TWI627137B - Method for recycling waste to produce aluminum sulfate - Google Patents

Abstract

The invention relates to a method for producing aluminum sulfate by recycling waste, which comprises the following steps: a. mixing aluminum-containing sludge and aluminum-containing waste liquid in a reaction tank to react to form aluminum hydroxide; b. mixing in the reaction tank Sulfuric acid waste liquid, allowing aluminum hydroxide to react with sulfuric acid to form aluminum sulfate; and c. performing solid-liquid separation to separate aluminum sulfate solution and sludge; wherein the aluminum-containing sludge is contained in the environmental protection department waste code D-0902 The aluminum sludge and aluminum-containing waste liquid are the aluminum-containing waste liquid of the Environmental Protection Agency's waste code C-0201, and the sulfuric acid waste liquid is the sulfuric acid waste liquid of the Environmental Protection Agency's waste code C-0202. Thereby, it is used to provide a method for recycling waste to produce aluminum sulfate, and has the effect of treating waste and recycling resources.

Description

Method for recycling waste to produce aluminum sulfate

The invention relates to a method for producing aluminum sulfate by recycling waste, in particular to first mixing an aluminum-containing sludge with an aluminum-containing waste liquid to form aluminum hydroxide, and then mixing the sulfuric acid-containing waste liquid at an appropriate pH and temperature. Under the conditions, the aluminum hydroxide is reacted with sulfuric acid to form a designer of aluminum sulfate.

According to the manufacturing process of aluminum extrusion products, the aluminum ingots and alloy metals are melted, cast, cast, neutralized and alkali washed; among them, the sewage program produces aluminum sludge (the EPA waste code is D) -0902), the alkaline washing process produces aluminum-containing waste liquid (pH value (equal) at 12.5, EPA waste code is C-0201), cleaning or etching process produces sulfuric acid-containing waste liquid (pH value is small (etc.)) 2. The EPA waste code is C-0202). However, if the aforementioned waste is properly treated, it not only avoids environmental pollution, but also has the value of recycling and recycling of resources.

The main object of the present invention is to provide a method for recycling waste to produce aluminum sulfate, which has the effect of treating waste and recycling resources.

In order to achieve the above effects, the technical features of the present invention include the following steps: a. mixing the aluminum-containing sludge and the aluminum-containing waste liquid in the reaction tank to form aluminum hydroxide; b. mixing the sulfuric acid-containing waste liquid in the reaction tank , allowing aluminum hydroxide to react with sulfuric acid to form aluminum sulfate; and c. performing solid-liquid separation to separate aluminum sulfate solution and sludge; wherein the aluminum-containing sludge is an aluminum-containing sludge of the Environmental Protection Agency's waste code D-0902 The aluminum-containing waste liquid is the aluminum-containing waste liquid of the Environmental Protection Agency's waste code C-0201, and the sulfuric acid waste liquid is the sulfuric acid waste liquid of the Environmental Protection Agency's waste code C-0202.

In addition, step b is controlled to carry out the reaction under conditions of low pH, wherein pH 3-5 is preferred; further, step b further adds sulfuric acid to control the reaction temperature, wherein step b is divided into two-stage reaction, first The reaction temperature of the stage is controlled at 70-90 ° C, and the reaction temperature of the second stage is controlled at 100 ° C; in addition, step a further adds excess aluminum raw material to carry out the reaction, wherein the further added aluminum raw material is aluminum ingot or aluminum hydroxide; Step c is subjected to solid-liquid separation by a plate press.

Thereby, the aluminum-containing sludge is mixed with the aluminum-containing waste liquid to form aluminum hydroxide, and then the sulfuric acid-containing waste liquid is mixed, and the aluminum hydroxide and sulfuric acid are reacted to form aluminum sulfate under appropriate pH and temperature conditions. And the aluminum sulfate product can be used as a coagulating agent for the wastewater treatment coagulation process, which not only processes a variety of wastes but also recycles reusable resources.

[Fig. 1] is a manufacturing flow chart of the present invention.

First, please refer to [Fig. 1], the present invention includes the following steps: a. mixing the EPA waste code D-0902 containing aluminum sludge and the EPA waste code C-0201 in the reaction tank. The aluminum-containing waste liquid reacts to form aluminum hydroxide, and the reaction formula: Al ³⁺ +3OH ^- → Al(OH) ₃ , and in order to ensure that sufficient aluminum raw material participates in the reaction, an excess of aluminum raw material may be further added for reaction, and added The aluminum raw material is aluminum ingot or aluminum hydroxide; b. mixed with the effluent containing sulfuric acid waste code C-0202 in the reaction tank, and reacting aluminum hydroxide with sulfuric acid to form aluminum sulfate, reaction formula: 2Al(OH ₃ +3H ₂ SO ₄ →Al ₂ (SO ₄ ) ₃ +6H ₂ O, and use aluminum to have high solubility at low pH, and control the pH at a low pH of 3-5 Further, sulfuric acid may be further added to control the reaction temperature, and is divided into two-stage reaction, the reaction temperature of the first stage is controlled at 70-90 ° C, the reaction temperature of the second stage is controlled at 100 ° C; and c. is solidified by a plate press. The liquid is separated, and the aluminum sulfate solution and the sludge are separated.

Based on the method of the present invention, the invention firstly combines the aluminum-containing sludge of the EPA waste code D-0902 with the aluminum-containing waste liquid of the Environmental Protection Agency waste code C-0201, and reacts to form aluminum hydroxide, and then mixes with the EPA. The waste code is C-0202 containing sulfuric acid waste liquid, and under the appropriate pH and temperature conditions, the aluminum hydroxide reacts with sulfuric acid to form aluminum sulfate, and the aluminum sulfate product can provide the coagulation process of the wastewater treatment coagulation process. The use of the chemical agent not only treats a variety of wastes but also recycles the reusable resources, and has the effect of treating the waste and recycling the resources.

To sum up, the technical means disclosed in the present invention have the invention patents such as "novelty", "progressiveness" and "available for industrial use", and pray for the patent to be invented by the bureau. German sense.

The drawings and the descriptions of the present invention are merely preferred embodiments of the present invention, and those skilled in the art, which are subject to the spirit of the present invention, should be included in the scope of the patent application.

Claims (8)

A method for recycling waste to produce aluminum sulfate comprises the following steps: a. mixing an aluminum-containing sludge of the Environmental Protection Agency with waste code D-0902 and an aluminum-containing waste of the Environmental Protection Agency waste code C-0201 in the reaction tank. Liquid, reacting to form aluminum hydroxide; b. mixing EPA waste gas with C-0202 waste code C-0202 in the reaction tank, allowing aluminum hydroxide to react with sulfuric acid to form aluminum sulfate; and c. performing solid-liquid separation and separation Aluminium sulfate solution and sludge. The method for producing aluminum sulfate from the recovered waste according to claim 1, wherein the step b controls the reaction to be carried out under a low pH condition. A method for producing aluminum sulfate from recycled waste according to claim 2, wherein the step b is controlled to carry out the reaction at a pH of 3-5. A method for producing aluminum sulfate by recycling waste as described in claim 2, wherein the step b further adds sulfuric acid to control the reaction temperature. The method for producing aluminum sulfate by recycling waste as described in claim 4, wherein the step b is divided into two-stage reaction, the reaction temperature of the first stage is controlled at 70-90 ° C, and the reaction temperature of the second stage is controlled at 100 ° C. The method for producing aluminum sulfate from the recovered waste according to any one of claims 1 to 5, wherein the step a further further adds an excess amount of the aluminum raw material to carry out the reaction. The method for producing aluminum sulfate by recycling waste according to claim 6, wherein the aluminum raw material further added in step a is aluminum ingot or aluminum hydroxide. A method for producing aluminum sulfate by recycling waste as described in claim 6 wherein step c is subjected to solid-liquid separation by a plate press.