Flocullation of gypsum in phosphoric acid

Follow a patent application I am studying now...Description: FIELD OF THE INVENTION [0001] The present invention is in the technical field of the wet process production of phosphoric acid and additives therefor, and in particular the present invention is a method to make down additives using crude phosphoric acid filtrate as the diluent. BACKGROUND [0002] Phosphoric acid is generally produced by the digestion of phosphate rock with concentrated sulfuric acid in a slurry of recycled phosphoric acid. This reaction also generates solid gypsum (CaSO4) particles, which are typically removed by filtration. In subsequent steps the phosphoric acid is clarified and concentrated by thermal evaporation to drive off more than half the water from the crude filtrate. [0003] Flocculants are added to the crude phosphoric acid gypsum slurry to increase particle size, which improves settling and filtration rate. Traditional flocculants used for this application are supplied as a liquid concentrate or dry powder. The dissolution kinetics of traditional powders and the emulsion inversion kinetics of liquid concentrates prevent their direct feed to the crude slurry. A crude phosphoric acid gypsum slurry reaches the filtering stage in tens of seconds to a few minutes after the flocculant feed point, while emulsions and powders require tens of minutes to a few hours for dissolution or inversion. Thus, a concentrate or powder flocculant is diluted with water at the site to yield a working solution (typically containing 0.5% to 1% of the concentrate) that is subsequently fed into the process stream. Traditional flocculant make-down systems consist of a mixing tank to which concentrate or powder is added with water. After sufficient mixing the dilute flocculant is transferred to a storage tank from which the dilute solution is fed to the process. Use of traditional dilute flocculant solution accounts for about 0.5% to 1% of the total volume of water present in the crude phosphoric acid slurry. A typical phosphoric acid production facility will use 5-10 million gallons of water per year for flocculant make-down. After addition, this water must be removed by thermal evaporation in subsequent processing stages requiring use of substantial thermal energy. Read more: http://www.faqs.org/patents/app/20120171099#ixzz2GIMqqZrQ

Agnelli (AGN) and Esteves (BTG) B&A to buy Rio Verde

By: Reuters 5th December 2012
RIO DE JANEIRO – B&A Mineração, the mining venture co-founded by former Vale CE Roger Agnelli and investment bank BTG Pactual Group, has offered to buy all of Toronto-based Rio Verde Minerals Development, a source with direct knowledge of the situation told Reuters on Tuesday.
B&A Mineracao has made a nonbinding proposal to buy the remaining 70% it does not own of Rio Verde, which is focused on the exploration and development of fertilizer projects in Brazil, said the source, who is not allowed to speak about the plan on the record.
The source declined to detail terms of the proposal, such as the price offered for Rio Verde.
Rio Verde has a market capitalisation of about $44-million, according to Reuters data. A statement on Rio Verde's website confirmed that the firm "is in negotiations with B&A regarding the potential acquisition of the company." Rio Verde added that it formed a committee and has hired financial and legal advisers to handle the process.
Agnelli and his partners at AGN Participações, a mining, fertilizers and logistics company, teamed up with BTG Pactual to found B&A in July. The executive was ousted from Vale , the world's second-largest mining company, last year after a decade at the helm.
The plan signals B&A's bet that fertilizers will thrive as demand for grains and protein grows while that for minerals and metals lags.
Analysts in Brazil have said that production and sales of food are not as vulnerable as demand for iron-ore, copper and other metals to an economic slowdown in China - the world's biggest consumer of raw materials.
Farm industry association Fiesp (sic: Fiesp is the São Paulo Industries' Association) said on Tuesday that Brazil will import a record $18.5-billion in fertilizers and other farm goods in order to plant a record soybean crop.
B&A Mineração's proposal follows the September purchase of a minority stake in Toronto-based MBAC Fertilizer Corp in September. The company has projects in the potash and rare-earth minerals sector in Brazil.
Agnelli returned to mining through AGN earlier in the year after a six-month break. AGN and BTG Pactual, which is controlled by Brazilian billionaire financier André Esteves, joined forces in the $500-million venture aiming to buy minerals, metals, fertilizers and logistics companies.

Santos and Cubtão are a phosphate hub

source: http://www.fao.org/docrep/007/y5376e/y5376e08.htm
Some of today’s large Brazilian fertilizer companies were already operating at the end of the 1940s and the beginning of the 1950s. Until the beginning of the 1960s, the domestic demand for fertilizer raw materials was met essentially by imports. Local production was limited to phosphate rock from a mine discovered in the 1940s in the State of São Paulo, to an ammonia, nitric acid, ammonium nitrate and calcium ammonium nitrate plant and to some producers of single superphosphate.
In the second half of the 1960s, new single superphosphate plants and the first complex fertilizer plant were constructed, marking the beginning of phosphoric acid production in the country. This enterprise also installed the first large-scale unit for the production of anhydrous ammonia, nitric and sulphuric acids, ammonium nitrate and DAP (diammonium phosphate). Other new projects became operational during the following decade.
Starting in 1971, the demand for fertilizers increased considerably, mainly as a consequence of agricultural development in the Cerrado in Central Brazil. This was constrained, however, by the need for additional imports at rising cost. This increasing demand, associated with high prices on the international market as a consequence of the conflict in the Near East and other factors, resulted, in 1974, in the development of the National Program for Fertilizers and Agricultural Limestone (PNFCA), whose main objective was the expansion and modernization of the fertilizer and agricultural limestone industry in Brazil. This program stimulated investment in several fertilizer and raw material complexes.
In the early 1990s, the fertilizer sector in Brazil underwent an intense privatization process, in which a substantial proportion of raw material production, until then undertaken the by state-owned companies, was transferred to the private sector.
The company responsible for the only production of potassium chloride in Brazil was transferred to the private sector. Some subsidiaries of a state-owned company producing a substantial portion of the nation’s phosphate and nitrogen fertilizers also were later privatized. Summaries of the capacities of the main producers of raw materials and fertilizers respectively are presented in Tables 8 and 9. Their geographical location is illustrated in Figure 6.
At least 250 mixed NPK compound fertilizers plants are located in the different agricultural areas of the country.

Yara commited with Brazilian Fertilizer Market

Yara to acquire Bunge's fertilizer business in Brazil Oslo (2012-12-07): Yara International ASA has entered into an agreement to acquire Bunge's fertilizer business in Brazil, significantly strengthening its fertilizer position in the country. The proposed transaction is valued at USD 750 million, and will be subject to the approval of Brazilian competition authorities (CADE) and other customary approvals. Yara and Bunge have also agreed to enter into a long-term fertilizer supply agreement, enabling Bunge to continue supplying fertilizer to farmers as part of its grain origination activities and creating a framework for logistics and other commercial activities.