Final Report: A New Innovative Low Cost Manufacturing Process to Produce TitaniumEPA Contract Number: EPD09044
Title: A New Innovative Low Cost Manufacturing Process to Produce Titanium
Investigators: Withers, James C.
Small Business: MER Corporation
EPA Contact: Manager, SBIR Program
Project Period: March 1, 2009 through February 28, 2011
Project Amount: $225,000
RFA: Small Business Innovation Research (SBIR) - Phase II (2009) 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, which utilizes the same demonstrated Kroll chemistry to produce titanium powder but is an environmentally benign green manufacturing process.
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).
The environmentally hazardous materials handling has been eliminated in this program through the alternate processing scheme shown in Figure 2.
The innovative processing to continuously produce low-cost titanium powder that results in an environmentally 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 produce TiCl4 in situ, 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 is vacuum separated with Kroll sponge separation from MgCl2.
A key to the continuous low-cost processing is a carbothermically produced titanium oxycarbide Ti:O:C in a preferred composition Ti2OC that is fed to the anode wherein the electrolytically liberated chlorine ion/gas reacts to form the TiCl4 in situ 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 environmentally benign one-step in situ MgCl2 electrolysis cell is substantially less than that for a 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 components analogous to Kroll sponge for standard ingot processing. The low-cost titanium powder provides the opportunity for application in transportation to reduce weight, and this translates to reduced consumption of petroleum and significant environmental benefits.
The United States imports approximately 90% of the titanium it uses. This technology could increase U.S. competitiveness and strengthen the manufacturing sector through innovative manufacturing of titanium. In addition, the technology can provide significant environmental benefits by utilizing green technology to eliminate hazardous materials exposure and reduce the pollution associated with titanium products.
This program demonstrated in a unique magnesium electrolytic cell low-cost continuous production of titanium powder in an environmentally benign green manufacturing process. This program demonstration provides the basis to project the production cost of titanium powder at substantially less than the cost of Kroll titanium sponge.
It was demonstrated in a scaled-up magnesium electrolytic cell that titanium powder could be produced continuously using 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, using 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 produced in situ. This 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 that produced titanium powder on a continuous basis results in a substantial cost savings over Kroll titanium sponge. In addition, the low-cost titanium powder provides the opportunity to produce low-weight components for the transportation sectoruse, which translates to savings in petroleum and environmental benefits.
Titanium, Low Cost Manufacturing, Benign Green Manufacturing, Pollution Reduction