John T. Fox

Binding waste anthracite fines with Si-containing materials as an alternative fuel for foundry cupola furnaces.

An alternative fuel to replace foundry coke in cupolas was developed from waste anthracite fines. Waste anthracite fines were briquetted with Si-containing materials and treated in carbothermal (combination of heat and carbon) conditions that simulated the cupola preheat zone to form silicon carbide nanowires (SCNWs). SCNWs can provide hot crushing strengths, which are important in cupola operations. Lab-scale experiments confirmed that the redox level of the Si-source significantly affected the formation of SiC. With zerovalent silicon, SCNWs were formed within the anthracite pellets. Although amorphous Si (+4) plus anthracite formed SiC, these conditions did not transform the SiC into nanowires. Moreover, under the test conditions, SiC was not formed between crystallized Si (+4) and anthracite. In a full-scale demonstration, bricks made from anthracite fines and zerovalent silicon successfully replaced a part of the foundry coke in a full-scale cupola. In addition to saving in fuel cost, replacing coke by waste anthracite fines can reduce energy consumption and CO2 and other pollution associated with conventional coking.

Characterizing Diesel Particulate Filter Failure During Commercial Fleet Use due to Pinholes, Melting, Cracking, and Fouling

Diesel particulate filters (DPFs) are essential particulate matter emission control devices. Some diesel particulate filters have been observed to fail during industrial-fleet vehicle use. DPFs that fail during vehicle use compromise particulate matter emission capture. Herein, failures in cordierite DPF substrates observed during commercial fleet use were characterized as pinhole failure, melt failure, crack failure, and fouling failure. The observed failures were correlated to particulate matter chemical composition and physical changes in the cordierite substrate of the exhausted DPFs. The physical-chemical characteristics of pinhole failure, melt failure, crack failure, and fouling failure were determined by applying scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Results indicate that the chemical composition and crystalline structures of cordierite DPF substrate changed according to the failure characterization. The specific changes to the cordierite substrate during failure can contribute towards understanding fundamental DPF failure mechanisms.

The Environmental Performance and Cost of Innovative Technologies for Ductile Iron Foundry Production

The authors and collaborators have devised innovative technologies that decrease foundry costs, pollution, materials use, and energy. These include: (a) applying advanced oxidation to green sand and baghouse dust to diminish clay, coal, sand, volatile organic compounds (VOCs), and costs; (b) replacing phenolic urethane core binders with collagen-alkali silicate binders to diminish VOCs; (c) replacing coke with anthracite fines held together with biomaterial to reduce energy and costs. It is proposed by the authors that if a foundry were to concurrently employ all these innovative technologies (with 50% anthracite bricks), it could potentially diminish overall costs by 6.6%, life cycle energy costs by 15%, VOC pollution by 57%, sand by 85%, clay and coal by 50%, and iron scrap by 9%. These computations are per full-scale operations for advanced oxidation; and R&D results for replacing binders and coke. This paper also notes that when electricity comes primarily from coal fired power plants, electric induction furnaces consumes more life cycle energy than do cupolas for melting iron.

Full-Scale Demonstration of a Hybrid Hydrolyzed Collagen-Alkali Silicate Core Binder

A novel core binder system has been devised that is comprised of hydrolyzed collagen and alkali silicates. Cores that employ this hybrid binder were tested in a full-scale demonstration at a partner foundry. Among the 244 iron castings manufactured at this facility while using these hybrid binders, none of the iron castings were rejected as scrap due to core-related defects. The core regions of these iron castings exhibited no deformation, veining, or erosion from molten iron exposure. Moreover, these hybrid silicate-collagen cores demonstrated satisfactory shakeout during full-scale demonstrations. This hydrolyzed collagen-alkali silicate binder yielded cores that achieved a higher tensile strength and less hot distortion than conventional phenolic urethane binders.