Hidden phosphorus flows related with non-agriculture industrial activities: A focus on steelmaking and metal surface treatment

Abstract

Due to the impact of increasing global demand for high-grade steel for a variety of applications at a time when high grade iron ore reserves are becoming depleted, the removal of impurities, and especially phosphorus, has become essential. Demand in the rapidly growing car industry, in particular, is increasing pressure on steelmakers to provide high quality steel. The dephosphorization step presents new opportunities to steelmakers: besides producing high-quality steels not prone to cracking or corrosion, and improving production efficiency, steelmakers are presented with the opportunity to recover phosphorus and market it as a value-added product. Another industry with potential to recover P as a secondary product is the surface treatment industry. Surface treatment and the galvanization of metal products requires phosphoric acid and generates waste containing phosphorus, which is typically not well recovered or recycled. In this study, we focus on the potential of steelmaking slag and waste sludge from nickel plating and metal surface treatment processes as non-traditional phosphorus resources. An MFA on the hidden phosphorus flow behind global iron ore trade showed that, that the hidden flow of phosphorus from the three major iron ore export countries to China alone was 331 kt in 2013, which is equivalent to 1.7% of the global consumption of P in fertilizers consumed that year. In 2013, 3.6 kilo ton of phosphorus was wasted in acid waste from the metal surface treatment industry.

Effect of Si Ion Concentrations on the Phosphorous Ion Separation from the Solution Containing Ca, Si, and P Ions by Ion-exchange Membrane Electrodialysis

“…Thus, alternative resources for phosphate ore must be found. [1][2][3][4][5] Municipal sewage sludge is one of the expected major secondary sources of phosphorus. The phosphorus extraction from sewage has been extensively studied worldwide and implemented in several places, although still with economic problems or required local government subsidiary aid.…”

“…When phosphorus is removed from the steelmaking slag, much phosphorus-free steelmaking slag can be recharged into the blast furnace, and CaO and iron can be effectively recycled. 5) This recycling is a tremendous benefit for the steel industry. Therefore, the phosphorus recovery from the steelmaking slag has attracted increasing attention, and many attempts have been carried out on the laboratory scale.…”

Simple technology for recycling phosphate from wastewater to farmland in rural areas

“…However, since this is costly and wasteful, it is desirable to develop an alternative technology option that can valorize unwanted CS for the cement and construction industry. On the other hand, steelmaking slag is the most abundantly available byproduct, which contains calcium silicates as a major component, in the steel industry (Matsubae et al 2015). Since the amount of steelmaking slag produced by a steelmaking process is very large, it is a matter of great concern for the steel industry to effectively recycle this byproduct.…”

Support Phosphorus Recycling Policy with Social Life Cycle Assessment: A Case of Japan

“…P is recovered in the form of struvite (MAP) or hydroxyapatite (HAP) and is transferred to a fertilizer factory for further processing [37]. One limitation of this study was that other recycled P sources such as manure, iron and steelmaking slag [35], and sludge from nickel plating and the surface treatment industry [38] were excluded from our scope.…”