Using Magnesium Calcium Alloy (MAG-CAL™) enables lead refineries to operate more efficiently and create a safe environment for workers. Our recommended debismuthizing process is based on the traditional Kroll-Betterton technique, employing our MAG-CAL alloy ingots.
The typical MAG-CAL mixture employs 70% magnesium and 30% calcium (70/30). By adding the ingot during the dibismuthizing process, refineries will save time and yield better results.
Our MAG-CAL is produced in 10 kg ingots that are stable in air and safe for worker handling.
QUIET DISSOLUTION WITHOUT SMOKE OR FUME
Reduces plant fugitive emissions, improves the workplace environment, and minimizes the formation of detrimental oxides.
IMPROVED PROCESS FLOW
MAG-CAL addition is recommended at temperatures above 480°C (895°F); allowing the MAG-CAL to be added immediately after the vacuum dezincing process.
IMPROVED PROCESS CONTROL
MAG-CAL’s controlled chemistry results in consistently high recoveries for Mg and Ca in the lead bath, allowing the lead refinery to minimize reagent additions and to better predict final bismuth levels.
IMPROVED BISMUTH REMOVAL
Our process substantially improves bismuth removal, enabling efficient processing of bismuth-enriched lead concentrates (>1%) and the ability to achieve ultra-low bismuth levels (<0.005%) in one processing step.
EASY TO USE AND HANDLE
MAG-CAL ingots have a consistent weight, eliminate the handling of hazardous materials (Ca), and reduce material handling / storage costs.
The final stage of lead refining is typically the removal of bismuth by either electrolytic refining or by the Kroll-Betterton (KB) process. In the KB process, calcium and magnesium metals are added to molten lead in a continuous stream or in batches to react with bismuth. There are difficulties with this traditional process due primarily to the reactivity of calcium metal. At normal operating temperatures, calcium readily oxidizes, giving rise to bright flaring, excessive fume generation and an inherent loss of reagent. This translates directly into lower recoveries, reduced efficiency, higher processing costs, unpredictable final bismuth levels and environmental concerns.
VORTEX ADDITION TECHNIQUE
Addition of MAG-CAL to the lead bath under agitation is the most effective and consistent technique. MAG-CAL is simply added to the vortex of the melt. A bath temperature of 480°C to 500°C (895°F – 930°F) produces complete dissolution of the alloy, with calcium recoveries of 90% or better.
Control of the process temperature is important for the successful addition of MAG-CAL. The process temperature ranges up to 520°C (970°F), however, the possibility of oxidation losses increases as process temperatures rise.
This technique eliminates the plunging cage and provides a homogeneous reaction environment. With MAG-CAL usage, bismuth levels as low as 0.003% have been achieved.
PRODUCT FORM / SIZE
MAG-CAL is available in standard 10-kg (22 lb) ingot bundles, specially suited for vortex conditions. All THM magnesium/calcium products are packaged to meet IATA, UN and CTC regulations. A Material Safety Data Sheet accompanies each TH Magnesium shipment.