1、A contribution to the development of a process to valorize the

Our study focuses the acidic effluent from the wet P-fertilizer production process, containing phosphates, fluorides, silicates, sulfates, and hardness-forming compounds. A novel wastewater treatment approach, encompassing both water and salt recovery, has been developed.

2、The Future of Phosphoric Acid Production –Why We Have to Leave Trodden

Abstract This paper examines the need for innovation in phosphorus fertilizer production. An important area requiring action is the use of sulfuric acid in the wet chemical process (WCP), which is the dominant process in phosphate fertilizer production.

3、A circular process for phosphoric acid plant wastewater

Suggested three-step treatment process for phosphoric acid industry wastewater, comprising selective electrodialysis (ED), reverse osmosis (RO), and neutralization with phosphate rock.

Production of Complex and Mixed Fertilizers by Acidic Processing of

This article examines the process of digesting phosphorites in an acidic solution to create complicated and mixed fertilizers. This study focuses on improving the nutritional content of phosphorus fertilizers by utilizing mineral acids, such as phosphoric, nitric, and sulfuric acids.

Phosphoric acid – Manufacturing process for Phosphoric acid

Phosphoric acid (H3PO4) can be produced by 3 main commercial methods: wet process, thermal process and dry kiln process. Wet process is by far the most common route and the acid can be used in phosphate fertilizers production (DAP, MAP, SPA).

A contribution to the development of a process to valorize

Our study focuses the acidic effluent from the wet P-fertilizer production process, containing phosphates, fluorides, silicates, sulfates, and hardness-forming compounds. A novel wastewater treatment approach, encompassing both water and salt recovery, has been developed.

"The methods of nitric acid processing of phosphate raw materials are

A technology has been developed for the nitric acid processing of phosphate raw materials into nitrogen-phosphorus fertilizer with the implementation of the process in a condensed pulp by adding sulfuric acid.

PRODUCTION OF PHOSPHORIC ACID

BAT covers both the technology used and the management practices necessary to operate a plant efficiently and safely. The EFMA Booklets focus primarily on the technologi-cal processes, since good management is considered to be independent of the process route.

(PDF) Phosphoric Acid Production

The wet process, which reacts sulfuric acid with phosphate rock, is the most common method for producing phosphoric acid. It accounts for the majority of global phosphoric acid production, primarily used in fertilizers.

Treatment of wastewaters from phosphate fertilizer industry

The present study reports the evaluation of an integrated precipitation and Enhanced Biological Phosphorus Removal (EBPR) process for the treatment of fertilizer plant wastewater and effluent detoxification, assessed by microtoxicity and seed germination tests.

In agricultural production, phosphate fertilizers are one of the essential materials for enhancing crop yields. the issue of wastewater generated during phosphate fertilizer production has become increasingly prominent. To address this problem, the acid process method is employed to produce phosphate fertilizers, resulting in wastewater. Below is a detailed explanation of the wastewater generation process and treatment methods associated with the acid process.

I. Overview of Phosphate Fertilizer Production

Phosphate fertilizers are crucial chemical fertilizers that provide abundant phosphorus elements for crops. Typically, phosphate fertilizers are produced using calcium phosphate (Ca₃(PO₄)₂) as raw material, through chemical reactions to generate intermediate products such as calcium dihydrogen phosphate (CaHPO₄) and normal calcium phosphate (Ca₃(PO₄)₂), ultimately yielding finished products like calcium dihydrogen phosphate or tricalcium phosphate.

II. Wastewater Generation in Acid Process Phosphate Fertilizer Production

The acid process is a common method in phosphate fertilizer production, involving the addition of sulfuric acid (H₂SO₄) solution into the reactor to react with calcium phosphate, producing calcium dihydrogen phosphate. During this process, a certain amount of wastewater is generated. This wastewater contains pollutants such as sulfuric acid, phosphates, organic compounds, etc., posing environmental risks.

III. Wastewater Generation Process

1. Raw Materials in the Reactor: In phosphate fertilizer production, raw materials typically include phosphate-containing ores (e.g., phosphorite, coal gangue) which, after crushing and grinding, are mixed with water to form a slurry.

2. Reaction Process: Sulfuric acid solution (usually at a concentration of 30%-40%) is added to the reactor and mixed with the slurry. During the reaction, sulfuric acid chemically reacts with calcium phosphate, producing intermediate products like calcium dihydrogen phosphate and normal calcium phosphate.

3. Wastewater Formation: After the reaction, substances such as sulfates and phosphates in the slurry exist in either suspended or dissolved forms, forming wastewater. This wastewater contains harmful substances like heavy metals, organic pollutants, and acids/alkalis.

IV. Wastewater Treatment Technologies

Considering the characteristics of wastewater from the acid process, the following treatment methods can be applied:

1. Physical Methods: Techniques such as precipitation and filtration remove suspended solids and some soluble pollutants. Common physical methods include coagulation-sedimentation, air flotation, sand filtration, etc.

2. Chemical Methods: Adding chemical agents transforms harmful substances into removable forms. Typical chemical methods include neutralization, oxidation-reduction, ion exchange, etc.

3. Biological Methods: Microbial metabolism converts harmful substances into harmless ones. Common biological treatments include activated sludge processes, biofilm reactors, anaerobic digestion, etc.

4. Adsorption: Using adsorbents like activated carbon or zeolite removes organic matter and pigments. Adsorption suits low-concentration, highly colored wastewater.

5. Evaporative Concentration: Heating reduces water content, simplifying subsequent treatment. Suitable for high-water-content wastewater.

6. Membrane Separation: Semi-permeable membranes selectively separate components. Effective for multi-contaminant wastewater.

V. Practical Application Case

A phosphate fertilizer plant using the acid process generated significant wastewater. To resolve this, advanced treatment technologies combining physical, chemical, and biological methods were introduced. Through multi-stage treatment, pollutants were effectively removed, meeting discharge standards. Additionally, a wastewater recycling system was established, reusing portions of the treated water in production, conserving water resources.

Wastewater from acid process phosphate fertilizer production requires comprehensive management using diverse treatment approaches. Combining physical, chemical, and biological methods effectively mitigates pollution. Implementing wastewater recycling systems enhances resource efficiency and reduces costs. As environmental technology advances, future wastewater treatment in phosphate fertilizer production will become more efficient and eco-friendly.