Publication: Assessment of electric arc furnace slag as soil stabilizer and fertilizer for mangrove seedling
| datacite.subject.fos | oecd::Engineering and technology::Materials engineering | |
| dc.contributor.author | Kong, Ern Hun | |
| dc.date.accessioned | 2024-02-01T06:10:39Z | |
| dc.date.available | 2024-02-01T06:10:39Z | |
| dc.date.issued | 2022-02-01 | |
| dc.description.abstract | Slag from Electric Arc Furnace (EAF) is generated from steelmaking processes, and it is the most in term of volume among the by-products. Production practices and processes, and the skill of operator are among the factors that will cause significant variation in chemical and mineralogical properties. Successful recycling of the slags depends on understanding the differences and how the properties can be exploited. This project aims to evaluate each of the slags and explore their potential use in agriculture as soil modifier and nutrients source. Three slag samples of NL (normal production CaO saturated slag), HM (MgO saturated slag) and HF (high Fe slag), which were taken from different points in production and practices were characterized. The experimental works were carried out purely on the raw slag from production. It was crushed, ground, and sieved into three sizes of 0.15 – 0.25 mm, 0.25 – 0.50 mm and 0.5 – 1.0 mm. The slags were characterized by chemical, mineralogical and leaching study, and then evaluated for their effects to the growth rate of mangrove seedlings in field study. Preliminary study of leaching test and consideration of environment in field study were carried out to set the parameters for field works. Leaching test was carried out to confirm the leached elements meeting the environmental regulation standard and nutrient required by mangrove seedlings. Parameters for leaching test are different pH values (distilled water 6.8, rainwater 5.78 and seawater 8.37), stirring speed (350 and 700 rpm), and duration up to 16 weeks. Meanwhile, the field study was carried out with soil from mangrove forest and nursery center, treated with the three types of EAF C slag. The result of leaching test has confirmed the maximum level of 15.8 µg/L Cr (VI) is still far below the control limit of 50 µg/L in DOE requirement in Standard B Limit as per Malaysia Environmental Quality (Industrial Effluents) Regulations 2009 and WHO advisory Cr (VI) control limit for drinking water. Meanwhile, maximum 49.7 mg/L of Si, 45.7 mg/L of Ca, 0.581 mg/L of Fe, and 19.9 mg/L of Mg obtained from elemental leaching test has confirmed the availability of elements as nutrients for mangrove seedlings. As disturbed muddy soil in mangrove forest from natural disaster or human activities would lead to formation of sulphate, creating acidic condition soil which will affect the mangrove growth, alkaline slag could be used to neutralize the soil and improve growth. Slag NL with highest alkalinity of pH value 11, capable to increase the pH value of acidic soil from 3.65 to 8.5, which provides suitable condition for nutrients uptake for seedlings. The field study showed that not all the nutrients uptake by seedlings can be correlated with chemical content in slags, but seedlings treated with slags did achieve higher growth rate compared with seedlings without treatment, especially the stem height and seedling leaf area. Magnesium saturated slag with > 8% MgO and oxidized slag with > 35 % FeO is suitable for acidic muddy soil as they would enhance the leaf growth of seedlings. The highest leaf generation rate of 195.3 mm2/day, was achieved by seedling in soil MF treated with slag HF which contain 39.9 % of FeO compared with 164 mm2/day of leaf area generation in seedlings without slag treatment. The highest stalk growth rate of 3.73 mm/day was achieved by seedlings in soil NC treated with slag HM which contain 11.4 % MgO compared with 2.77 mm/day in seedlings without slag treatment. Based on this study, EAF C slag has great potential as soil modifier and nutrients source for mangrove seedlings in nursery center, and this re-use of slags is safe and would not leach out harmful elements into the environment. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/18249 | |
| dc.language.iso | en | |
| dc.title | Assessment of electric arc furnace slag as soil stabilizer and fertilizer for mangrove seedling | |
| dc.type | Resource Types::text::thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |