Patents Assigned to MidAmerican Energy Holdings Company
  • PROCESS FOR DEPLETING CALCIUM AND/OR IRON FROM GEOTHERMAL BRINES
    Publication number: 20130068697
    Abstract: This invention relates generally to processes for extracting iron and/or calcium from geothermal brines.
    Type: Application
    Filed: November 14, 2012
    Publication date: March 21, 2013
    Applicant: Midamerican Energy Holdings Company
    Inventor: Midamerican Energy Holdings Company
  • Method of removing iron and calcium from a geothermal brine
    Patent number: 8313653
    Abstract: This invention relates generally to processes for extracting iron and/or calcium from geothermal brines.
    Type: Grant
    Filed: August 11, 2010
    Date of Patent: November 20, 2012
    Assignee: Midamerican Energy Holdings Company
    Inventors: John L. Featherstone, George Furmanski
  • Process for producing electrolytic manganese dioxide
    Patent number: 7776202
    Abstract: This invention relates generally to a process of producing electrolytic manganese dioxide (EMD). More specifically, a method of producing EMD from geothermal brine solutions is provided. Methods for production of manganese dioxide from geothermal brines through an electrolytic process are also provided.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: August 17, 2010
    Assignee: MidAmerican Energy Holdings Company
    Inventors: John L. Featherstone, George Furmanski
  • Process for producing electrolytic manganese dioxide from geothermal brines
    Patent number: 6682644
    Abstract: This invention relates generally to a process of producing electrolytic manganese dioxide (EMD). More specifically, a method of producing EMD from geothermal brine solutions is provided. Methods for production of manganese dioxide from geothermal brines through an electrolytic process are also provided.
    Type: Grant
    Filed: May 31, 2002
    Date of Patent: January 27, 2004
    Assignee: MidAmerican Energy Holdings Company
    Inventors: John L. Featherstone, George Furmanski
  • Recovery of zinc from geothermal brines
    Patent number: 6458184
    Abstract: Improved methods are disclosed for the efficient and cost-effective recovery of zinc metal from zinc-containing brines. Zinc is first bound to an anionic ion exchange resin (IX) which has been equilibrated with a solution containing a reducing agent, washed, and eluted with an elution solution. A reducing agent can be added to the brine prior to loading on the IX and can optionally be added to the IX after the washing step. The eluted zinc is extracted with a water-immiscible cationic organic solvent (SX), which is scrubbed, then stripped with concentrated acid. Substantially pure zinc is recovered by electrowinning the zinc-loaded concentrated acid solution.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: October 1, 2002
    Assignee: MidAmerican Energy Holdings Company
    Inventor: John L. Featherstone
  • Method for cleaning fouled ion exchange resins
    Patent number: 6080696
    Abstract: Methods are disclosed for the regeneration of fouled ion exchange (IX) resins. In one embodiment, the fouled resin is treated simultaneously with reducing agent and acid. In a preferred embodiment, fouled resin is treated with reducing agent and then with acid. Use of reducing agent prior to the use of acid results in surprisingly unexpected improved cleaning as compared to simultaneous treatment with reducing agent and acid.
    Type: Grant
    Filed: August 3, 1998
    Date of Patent: June 27, 2000
    Assignees: MidAmerican Energy Holdings Company, The Dow Chemical Company
    Inventors: Hilton Duke, John L. Featherstone, Charles R. Marston