Physicomechanical Assessments and Heavy Metals’ Leaching Potential of Modified Asphalt Binders Incorporating Crumb Rubber and Tin Slag Powders

Industrial solid waste has been widely used as an alternative additive for bituminous material modification. This study aims to evaluate the basic properties and quantify the leaching potential of modified asphalt binders incorporating crumb rubber powder (CRP) from waste tires and tin slag (TS) for a local smelting company. Three percentages of CRP and TS, at 5, 10, and 15%, were considered. The conventional asphalt binder (PEN 60/70), CRP, and TS-based modified asphalt binders were analyzed for toxicity, softening point, penetration value, elastic recovery, torsional recovery (TR), and coatability index. The findings indicated that the addition of the waste materials led to no significant heavy metal content in the asphalt binder mix. Moreover, the basic and physical properties of the asphalt binders were also improved by 5, 10, and 15% of the waste, respectively. However, TS waste exhibited limited effects on all the parameters and had a 5% optimum dosage. The modified binders’ results showed that the CRP modified asphalt binders had fewer heavy metals and responded more to elastic recovery and coatability.

Radiological Impact Assessment of Class 3 Landfill of TENORM Waste from Tin Industry in Bangka Island

This study assessed the potential radiological impact of a class 3 landfill as a disposal facility of the final tin slag from the tin industry in Bangka Island. Tin slag that contains TENORM (Technically Enhanced Naturally Occurring Radioactive Material) with activity concentrations above exemption level limits should be stored safely and securely. The radiological impact analysis of storing TENORM waste was carried out before and after the construction of a landfill facility. RESRAD OFFSITE version 3.2 software was used to simulate dose and cancer risk, and analyze the contribution of exposure pathways. Radionuclide concentration, landfill facility specifications, hydrogeological data, climatological data, and food and water consumption data were used as input parameters of RESRAD. The receptor was a resident farmer who lives 100 meters from the facility, grows his own food, and consumes water from his land. The total dose before and after the construction of the landfill were 3.13 mSv/year and 1.84×10-2 mSv/year while cancer risks were 5.69×10-3 and 6.50×10-5, respectively. The exposure pathways from inhalation of radon become a major contributor to dose acceptance and cancer risk. Based on these results, the landfill facility is effective in reducing the potential impact of radiological hazards from dose acceptance and cancer risk.

Mechanical Properties of Tin Slag Mortar

The increased demand for cement mortar due to rapid infrastructural growth and development has led to an alarming depletion of fine aggregate. This has prompted the need for a more sustainable material as a total/partial replacement for natural fine aggregate. This study proposes the use of tin slag (TS) as a replacement for fine aggregate in concrete to bridge this sustainability gap. TS was used to replace fine aggregate at replacement levels of 0%, 25%, 50%, 75%, and 100% in cement mortar. Fresh and hardened properties of TS mortar were obtained. Flow tests showed that, as the TS quantity and the w/c ratio increased, the mortar flow increased. Similarly, the compressive strength increased as the TS replacement increased up to 50% replacement, after which a decline in strength was observed. However, with the TS replacement of fine aggregate up to 100%, a compressive strength of 6% above control was attained. The morphological features confirm that specimens with TS had a denser microstructure because of its shape characteristics (elongated, irregular, and rough), and, thus, plugged holes better than the control mortar. The natural sand’s contribution to strength was a result of better aggregate hardness as compared to TS. Hence, TS can be used as alternative for fine aggregate in sustainable construction.

Processing of Sb-Pb-Sn-Containing Materials

During the processing of lead containing products and polymetallic alloys the recovery of tin and antimony from technology of lead production is carried out by oxidation refining of decopperized lead with rich oxides (Sn, Sb ≥ 20%).Tin oxides are melted in a short-drum furnaces to lead bullion (> 96% Pb) and tin-rich (> 20% Sn) slag. The slag is melted in an ore-smelting furnace to obtain a Sn-Pb alloy of next composition, %: 56.1 Sn, 18.2 Pb, 14.6 Sb, 6.9 As, which is refined by vacuum distillation with production of rough tin (Sn ≥ 90%). The additional profit of rough tin obtainment (∼310 tons/year), compared with sales of tin slag, is about ∼1.3 million $/year. Keywords: lead, tin, antimony, melting, vacuum distillation

COMPRESSIVE BEHAVIOUR OF TIN SLAG POLYMER CONCRETE CONFINED WITH CARBON FIBRE REINFORCED EPOXY

<p>Terak timah adalah hasil sampingan proses peleburan.Tujuan kajian ini adalah untuk mengkaji tingkah laku mampatan kolum konkrit polimer (PC) berisi terak timah yang dibalut dengan polimerdiperkuat fiber karbon (CFRP). Kajian ini dijalankan dengan tiga bilangan lapisan CFRP yang berlainan. Ciri-ciri mekanikal sampel seperti tekanan maksimum (<em>maximum stress</em>), ketegangan (<em>strain</em>) dan modulus keanjalan (<em>elasticity modulus</em>) ditentukan oleh ujian mampatan. Tekanan mampatan maksimummeningkat dengan ketara kepada 103% untuk PC yang tidak terkurung berbanding PC terkurung. Sementara itu untuk satu lapisan hingga dua lapisan hanya meningkat 14.9% dan kes yang sama untuk dua lapisan hingga tiga lapisan hanya mendapat peningkatan kira-kira 13.6%. Modulus mampatan meningkat kira-kira 26% hingga 39% untuk PC yang tidak terkurung berbanding satu lapisan PC terkurung. Modulus mampatan untuk PC yang satu lapisan, dua lapisan dan tiga lapisan hampir sama iaitu perbezaan tidak lebih daripada 10%. Nisbah pemanjangan bagi PC yang tidak terkurung berbanding dengan PC berkurung satu lapisan menunjukkan penurunan yang besar. Bilangan lapisan dua dan tiga menunjukkan penurunan nisbah kemuluran yang sedikit berbanding satu lapisan. Kekuatan satu-lapisan PC terkurung meningkat dengan ketara kira-kira 104.8% berbanding PC yang tidak terkurung. Sementara itu, untuk bilangan lapisan terkurung yang lebih dari satu hanya meningkat sedikit. Keberkesanan pengurungan meningkat sebanyak dua kali untuk satu lapisan PC terkurung berbanding PC yang tidak terkurung. Sementara itu, bilangan lapisan terkurung yang lebih dari satu, keberkesanan pengurungan hanya meningkat sedikit. Kesimpulannya, peningkatan jumlah lapisan terkurung lebih dari satu tidak memberikan perubahan yang signifikan terhadap sifat mekanik.Kata kunci: CFRP, konkrit polimer, pengurungan, sanga timah</p>

Behavior and properties of tin slag polyester polymer concrete confined with FRP composites under compression

Polymer concrete (PC) has acquired niche in construction industry due to superior mechanical properties, recyclability and adoption of variety of aggregates. This workpresents compressive behavior and properties of one such novel PC i.e. tin slag/polyester polymer concrete. Comparable siliceous content of tin slag was considered promising to provide better mechanical strength as in natural aggregates. Cylindrical short column specimens were fabricated to be tested under quasi-isostatic loading rate of 1 mm/min. Three different aggregate sizes in gap-graded configuration were tested to assess influence on mechanical properties. In addition, specimens were confined with GFRP and CFRP to determine and compare mechanical behavior with Portland Cement Concrete (PCC). Coarsest size (4+2 mm) aggregate offered the highest strength of 37.71 MPa for unconfined sample. This performance of coarsest size persisted in confined condition with compressive strength increment of 69.68 MPa (84.7%) and 98.36 MPa (160.8%) for one and two layers GFRP; 86 MPa (128.05%) and 125.07 MPa (231.66)% for one and two-layer CFRP, respectively. It was concluded that both increment in aggregate size and number of layers improved the compressive strength.