Final Report: A New Innovative Low-Cost Manufacturing Process to Produce TitaniumEPA Contract Number: EPD08038
Title: A New Innovative Low-Cost Manufacturing Process to Produce Titanium
Investigators: Withers, James C.
Small Business: Materials and Electrochemical Research (MER) Corporation
EPA Contact: Manager, SBIR Program
Project Period: March 1, 2008 through August 31, 2008
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2008) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Pollution Prevention
The purpose of this research was to develop a continuous low-cost innovative processing alternative to the production proven but segmented, batch, high-cost Kroll environmentally hazardous process that produces titanium sponge, that utilizes the same demonstrated Kroll chemistry to produce titanium powder, which meets environmental benign green manufacturing processing. The Kroll process reaction route as shown in Figure 1 consists of the magnesium reduction of titanium tetrachloride (TiCl4) to produce titanium sponge that involves the synthesis, storage, and transport of the hazardous reactants of TiCl4 liquid and gas, chlorine gas, molten magnesium (Mg) and molten magnesium chloride (MgCl2).
Figure 1. Reaction scheme of Kroll process to produce titanium sponge. The segments are carried out in batch in most cases as separate sites.
The environmental hazardous materials handling has been eliminated in this program through the alternate processing scheme shown in Figure 2.
Figure 2. Reaction scheme of Kroll chemistry performed in a magnesium electrolysis cell to in situ produce TiCl4 that yields Ti powder in a single step.
The innovative processing to continuously produce low-cost titanium powder that results in an environmental benign green manufacturing process consists of a MgCl2 electrolysis cell wherein the anodically liberated chlorine reacts within the anode with Ti:O:C/Ti2OC to in-situ produce TiCl4, which is ducted over the cathode surface where it is reduced to titanium powder by the electrodeposited Mg. The titanium powder is harvested from the MgCl2 electrolysis cell and the salt, vacuum separated standardly as with Kroll sponge separation from MgCl2.
A key to the continuous low-cost processing is a carbothermically produced stoichiometric titanium suboxide-carbon/carbide Ti:O:C in a preferred composition Ti2OC that is fed to the anode, wherein the electrolytically liberated chlorine ion/gas reacts to in-situ form the TiCl4 that is ducted to the cathode and is reduced to form the titanium powder according to the reaction scheme shown in Figure 2. The desired feed for the carbothermic reduction is low-cost ore fines that have little to no value in standard Kroll processing.
The cost to produce titanium powder from low-cost TiO2/ore feeds, produced continuously in an environmental benign one-step in-situ MgCl2 electrolysis cell is substantially less than that for Kroll produced sponge.
The low-cost titanium powder can be utilized in powder metallurgy to produce non-melted components at low cost as well as melted analogous to Kroll sponge for standard ingot processing. The low-cost titanium powder provides the opportunity for application in transportation to reduce weight that translates to reduced consumption of petroleum and significant environmental benefits.
The United States imports approximately 90 percent of its titanium usage, which provides a basis for this program technology to increase the U.S. competitiveness in the innovative manufacturing of titanium that can sustain a strong manufacturing sector by advancing the innovations of this program. This provides significant environmental benefits of utilizing green technology to eliminate hazardous materials exposure and reduce pollution.
This program utilized a bench-scale laboratory electrolytic cell that has demonstrated a paradigm in the low-cost continuous production of titanium powder in an environmental benign green manufacturing process. This demonstration provides the basis to project the production cost of titanium powder at substantially less than the cost of Kroll titanium sponge. A Phase II program can demonstrate the process on a pilot scale, which can be directly translated into commercial production.
It was demonstrated in a single laboratory-scale cell that titanium powder could be produced continuously utilizing the production proven Kroll reactants in one step from in-situ generated reactants that eliminated any transport or storage of hazardous materials. The use of low-cost TiO2/ore fines to carbothermically produce a preferred feed to the electrolysis cell with continuous operation results in producing titanium powder at a substantially lower cost than Kroll titanium sponge and in an environmentally benign green manufacturing process.
The magnesium reduction of titanium tetrachloride, which is the segmented batch Kroll process to produce titanium sponge, was performed in one step in a single electrolysis cell wherein the reactants were in-situ produced, which eliminated handling or storage of the hazardous reactants, thus resulting in an environmentally benign low cost green manufacturing process. The one step in-situ process performed on a continuous basis that produced titanium powder results in a substantial cost savings over Kroll titanium sponge. The low-cost titanium powder provides the opportunity to produce components for transportation that saves weight, which translates to saving in petroleum and environmental benefits.