To ensure a new production for the separation of the group rare-earth concentrate (GREС) with raw materials, GC «Skygrad» is conducting research in the field of complex processing of phosphogypsum - technogenic large-capacity raw materials – waste products of the production of mineral fertilizers. The total phosphogypsum reserves in Russia are estimated at 300 million tons (contain about 1 million tons of rare earths elements), 15 million tons are generated each year. Waste products are stored in dumps, which inevitably leads to pollution of soils and aquifers with harmful substances, primarily, soluble compounds of phosphorus and fluorine.

A unique technology for the extraction of GREC has been developed. The main goal in the production of phosphogypsum purified from REM is the creation of technologies that allow obtaining inexpensive building materials with improved characteristics. The introduction of our technological developments throughout the country will allow Russia not only to occupy one of the leading places in the world in the rare-earth metals industry, but to significantly improve the environmental situation in the area of phosphogypsum dumps.

Complex phosphogypsum processing technologies of GC «Skygrad» to produce REE concentrate, gypsum binder and building materials based on them

Phosphogypsum is a large-tonnage waste of the production of mineral fertilizers. Today in the dumps of industrial enterprises in Russia accumulated over 200 ml. tons of phosphogypsum (Voskresensk, Balakovo, Cherepovets, Meleuz, Volkhov, Uvarovo). This number is increasing by tens of millions of tons every year.

Relevance of the problem

Phosphogypsum dumps contain more than 1 million tons of REE. Extraction of REEs can significantly change the situation with rare-earth elements not only in the Russian, but also in the global economy.

Processing of phosphogypsum solves not only the matter of choice of new raw materials for REE and chemically precipitated gypsum, but also a number of environmental problems associated with pollution by harmful impurities of fluorine, phosphorus, strontium, etc.

Developments by GC «Skygrad»

In the period from 2011 to 2017, the specialists of the GC «Skygrad» conducted research in the field of complex processing of phosphogypsum with the production of gypsum binder, as well as products based on it – gypsum partition blocks, drywall partitions, dry mixes in assortment, as well as rare-earth concentrate (REC).

Based on the obtained results, two technologies, that significantly differed from each other, were developed.

Technology features

1. The technology is waste-free, differs from the known ones in the absence of liquid and solid wastes, low consumption of reagents and water;
   
   
2. The technology allows to consider phosphogypsum as a strategic raw material for the production of rare-earth metals;
   
   
3. The technology is characterized by a high rate of phosphogypsum processing with a wide range of products for various sectors of the economy.
   
   
4. The content of REO in the primary REC is more than 98.5%, however, a decontamination stage is required;
   
   
5. The cost of REC is about 7-10 $ US, the technology is profitable only with the complex processing of phosphogypsum.
   
   

The technology received 2 patents of the Russian Federation.

1. Patent RU2487834 «Method of extracting rare-earth metals from phosphogypsum» from 30.12.2013; authors: Abramov A.M., Sobol Y. B., Galieva Zh.N., etc.
   
   
2. Patent RU2573905 «Method of processing rare-earth concentrate» from 23.09.2014; authors: Abramov A.M., Sobol Y. B., Galieva Zh.N., etc.
   
   

The composition of the concentrate extracted from waste phosphogypsum of «VMF», %:

The composition of REO extracted from phosphogypsum of «VMF» according to option 2, %

Technology and equipment patents

1. Patent RU2645136 «Hydropneumatic device» from 30.05.2017; authors: Galieva Zh.N., Abramov A.M., Sobol Y.B., etc
   
   
2. Request RU2016152708 «Method of extracting rare-earth elements from phosphogypsum» from 30.12.2016; authors: Galieva Zh.N., Abramov A.M., Sobol Y.B., etc
   

Pilot installation for studying REE extraction from phosphogypsum pulp (Korolev, 2018)

GC «Skygrad» signed an agreement with the Administration of the Voskresensky Municipal District on intentions in the field of cooperation in implementing an investment project for the processing of phosphogypsum in the Voskresensky District. The administration intends to provide the GC «Skygrad» with a land plot and provide comprehensive assistance within its competence.

LLC «Skygrad Innovations» of GC «Skygrad» within the framework of this Project plans to create a production facility in Peresvet, Moscow Region, during 2019-2020 with a processing volume of up to 1,500 tons of GREC (in terms of TREO) per year for separation into individual REO and concentrate of medium-heavy REE group (MHG).

Separation technology based on centrifugal extractors has been developed as part of the project by LLC «LIT» in pilot production and has proven its effectiveness in the separation GREC of the JSC «Solikamsk magnesium plant» into individual compounds of the light REE group and MHG concentrate. The technology is universal and allows the use of various types of raw materials. In the production of LLC «Skygrad Innovations», in addition to production of individual oxides of the light REE group, the production of oxides of a moderate group, including yttrium, europium, samarium, gadolinium and dysprosium, will be ensured. The basic block diagram of the separation of GREC extracted from phosphogypsum is given below.