fluoride.

[0056] In the reaction of step B, the concentration and quantity of added sulfuric acid, the charging amount of the roasted material, the control range of the slurry temperature, and the reaction time are all the same, and the pH of the slurry filtrate is 3.9, and the Al 2 o 3 6.8m%, basicity 54; calculation of Al in roasted raw materials 2 o 3 The stripping rate is 80%, and Al has been subtracted from the 15...

Embodiment 3

[0058] Substantially repeat the steps of Example 1 to prepare the water purifying agent containing polyaluminum sulfate, the difference is that step A sodium hydroxide 550kg is changed into 650kg of sodium carbonate, calcium oxide 65kg is changed into 120kg of heavy calcium carbonate powder with an average particle diameter of 2.3 μm, and The final powder was roasted in the tunnel kiln at 850° C. for 4 hours to obtain a roasted product; step B was added with 1200 L of tap water, and the remaining tap water was replaced with 1500 L of washing water collected by washing the filter residue in step C of Example 2.

[0059] The roasted product obtained in the detection step A no longer contains fluorides other than metallic aluminum, aluminum nitride and calcium fluoride.

[0060] In the reaction of step B, the concentration and quantity of added sulfuric acid, the charging amount of the roasted material, the control range of the slurry temperature, and the reaction time are all the...