阅读说明：本技术 一种利用磷化污泥制备磷酸钙的方法 (Method for preparing calcium phosphate by using phosphated sludge ) 是由 马兵 张后虎 张强 康国栋 杜布云 于 2019-11-18 设计创作，主要内容包括：本发明涉及一种利用磷化污泥制备磷酸钙的方法,属于危险废物减量化、无害化、资源化利用领域。包括步骤,将磷化污泥加水搅拌；依次经过酸洗和碱洗,然后水洗至中性,得到浆体；在上述浆体中加入二硫代胺基甲酸、硫化钠的混合物,搅拌充分反应后,进行固液分离；将步得到的固体烘干后进行煅烧；液体中加入CaO,搅拌反应后得到磷酸钙。制成可作为资源利用的磷酸钙具有显著的社会和经济价值。(The invention relates to a method for preparing calcium phosphate by utilizing phosphated sludge, belonging to the field of reduction, harmlessness and resource utilization of hazardous wastes. Comprises the steps of adding water into phosphatized sludge and stirring; sequentially carrying out acid washing and alkali washing, and then washing with water to be neutral to obtain slurry; adding a mixture of dithiocarbamic acid and sodium sulfide into the slurry, stirring for full reaction, and performing solid-liquid separation; drying the solid obtained in the step and then calcining the dried solid; adding CaO into the liquid, and stirring to react to obtain the calcium phosphate. The prepared calcium phosphate which can be used as a resource has remarkable social and economic values.)

1. A method for preparing calcium phosphate by using phosphated sludge is characterized in that: the method comprises the following steps:

(1) adding water into the phosphated sludge and stirring;

(2) sequentially carrying out acid washing and alkali washing, and then washing with water to be neutral to obtain slurry;

(3) adding a mixture of dithiocarbamic acid and sodium sulfide into the slurry, stirring for full reaction, and performing solid-liquid separation;

(4) drying the solid obtained in the step (3) and then calcining;

(5) and (4) adding CaO into the liquid obtained in the step (3), and stirring for reaction to obtain the calcium phosphate.

2. The method for preparing calcium phosphate by using phosphated sludge as claimed in claim 1, wherein: in the step (1), the ratio of the phosphated sludge to water is 1: 3 to 5.

3. The method for preparing calcium phosphate by using phosphated sludge as claimed in claim 1, wherein: the proportion of the mixture of dithiocarbamic acid and sodium sulfide in the step (3) is 1-3: 1 by mass.

4. The method for the pretreatment of the cleaning and resource utilization of the phosphated sludge as claimed in claim 1, which is characterized in that: the calcination in the step (4) is sectional calcination.

5. The method for the pretreatment of the cleaning and resource utilization of the phosphated sludge according to claim 4, which is characterized in that: the segmented calcination process comprises the steps of heating to 800 ℃ at a heating rate of 20-25 ℃/min, preserving heat for 2-3 hours, heating to 1200 ℃ at a heating rate of 30-40 ℃, preserving heat for 5-7 hours, and naturally cooling to room temperature.

6. The method for preparing calcium phosphate by using phosphated sludge as claimed in claim 1, wherein: in the step (5), the ratio of the liquid to the calcium oxide is that 200-300 g of CaO is added to every 1 kg of the liquid.

Technical Field

The invention relates to a method for preparing calcium phosphate by utilizing phosphated sludge, belonging to the field of reduction, harmlessness and resource utilization of hazardous wastes.

Background

Along with the rapid development of industries such as automobile manufacturing, electronic processing, electroplating and the like, the metal surface phosphating treatment process is widely applied. The phosphating treatment is a process for forming an insoluble phosphate film on the surface of metal by using a solution containing phosphoric acid or phosphate, and is a commonly adopted process technology for treating the surface of the metal. The general phosphating process comprises alkaline cleaning oil removal, acid cleaning rust removal, phosphating and passivation treatment, a large amount of pollutants such as emulsified oil, a surfactant, phosphate and the like are generated in the process, the discharge amount of the phosphate is large and the standard exceeding is serious, and the waste water treatment is difficult due to various pollutants.

Disclosure of Invention

In order to solve the problems, the invention provides a method for preparing calcium phosphate by utilizing phosphated sludge, which realizes the reutilization of hazardous wastes and prepares the calcium phosphate capable of being used as a resource.

In order to achieve the above purpose, the specific scheme of the invention is as follows:

a method for preparing calcium phosphate by using phosphated sludge comprises the following steps:

(1) adding water into the phosphated sludge and stirring;

(2) sequentially carrying out acid washing and alkali washing, and then washing with water to be neutral to obtain slurry;

(3) adding a mixture of dithiocarbamic acid and sodium sulfide into the slurry, stirring for full reaction, and performing solid-liquid separation;

(4) drying the solid obtained in the step (3) and then calcining;

(5) and (4) adding CaO into the liquid obtained in the step (3), and stirring for reaction to obtain the calcium phosphate.

Further, the ratio of the phosphated sludge to water in step (1) is 1: 3 to 5.

Further, the proportion of the mixture of the dithiocarbamic acid and the sodium sulfide in the step (3) is 1-3: 1 by mass.

Further, the calcination in the step (4) is a stepwise calcination.

Further, the step-by-step calcination process comprises the steps of heating to 800 ℃ at a heating rate of 20-25 ℃/min, preserving heat for 2-3 hours, heating to 1200 ℃ at a heating rate of 30-40 ℃, preserving heat for 5-7 hours, and naturally cooling to room temperature.

Further, the ratio of the liquid to the calcium oxide in the step (5) is that 200-300 g of CaO is added to each 1 kg of the liquid.

Compared with the prior art, the invention has the beneficial effects that:

the method realizes resource recycling of the phosphatized sludge, has simple and efficient treatment process, treats the life hazardous waste, recycles the life hazardous waste, and has remarkable social and economic values when being prepared into the calcium phosphate capable of being used as a resource.

Detailed Description