Dust free proppant and method of making same

{
  "publication_number": "US10023790B1",
  "country": "US",
  "kind": "B1",
  "title": "Dust free proppant and method of making same",
  "abstract": "A long term dust free proppant comprising a mass of free flowing particles, where the particles are coated with a dust suppression solution containing 90 to 99.5 percent by weight water, 0.05 to 3.0 percent by weight a soluble polymer and an added, small amount of a surfactant. The mass has a very low dosage of the solution so the mass has a moisture content of less than 0.30 percent by weight. Preferably the solution is applied to the particles by an air mist jet.",
  "claims": [
    "1. A long term dust free proppant comprising inorganic granular particles with surfaces spray coated at ambient temperature by an air mist with a water soluble dust suppression solution which is attached to and spread over said surfaces of said particles, said dust suppression solution comprising 0.80 milliliters per pound of said proppant and has at least 90 percent by weight water, 0.10 to 6.0 percent by weight of water soluble polymer and a small amount of surfactant constituting less than 0.5 percent by weight of said solution, wherein said dust suppression solution comprises less than 10 milliliter per pound of said proppant and where the amount of solution added to the proppant is an amount resulting in a moisture content of said proppant of less than 0.30 percent by weight so said long term dust free proppant is also free flowing.",
    "2. A long term dust free proppant as defined in claim 1 wherein said inorganic granular particles are formed from a mineral selected from the class comprising frac sand and bauxite.",
    "3. A long term dust free proppant as defined in claim 1 wherein said dust suppression solution includes two water soluble polymers.",
    "4. A long term dust free proppant as defined in claim 1 wherein the average dust concentration is less than 0.05 mg/m 3 for at least 4 days.",
    "5. A long term dust free proppant as defined in claim 1 said ambient temperature is in the range of 5-30 degrees Centigrade.",
    "6. A long term dust free proppant as defined in claim 1 having an average dust concentration of less than 0.03 mg/m 3 for at least 4 days and containing two cationic polymers.",
    "7. A long term dust free proppant as defined in claim 6 wherein said surfactant is an anionic surfactant."
  ],
  "description_excerpt": "This application claims priority in provisional patent application Ser. No. 62/168,358 that was filed on May 29, 2015 and in provisional patent application Ser. No. 62/170,489 that was filed on Jun. 3, 2015, which are both incorporated by reference herein.\n\nThe present invention relates to an improvement in a proppant, specifically frac sand, used in hydraulic fracking and more particularly to a novel proppant that is modified to be dust free for a long period of time, i.e. at least 4 days. Thus, the new proppant is a “long term dust free” proppant.\n\nDust control of frac sand by applying a solution of water and polymers, such as cationic polymers, is disclosed in recently published applications by Baker Hughes (2013/0192835) and (2015/0104647). Applying dust control solutions onto the surface area of the sand is a well-known technology. These patent documents are incorporated by reference herein. Lab test showed that the Baker Hughes technologies were not effective to keep the measured average dust concentration of treated materials in airborne environment less than 0.05 milligrams per cubic meters, especially, the dust suppression effectiveness is temporary and short-life with less than four days, often if at all, for not more than a day or so. Such short time dust control is unacceptable in the hydraulic fracing field. In general, at least two to three days are required to make sure that the treated frac sand still has the needed potent of dust suppression efficiency. In addition, a re-drying operation in most dust suppression operation is needed in order to effectively flow the chemically treated frac sand.",
  "cpc": [
    "C09K 8/805"
  ],
  "ipc": [
    "B05D 1/02",
    "B05D 1/36",
    "C09K 8/80"
  ],
  "assignees": [
    "Covia Holdings LLC"
  ],
  "inventors": [
    "Richard C. Zielke",
    "Feipeng P. Liu"
  ],
  "filing_date": "2016-04-05",
  "publication_date": "2018-07-17",
  "grant_date": "2018-07-17",
  "priority_date": "2015-05-29",
  "application_number": "US-201615091034-A",
  "family_id": "62837108",
  "cited_by_count": 7,
  "citations": [
    "US20060148928A1",
    "US20130233545A1",
    "US20130192835A1",
    "US20150104647A1",
    "US20150119301A1"
  ]
}